/15.04.0'2 1 ~BA STUDIES ON EPIDEMIOLOGY AND EFFE_CTS OF HUMAN ~ Qc}_ f1 ~ ONCHOCERCIASIS ON PRODUCTIVITY AND SOCIAL LIVES OF

RURAL COMMUNITIES IN UZO-UW ANI LOCAL GOVERNMENT

PG /Ph.D ./95/22232

A THESIS SUBMITTED TO THE DEPARTMENT OF ZOOLOGY,

UNIVERSITY OF NIGERIA, NSUKKA, IN FULFILMENT OF THE

REQUIREMENTS FOR THE AWARD OF THE DOCTOR OF

PHILOSOPHY DEGREE.

CODESRIA-LIBRARYSUPERVISOR: PROF. A. 0. ANYA, FAS, NNOM DEPARTMENT OF ZOOLOGY,

UNIVERSITY OF NIGERIA,

NSUKKA.

DECEMBER, 2000 ·-

CERTIFICATION

Mrs. Patience Obiageli Ubachukwu, a post-graduate student in the Department of Zoology;· ' '

University of Nigeria, Nsukka with registration number PG/Ph.D./95/22232 has satisfactorily completed the research work for the award of the degree of Doctor of Philosophy in Zoology with emphasis on­

Parasitology and Entomology. The work embodied in this thesis is originafand has npt been submitted· · in part or full for any other degree of this or any other university. Any other work referred to is duly acknowledged.

Supervisor Ag. Head of Department Prof. A. O. Anya Dr, B. 0. Mgbeilka Department of Zoology, Department of Zoology, University of Nigeria, Nsukka. University of Nigeria Nsukka.. · ' '

CODESRIA-LIBRARY iii

DEDICATION

To all who wait for the appearing of the Lord, Jesus Christ.

I

CODESRIA-LIBRARY iv

PREFACE

The field studies described in this thesis were carried out in 16 rural communities that 11:ake up Uzo-Uwani Local government area of Enugu State,

Nigeria, between October, 1997 and March, 2000, under the supervision of Prof.

A. 0. Anya, FAS, NNOM. The work covered various aspects of the epidemiology of onchocerciasis including the prevalence of the disease in the area

(Chapter 3) and local disease perception and treatment (Chapter 4). Other aspects of the disease such as the effects of the disease on the productivity and social lives of the people (Chapter 5), the effects of Mectizan treatment on the histology of the nodule (Chapter 6) and the daily biting patterns of the vector,

Simulium flies, in different seasons of the year (Chapter 7) were also studied.

Chapter 8 is the general discussion of the results. Recommendations based on the findings were made on how best to control onchocerciasis in the study area.

P. 0. UBACHUKWU December, 2000 CODESRIA-LIBRARY

1. V

ACKNOWLEDGEMENTS

· I wish to express my profound gratitude to all who contributed in different

capacities to make this work a success.

I hereby acknowledge with thanks the Council for Development of Social

Sciences Research in Africa (CODESRIA) Dakar, Senegal, for sponsoring the

project under the 1997 Small Grants Programme for Thesis Writing.

I am very grateful to my supervisor, Professor A. 0. Anya, for his fatherly direction, patience and valuable suggestions and criticisms throughout the period

of the study. His encouragement to do further field work at a time I thought I had finished yielded great dividends.

I wish to thank the traditional rulers of the 16 communities of Uzo-Uwani · local government area, the principals/head teachers, staff and students/pupils of the secondary and primary schools used for the studies and the entire people of

Uzo-Uwani local government area for their co-operation during the field studies.

My thanks also go to the field assistants used for the work. The staff of zonal

Ministry of Health, especially Mr. Nwobu and the health superintendent of

Ukpata healthCODESRIA-LIBRARY centre, deserve special mention for their co-operations.

I thank the members of staff of West African Examinations Council

(WAEC) and Examinations Development Centre (EDC), Enugu for supplying me with required school results. · vi

I acknowledge with gratitude the Heads (Dr. N. M. Inyang, Dr. H. M. G.

Ezenwaji and Dr. B. 0. Mgbenka) and members of staff of Department of

Zoology during the period of the study for their contributions and encouragement.

I specially acknowledge Dr. (Mrs.) U. 0. Amazigo who introduced me to onchocerciasis studies in friy final year as an undergraduate, Rev. (Prof.) E. U.

Iheagwam who initiated this work and Professor F. C. Okafor who corrected some of the early manuscripts.

I wish to thank my elder brother, Professor D. N. Ezeasor, of the

Department of Veterinary Anatomy, University of Nigeria, for making his facilities available for the sectioning and staining of the nodules and for taking the microphotographs. I also acknowledge Mr. Aloka who helped in the sectioning and staining of the nodules and Mr Dim who helped to take the microphotographs ..

I am very grateful to Professor B. E. B. Nwoke of Federal University of

Technology, Owerri, for supplying me with literature materials and useful suggestions CODESRIA-LIBRARYand encouragement. I acknowledge all my Christian brethren for their prayers and support.

Finally, I wish to express my profound gratitude to my entire family for their understanding and patience especially my husband, Dr. A. A. Ubachukwu, for his support and encouragement in every way and for carrying the burden of the work with me throughout the study period. I ! ! vii

To all others who contributed in one way or the other to make this work a sticcess, especially Dr. Eric Eboh of the Department of Agricultural Economics,

Mrs. Uzoma Okoye of Department of Sociology and Anthropology, Dr. J. E. Eyo of Zoology Department and all staff of Divine Love Computers, I say a big thank you.

May the good LORD reward you all in Jesus' Name - Amen. To GOD

ALMIGHTY, who kept me alive and helped me to complete this work successfully, I owe my life.

NSUKKA P. 0. UBACHUKWU 2000

CODESRIA-LIBRARY viii

LIST OFT ABLES

TABLE PAGE

3 .1 General Distribution of Onchocerciasis in Uzo-Uwani

Local Government Area. 69

3.2 The Distribution Of Onchocerciasis in the Different Health

Districts in Uzo-Uwani Local Government Area. 70

4.1 Names of Blackfly and Manifestations of Onchocerciasis

in Uzo-Uwani Local Government Area. 105

6.1 Age-Sex Distribution And Location Of Excised Nodules in

Mectizan-Treated Onchocerciasis Patients in Uzo-Uwani

Local Government Area. 160

7.1 Summary of Fly Collections in Uzo-Uwani Local Govenunent

Area during the Study Period. 178

7.2 Daily Biting Pattern in Early Raining Season. 179

7.3 Daily Biting Pattern in Late Raining Season. 180 7.4 DailyCODESRIA-LIBRARY Biting Pattern in the Dry Season (without Harmattan). 181 7.5 Daily Biting Pattern in the Dry Season with Harmattan. 182 ix

LIST OF FIGURES

FIGURE PAGE

2.1 Map of Uzo-Uwani Local Government Area

Showing the Study Areas. 36

5.1 Performance against Onchocercal Manifestations. 138

7.1 Daily Biting Pattern of Blackfly (Simulium) in Uzo-Uwani

Local Government Area of Enugu State, Nigeria. 183

7.2 Daily Biting Pattern of Blackfly (Simulium) in Uzo-Uwani

Local Government Area of Enugu State, Nigeria, during Early

Raining Season. 184

7.3 Daily Biting Pattern of Blackfly (Simulium) in Uzo-Uwani

Local Government Area of Enugu State, Nigeria, during Late

Raining Season. 185

7.4 Daily Biting Pattern of Blackfly (Simulium) in Uzo-Uwani

Local Government Area of Em:tgu State, Nigeria, during the Dry SeasonCODESRIA-LIBRARY (without Harmattan). 186 7.5 Daily Biting Pattern of Blackfly (Simulium) in Uzo-Uwani

Local Government Area of Enugu State, Nigeria, during the

Dry Season with Harmattan. 187

9.1 Schematic Representation of Strategies for Controlling

Onchocerciasis in Uzo-Uwani Local Government Ar~a. 227 ! i . \

X

LIST OF PLATES

PLATE PAGE

2.1 River Adada at Nkpologu. 38

2.2 River Adada at Ukpata. 39

2.3 River Obina at Adani. 40

2.4 River Obina at Asaba. 41

2.5 River Obina at Adani-Omor Road. 42

2.6 . River Duu at Umulokpa. 43

2.7 River Eshi at Ogurugu. 44

2.8 River Anambra at Ogurugu. 45

2.9 Awara Stream at Umulokpa. 46

2.10 Dammed Section of River Obina at Adani. 47

2.11 Interviewed Primary School Children from lgga. 50

2.12 Interviewed Elders from Nkume. 51

2.13 Interviewed Elders from Uvuru. 52 2.14 InterviewedCODESRIA-LIBRARY Elders from Nkpologu: 53 2.15 Interviewed Elders from Ogurugu. 54

2.16 Interviewed Elders from Asaba. 55

2.17 Interviewed Elders from Adani. 56

2.18 Interviewed Elders from Abbi. 57

2.19 Interviewed Elders from Nrobo. 58 .xi

3.1 The Legs of a 19-Year Old School Girl from Ukpata

showing Leopard Skin. 72

3.2 The Legs of an Elderly Woman from Nkpologu

showing Leopard Skin. 73

3.3 The Back of the Legs of a Middle-Aged Woman from

Nkpologu showing a Nodule. 74

3.4 The Legs of an Elderly Man from Nkume showing Nodules. 75

3.5 The Legs of Men from Ukpata showing Leopard Skin. 76

3.6 The Legs of Women from Ukpata showing Leopard Skin. 77

3.7 The Legs of Men and Women from Adani showing Leopard Skin. 78

3.8 The Legs of Men from Asaba showing Leopard Skin. 79

3.9 The Legs of Men from Nkpologu showing Leopard Skin. 80

3.10 The Legs of Elders from Akpugo showing Leopard Skin. 81

3.11 The Legs of Men from Uvuru showing Leopard Skin. 82

3.12 The Legs of Men from Nimbo showing Leopard Skin. 83 3.13 The LegsCODESRIA-LIBRARY of Men from Abbi showing Leopard Skin. 84 3.14 The Legs of Men from Ugbene-Ajima showing Leopard Skin. 85

3.15 The Legs of Men from Nrobo showing Leopard Skin. 86

3.16 A Man met Working in the Farms at Nkpologu

Wearing only Trousers. 93

3.17 A Woman met Working in the Farms at Nkpologu Wearing xii

Clothes that Cover the Trunk. 94

6.1 The External Appearance of Nodul~s. 161

6.2 A Section of Nodule showing Part of Outer and Inner Zones. 162

6.3 A Section of Nodule showing Congested Blood Vessel. 163

6.4 A Section of Nodule from Untreated Patient showing Macrophages

and Foreign Body Giant Cells. 164

6.5 A Section of Nodule from Treated Patient showing Sections

of Worms Surrounded by Infiltrated Cells. 166

6.6a A Section of Nodule from Untreated Patient showing

Sections of Wonns Containing Egg Packets and Microfilariae. 167

6.6b A Section of Nodule from Treated Patient showing

Empty Sections of Worms. 167

6.7a A Section of Nodule from Untreated Patient showing

Sections of Wonns with Egg Packets and Microfilariae. 168

6. 7b A Section of Nodule from Treated Patient showing EmptyCODESRIA-LIBRARY Sections of Worms. 168 6.8a A Section of Nodule from Untreated Patient showing Free

Microfilariae in the Cotmective Tissue. 169

6.8b A Section of Nodule from Treated Patient showing no

Microfilariae in Connective Tissue. 169 xiii

LIST OF APPENI>ICES

APPENDIX PAGE

I. Questionnaire Schedule on Epidemiology and Effect

Of Human Onchocerciasis on Social Life in Uzo-Uwani

Local Government Area. 252

2. Interview Schedule on the Effects of River Blindness

on Productivity. 267

3. Weighted Average Performance of Secondary Schools

in Uzo-Uwani Local Government Area. 271

4. Processing of Nodules. 273

CODESRIA-LIBRARY XIV

TABLE OF CONTENTS

CONTENT PAGE

Title Page

Certification 11

Dedication lll

Preface IV

Acknowledgements V

List of Tables viii

List of Figures ix

List of Plates X

List of Appendices xiii

Table of Contents XIV

Abstract xxi

CHAPTER!

GENERAL INTRODUCTION AND LITERATURE REVIEW 1.1 IntroductionCODESRIA-LIBRARY 1 1.2 Statement of Problem 3

1.3 Review of Literature 5

1.3.1 Geographical Distribution of Onchocerciasis 5

1.3.2 The Parasite 7

1.3.3 The Disease Vector 9 xv

1.3.4 Pathology of Onchocerciasis 13

1. 3. 5 Diagnosis of Onchocerciasis 17

1.3 .6 Effects of Onchocerciasis on Socio-economic Life 20

1.3.7 Local Disease Perception and Treatment 23

1. 3. 8 Chemotherapy and Control of Onchocerciasis 25

1.3. 9 Parasite-Vector-Host complex in Onchocerciasis 31

1.4 Objectives of the Study 33

1.4.l General Objectives 33

1.4.2 Specific Objectives 33

CHAPTER2

GENERAL MATERIALS AND METHODS

2.1 The Study Area and Study Population 35

2.2 Sampling Procedure and Study Sample 48

2.3 Data Collection Methods 49

2.4 Method of Data Analysis 59 CODESRIA-LIBRARYCHAPTER3 ' STUDIES ON THE PREVALENCE OF ONCHOCERCIASIS IN

UZO-UW ANI LOCAL GOVERNMENT AREA

3.1 Introduction 60

3.2 Materials and Methods 67

3.2.1 The Study Area and Study Population 67 xvi

3.2.2 The Study Sample 67

3.2.3 Physical Examination of Sample Units for Indices of

Onchocerciasis 67

3.3 Results and Observations 68

3.4 Discussion 88

3.5 Summary and Recommendations 98

CHAPTER4

STUDIES ON THE LOCAL DISEASE PERCEPTION AND TREATMENT

4.1 Introduction 100

4.2 Materials and Methods 102

4.2.1 The Study Area and Study Population 102

4.2.2 The Study Sample and Sampling Procedure 102

4.2.3 Data Collection 103

4.2.4 Data Analysis 103

4.3 Results and Observations 103 4.3.1 UmulokpaCODESRIA-LIBRARY Health District 104 4.3.1.1 Umulokpa Community 104

4).1.2 Nkume Community 106

4.3.1.3 Adaba Community 107

4.3 .1.4 Ukpata Community 108

4.3.2 Nkpologu Health District 109 xvii

4.3.2.1 Nkpologu Community 109

4.3.2.2 Uvuru Community 110

4.3.2.3 Akpugo Community I 11

4.3.3 Ogboli Health District 112

4.3.3. l Adani Community 112

4.3.3.2 Asaba Community 113

4.3.3.3 Igga Community 115

4.3.3.4 Ojjor Community 116

4.3.3.5 Ogurugu Community 117

4.3.4 Nimbo Health District 118

4.3 .4.1 Nimbo Community 118

4.3.4.2 Abbi Community · 119

4.3.4.3 Ugbene-Ajima Community 120

4.3.4.4 Nrobo Community 122

4.4 Discussion 123 4.5 SummaryCODESRIA-LIBRARY and Recommendations 127

CHAPTERS

STUDIES ON THE EFFECTS OF HUMAN ONCHOCERCIASIS ON

PRODUCTIVITY AND SOCIAL LIFE IN UZO-UWANI LOCAL

GOVERNMENT AREA OF ENUGU STATE xviii

5. l Introduction 131

5.2 Materials and Methods 134

5.2.1 The Study Area and Study Population 134

5.2.2 Data Collection Methods 135

5.2.3 Data Analysis 136

5.3 Results and Observations 137

5.3.l Studies on the Effect of Human Onchocerciasis on Academic

Performance 13 7

5.3.2 Effects of Human Onchocerciasis on Productivity of Fanners 137

5.3.3 Effects of Human Onchocerciasis on Social Life 140

5.3.3.1 Umulokpa Health District 141

A Effects on Social Interactions 141

B Effects on Age of Marriage 142

C Effects on Married Life 142

5.3.3.2 Nkpologu Health District 142 A EffectsCODESRIA-LIBRARY on Social Interactions 142 B Effects on Age of Marriage 143

C Effects on Married Life 143

5.3.3.3 Ogboli Health District 143

A Effects on Social Interactions 143

B Effects on Age of Marriage 144 xix

C Effects 011 Married Life 144

5.3.3.4 Nimbo Health District 144

A Effects on Social Interactions 144

B Effects on Age of Man"iage 145

C Effects 011 Married Life 145

5.4 Discussion 145

5.4.1 Effects of Human Onchocerciasis on Academic Performance 146

5.4.2 Effects of Human Onchocerciasis on the Productivity of Farmers 149

5.4.3 Effects of Human Onchocerciasis on Social Life 151

5.5 Summary and Recommendations 152

CHAPTER6

STUDIES ON THE EFFECTS OF MECTIZAN TREATMENT ON THE

HISTOLOGY OF THE NODULE

6.1 Introduction 155

6.2 Materials and Methods 158 6.2.1 TheCODESRIA-LIBRARY Study Area 158 6.2.2 Nodule Collection and Processing 158

6.3 Results and Observations 159

6.4 . Discussion 165

6.5 Summary and Recommendations 171 XX

CHAPTER 7 · STUDIES ON THE DAILY AND SEASONAL BITING PATTERNS OF SJMULIUM DAMNOSUM (BLACKFL Y) (DIPTERA: SIMULIIDAE) IN UZO-UWANI LOCAL GOVERNME~T AREA OF ENUGU STATE 7 .1 Introduction 172 7 .2 Materials and Methods 176 7.2. l The Study Area 176 7.2.2 Fly Collection 176 7.3 Results and Observations 177 7.3.1 Daily Biting Patterns 177 7 .3 .2 Seasonal Variations in Biting Densities 191 7.3.2.l Early Rainy Season 191 7 .3 .2.2 Late Rainy Season 191 7.3.2.3 Dry Season (without i-Iarmattan) 192 7.3.2.4 Dry Season (with Harmattan) 192 7.4 Discussion 193 7.5 Summary and Recommendatioi1s 205 CHAPTERS GENERAL DISCUSSION 208 CHAPTER9

SUMMARYCODESRIA-LIBRARY AND RECOMlVIENDATIONS 220 REFERENCES 228 APPENDIX 252 xxi

ABSTRACT

Some aspects of the epidemiology of human onchocerciasis as well as the effects of the disease on the productivity and social lives of rural communities in

Uzo-Uwani local government area of Enugu State were studied using the survey method. The prevalence of the disease among the 16 communities that make up the local government area based on the rates of nodule, leopard skin and impaired vision were investigated. The knowledge of the blackfly vector of the disease and its association with the manifestations of the disease in the population were also studied. The effects of the choice drug, ivermectin (Mectizan) on the nodule and the daily biting patterns of the vector (Simulium) for different seasons of the year were investigated. On the effects of onchocerciasis on the productivity of the inhabitants, two aspects were studied namely the effects on the productivity of farmers and on academic performance of school children. With regard to the effects of the disease on social lives, three aspects were studied namely the effects on social interactions between the infected and uninfected individuals, the effects on the ageCODESRIA-LIBRARY at which infected persons marry and the effects on married life. The results of the studies. on the prevalence of onchocerciasis in Uzo­

Uwani local govermnent area showed that the whole area (100%) is endemic for the disease but the level of endemicity varied from community to community.

One of the outstanding observations was that the northern part of the local government area closer to the savanna zone had higher prev·alence if based on rate xxii of impaired vision (26.9%) rather than rate of nodules (16.9%). The southern part of the area closer to the forest zone however had higher prevalence rates if based on nodule rate (33.3%) rather than rate of impaired vision (18.9%). All communities in Uzo-Uwani local government area have the knowledge of the blackfly vector of onchocerciasis although the level of knowledge varied between communities; Generally, communities with higher prevalence of the disease have better knowledge of the vector. Unfortunately, none of the communities had any knowledge of any association between the bit~s of the blackfly (Simulium) and the observed manifestations of onchocerciasis. Rather they attributed these manifestations to old age or familial traits.

On the effects of onchocerciasis on the productivity of farmers, it was found that impaired vision and blindness Were the major disabilities that hindered farmwork. Other disturbances resulted from the distractions attributable to

Simulium bites which made the farmers lose some man-hours and this resulted in lower output. The study on the effects of different manifestations of onchocerciasisCODESRIA-LIBRARY on academic performance of school children gave some interesting results. From regression analysis of different manifestations, namely impaired vision, rashes and palpable nodules, and academic performance, it was observed expectedly that impaired vision had the highest correlation with performance

( correlation coefficient, r = - 0. 72). The higher the rate of impaired vision, the poorer the performance. Rashes had a marginally significant correlation with xxiii

performance (r = - 0.014) while the nodule rate had no negative effect on

performance (r = 0.36).

Results from respondents on social effects of onchocerciasis showed that

there is social . discrimination against people suffering from onchocerciasis

especially those with the presence of rashes. Other manifestations did not attract

any social stigmatization. Young people, especially girls, with rashes marry later

than those without such manifestations and they marry partners that they would

not ordinarily have married such as old people, divorced people and people that

did not have children from their previous marriages. The appearance of

onchocerciasis manifestations did not, however, have any significant effect on

already established marriages.

On the study of the effects of the choice drug for onchocerciasis treatment

(ivermectin) on the histology of the nodule, it was observed that the female

worms whose uteri were normally filled with microfilariae were empty and there

were no intact micro:filariae within the connective tissue of the nodules contrary to the observationsCODESRIA-LIBRARY in untreated onchocerciasis patients. On the daily biting patterns of the Simulium, it was observed that the peak

biting periods displayed a ~imodal pattern. The pattern varied slightly with

seasons. During the early rains, there was a low morning peak between 9.00 and

11.00 a.m .. and a higher evening peak between 4.00 and 6.00 p.m. Within the dry season, the harmattan period generally showed a low biting density up to 2.00 xxiv p.m. when more intense biting ensued with a peak occurring between 4.00 and

6.00 p.m. The greatest number of flies per man per day was recorded during the hannattan season.

The possible implications of the findings in these studies are discussed and suitable control strategies against onchocerciasis based on the results recommended.

CODESRIA-LIBRARY 1

CHAPTER 1

GENERAL INTRODUCTION AND LITERATURE REVIEW

1.1 Introduction

Human onchocerciasis is usually a chronic parasitic disease due to infection

by the filarial nematode, Onchocerca volvulus. The disease is commonly known as

'River blindness' because of its association with rapidly flowing and usually

unpolluted water of streams and rivers with high oxygen content. The disease is

transmitted by different species of blackfly (Simuliwn) in different parts of the world

where the disease is endemic.

Onchocerciasis is essentially a focal disease within its endemic areas with

new foci still being discovered in remote places (WHO, 1997). It is a disease of the

warm tropical environment in which the flies that carry it live under conditions

favourable for their development all year round (Crosskey, 1990). The disease is

characterized by dermatologic, ophthalmologic, lymphatic and systemic

manifestations. Blindness and impaired vision are the major and most dangerous disabilities associatedCODESRIA-LIBRARY with the disease and are more prevalent among endemic communities living around the foci of transmission (fast flowing rivers) (Nwoke and

Ikonne, 1993). Onchocerciasis is a widespread filarial disease that produces grave socio-economic effects. The impact of the disease in social, economic and cultural terms in Nigeria has been shown to be enormous as it affects the productivity, social life and sexual life of the sufferer due to blindness or other debilitating effects 2

(Nwoke, 1990). In endemic communities in Nigeria, girls who engage in frequent

visits to the foci of infection to fetch water or to do laundry as well as boys who

actively engage in fishing, hunting and swimming are at risk. Since these activities

together with farming are.· almost maintained throughout life, the contact with

infected vectors is permanently sustained. The intensity of lesions shows a gradual

increase with advancing age, with the older subjects showing significantly higher

onchocerciasis prevalence and intensity than the younger ones (Nwoke et al, 1991).

Disease distribution in onchocerciasis has been shown to be associated with

proximity of villages to breeding sites of vectors, disease prevalence and intensity,

accessibility to hospitals/clinics and awareness of the disease aetiology (Nwoke et al,

1987).

According to Nwoke (1990), the socio-economic and cultural disabilities

associated with human onchocerciasis in the devastated endemic communities in

West Africa are damaging especially among the farming population which produce

the bulk of our food and industrial raw materials. The disease constitutes, therefore, a major publicCODESRIA-LIBRARY health problem and an obstacle to socio-economic development in the sub-region. In Africa, onchocerciasis has been described as a disease of the future.

This is because as the development of the hinterlands proceed, particularly as dams and water projects increase, it will cease to be a disease affecting only small, isolated, poverty stricken and primitive communities in the bush and will become 3 more and more a threat to sophisticated development personnel and other such workers (Duke, 1972).

1.2 Statement of Problem

Onchocerciasis is a disease that seriously affects the productivity and social lives of farmers, teachers, students and other rural dwellers. The degree of these effects depends largely on the endemicity of the disease in the area. Other factors that influence the degree of the effects include the local disease perception and treatment in the given area as well as the attitude of the non-infected to the infected individuals.

Onchocerciasis affects the population in various ways - it has many unsightly manifestations such as rashes, lizard skin, leopard skin, subcutaneous nodules, lymphadenitis, and scrotal elephantiasis among others. The disease interferes with the normal day to day life activities of infected individuals such as farming, teaching, learning and other activities through excessive itching, loss of sleep, impaired vision and blindness. This results in low productivity of the infected individuals in their life's endeavoursCODESRIA-LIBRARY since the most affected subjects are in their most productive age (30 - 39 years age group) (Vajime, 1982; Nwoke and lkonne, 1993). As a permanent disability through blindness or serious visual impairment, this disease withdraws the affected individual's potential supply of labour years requiring vision. Severe itching and scratching cause absent mindedness in some infected individuals and sometimes lead to loss of sleep and absenteeism from work (Nwoke, 1990). In terms 4

of agriculture, it results in low production of crops and subsequently affects food

supply to urban centres which largely depend on these rural communities for their

food supply.

Onchocerciasis affects the social lives of the infected individuals. The

disease hinders free social interactions between infected and uninfected individuals.

It also hinders sexual relationships between married couples and delays young girls

having the disease from getting mmTied as early as their non-infected counterparts

(Amazigo and Obikeze, 1991 ). In addition, the people affected by onchocercal

blindness constitute destitutes in urban centres where they go to beg for alms

(Nwoke, 1990). Onchocerciasis also leads to clese1:tion of fertile lands,

overpopulation and overuse of onchocerciasis - free lands (Budden, 1956; Bradley,

1976; Nwoke, 1990).

In Uzo-Uwani Local government area of Enugu State of Nigeria, which is a

significant source of food supply in the state, there is scanty information on the

epidemiology of onchocerciasis and there seems to be no data on the effects of this debilitating diseaseCODESRIA-LIBRARY on the social and economic lives of these rural communities. It was therefore considered necessary to investigate the epidemiological status of

onchocerciasis in Uzo-Uwani local government area and the extent to which the

disease affects the productivity and social lives of these rural communities. The

results would enable implementation recommendations to be made as to the most appropriate intervention strategies in the area in order to reduce the disease 5

prevalence, increase the productivity of the inhabitants and control the effects of this disease on the social lives of the people.

1.3 Literature Review

1.3.l Geographical Distribution of Onchocerciasis

Human onchocerciasis is found both in the Old and New Worlds.

Onchocerciasis is prevalent in tropical Africa, Yemen and parts of Latin America

(WHO, 1997). An estimated 20-40 million people are suffering from the disease in

34 countries with over 3.5 million blinded by it (WHO, 1987). Additional 86 million people are at the risk of developing the disease (WHO, 1987; Brundtland, 1990). The range of the disease in Africa extends across the continent from Senegal to the Sudan and Ethiopia in the north and from Angola to Tanzania in the south. The disease has been eliminated from Kenya with the exception of a small focus at the Ugandan border (Duke, 1972; WHO, 1976). The worst affected area is the savanna zone of

West Africa especially in the Volta River basin comprising parts of Benin, Ghana,

Mali, Niger and Togo and the whole of Burkina Faso, where there may be up to 15 % blindness CODESRIA-LIBRARYrate in some endemic villages. At least 70,000 people are blind in these areas (WHO, 1980; Nwoke, 1990). In Nigeria, onchocerciasis is widespread and a cause of blindness in most rural communities. Of all the countries of the world,

Nigeria has the greatest number of persons with onchocerciasis (Edungbola, 1991 ).

There are currently about 7 million Nigerians infected with about 1.5 million blinded by it (WHO, 1989; Nwoke, 1990). Edungbola (1991) reported that out of over 80 6

million Nigerian population which is about twice the combined population of all 11

participating countries of Onchocerciasis Control Programme, an estimated

population of 40 million are at the risk of infection. In the New World, there are

important endemic areas in Guatemala, Mexico, Venezuela, Ecuador and Brazil

(Duke, 1972; WHO, 1976; 1996). The disease is relatively severe in Guatemala and

Mexico, and a new focus was recently discovered among the Amerindians between

Brazil and Venezuela (WHO, 1980).

Many researchers have carried out epidemiological studies on onchocerciasis

in various parts of the world such as Tanzania (Woodruff et al, 1966a); Guatemala

(Diaz, 1957); British Cameroon (Kershaw et al, 1954; N gu et al, 1981 ); Ecuador

(Guderian et al, 1983a; 1983b, 1984); Liberia (Brinkmann, 1973; Burchard et al,

1979); Ghana (Brinkmann et al, 1976, De Soel et al, 1992); Togo (Bonucci et al,

1979; Brinkmann, 1980, De Soel et al, 1992); Benin (De Soel et al, 1992) and in

Yemen (Omar et al, 1979; Buttner et al, 1982; Buttner and Racz, 1982).

A number of surveys have been carried out in Nigeria establishing some basic facts aboutCODESRIA-LIBRARY the disease. Reports of the vector and parasite of onchocerciasis occurred sporadically until the 1950s when wider investigations on them were made.

Budden in 1954 studied ocular and cutaneous onchocerciasis in Nqrthern Nigeria and

accounted onchocerciasis as a major endemic disease with socio-economic

consequences. Budden (1956) in a survey of the whole of Northern Nigeria discovered that onchocerciasis was endemic in all the area and that the distribution of 7 the disease was limited by the distribution of the Simulium vector as surveyed by

Crosskey ( 1956). Later, special studies were made of onchocercal ophthalmology

(Budden, 1957) and of the biology of Simulium damnosum in relation to Onchocerca volvulus infection (Lewis, 1958; Crosskey, 1962). Further investigations have continued in parts of Northern Nigeria as in Jos (Nwoke, 1986; Nwoke et al, 1987);

Manor (Gemade and Dipeolu, l 983a,); Babana district of K wara State (Edungbola et al, 1983; Edungbola and Asaolu, 1984); lle-Ire district (lfelodun) of Kwara State

(Edungbola, 1982) and Jarawa valley area of Plateau State (Nwoke et al, 1989).

There is still lack of sufficient epidemiological data from the southern part of

Nigeria. Few surveys have, however, been carried out such as in Ibadan area of Oyo

State (Nnochiri, 1964a); Enugu and other parts of Southeastern Nigeria (Ikejiani,

1959); Achi, Adorn and Adani in Eastern Nigeria (Amazigo et al, 1993) and Ette

(Amazigo and Obikeze, 1991 ).

1.3.2 The Parnsite

Onchocerca volvulus is a long thread-like filarial worm that lives in the subcutaneousCODESRIA-LIBRARY connective tissues of man. Adult worms are commonly located in tumours in the sub-cutaneous co1mective tissues, although at times they are so deeply situated that they cannot be easily palpable (Nnochiri, 1964b; Duke, 1970). The living worms are white, opalescent and transparent, with distinct transverse striations of the cuticle. They are wire-like, filifonn and blunt at both ends. At the anterior extremity, there are eight small, sub-median sessile papillae arranged in two rings 8

and a pair of large oval, lateral papillae. The worms are characteristically tightly

coiled in couples within the nodule. The females are extremely long, sometimes reaching a length of 500-700 mm, with the diameter of a coarse sewing thread (0.3-4 mm) (Chandler and Read, 1961). The males are very small by comparison, about

20-50 mm long with a diameter of 0.2 mm. The microfilariae are 270-320 microns long and unsheathed with a characteristic head and a pointed tail. They usually do not enter the bloodstream but localize in the skin and eye tissues (Duke, 1972;

Hamon and Kartman, 1973).

Infective larvae are inoculated into man when the infective female Simulium bites for a blood meal. These larvae mature usually over a year. The worms collect together in nodules of fibrous tissues many of which are subcutaneous. The mature fertilized females produce large numbers of microfilariae which invade the skin. The microfilariae do not undergo further development in the human body, and unless ingested by a feeding Simulium, they remain in the skin until they die. If ingested, their development continues in the vector, reaches infective larval stage and they are ready to be returned to man.

FromCODESRIA-LIBRARY the introduction of infective. larvae until, the first appearance of microfilariae in the skin, there is a prepatent interval of some 15-18 months with a maximum of 34 months, but it is possible that there are strain differences in this respect (Prost, 1980). The life span of the microfilariae in the skin maybe as long as

30 months and the fecund female worms can live for up to 15 years. Development in 9

Simulium from microfilariae to infective larvae takes 6-12 days depending on the ambient temperature. Since the inoculated worm does not multiply during its development in man, heavy infections can build up only from exposure to repeated bites by infective Simulium over a prolonged period (Duke, 1972).

1.3.3 The Disease Vector

Simuliids or blackflies are the only known vectors of Onchocerca volvulus both in Africa and the New World although the species of Simulium acting as vectors of the disease in different parts of the world differ.

In Africa, the main vectors are the Simulium damnosum complex and

Simulium neavei complex. These complexes can be identified based on non­ morphological taxonomic criteria. The S. damnosum complex is distributed in West

Africa and consists of at least 26 distinct cytological categories (Dunbar and Vajime,

1972; Dunbar, 1976). Of these, 10 siblings have been recorded in West Africa and so far 7 of these have been found in Nigeria (Vajime and Dunbar, 1975). Several of these have been identified as important vectors including, S. damnosum s. s. and S. sirbanum in CODESRIA-LIBRARYthe Sudan and Guinea savanna; S. soubrense; S. yahense, S. squamosum and S. sanctipauli in the forest zone (V ajime, 1982). These flies breed mainly in fast flowing streams and rivers. Species of Simulium neavei complex are the main vectors of onchocerciasis in East and Central Africa and include S. neavei s.s; S. woodi; S. nyasalandicum; S. hightoni, S. goinyi and S. ovazzae. These flies breed mainly in rivers and streams in highland areas of East and Central Africa. 10

In Central and South America, the mam vector is Simulium ochraceum.

Others include S. simplicicolor, S. metallicum, S. sanguineum and S. guianense

(Lacey and Charlwood, 1980).

A lot of work has been done on the vector in Nigeria, in West Africa and in

other parts of the world. The average feeding time of S. damnosum has been found

to be 4 minutes (Sato et al, 1987). Also blood sucking in S. damnosum occurs in the

lower parts of the body more than on the upper parts of the body unlike S.

ochraceum which is known to bite on the upper parts of the body (Woodruff et al,

1966 b). In Cameroon, Renz and Wenk (1983) reported that the fly attacked both the upper and lower parts of the body;. Gemade and Dipeolu (1983a) in Manor (Benue

State of Nigeria) observed that the population density of S. damnosum increased with distance from the breeding sites along the river during the rains with the reverse during the peak of the rains but Crosskey (1954) had earlier reported that fly population decreases with distance from the main breeding sites.

The factors that influence the population density of S. damnosum include preponderanceCODESRIA-LIBRARY of breeding sites and climatic conditions. On the effects of climatic factors on the diurnal biting behaviour of the vectors of onchocerciasis, it has been shown that heavy rains inhibit biting activity (Nwoke, 1988) and the two factors that affect the biting activity most are illumination and temperature (Gemade and

Dipeolu, 1983b, Nwoke, 1988) with illumination having the greatest influence.

There is, however, an optimum intensity that enhances biting activity but when

.. ,.. ~·, .,, .... . 11 illumination becomes too strong as in mid-afternoon, biting activity is suppressed

(Lacey and Charlwood, 1980; Nwoke, 1988; Nwoke et al, 1992). Other factors that influence the biting activity of Simulium flies include wind speeds, relative humidity, cloud cover and shade (Nwoke, 1988).

There is evidence from the onchocerciasis Control Programme (OCP) countries that migration of adult females of S damnosum can occur over distances of up to 400 km or even more from their breeding sites (Garms et al, 1979). Studies have shown that the savanna flies can penetrate deep into the forest zone during the dry season, presumably aided by the prevailing north-easterly harmattan winds and these savanna species of S. damnosum complex are the most important vectors of blinding onchocerciasis. Their capacity to fly long distances has caused considerable problems in the control of onchocerciasis (Garms, 1987). It has also been shown that the transmission of onchocerciasis is not largely dependent on fly population density but on the fly infectivity rate. The critical factor in transmission is the proportion of the parous flies to nulliparous ones since it is the parous ones that are likely to carry infections (GemadeCODESRIA-LIBRARY and Dipeolu, 1983b). Blackflies have a worldwide distribution being found from the arctic to the tropics wherever there is running water. Although blackflies breed exclusively in running water, the species vary greatly in the kinds of streams they select and in the speed of current they prefer (Duke, 1972). The adult blackfly is small, black in colour, hump-shaped insect with a charactel'istically curved body and pronounced 12

thorax. It has short antennae and the mouth is adapted for biting and sucking up

fluid. The immature stages develop only in rapidly flowing, usually unpolluted

water of streams, rivers and dams with high oxygen content. The eggs are deposited

on vegetation and hatch into larvae which hold unto the various materials by means

of silken threads which they spin. The duration of development of the blackfly from

egg to adult depends on the water temperature and varies from place to place. In

Central America, development takes 14 -31 days in S. ochraceum and 13-50 days in

S. metallicum. There are about 8-16 generations annually. In West Africa, on the

other hand, development of S. damnosum complex from egg to adult takes between

8-10 days and as short as 7 days in S. sirbanum in very warm rivers of the open

savanna. There are about 20 generations annually (Crosskey, 1990).

Some species of Simulium are termed 'area' breeders in which larvae occur in .

multitudes of generally distributed trickles and rivulets e.g. S. ochraceum while others are termed 'linear' breeders in which larvae are found only along major rivers and not in small-stream tributaries. These large rivers typically have resistant rocks in the riverbedsCODESRIA-LIBRARY and immature stages characteristically attach to trailing grasses that sway in the turbulent current of rapids (Crosskey, 1990).

The adult female blackflies are day and outdoor biting insects. They bite from dawn to dusk but seldom at the same sustainable level throughout the day.

Biting tends to be strongly concentrated into activity peaks with lulls in-between

(Crosskey, 1990). 13

1.3.4 Pathology of Onchocerciasis

Onchocerciasis is characterized by four cardinal manifestations which

include subcutaneous nodules, dermatitis, lymphadenitis and eye disease (Nwoke,

1990). The clinical manifestations of onchocerciasis include eye lesions which lead

to blindness, dermatitis, lymphatic involvement causing elephantiasis, nodules

containing adult worms in subcutaneous or deep tissues (Myers et al, 1977; Gibson

and Connor, 1978; McKenzie and N gu, 1979) and renal involvement with

microfilauria (Buck et al, 1971) or heavy proteinuria (Greene et al, 1980; Ngu et al,

1980). The most severe of these manifestations, particularly eye, skin and kidney

lesions are associated with microfilariae infiltration or their products and are thought

to be causally related to immunopathogenic mechanisms evoked in the host by these

larvae (Ngu et al, 1981).

On the Jos Plateau, Nigeria, Nwoke et al (1987) reported that the maJor

clinical manifestations of onchocerciasis were nodules, depigmentation of the skin, ,,l pruritus, blindness, as well as hanging groin and scrotal elephantiasis which have been reportedCODESRIA-LIBRARY to be caused by obstructive:; lymphadenitis due to deposition of immune complex from antigens released from microfilariae of 0. volvulus (Gibson

and Connor, 1978).

Blindness and impaired vision are the most dangerous disabilities associated with the

disease ad are seen more among ende111.ic communities living around the foci of transmission (Nwoke and Ikonne, 1993). Anterior blindness is the most frequent 14 ocular problem in the country. Onchocercal blindness is more in the savanna bio­ climatic zone than in the rain forest zone with sclerosing keratitis standing out as the ocular lesion with the highest prevalence. Males are more affected than their female counterparts, with the sex differentials observed to be most marked in the savanna.

On the whole, the clinico-pathological picture of ocular lesions of onchocerciasis in

Nigeria and elsewhere is the summation of a complex array of contributory factors, both intrinsic to the microfilariae strain and resulting host immune response, bio­ climatic factors and vector complex (Nwoke and Ikonne, 1993).

Although the bite of female Simulium vectors is not particularly painful, it is followed by an intensively raised ulcerative lesions at the site of bite due to irritation produced by their salivary secretions containing several low molecular weight proteins that promote agglutinin activity or serve as an anticoagulant in the wound

(Yang and Davies, 1974). Later skin changes include papular eruption, hypopigmentation and scaling, oedema, depigmentation and in long-standing infection, it develops to a shiny, fragile, atrophic epidermis resembling tissue paper. The changes CODESRIA-LIBRARYare provoked or modulated by antigens released by microfilariae or adult worms. The resultant loss of skin elasticity gives the patients a prematurely aged appearance while old people develop dry, scaly skin commonly called lizard I skin. Dead or dying microfilariae also provoke inflammation which leads to disruption of the basal layer, culminating in melanin incontinence and pigmentary changes in the upper dermis. This results in striking dermatological feature - 15

depigmentation or leopard skin, which is associated with long-standing infection

(Nwoke, 1990);

The prevalence of onchocercal eye lesions and blindness are associated with

the disease prevalence and more closely with the intensity of the infection in a

community. In Nigeria, males show significantly higher ocular lesions than their female counterparts and microfilariae are more commonly found in the eyes of males than those of females and ocular lesions follow that same pattern. This pattern may

be as a result of resistance to infection and exposure in females. Sex differentials are more marked in the savaima area of high transmission and less marked in the forest area (Nwoke and lkonne, 1993). In endemic communities in Nigeria, girls engage in frequent visits to the foci of infection to fetch water and to do laundry while boys actively engage in fishing, hunting and swimming. Since these activities together with farming are almost maintained throughout life, the contact with infected vectors are permanently maintained and the intensity of lesions shows a gradual increase with advancing age with the older subjects showing significantly higher oncho­ blindness thanCODESRIA-LIBRARY the younger ones. Budden (1963a) observed that among the male patients in the heavily infected savanna villages in the country, the incidence of microfilariae in the eye increased up to the age of 40 years and decreased thereafter.

This supports the report of WHO (1976) that ocular onchocerciasis lesions in hyperendemic areas show a peak in the 30-39 years age group. 16

Ocular onchocerciasis has been found to be more severe in the savanna region than in the rain forest region of Nigeria and of other West African countries

(Budden, 1963b ). Such· differences are due to the fact that the savanna strain of microfilariae of Onchocerca volvulus are more invasive and more pathogenic on the cornea than those of the rainforest strain (Duke, 1981; Nwoke and lkonne, 1993).

The prevalence of Nigerian onchocerciasis shows significant variations with those villages near the breeding sites of vectors having the highest infection rates

(Onwuliri et al, 1978). Studies have shown that the onchocerciasis infection rate increases gradually with advancing age in Nigeria (Edungbola et al, 1983; Nwoke,

1986; Nwoke et al, 1987) due to the chronic and cryptic nature of onchocercal infections (Buck, 1974). Sex related onchocercal infection in Nigeria varies depending on the degree of endemicity. In hyperendemic villages, male subjects have slightly higher but non-significant infection rate than females. This is because inhabitants in such hyperendemic villages live in homes very close to the foci of infection with the result that even when there are sex differences in occupation, both sexes are moreCODESRIA-LIBRARY or less equally exposed to the same number of infective vectors (Bradley 1976; Edungbola et al, 1983). On the other hand, in hypoendemic and mesoendemic villages living far away from the foci of infection, male subjects show significantly higher intensity and prevalence rate than females. This is because the surroundings of such villages are not easily accessible to vector flies and therefore occupation tends to play more prominent role (Crosskey, 1954). 17

The severity of onchocerciasis and ,in particular its ocular complications varies greatly from one endemic region of the world to another and from one bio­ climatic zone within the same region to the next. Extreme differences between bio­ climatic zones exist in West Africa, especially where little blindness is found in the southern forest zone on the oi1e hand, but rampant blindness occurs in the northern savanna on the other hand (Budden, 1963; Anderson et al, 1974). It is generally believed that these differences can be explained in terms of different parasite strains with varying degrees of pathogenicity (Duke et al, 1966). The severity of ocular onchocerciasis is known to be related to the· intensity of infection (Anderson et al,

1976; Thylefors and Brinkmann, 1977). Remme et al (1989b) reported that there exists a clear relationship between most indices of ocular onchocerciasis and the community microfilariae load. They concluded that the community microfilariae load is superior to the prevalence of microfilariae in the skin as an index of endemicity. It allows a good prediction of the severity of onchocercal ocular disease in Savanna communities using parasitogical information only. 1.3.5 DiagnosisCODESRIA-LIBRARY of Onchocerciasis In onchocerciasis, the most popular diagnostic technique is the demonstration of microfilariae in skin biopsies using the skin snip method. This is the most conventional diagnostic method for onchocerciasis on individual basis. The merits of skin snipping as a diagnostic technique include the fact that it is the most conclusive method and valuable for monitoring and evaluation of impact of control. 18 r i i The limitations include the fact that the worms may not be readily demonstrated in

lightly infected individuals. Also it involves expensive equipment, is highly

technical, time consuming and in most cases villagers show poor cooperation. In

addition, this method is likely to increase the risk of other infections such as HIV,

infective hepatitis etc (Nwoke et al, 1992).

I. Recently immunodiagnostic techniques have been employed to enhance : I sensitivity (Ngu et al, 1981 ). These comprise use of antigen preparation from

Dipetalonema vitae for immunoelectrophoresis, indirect fluorescent antibody tests on

sections of adult worms (Ambroise-Thomas, 1969) or whole microfilariae (Ngu and

Blackett, 1976) and use of worm extracts in radio-allergosorbent test (Somorin and

Heiner, 1976) or enzyme-linked immunosorbent assay (Bm1lett et al, 1975). The

main drawback of these techniques has been false positive reactions in patients

harbouring other nematodes which have cross-reacting antigens with 0. volvulus

(Tada et al, 1970; Voelker and Ganns, 1972; Neppert, 1974; Ambroise-Thomas,

1980; Tada et al, 1987). Further some of these methods are too sophisticated for use in the field. RecentlyCODESRIA-LIBRARY again, the enzyme-linked immunosorbent assay (ELISA) has become popular in the immunodiagnosis of onchocerciasis because of its high sensitivity and convenience.

In view of the limitations of skin snip method and immunodiagnosis, there has been a search for an alternative rapid assessment method. Edungbola et al

(1993) found out that the rate of leopard skin (LS) and palpable nodules showed 19

significant variation with the microfilarial rates. The prevalence rates of these

clinical features increase with increase in the community micro.filariae rate. The

development of rapid assessment methods also became necessary in order to meet

the need and challenge of Mectizan treatment of onchocerciasis. Based on the merits

and limitations of the different diagnostic methods, the Nigerian National

Onchocerciasis Control Programme (NOCP) has accepted and adopted Rapid

Assessment Method (RAM) based on nodule palpation and leopard skin to replace

skin snip method for nation-wide mapping of onchocerciasis endemic communities.

The Rapid Assessment Method (RAM) is a standardized epidemiological

procedure with proven reliability. It is relatively cheap and quick for the

identification of endemic communities (not individuals) that should receive most

urgent attention for large scale Mectizan treatment. The RAM is simple, rapid, non­

invasive, cheap, applicable and practicable over a wide range of ecological

conditions, reliable regardless of the severity and duration of the infection, non­

technical, acceptable to villagers, with absence of risk of other infections and good

for impact monitoring and evaluation (Edungbola et al, 1993). They recommended

that RAM CODESRIA-LIBRARYis useful in . preliminary screening for detailed prospecting of onchocerciasis endemicity alternative to skin sniping for community diagnosis, determination of suitable areas for operational and socio-economic studies of the impact of onchocerciasis, implementation of drug trials, identification of priority 20

areas for large-scale Mectizan delivery, evaluation and monitoring of interventions.

The usefulness of RAM was confirmed by Whitworth and Gemade (1999).

1.3.6 Effects of Onchocerciasis on Socio-economic Life

The socio-economic liabilities as a result of onchocerciasis are enormous.

The black.fly vectors of Onchocerca volvulus are a serious nuisance in the endemic

communities because of the resultant skin lesions from their bites. Susceptible

persons may be uncomfortable for weeks with an almost unbearable pruritus and

scratching. In many individuals, this persists throughout the whole course of the

infection. Sometimes the itching and scratching may be so severe as to cause

insomnia (Nwoke et al, 1987).

The various skin changes associated with onchocerciasis such as papular

eruption, hypopigmentation and scaling, oedema and depigmentation have distressing effects on the life style of infected individuals (Nwoke, 1986; Nwoke et al, 1987). In Africans antige11s released from the microfilariae of 0. volvulus lead to the deposition of immune complex in the tissue, which in turn causes inflammation and fibrosis andCODESRIA-LIBRARY eventually obstructive lyrnphadenitis (Gibson and Connor, 1978). This results in the development of hanging groin (adenolymphocoele) and elephantiasis of the genitalia commonly seen in adult males and genital distortion

( onchocercal lymphadenomatous skin) in _females (Cherry, 1959; Connor and

Palmieri, 1985; Nwoke et al, 1987). These dreadful malformations nearly always results in the infected individual's unwillingness towards a free social interaction ~1 within his or her locality. In affected patients with the pendulous sacs, sexual .life is greatly affected if not completely hindered (Nwoke,' 1986; Nwoke et ai, 1987).

Due to the habitual migration of disabled people from endemic areas to urban centres to beg for alms, it is often a common trend to see chains of blind adults being led to markets or around cities by children with good vision (Nwoke, 1990). This is an economic liability since these children are hindered from sc~ooling or any other. gainful employment.

Onchocercal blindness which is irreversible is the most serfous clinical · manifestation of onchocerciasis in Africa. In Nigeria, onchocercal blindness is· a serious public health problem. About 1.5 million are permanently blinded by it and the socio-economic liability due to this debilitating disease .has been confirmed as damaging. This is because most blind subjects are in their most productive years.

There is gradual increase in the blindness rate with advancing age with the. peak incidence between 30-39 years age group (Vajime, 1982; Nwoke and lkonne, 1993).

As a permanent disability through blindness or serious visual impairment, this

' . disease withdrawsCODESRIA-LIBRARY the affected individual's potential supply of labour years tci activities requiring vision. Severe itching and scratching cause absent-mindedness in some infected individuals and sometimes may cause loss of sleep (insomnia) and complete absenteeism from work.

Onchocerciasis affects the effective supply of labour years in three ways (1) · as a cause of death, it removes the individual's. supply of labour years in the future 22

(2) as a cause of permanent disability through blindness and serous visual impairment, onchocerciasis withdraws the individual's potential supply of labour years to activities requiring vision (3) partial visual impairment and/or other disabling manifestations may also reduce the efficiency of labour days worked

(Nwoke, 1990). WHO (1987) report on onchocerciasis states that as a result of so many people suffering from onchocercal blindness, there is loss of a huge number of potential working days.

There are reports that low population densities and desertion of many fertile river valleys in the savaima zone of West Africa are mainly due to onchocerciasis

(Budden, 1956; Bradley, 1976; Hunter, 1988; Nwoke, 1990). Serious economic and social set- back result from distorted distribution of population due to depopulation.

If emigration is not checked, onchocerciasis free lands can become increasingly ! overused and possibly ruined beyond recovery. Demographic imbalance also results, marked by uneven distribution of the population by age and sex because men afflicted by onchocercal blindness desert the villages while women and children stay back. This jeopardizes family life and the division of labour (Bradley, 1976). Other effects of onchocerciasisCODESRIA-LIBRARY include male sterility (Hughes, 1954, cited by Budden,

1956) and habitual abortion (Ikejiani, 1954). Ikejiani (1954) reported two cases of habitual abortion involving onchocerciasis patients in Nigeria. After treatment with hetrazan, these women produced children without difficulty.

-·:,,.. 23

Hamon and Kartman (1973) summarized the socio-economic effects of onchocerciasis as follows:

(1) blindness lowers farming capacity seriously

(2) fertile lands become deserted while less fertile uplands become overcrowded

(3) fishing in infested water is reduced

(4) labour forces engaged in development activities e.g. building of dams are

protected at great cost.

1.3.7 Local Disease Perception and Treatment

Few studies have been carried out on local disease perception in rural endemic areas. Nwoke et al (1992) observed that the assessment of local disease perception and treatment in any onchocerciasis endemic area is significant for effective planning and mobilization of communities in control programmes and in ascertaining whether local treatment is of any chemotherapeutic potential.

In some endemic communities in Pfateau State of Nigeria, Nwoke et al

( 1992) found that the villagers in these endemic communities were aware of the nuisance of theCODESRIA-LIBRARY blackflies locally called 'Bekin Kuda' through intense biting and itching especially during the farming season. However, the villagers in these endemic communities did not show any knowledge of the association between the blackfly bites and onchocerciasis. Some elderly patients attributed the characteristic onchocercal depigmentation (leopard skin) and other dermatitis to old age or familial traits, others implicated their enemies or the gods as the cause of their infection while 24 a few others did not know the cause. As a result of lack of knowledge of the aetiology of onchocercal lesions, the management of the disease in these endemic areas is misdirected towards consulting the oracle and appeasing their gods. Only very few individuals attended hospitals and were treated with Banocide. In few cases, topical application of oil such as groundnut oil was used as a means of treating intense itching and scratching.

In a previous but similar work carried out by Edungbola (1982) in K wara

State of Nigeria, he also obtained similar results. The natives were aware of the menace of Simulium flies locally called 'Amukuru' and had recognized onchocerciasis locally called 'Inaru' for a long time but they showed no knowledge of the association between blackflies, blindness, leopard skin and other clinical signs of the disease. Most of the people attributed leopard skin to old age or familial traits and all the blind persons interviewed implicated their enemies as the cause of their blindness but on examination, they were all found to have microfilariae with nodules, hanging groins and/or leopard skin and had lived in the area farming for most of their lives. Because of ignorance, management of the disease was often misdirected towardsCODESRIA-LIBRARY appeasing enemies or devils. Rashes and onchodennatitis were, however, treated with various medicinal herbs and prevention of bites was attempted through topical application of palm kernel juice or cream, fresh juice of bitter leaves and the application of a solution of dettol to 'the exposed parts of the legs and arms when at work. Physical materials like banana leaves and fire smokes were used in 25 preventing attacks of black.flies. Few people admitted taking Banocide but complained about the side reactions; a number of them said that they wold never take

Banocide again.

Other studies of local disease perception and treatment have also been carried out. Edungbola et al (1983) and Edungbola and Asaolu ( 1984 ), in Babana district of

Borgu local government area of K wara State, Nigeria, reported that although various indications suggest that the district has a history of long-standing onchocerciasis, the knowledge of river blindness and its association with black.flies was poor throughout the district and, except for two teachers, no other subjects had ever received onchocercal chemotherapy. At Ette, in lgboeze local government area of Enugu

State, Nigeria, Amazigo and Obikeze (1991) also reported similar results. The people of the area are aware of the bites of black.fly locally called 'Ita' but do not associate these with the manifestations of onchocerciasis. They rather attributed these manifestations to other causes such as old age, charm and familial traits.

1.3.8 Chemotherapy and Control of Onchoccrciasis

The curative treatment of onchocerciasis involves the use of three anthelmintics-diethylcarbamazineCODESRIA-LIBRARY (DEC) or Banocide which is essentially a microfilaricide, Suramin which is predominantly a macrofilaricide with some microfilaricidal activity (Duke and Anderson, 1972) and Mel W which is also a macrofilaricide. These drugs can produce a wide variety of side effects and death may follow their use in what is essentially a non-fatal disease (Oomen, I 967). Due 26

to the heightening of immune reactions following death of the worms in heavily

infected individuals, there has been a search for alternative drugs effective against 0.

volvulus but without serious side effects. The drugs tried include metrifonate (Duke,

1972; Kale, 1978; Awadzi, 1980), mebendazole (Kale, 1978; Rivas-Alcala et al,

1981; Awadzi et al, 1982), levamisole (Rivas-Alcala et al, 1981; Awadzi et al,

1982), flubendazole (Awadzi et al, 1982), mepacrine (Kale, 1980), furazolidone

(Kale, 1981 ), metronidazole, tinidazole, oxamniquine and pyrantel pamoate

(Combantrin) (Kale, 1978) and ivermectin (Mectizan) (Awadzi et al, 1989, Remme

et al, 1989). Among the drugs tried, ivermectin was found to be effective against

microfilariae and also suppressed the production of microfilariae by the adult

females. It was also found to have less side effects than diethylcarbamazine (De

Soel et al, 1989; Remme et al, 1989).

Drug treatment of onchocerciasis may be undertaken for two reasons. One is to relieve the individual victim of acute manifestations of the infection and to prevent or arrest serious complications such as blindness. The other reason is for mass treatment to controlCODESRIA-LIBRARY transmission by reducing the microfilarial reservoirs of infection in man. There are only two drugs with proven action against Onchocerca volvulus that are currently widely used to treat onchocerciasis as mentioned above.

Diethylcarbamazine citrate (DEC), which is given by mouth, has a rapid microfilaricidal action but little or no effect on the adult worm; and Suramin given by intravenous injection kills the adult worms but is weakly effective against 27

microfilariae in the tissues. These two drugs, although suitable for treating

individual patients under careful medical supervision, are not generally safe for use

in large-scale control campaigns (Kale, 1978). Chemotherapy had played a very

limited role in control strategies because the two drugs available for treatment (DEC

and Suramin) cause serious side effects (WHO, 1987). Recently, ivermectin

(Mectizan) was discovered to be very effective against nematode and arthropod

parasites including Onchocerca volvulus. After trials of the drug (Remme et al,

1989; De Soel et al, 1989), it has been accepted as the drug of choice for the control

of onchocerciasis. They fotmd that the drug is effective against microfilariae in

heavily infected individuals and so reduce transmission of 0. volvulus and is

sufficiently safe to be used in mass treatment of onchocerciasis. The important

benefits of the dramatic reduction of over 96% in microfilarial loads in the treated population and the associated decrease in the risk of developing ocular lesions and other onchocercal pathology greatly outweigh the mild side reactions that occur when the drug is used (Awadzi et al, 1989). Although ivermectin is microfilaricidal for 0. volvulus,CODESRIA-LIBRARY it also has some effect on the adult worms by an intrauterine sequestration with subsequent degeneration of normally formed microfilariae resulting in their failure to reach the skin or eye ( Awadzi et al, 1985).

Control of onchocerciasis had depended largely on control of the vector by means of insecticides used against Simulium larvae in the watercourses where they breed, but reinvasion of the controlled areas by blackflies from neighbouring and 28 adjoining uncontrolled regions usually occurs (Nwoke, 1992). Ideally such measures should be reinforced by an attack on the parasite in man by means of nodulectomy or chemotherapy (Duke, 1972). Widespread larvicide applications result in a substantial drop in prevalence over most of the control area but the incidence of the infection in children remains high despite the low vector densities brought about by control. This can be attributed to the migratory reinvasion potential of savanna cytospecies of the S. damnosum complex (Garms et al, 1979).

In Nigeria, the strategies and goals for control of onchocerciasis include a combination of health education, large-scale chemotherapy with ivennectin in communities where the prevalence of skin microfilariae is 30 % and above. Large­ scale treatment with ivermectin has been given priority because of

(1) the proven efficacy and safety

(2) the small dosage required ( a maximum of two tablets once or twice a year),

(3) the convenience of its oral administration

(4) its ability to bring about a dramatic reduction in the skin microfilarial load and potentiallyCODESRIA-LIBRARY to reduce the morbidity and (5) the additional benefit of expelling many intestinal worms from persons who are

treated for onchocerciasis

( 6) the fact that the donations of the drugs by the manufacturer- Merck, Sharp and

Dohme (MSD) are free 29

(7) the ease with which its distribution can be integrated into the existing high

priority Primary Health Care (PHC) programme and

(8) the commitment that the distribution, coverage and acceptance will be sustained

long enough to reduce onchocerciasis to a level at which it is hoped that the

disease will no longer be an important public health problem (Edungbola, 1991 ).

Onchocerciasis has constituted a major public health problem and an obstacle to

socio-economic development in the endeinic communities. In West Africa, a control

programme was initiated in 1974 and is commonly called Onchocerciasis Control

Programme (OCP). It is a joint programme sponsored by World Health Organization

(WHO), World Bank, United Nations Development Programme (UNDP) and Food

and Agricultural Organization (F AO) with .WI-10 as executing agent. The OCP

controls the disease in 11 nations in West Africa, which cover a total area of 1.3

million kni. The programme is designed to benefit over 15 million rural West

Africans (Nwoke, 1992). The disease has been eliminated as a public health problem

from the OCP countries through extensive insecticide spraying of the exposed vector breeding sitesCODESRIA-LIBRARY in the region, mostly from helicopters. Remme et al, (1990b) reported that after 12-14 years of vector control, the community microfilarial load (CMFL) was close to zero in all villages they surveyed. Today, some 1.5 million people who were once infected no longer have any trace of the disease. About I O million children born in the operational area since the programme began are now free of any risk of contracting the disease. In a study by Daclzie et al (1990) reported of 30 reduction of the incidence of onchocercal blindness by 40% resulting in lack of onchocercal blindness in children below the age of 20 years. To complement vector control activities, the drug ivermectin is distributed free of charge to more than 2.2 million people in the operational area (De Soel & Remme, 1991; WH.O, 1996).

Since the WHO Onchocerciasis Control Programme was launched in 1974 in West

Africa, more than 1.7 million additional years of productive labour have become available as a result of control measures. An additional 25 million hectares of usable land could be made available for agricultural production. This could feed 17 million more people (WHO, 1996).

A programme to eliminate onchocerciasis as a public health problem in the

Americas is being coordinated by the Pan American Health Organization with the support of non-governmental development organizations (NGDO) and the Inter­

American Development Bank (IADB). Concerted efforts had been made to control the disease in areas where it is endemic through coordination of ivermectin distribution activities but a conference held in 1991 resulted in the launching of a regional onchocerciasisCODESRIA-LIBRARY elimination programme (Onchocerciasis Eradication Programme of the Americas, : OEPA) to . reduce morbidity through the mass distribution of ivermectin in Brazil, Colombia, Ecuador, Guatemala, Mexico and

Venezuela (WHO, 1996; Etya'ale, 1998).

WHO in 1995 launched a new programme - the African Programme for

Onchocerciasis Control (APOC) - in close cooperation with the World Bank, the 31

governments of 16 participating countries where the disease exists but which were

not covered by the earlier programme, donors and non governmental development

organizations (NGDO) (WHO, 1996; Benton, 1998). This new programme which

became operational in January 1996, aims to control and eventually eliminate the

disease as a public health hazard from the entire African continent by the year 2002.

APOC will directly benefit more than 15 million people infected with onchocerciasis

and nearly 100 million people estimated to be at risk in these 16 participating

countries (WHO, 1996). Fortunately, Nigeria is one of the beneficiaries of this

programme.

In Nigeria, the Federal Ministry of health has given priority to the control of

onchocerciasis. Under the auspices of National Onchocerciasis Control Programme

(NOCP) and in collaboration with WHO, UNICEF, Africare and River Blindness

Foundation, the Federal Ministry of Health has initiated a well-planned programme

for the distribution of ivermectin (Nwoke, 1992).

1.3.9 Parasite-V cctor-Host Complex in O~chocerciasis. It has CODESRIA-LIBRARYbeen shown that the parasite - vector - host complex plays an important role in the distribution of onchocercal .nodules and microfilariae in the skin. In

Africa, Simulium damnosum and Simulium neavei bite in the ankle region and maximum density of nodules and n1icrofilariae are therefore found in the lower parts of the body (Woodruff et al, 1966a). In Central America, S. ochraceum bites mostly in the head and neck regions, resulting in high microfilarial densities in the upper 32 parts of the body. In Ecuador, the nodule distribution and microfilarial densities resemble both the African and Central American forms of the infection (Guderian et al, 1983 b) suggesting the existence of more than one vector, each with distinct biting habits. A first complex is formed by a vector which bites on the lower parts of the body. This causes the greater incidence of nodules and the higher microfilarial densities in the region of the iliac crest. However, a moderate number of nodules located on the head and lateral thoracic region suggests a second complex formed by a vector which bites on the upper region of the body (Guderian et al, 1984). In general, the clinical features of onchocerciasis in Ecuador were found to be similar to the African form of the disease rather than that seen in Central America, for example, nodules were predominantly distributed on the lower portion of the body in contrast to that found in Central America where most nodules were located on the head and upper parts of the body. Also there were cases of lymphadenitis, elephantiasis and hanging groin as found in West Africa (Guderian et al, 1984).

In the northern Guinea Savanna of Nigeria, Sato et al (1997) reported that S. damnosum attackedCODESRIA-LIBRARY mainly the sites lower than the knee on man whether in standing position and /or sitting position. On the other hand, in the survey by Renz and Wenk

(1983) in the northern parts of Cameroon, the fly attacked the upper parts of the body as well as the lower parts. When compared with S ochraceum, the main vector of onchocerciasis in Guatemala, S. damnosum attacked the lower parts of the body. It is 33 significant to note that the distribution of rnicrofilariae in patients and the biting sites of Simulium seem to coincide fairly well (Sato et al, 1987).

1.4 Objectives of the Study

1.4.1 General Objectives

The general objectives of the study include:

1. to determine the epidemiological status of human onchocerciasis m Uzo­

Uwani local government area of Enugu State, Nigeria, with the aim of

identifying the focal endemic areas;

2. to assess the effects of the disease on the productivity and social lives of the

inhabitants of the endemic communities;

3. to carry out studies on the vector-blackfly Simulium species;

4. to undertake histological studies of Onchocerca nodules in the study area;

and arising from the epidemiological and biological studies 1-4,

5. to develop appropriate intervention strategies.

1.4.2 Specific Objectives The specificCODESRIA-LIBRARY objectives of the study include: l. to estimate the prevalence of onchocerciasis among the inhabitants of the

rural communities in Uzo-Uwani local government area of Enugu State based

on the demonstrable symptoms of t.he disease especially the presence of

palpable nodules, leopard skin and impaired vision/blindness. 34

2. to ascertain the local disease perception and any local treatment methods

among the inhabitants of the onchocerciasis endemic communities;

3. to find out the effects of the disease on the productivity of the infected

persons;

4. to ascertain the effects of the disease on the pattern of social interactions

of infected persons with the uninfected;

5. to establish the effects of the diseases on the age of marriage of infected

individuals;

6. to assess, if any, the effects of onchocerciasis on marital relationships of

infected persons with their uninfected spouses;

7. to study the daily biting patterns of the blackfly vector of onchocerciasis

8. to carry out histological studies of Onchocerca nodules with the aim of

identifying the effects of Mectizan treatment on histology of the nodules;

9. to make appropriate recommendations based on the findings.

CODESRIA-LIBRARY 35

CHAPTER2

GENERAL MATERIALS AND METHODS

2.1 The Study Arca and Study Population

The study area was Uzo-Uwani local government area of Enugu State, Nigeria. It consists of 16 communities divided into four health districts namely:

1. Umulokpa district consisting of Umulokpa (local government headquarters),

Nkume, Adaba and Ukpata

11. Nkpologu district made up ofNkpologu, Uvuru and Akpugo m. Ogboli district consisting of Adani, Asaba, lgga and Ojjor and Ogurugu

1v. Nimbo district comprising Nimbo, Abbi, Ugbene-Ajima, and Nrobo.

Uzo-Uwani local government area (Figure 2.1) lies between longitude 6° 30' and 7° 00 East and between latitude 6°55' and 7° 15' North. It belongs to the forest­ savanna-mosaic vegetational zone of Nigeria (Crosskey, 1981 ). The vegetation is a mixture of tall grasses and shrubs with few tall trees. This local government area is generally not hilly when compared with the neighbouring Nsukka, Igbo Etiti and Udi local governmentCODESRIA-LIBRARY areas of Enugu State: Uzo-Uwani local government area, like other parts of Enugu State, has in general 7 months of rainy season (April to

October) with a break around July/August and 5 months of dry season (November to

March) with harmattan occurring sometime within the dry season months. The weather is usually hot during the dry season especially in Ogboli district. ------~7~0~0!'!!0...... ;;-iii,,;;;,,------~- .... ---.....lilliiiliii-~--:r:· 15~':t·· -----~·· l I ·I , NSUl

KOGI s:raTE :1I ,l .,·i r •)

Oyl Nnt1Qd

Ak9akum1 ,.., Slate Boundary

L.G.A L-G.·· A. Boundary Main Road Sieonib; Rood

Mfnc,r Rocttf .,- t Alvtr/Strlamt CODESRIA-LIBRARYI 1..o~al Govti H10«111uq,itr . o · 1'01m1/ Vi'lla911 . Mkt lbltt Olo g ·&. D11p1n1ciry : Mat1r11fty ~~. ·. " £ ...... 10km 0 s ,, Private HHp.lta.1 · . , ...... t Scale I : 250,000

1 oo.' 7°t!$'E Fig. :t•t Mqp of Uzo-Uwani L.G-A. ·showing study areas 37

Uzo-Uwani local government area is traversed by many rivers and streams. These

include River Adada (Plates 2.1 and 2.2), River Obina (Plates 2.3-2.5), River Duu

(Plate 2.6), River Eshi (Plate 2.7) and Anambra River (Plate 2.8) in addition to many

streams (Plate 2.9). These rivers and streams belong to the Anambra River System

which had been identified by Crosskey (1981) as part of the breeding sites for

Simulium damnosum (blackfly) in Eastern Nigeria. · Most of these rivers are clean,

rapidly flowing and with resistant rocks in the river beds at some points while others

have been dammed at some points for agricultural purposes (Plate 2.10). These

conditions encourage the breeding of Simulium damnosum in these rivers. Most of

the rivers are perennial and this makes them suitable for Simulium breeding all year

round.

The communities within Uzo-Uwani local government area are mostly connected by minor roads while the area is joined to neighbouring local government areas by secondary roads. Road transportation is the major transport system within and out of this area. Majority (about 90%) of the communities in this local government area do not have pipe-borne water and electricity. Each community, however, hasCODESRIA-LIBRARY a health centre and/or health post. The larger communities like Adani,

Umulokpa, Nkpologu, Nimbo, have private hospitals in addition.

Uzo-Uwani local government area is inhabited by two ethnic groups namely i the Ibos and the Igallas but the Igallas are in the minority being part of only three communities (Igga, Ojjor and Ogurugu). The inhabitants of all the communities that 38

CODESRIA-LIBRARY

.)

Plate 2.1 River Adada at Nkpologu. 39

CODESRIA-LIBRARY

Plate 2.2 River Adada at Ukpata. 40

CODESRIA-LIBRARY

Plate 2.3 River Obina at Adani.

------· --· ·--· ·------~ 40 ·

CODESRIA-LIBRARY

Plate 2.3 River Obina at Adani. 41

CODESRIA-LIBRARY

Plate 2.4 River Obina at Asaba. 42

CODESRIA-LIBRARY

Plate 2.5 River Obina at Adani-Omor Road. 43

CODESRIA-LIBRARY

Plate 2.6 River Duu at Umulokpa. 44

CODESRIA-LIBRARY

Plate 2.7 River Eshi at Ogurugu 45

------~- - .

CODESRIA-LIBRARY

Plate 2.8 River Anambra at Ogurugu

-, 46

CODESRIA-LIBRARY

Plate 2.9 Awara Stream at Umulokpa. 47

CODESRIA-LIBRARY

Plate 2.10 Dammed section of River Obina at Adani. 48

make up this local government area E;ngage in agriculture as their major economic

activity, cultivating yams, cassava, maize and rice. Most farmers in Ogboli district

cultivate mainly rice and the establishment of Adarice Project by the government in

this district is an encouragement to rice cultivation. Some people, in addition to

farming, engage in fishing and hunting activities. The level of engagement in

farming activities in the local government a1·ea is so high that almost every adult,

including the civil servants, are involved. As a result, Uzo-Uwani local govermnent

area forms the major agricultural area in Enugu State and a major source of food

supply in Enugu State and the neighbouring Anambra State.

Uzo-Uwani local government area was chosen as the study area because of a

previous study in the same area carried out in Adani by Amazigo, Ezigbo and Ezeasor

( 1993). The results of that study showed that Adani was highly endemic for onchocerciasis in Enugu State.

2.2 Sampling Procedure and Study Sample

The sampling procedure was a combination of different sampling methods - random sampling, cluster sampling and purposive sampling. In each of the 16 communities,CODESRIA-LIBRARY one or two primary schools were sampled deperiding on the number of primary schools in the community. All the twelve secondary schools in the local government area were also sampled. In each school, a class was randomly selected and used for the study. In addition, in each community, a group of elders were randomly

J 49

selected as part of the sample. The sample included a good representation of males and

females in each group.

2.3 Data Collection Methods

A structured and pre-tested questionnaire was administered personally to the

secondary school students selected while group interviews using the questionnaire as a guide were conducted for the primary school children (Plate 2.11) and the community elders (Plates 2.12 - 2.19). The questions in the questionnaire were meant to obtain information on the local disease perception and treatment of onchocerciasis in each community and also on the effects of the disease on the social life of these rural communities including effects on so_cial interactions between the infected and uninfected individuals, the effects on the age at which young infected individuals marry and the effects on married life. The sample units. were also examined for the various manifestations of onchocerciasis namely rashes, leopard skin; palpable nodules and impaired vision.

An interview schedule was administered _ on subjects with vanous manifestations of onchocerciasis to obtain information on the effects of the disease on the productivityCODESRIA-LIBRARY of farmers. The study on the effects of onchocerciasis on academic performance was done using 5-year (1994 -1998) JSSCE result collected from Examinations Development Centre (EDC) Enugu and analysed to check for correlations between various manifestations of onchocerciasis and academic performance of the twelve secondary schools used. 50

CODESRIA-LIBRARY

Plate 2.11 Interviewed Primary School Children from Igga. 51

CODESRIA-LIBRARY

Plate 2.12 Interviewed eiders from Nkume. 52

CODESRIA-LIBRARY

Plate 2.13 lnterviewed eiders from Uvuru. 53

CODESRIA-LIBRARY

Plate 2.14 Interviewed eiders from Nkpologu. 54

CODESRIA-LIBRARY

Plate 2.15 Interviewed eiders from Ogurugu. 55

CODESRIA-LIBRARY

I

Plate 2.16 Interviewed eiders from Asaba. 56

CODESRIA-LIBRARY

Plat 2.17 Interviewed eiders from Adani. 57

CODESRIA-LIBRARY

Plate 2.18 lnterviewed eiders from Abbi. 58

CODESRIA-LIBRARY

Plate 2.19 lnterviewed eiders from Nrobo. 59

For the study on the effects of Mectizan tre-atment on the histology of the

Onchocerca nodule, there was collection, sectioning, staining and microscopic examination of nodules from Mectizan treated individuals. · The results were compared with sectioned nodules from untreated individuals.

· The study on the biting patterns of the Simulium vector of onchocerciasis involved the use of human baits to monitor the daily biting densities of the blackfly for different seasons over a year.

2.4 Methods of Data Analysis.

The information obtained, with the questionnaire and interview schedules were coded and analysed statistically using percentages and averages. The school results were analysed using weighted averages and regression . analysis was. performed between onchocerciasis indices and performance. The sectioned nodules were examined under the light microscope to study differences between the nodules of Mectizan-treated and non-treated individuals. The results obtained in the studies of diurna:l and seasonal distributions of the blackfly were analysed statistically. CODESRIA-LIBRARY 60

CHAPTER3

STUDIES ON THE PREVALENCE OF ONCHOCERCIASIS IN UZO­

UW ANI LOCAL GOVERNMENT AREA OF ENUGU STATE, NIGERIA

3.1 Introduction

Onchocerciasis 1s endemic in parts of sub-saharan Africa, the Arabian

Peninsula and South and Central America. WHO (1987) reported that an estimated

20 to 40 million people are suffering from the disease in 34 countries of the world with over 3 million people blinded by it. An additional 85 million people are at the risk of getting the disease. The worst affected area is the savanna zone of West

Africa where there may be up to 15 % blindness rate in some villages.

It has been known for many years that Onchocerca volvulus is not a uniform species and that a number of distinct strains or biological variants of the parasite occur (Braun-Muzinger and Southgate, 1977). Duke et a!'(l 966) had shown that microfilariae from persons infected in the forest zone which develop well in forest

Simulium damnosum show almost no development to infective larvae in Sudan­ Savanna SimuliumCODESRIA-LIBRARY damnosum. The reverse is also true: microfilariae from Sudan savanna zone carriers failed to develop to infective larvae in forest S. damnosum.

The strains of Onchocerca volvulus and the forms of S. damnosum transmitting them are thus probably different in the two ecological zones. Similar experiments carried out in Central and South America have shown that New World parasites in

Guatemala and Venezuela exhibit many similarities but are widely different from the 61

West African strains (Duke, 1972). Strain differences in the parasite coincide with

marked differences in the pattern of the disease in man. In the southerly forest areas

of West Africa, gross skin lesions, hanging groins with associated hernia, and even

elephantiasis are encountered but eye lesions are only of limited significance.

Further north, in the Sudan-Savanna areas, on the other hand, the skin manifestations

are not much in evidence but the incidence of eye lesions and blindness reaches an

alarming rate of 10-15% (Duke, 1972). The parasite-vector complex is thus a factor to be considered in any attempt to explain observed clinical differences from one area to another. Other factors of importance include the biting habits of the main vector species, the longevity of the vector fly population and other environmental factors (Duke, 1968).

The severity of onchocerciasis and in particular its ocular complications vary greatly from one bio-climatic zone within the same region to the next. Extreme differences between bio-climatic zones exist in West Africa, especially where little blindness is found in the southern forest zones on the one hand, but rampant blindness occurs in the savanna zone (Budden, 1963). At individual level, the severity of ocularCODESRIA-LIBRARY onchocerciasis is known to be assodated with the intensity of infection (Anderson et al, 1976; Thylefors and Brinkmann, 1977). In the savanna, there exists a clear linear relationship between most indices of ocular onchocerciasis and the community microfilarial load (Rem1~1e et al, 1989a). In the rainforest, the pattern of onchocerciasis is entirely different from that found in the savanna. 62

Onchocercal blindness either do not occur or occur sporadically with increasing community microfilarial load while a steep linear relationship exists between the prevalence of these lesions and the c011111rnnity microfilarial load in the Savanna

(Dadzie et al, 1989a).

The eye lesions of onchocerciasis are the most serious manifestations of the' disease and account for the dramatic popular name of "river blindness". In the small communities involved, it is not uncommon to find 10 % of the total population blind and 25-50 % of the adult male population (who are usually those most affected) being blind. The pathetic picture of a string of blind men being led to the fields by a child so that they may do their limited best to help with growing the village crops in some places is all too real (Duke, 1972). Microfilariae invade the eye from the adjacent skin and the local reactions caused by their death in the delicate specialized ocular tissues are undoubtedly responsible for many of the lesions encountered. An abundance of microfilariae in the conjunctiva leads to a clu·onic, almost brick red conjunctivitis. Invasion of the cornea is very common and may be associated with photophobiaCODESRIA-LIBRARY (Duke, 1972). Most of the tissue changes in onchocerciasis that contribute to the development of various clinico-pathological manifestations appear to be associated with the microfilariae rather than related directly to the presence of adult worms. The release of large amount of parasitic antigens that follow the destruction of microfilariae have more serious pathological consequences in the skin and eyes than in the organs with more efficient antigen-clearing mechanisms e.g. 63 liver (Nwoke and Ikonne, 1993). Although onchocercal blindness is usually seen as associated with a chronic infection, some severe ocular involvemeBt can occur within significantly shorter period (Buck, 1974). The prevalence of onchocercal eye lesions and blindness are related to the prevalence and the intensity of the infection in the community (Nwoke, 1986, Remme et al, 1989a).

Nigeria has a population of over 100 miUion people, about twice the combined population of all the 11 countries in the Onchocerciasis Control

Programme (OCP) regio1i · (Edungbola, 1991 ). In Nigeria, onchocerciasis is widespread and a cause of blindness in most rural communities. Of all the countries of the world, Nigeria has the largest number of persons with onchocerciasis accounting for over a third of the global prevalence (Edungbola, 1991 ). There are . currently about 7 million Nigerians infected out of which about 1.5 million have been blinded by it. About 40 million Nigerians are living at the risk of infection

(Nwoke, 1990). Onchocerciasis in Nigeria is more common among the poorer sections of the community. This is possibly due to their tendency to expose their bodies as they may not always afford elaborate clothing thus predisposing them to increased SimuliumCODESRIA-LIBRARY bites (Nwokolo, 1950).

The prevalence of Nigerian onchocerciasis shows variations between villages with those villages near the breeding sites of vectors having the highest infection rates. Also infection rates have been shown to increase gradually with advancing age pointing to the chronic nature of human onchocerciasis (Buck, 1974; Nwoke et al, 64

1991). Sex-related onchocercal infection in Nigeria varies depending on the degree

of endemicity. In hyperendemic villages, male subjects have slightly higher but not

always significant infection rates than females. This is because inhabitants in such

hyperendemic villages live in homes very close to the foci of infection with the result

that even when there are sex differences in occupation, both sexes are more or less ·

equally exposed to the same number of infective vectors. On the other hand, in hypo­

and mesoendemic villages living far away from the foci of infection, males show

significantly higher intensity and prevalence rates than females. This is because the

surroundings of such villages are not easily accessible to vector flies and therefore

occupational exposure tend to play more prominent role (Crosskey, 1954; Bradley,

· 1976; Edungbola et al, 1983, Nwoke et al 1991 ).

In Nigeria, males show significantly higher ocular lesions than their female

counterparts and micro:filariae are more commonly found in the eyes of males than

those of females. The resistance to infection as well as exposure may explain the

less severe manifestations of onchocerciasis in the females. The differences are most

niarked in savanna area of high transmission and less marked in the forest area

(Nwoke andCODESRIA-LIBRARY Ikonne, 1993). Ocular onchocerciasis has been shown to be more

severe in the savanna region than in the rain-forest region of Nigeria and other West

African countries (Budden, 1963). Such difference is because. the microfilariae of the savanna strain of Onchocerca volvulus are more invasive and more pathogenic than those of the forest strain. There is gradual increase in the blindness rate with 65

advancing age with the peak incidence between 30-39 years age group (Nwoke and

lkonne, 1993). In the rain-forest form of onchocerciasis, the disease is characterized

by abundant nodules and moderate microfilariae density while in the Savanna form, the nodules are less numerous with characteristic high microfilariae density in the skin (Nwoke, 1986; Onwuliri et al, 1987).

The maximum duration of the pre-patent phase of onchocerciasis is about 34 months. Before this time, mild infections with Onchocerca volvulus could go undetected if diagnosis is by demonstration of microfilariae in skin snips (Prost,

1980).

For the diagnosis of onchocerciasis, many different methods had been in use but the mainstay of diagnosis had been the demonstration of microfilariae in skin snips obtained with the Walser's scleral punch instrument (Brinkmann, 1973; WHO,

1976). Skin snipping, although the most conclusive of the diagnostic techniques, has some limitations which include the fact that it is highly teclmical, light infections cannot usually be detected, the equipment is expensive and there is poor cooperation from communityCODESRIA-LIBRARY members due to discomfort caused by fear of skin snipping. Above all, skin snipping is beset with the risk of other infections such as HIV and hepatitis

B virus (Edungbola et al, 1993; Gemade et al, 1998). Other diagnostic methods include the Mazzotti test in which an itching papular rash develops within 1-24 hours of the ingestion of 50 mg of diethylcarbamazine citrate (Duke, 1972); histological examination of the skin of infected person to determine the presence or absence of 66

the characteristic onchocerciasis dermatitis, and the skin response of onchocerciasis

patients to topically applied diethylcarbamazine citrate (Langham and Richardson,

1981; Sting et al, 1984). Immuno-diagnostic techniques can also be used for

diagnosis of onchocerciasis, for example, immunoelectrophoresis (WHO, 1976); .

indirect antibody test (Ngu and Blackett, 1976); use of worm extracts in

radioallergosorbent test (Somorin and Heiner, 1976); or enzyme-linked immunosorbent assay (Bartlett et al, 1975) and use of Onchocerca supernatant containing microfilariae excretory/secretary products (Ngu et al, 1981). These methods, have the disadvantage of being too sophisticated for use in the field and showing false positive reactions in persons having other nematodes with cross­ reacting antigens with Onchocerca volv11!11s . (Neppert, 1974). The most recent diagnostic technique for community diagnosis of onchocerciasis is the Rapid

Assessment Method (RAM) which involves the use of two indicators - the presence of palpable nodules and leopard skin. This method has many advantages which include being simple, rapid, cheap, reliable, acceptable and without any risk of other infections to bothCODESRIA-LIBRARY the subjects and investigators (Edungbola et al, 1993; Gemade et al, 1998; Whitworth and Gemade, 1999).

In this study, the prevalence of onchocerciasis in Uzo-Uwani local government area was based mainly on the presence of palpable nodules and leopard skin. The prevalence of impaired vision and blindness was also considered. 67

3.2 Materials and Methods

3.2.1 The Study Area and Study Population

The study area is Uzo-Uwani local government area of Enugu State, Nigeria described in Chapter 2.1

3.2.2 The Study Sample

The study sample consisted of a total of one thousand, nine hundred and fifty-eight ( 1958) individuals comprising one thousand, one hundred and seventy­ two ( 1172) males and seven hundred and eight-six (786) females randomly selected from twenty-one (21) primary schools, twelve (12) secondary schools and elders of each of the sixteen (16) communities that make up Uzo-Uwani local government area. Out of this number, eight hundred and fifty-two (852) were from the primary schools comprising four hundred and sixty-nine ( 489) males and three hundred and eighty-three (383) females; four hundred and seventy-nine (479) were from the secondary schools consisting of two hundred ·and seventy-three (273) males and two hundred and six (206) females. From the adult population were six hundred and twenty-sevenCODESRIA-LIBRARY (627) individuals made up of four hundred and thirty ( 430) males and one hundred and ninety-seven ( 197) females.

3.2.3 Physical Examination of Sample Units for Indices of Onchocerciasis

The sample units were physically examined for the various manifestations of onchocerciasis and necessary records taken. Other records such as age, sex, occupation, hometown and place of abode were also taken. Although other indices 68

of the disease, especially visual impairment. were considered, the major indices used. for the determination of prevalence of onchocerciasis in this study were the presence of palpable nodules and leopard skin (RAM).·

3.3 Results and Observations

The results of the studies on the prevalence of onchocerciasis are shown in

Table 3.1 for general distribution and Table 3.2 for the distribution in the different health districts and in Plates 3.1-3.15. Among the manifestations of onchocerciasis considered, the prevalence rate of impaired vision was highest (20.2%), followed by the prevalence rate of palpable nodules (20.0%) and leopard skin (5.9%) ..

Out of the 1958 individuals examined comprising 1172 males and 7.86 · females, 392 (20.0%) made up 278 (23.7%) males and 114 (14 .. 5%) females were. positive for onchocerciasis based on the presence of palpable nodules while 116

(5.9%) made up of 84 (7.2%) males and 32 (4.1 %) females were. positive based on the presence of leopard skin. Among the primary school population; 148 (17 .4%) had palpable nodules. This consists of 99 (21.1 %) males and 49 (12.8%) females. There was noCODESRIA-LIBRARY record of leopard skin among the primary school population. Among the secondary school population, 88 (18.4%) cases. had palpable nodules. This consists of 65 (23.8%) males and 23(11.2%) females. Two cases of leopard skin were recorded making up 0.42% of the secondary school population and consisting of one. male (0.36%) and one female (0.49%). · The two students were teenagers.

Among the adult population above the age of 25 years, 151 (24.1 % ) out of 627 :7 --· ... ' ., . ... - : .. - . ? . ~- __ _, ___ . ... ' .- -~ ---"'"--·.- .

69 ..;~ ..

. . Table 3~1 Gener~I Distributi~nofOnchocercia~is in Uzo~Uwani Local Government Area...

No. Sampled No. Positive for Nodules . ; No. Positive fo:r Leopard Skin No. Positive for Visual Impairment

,M F TOTAL.· M F TOTAL M F TOTAL M. F. TOTAL

A. Primary Schools 469 383 .· 852- 99 · 49 148 · 0 0 0 35 11 . . 46 (21.1 %) (12.8%) (17.4%) (0%) . (0%) (0%) C7:5%) (2.4%) ·.. (5.4%)

B.· Secondary Schools . 273 206 479 65 23 88 1 .l 2 36 19 , 55· · (23.8%) (11.2%) (18.4%) (0.36%) . (0.49%) (0.42%) (13.2%) · (9.2%) (11.5%) ·

C. Adult Population 430 197 627 110 41 156 79 29 108 202 92 294 ,. (25.6%) . (20.8%) (24.8%) (18.4%) (14.7%) (17.2%) ;(47.0%) . (46.7%) (46.9%)

1958 274 113 392 80 Total 1172 786 30 110 273 122 .. 395 (23.4%) (14.4%) (20.0%) (6.8%) (3.4%). . (5.7%) (23.3%) (15.5%). (20.2%)

CODESRIA-LIBRARY • - '' T,, ., _,. . ' . ' ·...... ; ·. - .. -----·~· -· . -- . -·-- :· -· _...... ·---, ...·-- ...... ·.~--- · . ·· .. -..- .. ··- ..~

·, 70

· Table 3.2 The Distribntion of Onchocerciasis -in the Different Health Dist~icts in Uzo-Uwani Local Government Area.·

· HEALTH DISTRICT. Number S~mpled Number.Positive For Nodules Number Positive For Leopard . Number Positive For Vis:ual .. · Skin lml!airment UMULOKPA M F TOTAL. M F TOTAL·. M F TOTAL M ·F · TOTAL

A. Primary Schools 166 101 267 . 51 28 79 0 0 . ·O 16 1 17 (30.7%) (27.7%) · (29.6%) (0 %) (0 %) '(0 %) (9,6 %) ·(1.0 %) (6.4 %) B. Secondary Schools 92 97 1891 26 1.0 36 1 1 ' ·.' 2 3 7 '10 (28.3 %) (10.3 %) (19~0 %) (1.0 %) (1.1%) (1.1 %} . (3.3 %) (7.2 %). (5.3%) C. Adult Population·. · 112 65 177 51 29 80 29 · 16 45 44 27 71 (45.5 %) · (25,9%) (45.2%) (25.9%) (24.6 %) · (25.4 %) · (39.3%) (41.5%). (40.1%) TOTAL 370 263 · 633 128 67 195 30 17 47 63 35 98 (34.6%) · (25.5%) (30.8%) .(8.1%) (6.5%) .· (7.4%). (17.0%) '(13.3%) (i5.5%)

NKPOLOGU

A. Primary Schools 42 . 40 82 . 19 9 .28 · ' 0 0 ' 0 1 2 3 (45.2%) (225%) (34.1%) . (0%) (0%) (0%)'. (2.4%) (5.0%) (3.7%). B. Secondary Schools 48 36 84 22 . 11 33 0 0 0 5 10 15 (45.8%) (30.6%) (39.3%) (0%) (0%) (0%). (10.4%) (27.8%). (17.9) C. Adult Population 95 36 131 31 7 38 22 · 9 31 26 12 38 (32.6%) . (19.4%) (28.8%) (23.2%) (25.0%) · (23.7%) (27.4%) (33.3%) (29.0%) TOTAL 185 112 297 72 27 99 22 9 31 32 24 56 · (38.9%) (24.1%) (33.3%) · (11.9%) (8.0%) (10.4%) (17.3%) (21.4%) (18.9%) OGBOLI

A. Primary Schools 145 121 266 16 5 20. 0 0 0 17 8 25 . CODESRIA-LIBRARY(10.3%) (4.1 %) (7.5%) (0%) (0%) . (0%) (11.7%) (6.6%) (9.4%) B. Secondary Schools 56 25 81 3 0 '. 3 0 'O. ·o 14 0 14 (5.4%) (0%) (3.7%) (0%) (0%) '. (0%2 (25.0%) (0%) . V7.3%2 .. 11···· '>-.\· ,:-·,:. ·~·: '

.· ...... ' .. - . .- ......

.- ·· (:. Adult Population .•... 1Q7 ·-,.52 159 10,·· 2 12 16 5:(9.6'Yo~ ·. 21 66 ·31 .. 97 ., .. .. -t9.~%) .·.·· (3:8%) (7.5%). · (15.0o/o) : : (13.2%) ~ (61.7%) ii (59.6%) (61.0%} ., 35 .. ·. TOTAL ·308 . · 198 506 · . :28 7 ·16 .. ·. :·.5 q:5%)·· '21 97 - . 39 ... 13fr. -- : (9:1%) -.(3.5%) .• (6:9%) ..(5;2%) (4.2%) . (31.5%) (26.9%) . . - : :(19.7%) ··· ... .. 4.NIMBO: -·

.. •' ·- . .. -·:. . .. A. Primary Schools . ,: . :116 121 237 14 7 .. ··.21 .. 0 ·O T 0 l •' : (12.1%) -·-cs·.8%) ~ (8.9%}' . . . (0%).: (0%) (0%)·· . :(0:9%). (0%) . (OA°!o)

B. Se~ondary Schools . 77- 48 125 14 2 ' · 16 ., 0 .· ·'O 0 · 14. 2 16. (18.2%) (4.2%) · (12.8%) (0%) (0%) (0%). (18.2%) (4.3%) (2;8%) C. Adult Population . 116 44 160 22 4 .26 16 1 17 66 22 . 88 (19.0%) (9.1%) (16.3%) (13-.8%)' (2.8%) oo:6%) {56:9%) (50.0%) (55.0%) .TOTAL '309. 213 522 50 13 63 16 1 . 17 81 24 ·· 105 (16.2%) · '(6.1%) (12.1%) (5'.201) (0.5%) (3.3%) (26.2%) (11.3%) (20;1 %) GRANDTOTAL. 1172 ·. 786 : 1958 278 114 ·392 .· 84 32 116 273 122 395 (23.7%) (14.5%) (20.0%) · .. (7.2%). (4.1%) (5.9%) (23.3%) (15.5%) -(20.2%).

CODESRIA-LIBRARY 72

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Plate 3.1 The legs of a 19-year old school girl from Ukpata showing leopard skin. 73

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Plate 3.2 The legs of an elderly woman from Nkpologu showing leopard skin. 74

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Plate 3.3 The back of the legs of a middle-aged woman from Nkpologu showing a nodule. 75

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Plate 3.4 The legs of an elderly man from Nkume showing nodules. 76

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Plate 3.5 The legs of men from Ukpata showing leopard skin. 77

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Plate 3.6 The legs of women from Ukpata showing leopard skin. 78

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Plate 3.7 The legs of men and women from Adani showing leopard skin. 79

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Plate 3.8 The legs of men from Asaba showing leopard skin. 80

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Plate 3.9 The legs of men from Nkpologu showing leopard skin. 81

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Plate 3.10 The legs of eiders from Akpugo showing leopard skin. 82

f

1 . CODESRIA-LIBRARY 1

Plate 3.11 The legs of men from Uvuru showing leopard skin. 83

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Plate 3.12 The legs of men from Nimbo showing leopard skin. 84

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Plate 3.13 The legs of men from Abbi showing leopard skin. 85

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Plate 3.14 The legs of men from Ugbene-Ajima showing leopard skin. 86

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Plate 3.15 The legs of men from Nrobo showing leopard skin. \ \

87

people examined had palpable nodules. Out of this number, there were 110 (25 .6%)

males and 41(20.8%) females. Also 108 adults (17.2%) had leopard skin. This

consists of 79 (18.4%) males and 29 (14.7%) females. For the anatomical

distribution of nodules, it was observed that the prevalence of head nodules decreased with increasing age. There was as high as 41.2% of head nodules among the primary school population; 14.2% among the secondary school population and only 1.3% among the adult population. The rest of the nodules were located on other parts of the trunk and limbs.

Impaired vision was recorded in 395 individuals (20.2%) out of the sample population. Males had a higher rate of 23.3% (273 males) while females had 15.5% prevalence rate (122 females). Visual impairment was recorded in 45 (5.5%) of the primary school population made up of 34 (7.6%) males and 11(2.4%) females. In the secondary school population, the prevalence rate of impaired vision was 11.5%

(55 individuals) consisting of 36 (13.2%) males and 19 (9.2%) females. Among the adult population, 289 (46.1%) had visual impairment. This includes 199 (46.3%) males and 90 CODESRIA-LIBRARY(45.7%) females. Out of the positive cases, 4 people (1.0%) made up of 2 men (0.7%) and 2 females (1.5%) were totally blind. One of the men from ' ' Adani got blind within the 1998 farming season and could not harvest the crops he planted.

Of the four health districts, Nkpologu health district had the highest prevalence rate of onchocerciasis based on palpable nodules (33.3%) and leopard 88

skin (10.4%) and ranked third in the rate of impaired vision with 18.9%: the males

having higher prevalence rates as usual than the females. 01~ the other hand, Ogboli

district had the highest prevalence rate of impaired vision (26.9%) and lowest nodule rate ( 6. 9%) and ranked third in the rate of leopard skin ( 4.2% ), with the rates being higher in the males in all the indices than in the females (Table 3.2)

3.4 Discussion

The results of the studies on the prevalence of onchocerciasis in ~zo-U:wani local government area show that the whole of the 16 communities that inake up this local government area are endemic for the disease based. on the indices used but the . level of endemicity varies from community to community. The indices used for measuring endemicity are those recommended in the Rapid Assessment Method

(RAM) (Edungbola et al, 1993). These are the presence of palpable nodules.and depigmentation of the skin commonly called leopard skin (LS). The prevalence of impaired vision was also considered.

The nodule rate was found to be 20.0%.in the area; 23.7% among the males and 14.5% amongCODESRIA-LIBRARY the females. The nodule rate was found to in!3rease with increase in age. Among the primary school population examined which ranged from 9-15 years, the nodule rate was found to be 17.4%; 21 % among the males and i2.8% among the females. In the secondary school population which ranged form 12 to 25 years of age, there was an increase in the nodule rate to 18.4%; 23.8% among the inales and 11.2. % among the females. In the adult population which ranged form 25 89

years of age and above, the_ nodule rate .was 24.1 %; 25.6% among he males and

20.8% among the females:

The index of leopard skin followed the same pattern of increase in prevalence

rate with increasing age. In general, the prevalence rate of leopard skin was 5.9%;

7.2% among the males and 4.1. % among the females. In the primary school

population, there was no record of leopard skin. In the secondary school population,

two teenagers, a boy and a girl, were found to have leopard skin, the girl on the two

legs (Plate 3.1) and the boy on the two legs and one hand. This gave a prevalenc~

rate of 0.42 %; 0.36% among the males and 0.49% among the females.· In the adult

population, the rate was 17.2%; 18.4% among the males and 14.7% among the

females.

The third index considered, impairment of vision, also took the same pattern

of increase in prevalence with increasing age. In general, the rate of impaired vision

. was 20.2%; 23.3% among the. males and 15.5% among the females. In the primary school population, the rate was 5.5%; 7.6% among the males and 2.4% among the females. In theCODESRIA-LIBRARY secondary school_population,_the rate of impaired vision increased to 11.5%; 13.2% among the males and 9.2% among the females. In the .adult

population, the rate was as high as 46.l %; 46.3%. among. the males and 45.7% among the females. · Among the positive cases four adults (2 men and 2 women) were totally blind, making up 1.0% of the positive cases; 0;7% among the males and

1.6% among the females. 90

The increase in prevalence rate with increasing age is in agreement with results from previous studies (Buck, 1974; Edungbola and Asaolu, 1984; Nwoke,

1986; Nwoke et al, 1989; Amazigo et al, 1993), and bears witness to the cumulative nature of human onchocerciasis. The longer the length of exposure to the vector

Simulium flies, the more the accumulation of the parasites in the body. This results in greater severity of the disease in a person and hence greater manifestations of the disease. The higher prevalence rate of all the indices considered in the adult population is due to the fact that the adult population has lived in the endemic communities for very long periods and accumulated the Onchocerca volvulus over the long period with subsequent manifestations. The finding of leopard skin almost exclusively among the adult population supports the fact that this manifestation is particularly associated with long-standing onchocercal infection (Nwoke et al, 1989).

It was generally observed that farmers showed more manifestations of onchocerciasis than the civil servants. Few civil servants had nodules, both males and females, but majority of the people with nodules were farmers. All cases of leopard skin andCODESRIA-LIBRARY blindness, apart from the two teenagers, were found among farmers. Although it was observed that almost every adult in Uzo-Uwani local govermnent area, including civil servants, is involved in agriculture, there are differences in the level of involvetnent and hence in the level of exposure to blackfly bites. The full- 1 time farmers stay in the farms, where the black.flies appear to bite most, more than the part-time farmers and are, therefore, exposed for longer periods to the bites of 91

Simulium flies than the others. Consequently, they accumulate more parasites and

therefore show greater manifestations of onchocerciasis than the other occupational

groups.

Consistently, there was higher prevalence rate of every examined

manifestation of onchocerciasis in the males than in the females among the primary,

secondary and adult populations. This is consistent with existing records and has

been attributed to differences in the level of exposure to Simulium flies. In addition to differences in susceptibility of different individuals to Onchocerca volvulus

infection, tlu·ee factors, all of which are related to the level of exposure to blackfly bites, appear to underlie the observed differences in prevalence rates between males and females. These include occupational differences between males and females especially in the adult population; the difference in the length of exposure of males I ' and females to Simulium bites even among people of the same occupation, and the difference in the mode of dressing of males and females while fanning, swimming or working around the rivers. In Uzo-UwaniCODESRIA-LIBRARY local government area, males, right from childhood, are involved in more outdoor activities such as playing football, fishing, hunting, farming, swimming etc than females while the females are involved more in indoor activities such as cooking, washing etc. Even when the females are involved in outdoor activities such as fetching water, washing clothes or preparation of cassava around the rivers or even swimming, they spend less time than the males. Also, 92 when working around the rivers or streams, males mostly wear only shorts exposing most of their trunk and limbs while females mostly wear clothes that cover their bodies except the lower legs and hands. The differences in activities, length of time spent outdoors and mode of dressing of males and females lead to differences in the length and level of exposure to blackfly bites and hence the difference in prevalence rates between males and females right from childhood. In addition, among the adult population, the difference in prevalence rates between males and females can be attributed to occupational differences between them. The men are mostly full-time farmers while women combine farming with other activities such as trading and some indoor activities. Men, therefore, spend longer time in the farms than women and so have higher man-fly contact with the subsequent manifestations. Even women who are full-time farmers admitted leaving the farms earlier (between 1.00 and 3.00 p.m.) while men mostly stay till evening (between 5.00 and 6.00 p.m.).

Another factor that results in differences in prevalence rates between adult males and females is the mode of dressing of the two sexes while farming. Men generally work in the farms wearingCODESRIA-LIBRARY only shorts or rolled up trousers (Plate 3 .16) while women work in the farms covering most parts of their bodies apart form the hands and head region

(Plate 3.17). This again results in higher level of exposure in men even among adults of the same profession and hence the higher prevalence rates in men ..

With regard to the distribution of nodules in an infected person, it was observed that in adults, the nodules were located almost entirely on the trunk with 93

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Plate 3.16 A man met working in the farms at Nkpologu wearing only trousers. 94

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Plate 3.17 A wonian met working in the farms at Nkpologu wearing clothes that cover the trunk. 95

rare incidence of head nodules (1.3%) but in children, it was observed that head

nodules were quite rampant being higher in the primary school population ( 41.2%)

than in the secondary school population (14.8%). It has been known for a long time

that in parts of Africa, the nodules are largely confined to the trunk especially around

the hip region but in some regions of Congo and particularly in Central America,

nodules are commonly found on the head (Woodruff et al; 1966b, Choyce, 1972;

WHO, 1982). Crosskey (1954) reported that head nodules were rare in Nigeria but

Onuigbo (1975) later reported that many lgbos exhibit such nodules. Some studies carried out in different parts of Eastern Nigeria (Ezeasor, 1986; Amazigo et al, 1993) showed that head nodules were more common in children than in adults. The reason for the differential distribution of nodules in individuals from different geographical areas had not been well established but many researchers had suggested that it was related to the parasite-vector-host complex in onchocerciasis. In Africa, Simulium damnosum and Simulium neavei bite in the ankle region producing greater density of nodules and microfilariae in the lower parts of the body (Woodruff et al, 1966a) while in CentralCODESRIA-LIBRARY America, Simulium ochraceum bites mostly in the head and neck regions producing higher density of nodules and microfilariae in the upper pmts of the body (Woodruff et al, 1966b ). In Ecuador (Latin America), Guderian et al

(1983b) reported distribution of nodules and microfilariae on both upper and lower parts of the body and suggested the existence of more than one vector, one biting on the upper part of the body and the other biting on the lower part of the body. Based 96

on these suggestions, it is possible that there is more than one vector complex in

Uzo-Uwani local government area of Enugu State of Nigeria and other parts of

Eastern Nigeria such as Oji River area where similar observation has been made.

These two areas incidentally belong to the forest-savaima-mosaic zone of Nigeria

where there may exist both the forest and savanna strains of Simulium damnosum

complex. Another factor that could cause cephalward trend in the distribution of

nodules in children may be related to the height of the children in relation to the

height at which Simulium bites. It is possible that the height at which Simulium

damnosum mostly bites is lower than the average height of an adult such that in

children, the Simulium flies are able to bite on the head region as well as other parts

of the body whereas in adults, the flies do not commonly reach the head regions of a

standing adult. These two suggestions need to be further investigated in this area.

The low prevalence of total blindness, less than I% of the sample population and about 1% of those with visual impairment can be attributed to the difference in blindness rate of onchocerciasis in different geographical areas in Nigeria and other West AfricanCODESRIA-LIBRARY countries. Ocular onchocerciasis has been repo1ted to be more severe in the savanna region than in the rain-forest region of Nigeria and other West Africa countries (Budden, 1963) due to the fact that the microfilariae of the savanna strain of Onchocerca volvulus are more invasive and more pathogenic on the cornea than those of the rain-forest strain (Duke, 1981 ). Uzo-Uwani local government area belongs to the forest-savanna-mosaic zone of Nigeria (Crosskey, 1981) and so has 97 lower blindness rate than the savanna zone but higher than the rain forest zone. It is believed (Amazigo et al 1993) that both savamrn and rain-forest strains of Simulium damnosum and Onchocerca volvulus may be co-existing in this vegetational zone producing a mixture of the forest and savanna manifestations of onchocerciasis.

Although there is a moderately high nodule rate (20%) in the area, the rate of impaired vision is also high (20.2%) especially in the adult population (46.1%) but only 1% of those with eye complaints are totally blind. It should be noted, however, that there are other possible causes of impaired vision but the fact remains that wherever onchocerciasis is prevalent, the rate of visual impairment is higher than is commonly found in onchocerciasis-free areas.

As mentioned earlier, Uzo-Uwani local government are is made up of 16 communities divided into four health districts namely Umulokpa, Nkpologu, Ogboli and Nimbo health districts. Out of the four health districts, Nkpologu and Umulokpa districts had the highest prevalence rates of onchocerciasis based on the presence of palpable nodules (33.3% and 30.8% respectively) and leopard skin (10.4% and 7.4% respectively) and ranked third and fourth respectively in the rate of visual impairment;CODESRIA-LIBRARY males having higher prevalence rates as usual than the females. On the other hand, Ogboli district had the highest prevalence rate of impaired vision

(26.9%) and ranked third and fourth in prevalence rates of leopard skin and nodules respectively. (Table 3.2). This is significant because Ogboli district is the northern boundary of Uzo-Uwani local government area next to Kogi State which belongs to 98

the Guinea-savanna vegetational zone of Nigeria (Crosskey, 1981 ), while Nkpologu and Umulokpa districts are the southern boundary of the local govenm1ent area being closer to the rain - forest zone of Nigeria and there have been reports that the rain­ forest form of onchocerciasis is characterized by abundant nodules and moderate microfilarial density while in the savanna form, the nodules are less numerous with characteristic high microfilarial density (Nwoke, 1986; Onwuliri et al, 1987). It has also been commonly reported that onchocercal blindness is more severe in the savanna bio-climatic zone than in the rain-forest zone (Budden, 1963; Nwoke and

Ikonne, 1993). Uzo-Uwani local government area has a mixture of rain-forest and savanna forms of onchocerciasis with the part closer to the savanna zone having more of the savanna form with less prevalent nodules and higher prevalence of visual impairment and the part closer to the rain-forest zone having more of the forest form of the disease with higher prevalence rate of nodules and lower prevalence rate of visual impairment.

3.5 Summary and Recommendations

The studies on the prevalence of onchocerciasis in Uzo-Uwani local government area shows that theCODESRIA-LIBRARY area is endemic for onchocerciasis based on the presence of palpable nodules, leopard skin and visual impairment which were the indices considered.

Occupational differences determine the level of exposure of individuals to

Simulium bites thus resulting in differences in prevalence rates between different occupational groups with farmers being the most affected group. Prevalent rates 99

were consistently higher in the adults than in children pointing to the age-related,

cumulative and chronic nature of onchocerciasis. Also prevalence rates were higher

in males than in females. This can be attributed partly to occupational difference

between males and females and partly to the difference in the length of exposure to

blackfly bites even within the same occupational group such as farmers where men

stay in the farms from morning till evening being exposed to bites of Simulium flies

during the morning and evening peak biting periods while women leave the farms

earlier between 1.00 and 3.00 p.m. before the evening peak biting period. In

addition, the mode of dressing of males and females during outdoor activities such as

" farming, swimming or working around the rivers also help to determine the level of exposure to blackfly bites and the consequent manifestations. Women cover

themselves more than men in such outdoor activities and so are less exposed to

Simulium bites. As a result, they harbour fewer parasites and show less i manifestations of onchocerciasis than men.

It is recommended, therefore, that farmers and other outdoor workers be prevailed uponCODESRIA-LIBRARY to cover their bodies as much as possible while farming or while pursuing other outdoor activities such as hunting in or collecting firewood from

bushes or farms where blackflies are usually abmJ.dant or while bathing, swimming,

fishing, washing clothes or preparing cassava around the rivers or yet while fetching

water from the rivers or streams which form the breeding sites of these Simulium

flies. 100

CHAPTER4

STUDIES ON THE LOCAL DISEASE PERCEPTION AND TREATMENT

OF ONCHOCERCIASIS IN UZO-UWANI LOCAL GOVERNMENT AREA.

4.1 Introduction

Few studies have been carried out on the local disease perception and treatment of onchocerciasis in different parts of Nigeria. Nwoke et al (1992) for example, assessed the local disease pe.rception and treatment in Jos, Plateau State. In northwestern Nigeria, Edungbola (1982) carried out similar studies in Ile-Ire district of Kwara State; Edungbola et al (1983) and Edungbola and Asaolu (1984) did similar works in Babana district of Kwara State. In the east, Amazigo and Obikeze

( 1991) carried out a similar study in Ette in the northern fringes of Enugu State.

Edungbola (1982) reported that the natives of Ile-Ire district of Kwara State were aware of the nuisance of the blackfly locally called "Amukuru" and knew onchocerciasis locally called "Jnaru" but were not aware of the association between them. They attributed onchocerciasis manifestations to old age, familial traits or enenues. CODESRIA-LIBRARYThe treatment is, therefore, misdirect~d towards appeasing enemies or devils.

Edungbola et al (1983) and Edungbola and Asaolu (1984) reported that although most subjects of Babana district of K wara State were aware of the blackfly locally called "Kusena", they were ignorant of its association with the various manifestations of onchocerciasis. for this reason, no attempts were made by the 101

subjects to seek appropriate remedy, as reflected in the finding that all the infected

individuals interviewed, except two teachers, had never been treated for onchocercal

infection.

Nwoke et al (1992) studied local disease perception in .Tos area and found out

that villages in endemic communities were aware of the menace of the blackflies

locally called "Bekin Kuda" because of intense biting and itching especially during

the farming season but they were not aware of any association between the balckfly

bites and onchocerciasis. They attributed the manifestations to various causes

including old age, familial traits, affliction from enemies or the gods. As a result,

majority did not attend hospitals but consulted oracles and appeased gods for help.

At Ette, Amazigo and Obikeze, ( 1991) reported that the villagers knew the black.fly locally called "Ita" but Imel no knowledge of its association with the manifestations of onchocerciasis which they attributed to other causes. They treated the disease with local herbs.

According to Nwoke et al (1992), the assessment of local disease perception and treatment in any onchocerciasis endemic area is significant in effective planning and mobilizationCODESRIA-LIBRARY of communities for control programmes and in ascertaining whether local treatment is of any chemotherapeutic potential. In the present study, the local disease perception and treatment of onchocerciasis were investigated in the

16 communities that make up Uzo-Uwani local government area of Enugu State with the objective of finding out what the inhabitants of these rural communities know r 102 about Simulium flies and onchocerciasis and how they manage the disease in terms of treatment methods in their communities. This it was hoped will help in recommending appropriate intervention strategies to help these agricultural communities.

4.2 Materials and Methods

4.2.1 The Study Area and Study Population

The study area was Uzo-Uwani local government area of Enugu State,

Nigeria described earlier ii1 Chapter 2.1. The study population comprises the inhabitants of the 16 communities that make up the local government area.

4.2.2 The Study Sample and Sampling Procedm·e

The study sample consists of randomly selected pnmary school pupils, secondary school students and elders of each of the 16 communities.

Different sampling methods were used in the selection of the sample. The included pmposive sampling, cluster sampling and random sampling methods. Uzo­

Uwani local government area was selected for the study because of previous knowledge ofCODESRIA-LIBRARY the presence of onchocerciasis in the area. The subjects were selected in clusters - the primary school pupils, the secondary school students and the elders of the individual communities. Within each cluster, subjects were randomly selected.

. . 103

4.2.3 Data Collection

A structural and pre-tested questionnaire was administered to the selected secondary school students in face to face e11counters. The questionnaire schedule was also used as a guide to interview the primary school pupils, some indigenous teachers and some elders of each community to find out their knowledge and beliefs about onchocerciasis including the vector, blackfly and vanous visible manifestations of the disease and local treatment methods for these manifestations.

4.2.4 Data Analysis

In each community during the interview, the majority opinion was taken as representing the opinion of the community. The questionnaires were coded and analysed using simple percentages and the answer with the highest percentage in each question was accepted as majority opinion.

4.3 Results and Observations

The knowledge of the blackfly and the vanous manifestations of onchocerciasis as well as treatment methods are presented for every community in Uzo-Uwani localCODESRIA-LIBRARY government area. Although there are similar knowledge and beliefs in most communities, some communities have their own peculiar beliefs.

The commw1ities all know that black.fly and the various manifestations called different names in different communities and treatment methods are more or less similar but the extent of knowledge varies from one community to another d'epending on how common the blackfly and the manifestations are in that 104

community. It was, however, observed that ~ommunities in the same health district

have similar names for both the balckfly and the various manifestations (Table 4.1)

and their beliefs about these are also closely related.

4.3.1 Umulokpa Health District: made up of Umulokpa (headquarters), Nkume,

Adaba and Ukpata

4.3.1.1 Umulokpa Community

The people of Umulokpa community know the black:Oy, Sinzulium species locally called "Nta oji" but it is not very abundant in their community. It is most abundant in the farms and bites mostly in the morning and evening. The black:Oy bites from dry season into the rainy season. The people do not know where it breeds.

It bites everybody and on all exposed parts on the body. There is no disease associated with the bites of the black:fly. The bites are not prevented by any definite method except by killing or chasing away those that perch on the body with either bare hands or with plant branches.

The people of Umulokpa know the onchocercal rashes locally called "Iti" but they do not knowCODESRIA-LIBRARY the cause. The elders believe it can be passed from mother to child and the disease can be prevented by not marrying an infected person. The young ones, on the other hand, believe that it can be passed from one person to another through contact with infected person. They all believe oncho-rashes can be cured with either local herbs or drugs but majority of the people do not know any drug used in its treatment. . 105

Table 4.1 Names of Blackfly and Manifestations of Onchocerciasis in Uzo~

UwaniLGA.

S/No Community Blackfly Rashes Nodules Leopard skin A Umulokpa District 1 Umulokpa Nta oji Ita Akpurukpu. 2 Nkume · Nta ipo Ita Akpurlikpli Ukpo likwu .' 3 Adaba Nta Ita Akpurukpu Ukpo ocha 4 Ukpata Nta Etu Akpurukpu · l;kpo tikwu B Nkpologu District 5 Nkpologu Nta Etu Akpu Akpaala 6 Uvuru Nta Akpu Akpurukpu Akpaala . 7 Akpugo Nta . Korugaba Akpurukpu · Nchaba ukwu C Ogboli District 8 Adani Ntankwuisi Akpu Akpurukpu . Akpaala ': 9 Asaba: ljiji ndi Fulani Iti Akpu Akpaala . "i. 10 Igga Ita or ljiji ndi Etiri Okpo Akpaala Fulani 11 Ojjor Ijiji ndi Fulani Etiri · Okpo Akpaala ! . i' 12 Ogurugu Ita oloko Ifoo or Kachuabeg Okpo Akpaala D Nimbo District 13 Nimbo CODESRIA-LIBRARYNta akpurike Akpu Akpurukpu · Akpaa~a 14 Abbi Nta akpurike Akpu Mkpo Akpaala 15 Ugbene-Ajima Nta akpurike Etu Akpu Akpaala 16 Nrobo Nta akpurike Etu Akpu Akpaala 106

The people also know the Onchocerca nodule which is locally called

"Akpurukpu". They, however, do not know the cause or any preventive measure except that the nodule can be cured by removing it. The drug for its treatment is not \ generally known. The young ones do not know of any \onnection between oncho- rashes and nodules but the elders believe that the presence of nodules results in rashes. There is no knowledge of any connection between rashes or nodules and any other manifestations of onchocerciasis such as leopard skin locally called "Ukpo ocha".

4.3.1.2 Nkumc Community

The people of Nkume know the blackfly locally as "Nta ipo". It is abundant in their community especially in the farms and bushes. The blackfly bites all day and all seasons except hannattan season. The people believe it bites more on the legs and that it bites everybody. There is no disease associated with the bites of the blackfly at Nkume. There is also no definite method of preventing the bites except by killing those that perch to bite. The NkumeCODESRIA-LIBRARY people know onchodennatitis locally called "Iti". They believe it runs in families but develops in aduit age. It is believed to be contagious by either direct contact or by common use of such materials as clothes, bedsheets, towels etc.

They believe it can be prevented by avoiding contact with infected persons.

Onchocerciasis, they believe can be cured with local herbs but with difficulty. They are not aware of any drugs used for its treatment. 107

The people of the community also know the Onchocerca nodule locally

called "Akpurukpu" but they do not know the cause. They believe it cannot be

prevented but can be cured through nodulectomy. They accepted that there is a

connection between rashes and nodules in that rashes result from nodules but they do

not know of any connection between nodules or rashes with any other disease

condition including leopard skin which is a common manifestation in the community

and locally called "Ukpo ukwu" and attributed to old age.

4.3.1.3 Adaba Community

The people of Adaba know the blackfly locally as "Nta". The blackfly is

very abundant in the community especially in the bushes and farms. It bites more in

the morning and evening and in the dry season. It bites everybody and on all

exposed parts of the body. They are not aware of any association between the

Simulium bites and any disease. The people have no definite way of preventing the

bites of the blackfly.

The people know oncho-rashes locally as "Iti" and believe it is caused by poor hygieneCODESRIA-LIBRARY or dirty habits. They believe it can be passed from one person to another through contact either directly or indirectly tlu·ough the common use of materials such as towels, clothes, bedsheets etc. They also believe it can be prevented by personal hygiene and avoiding contact with infected persons. The people believe that oncho-rashes cannot be cured. They are not aware of any drugs used for the treatment of onchodermatitis. 108

The people of Adaba community also know the Onchocerca nodule locally

known as "Akpurukpu". They neither know the cause nor any preventive method

but believe that nodules can be cured by removal in health centres or government

hospitals. They are not aware of any drug used for the treatment of the nodule. They

believe that nodules result in rashes but are not aware of any connected between

rashes or nodules with any other disease condition not even the leopard skin which is

well known and very common in their community and locally called "Ukpo ocha".

4.3.1.4 Ukpata Community

In Ukpata, the blackfly is well known and locally called "Nta" and it is very

abundant. It is found mostly in the bushes, in the fa1ms and near the rivers and is

most abundant in the morning and evening. It is most common during the rainy

season. The people do not know where the black.fly breeds. The black.fly bites

everybody and on all exposed parts of the body. Although the people are aware of

the menace of the black.fly, they do not associate the bites with any disease. They do

not have any definite method of preventing the blackfly bites except by killing or

chasing them away when they perch to bite.

The peopleCODESRIA-LIBRARY of Ukpata also know the oncho-rashes locally called "Etu" but

they do not know the cause. The young people believe it can be passed from one

person to another through direct body contact or through the common use of

materials such as towels, bedding, clothes etc and so can be prevented by avoiding direct or indirect contact with infected persons. The elders, however, claimed that 109

they do not know whether it is contagious or not and that it cannot be prevented.

Onchodermatitis, they claimed, can be cured by use of local herbs from herbalists.

They are not aware of any drugs used for its treatment.

The people of Ukpata community are aware of the Onchocerca nodule locally called "Akpurukpu" but do not know the cause and so do not know any preventive method for it. The common curative method for the nodule is by removal either by health officers or local excisors. The people of the community are not aware of any drug used for treating the Onchocerca nodule. The elders believe that onchodermatitis and nodules usually go together but do not know any connection between them and any other manifestation although leopard skin is common and locally called "Ukpo ukwu".

4.3.2 Nkpologu Health District: This consists ofNkpologu, Uvuru and Akpugo.

4.3.2.1 Nkpologu Community

The people of Nkpologu community know the Simulium (blackfly) locally called "Nta". It is very abundant in their community especially in the farms. The bites are moreCODESRIA-LIBRARY in the morning and evening than in the afternoon and more in the dry season without harmattan than in other seasons. The people do not know anything about the life history of the Simulium species. The blackfly bites everybody and on all exposed parts of the body from neck down. In Nkpologu community, the bites of the Simulium flies are prevented by rubbing palm oil on the body as a repellent. 110

The people of the community also know the oncho-rashes locally called

"Etu" and they believe, especially among the older generations that the oncho-rashes

cannot be passed from one person to another. The rashes cannot be prevented but

can be cured by the use of local herbs and drugs administered by herbalists or

medical personnel respectively. The people do not know any drugs used in the

treatment of onchodermatitis.

The people of Nkpologu also know the Onchocerca nodule locally called

"Akpu". They neither know the cause nor any preventive method against the nodule

but it can be cmed by removal in their health clinics. They do not know any drug

used for the treatment of the nodule. Apart from the connection with rashes, the people do not know any other connection between rashes or nodules and any other disease condition including leopard skin that is very common among the elders and locally called "Akpaala".

4.3.2.2 Uvuru Community

The people of Uvuru community know the black.fly locally called "Nta". The black.fly is veryCODESRIA-LIBRARY abundant in the bushes and farms. It bites from morning till evening and is more abundant during the rainy season. The black.fly bites everybody and on all exposed parts of the body but there is no disease associated with its bites. They have no definite way of preventing the bites.

The Uvuru people also know oncho-rashes locally called "Akpu" but they do

,not know the cause. The young ones believe it can be passed from _one person to 111

another tlu-ough contact while the elders believe it is not contagious. In the same

manner, the young ones believe it can be prevented either by personal hygiene or by

avoiding contact with infected persons but the elders believe it cannot be prevented.

Oncho-rashes, according to the people, can b_e cured with drugs or, according to the

elders, by removing the nodule. They are not aware of any drug used for its

treatment.

The people of Uvuru know the Onchocerca nodule locally called

"Akpurukpu" but they do not know the cause. It caimot be prevented but can be

cured through removal. They know there is a connection between rashes and

nodules in that nodules result in rashes but they are not aware of any com1ection

between any of them and any other disease condition. However, they know leopard

skin locally called "Akpaala" and attributed same to old age.

4.3.2.3 Akpugo Community

All the people of Akpugo know the blackfly locally called "Nta" and agree

that it is very abundant in the community and found everywhere especially in the bushes and farms.CODESRIA-LIBRARY They believe it bites mostly in the morning and evening and in the dry season without harmattan. They do not know where it breeds. The blackfly bite's

everybody, for example, all the people interacted with accepted that they have often

· been bitten by the blackfly. It bites on all exposed parts of the body. There is no

disease attributed to the bites of the black:fly ·and there is no particular _method used to prevent the bites except by killing those that are biting. 113 repellent while others use fire smoke to drive them away but the most common way is by killing those that perch or by driving them away with plant branches

The Adani people know onchodermatitis locally called "Akpu". It is attributed to various causes such as inheritance, poor hygiene, etc. The elders believe that the Onchocerca nodule sometimes causes it. . Many people, especially young people believe it can be passed from one person to another through the common use of such materials as towels, clothes, bedding etc, but the elders believe it is not contagious. Many young people believe it can be cured by the use of local herbs or medicated soap but the elders believe it can be cured by removal of the nodule. The people of Adani go to native doctors, patent medicine dealers or health centres to receive treatment for onchodermatitis.

The Adani people also know the Onchocerca nodule locally called

"Akpurukpu". They do not know· either the cause or any preventive measure.

However, it is generally known that the Onchocerca nodule can be cured by removal by local excisors or by medical personnel. They do not know any drug for its treatment. ThereCODESRIA-LIBRARY is no association between the rashes or nodules with any other disease condition including leopard skin that is well known in the community and locally called "Akpaara".

4.3.3. 2 Asaba Community

The primary school children interviewed at Asaba did not know either the blackfly or any of the manifestations of onchocerciasis and there was no record of 114

any manifestation in any of the sample units. The elders are aware of the existence

of the blackfly locally called "IjUi ndi Fulani" but it is not abundant in their community. The blackflies are mostly found in the bushes and farms and bite more in the morning and evening periods. They believe that they are most abundant in the dry season without harmattan. The blackflies bite everybody and on all exposed parts of the body. They are not aware that they transmit any disease. There is no definite way of preventing the flies from biting apart from killing them when they perch to bite.

· The people of Asaba know onchodermatitis locally called "lti". They are not aware of the cause but believe it can be passed from one person to another through either direct body contact or through common use of body materials such as clothes, bedsheets, towels etc. It can be prevented by avoiding contact with infected persons and can be cured by the use of local herbs from native doctors. They do not know any drug for its treatment.

Asaba community knows the Onchocerca nodule locally called "Akpu" but they do not knowCODESRIA-LIBRARY the cause. The nodule can be cured by removing it at health centres by medical personnel. The people are not aware of any drug used in the treatment of the nodule and do not know any connection between Onchocerca nodule and oncho-rashes nor between any of them and any other manifestation of onchocerciasis such as leopard skin, which is common and locally called "Akpaala". 115

4.3.3.3 lgga Community

The people of Igga community lmow the blacld1y locally called "lta or "Ijiji ndi Fulani". The blackfly is abundant in the farms and bushes and bites mainly in the morning and evening periods. It is most abundant in the dry season except during the harmattan season. They are not aware of the life history of blackflies.

The blackfly bites everybody and on all exposed parts of the body. Generally, the people of Igga do not associate the bites of the blackfly with any disease. There is no special method of preventing the bites except by killing them when they are caught biting.

The Igga people are aware of onchodermatitis locally called "Etiri" but they cannot tell the cause although the elders believe that it is caused by the bite of termite. Most people, especially women and children, believe that onchodermatitis can be transferred from one person to another through either direct body contact or through common use of materials such as towels, clothes, bedsheets etc. According to them, oncho-rashes can be prevented _by avoiding contact with infected persons. The men, however,CODESRIA-LIBRARY believe that oncho-rashes are not contagious. The people believe it can be cured through the use of local herbs administered by herbalists but they do not know any drug used in its cure.

Igga people also know the Onchocerca nodule locally called Okpo but they do not know the cause except the elders who believe that nodules result from the presence of oncho-rashes ("Etiri"). The manifestation of the nodule cannot be 116

prevented but the nodule can be cured by removal in health centres/hospitals. The

people are not aware of any drug used for its treatment. There is no association of

the presence of nodules or rashes with any other disease condition including leopard

skin which is also common and locally known as "Akpaala".

4.3.3.4 Ojjor Community

The black.fly, Simulium species, is known by Ojjor people and locally called

"ljiji ndi Fulani". They associate it with the cattle reared by the Fulanis. The

black.fly is abundant in their community especially in the farms and bushes. It bites

from mid morning till evening. They believe that the blackfly is most abundant

during the dry season without harmattan when the cattle rearers graze cattle around

their area. They agree that the flies bite everybody and on all exposed parts of the

body: There is no disease 'associated with the bite of the black.fly and there is no

definite way of preventing the bites except by killing those that perch on the body.

The conununity is aware of onchodennatitis locally called "Etiri". The

people, especially the elders, believe oncho-rashes ("Etiri") is caused by the bite of an unknown CODESRIA-LIBRARYinsect. It is contagious and can be contracted either through the common use of materials such as clothes, towels, bedsheets, etc. As far as they

know, this skin condition can be prevented by avoiding either direct or indirect

contact with infected persons. Onchodermatitis can be cured by use of drugs given at the hospitals or health centres but the people do not know any drug used for its treatment. 117

The people of Ojjor community also know the Onchocerca nodule locally

called "Okpo". They do not know what causes it or any means of prevention but it is

curable and the known curative method is by removal of the nodule in health centres

or hospitals. They are not aware of any drug used for the treatment of nodules. They

believe that there is a connection between oncho-rashes and nodules in the sense that

the rashes can cause nodules to appear on the body but they do not believe there is

any connection between them and any other disease. The leopard skin is, however,

well known and locally called "Akpaala".

4.3.3.5 Ogurugu Community

The blackfly, Simulium, is well known to the people of Ogurugu and loca11y they call

it "lta oloko or "Ijiji ndi Fulani". The blackfly is abundant in their community and most common in the farms and bushes especially in the afternoon. "Ita oloko" is very abundant during the dry season but disappears during the harmattan. The breeding place of the blackfly is not known to them. During its abundant season, the fly bites everyday, and on all exposed parts of the body. The people do not associate the bites of Simulium with any disease. There is no serious effort to prevent the bites except by usingCODESRIA-LIBRARY something like local fan to drive them away or by killing perched ones.

The people of Ogurugu community lmow onchodermatitis locally called

"lfoo or "Kachuabeg" or "Etiri". They believe it is caused by poor hygiene or dirty habits or by charm. They believe the disease is infectious and can be passed from 118

one person to another through direct contact or use of the same body materials. The

spread of the disease can be prevented by avoiding contact with infected persons

either directly or indirectly. They believe that onchodermatitis can be cured but majority of the community members do not know how. Few, however, believe it can be cured by the use of local herbs. Any drug for the treatment of onchodermatitis is not known to the community.

Ogurugu people know the Onchocerca nodule locally called "Okpo" but they do not know the cause. To them, nodules cannot be prevented but can be cured through removal in health centres and hospitals. They do not know any drug for its treatnient and are not aware of any association between onchodermatitis and nodules or between them and any other disease condition including leopard skin which is common and locally called "Akpaala".

4.3.4 Nimbo Health District: This comprises Nimbo, Abbi, Ugbene-Ajima and

Nrobo.

4.3.4.1 Nimbo Community

The people of Nimbo know the blackfly, Simulium, locally called "Nta akpurike" butCODESRIA-LIBRARY it is not abundant in their community. It is mostly seen in the farms and near the river. It bites from morning till evening and is most abundant in the dry season and early rain season. The people do not know where the blackfly breeds but know that it bites everybody and on all exposed parts of the body. The people of the community do not associate the bites of the blackfly with any disease and do not 119

have any general method of preventing the bites. Some people use palm oil on the

body as a repellent, others use fire smoke while some others just kill or chase away

perched ones.

The people of Nimbo also know onchoderrnatitis locally called "Akpu" and

nicknamed "Korugaba". The young people believe that it is either inherited or

caused by poor hygiene and so believe it is contagious and can be prevented by

avoiding contact with infected persons. The elders, however, believe that such

rashes are caused by the presence of nodules and are not contagious and cannot be

prevented. The younger people think oncho-rashes can be cured by the use of

medicated soap while the elders believe that it can be cured by the removal of the

nodule. The generality of the people are not aware of any drug used in treating

onchodennatitis.

Nimbo people know the Onchocerca nodule locally called "Akpurukpu" but

they do not know the cause. The nodule, according to them cannot be prevented but

can be cured by removal either by patent medicine dealers or by local excisors or by

medical persoru1el. They do not know any drug used for the treatment of the

Onchocerca nodule.CODESRIA-LIBRARY

4.3.4.2 Abbi Community

The people of Abbi know the blackfly locally called "Nta akpurike" but it is not abundant in their community. It is usually found mostly in the farms and bushes particularly in the evening. It is more abundant in the rainy season especially during ·1 I I 120 the late rains. They are not aware of where it breeds. The blackfly bites everybody and on all exposed parts of the body. It is a common practice in Abbi to drive away the blackflies with fire smoke. The people of Abbi also know onchodermatitis locally called "Akpu". The young ones believe it is caused by poor hygiene while the elders do not know the cause but they all believe it can be passed form one person to another through contact either directly or indirectly through common use of clothing and bathing materials. Oncho-rashes can be prevented by avoiding such contacts. Onchodermatitis can be cured by the use of local herbs. The people are not aware of any drug used for its treatment.

Abbi people also know the Onchocerca nodule locally called "Mkpo". Apart from the elders who believe that the nodules result from oncho-rashes, others do not know the cause. The nodule, according to them, cannot be prevented but can be cured through nodulectomy. They are not aware of any drug used for the treatment of the Onchocerca nodule. Apart from the belief that nodules result from rashes, there is no other known connection between rashes or nodules with any other disease, not even the leopard skin which is well known in the community and locally called "Akpaara".CODESRIA-LIBRARY

4.3.4.3 Ugbene-Ajima Community

The people of Ugbene-Ajima community generally know the blackfly,

Simulium, locally called "Nta akptirike" but it is not common in their community.

As a result not many school children know it. It is found mainly in the farms and 121 bushes. It is more common during the dry season and early rains. The blackfly bites more in the morning and evening periods than in the afternoon. They are not aware of where it breeds. The blackfly bites everybody and on all exposed arts of the body.

However, the people do not associate the bites with any disease. There is no particular way of preventing the black.fly bites except by killing those caught biting and by covering the body.

The people of the community also know onchodennatitis locally called "Etu" and do not know what causes it. The younger people think it is caused by poor hygiene while some elders believe it is caused by certain herbs when they touch the body. They generally believe it can be transferred from one person to another either through contact or from parents to children. The young people believe onchodermatitis can be prevented by avoiding contact with infected persons but the elders believe it cannot be prevented. It can be cured by the use of local herbs given by native doctors. Generally, the people of Ugbene-Ajima do not know any drug used for the treatment of oncho-rashes.

Ugbene-Ajima people know the Onchocerca nodule locally called "Akpu".

Most people, especiallyCODESRIA-LIBRARY young people, do not know the cause but the elders believe that it is caused by the presence of onchodermatitis. The nodule cannot be prevented but can be cured by removal in chemists, health centres or government hospitals.

The drug for its treatment is not known. Apart from the association of nodules with rashes, there is no association of either nodules or rashes with any other disease 122

although the leopard skin 1s well known m the community and locally called

"Akpaara".

4.3.4.4 Nrobo Community

In Nrobo community, primary and secondary school children do not know the black.fly but the elders know it. The black.fly is locally known as "Nta akpurike" and the elders agree that it is not abundant i1~ their community. It is mostly found in the farms and during the morning hours. It is also more common in the rainy season.

The black.fly bites everybody and on all exposed parts of the body. The people do not associate the bites of the black.fly with any disease. There is no means of preventing the fly bites except by killing perched ones.

Every group interviewed knows onchodermatitis locally called "Etu" but they do not know the cause. They believe it is contagious and can be prevented by avoiding contact with infected persons. Onchodermatitis, according to them, can be cured by the use of local herbs. The people. are not aware of any drug used for its treatment.

The people of the community also know the Onchocerca nodule locally called "Akpu".CODESRIA-LIBRARY They neither know the cause nor how to prevent it but it is commonly cured by nodulectomy in their health centres or government hospitals.

The elders are aware that oncho-rashes and nodules go together but they do not know any connection between them and any other disease including leopard skin which is well known in the community and locally called "Akpaala". 123

4.4 Discussion

The studies on the local disease perception and treatment reveal a high level of ignorance of the aetiology of onchocerciasis in the 16 communities that make up

Uzo-Uwani local govenunent area of Enugu State, Nigeria. All of these communities are aware of the presence of the blackfly and its nuisance in terms of its bites but they are not aware that the bites are associated with any disease.

Consequently, there is no serious effort to prevent them from biting. It was also observed that the black:fly is not equally abundant in all the communities and that the abundance of the black:fly in a community is closely related to the level of its knowledge in that community especially among the younger members of the community, for example, the three communities where the primary and/or secondary school children did not know the blackfly (Asaba, Nrobo and Ugbene-Ajima) were also the communities in which their elders accepted that the Simulium flies were not abundant. When compared with studies on the prevalence of onchocerciasis

(Chapter 3), it was observed that the abundance of the blackflies in a given community coincides, to a large extent, with the prevalence of onchocerciasis in that community. TheCODESRIA-LIBRARY communities where the blackfly is claimed not to be abundant and not well known, at least among the younger members of the communities, had the least manifestations of the disease especially among the youth, for example, at

Asaba, Nrobo and Ugbene-Ajima. The fact that the blackfly bites everybody implies that in every community where Simulium flies exist and especially where they are 124

abundant, everybody is at the risk of infection with Onchocerca volvulus. This

means that every inhabitant of Uzo-Uwani local government area, especially in the

11 communities where the blackflies are claimed to be abundant, have the possibility

of developing onchocerciasis in their life time. Again, the fact that the blackfly bites

on all exposed parts of the body means that the greater the area of the body exposed,

the greater the man-fly contact and so the greater the risk of getting Onchocerca

volvulus infection.

Every community m Uzo-Uwani local government area knows

onchodermatitis ( oncho-rashes) called various names in different communities. It

was observed that the communities in the same health district tend to use ·similar

names to describe these manifestations (Table 4.1 ). Except in a few communities

whose elders believe that these rashes result from the presence of nodules, majority

of the people of Uzo-Uwani local government area attribute onchodermatitis to various causes such as dirty habits or poor hygiene, charms etc while many do not have any idea or opinion about the cause. Because of this erroneous belief, most people of this area think that onchodermatitis can be passed from one person to another throughCODESRIA-LIBRARY either direct body contact or through common sharing or use of personal materials such as towels, bedsheets, clothes, etc. They wrongly believe also that it can be prevented by avoiding contact with infected persons. These wrong beliefs are at the root of the discrimination practised against people with onchodern1atitis in many of these communities. The people believe onchodermatitis 125

can be cured either by use of local herbs, medicated soaps or drugs but they have no

idea of the drugs used for its treatment.

The Onchocerca nodule is also generally known in Uzo-Uwani local

government area and called by various names in different communities. The cause

of the nodule as well as any means of its prevention are not known by the

communities. The gereral curative measure for the Onchocerca nodule in Uzo­

Uwani local government area is removal of the nodule (nodulectorny). This is done

either by local excisors or by medical personnel in health posts, health centres or

government hospitals. According to the people interviewed, what determines where

one goes for treatment of nodule or oncho-rashes is the amount of money available

to the persons. Most members of the communiti~s know that private hospitals may

give better medical care but they cannot afford the cost of treatment. As a result,

they go to either local excisors, patent medicine dealers or health centres for

treatment. The people do not however, know any drug used in the treatment of

Onchocerca nodule.

Although leopard skin is common in all the communities studied, no community studiedCODESRIA-LIBRARY knows of any connection between such a manifestation and any other manifestation of onchocerciasis. They attribute leopard skin to old age or inheritance. Apart form itching, leopard skin is not a source of problem in the communities. It does not hinder them from doing their normal duties neither is it an object of discrimination. 126

As mentioned earlier, ignorance is at the root of most of the beliefs

concerning the manifestations of onchocerciasis. Another area of ignorance is in the

treatment of these manifestations. In Uzo-Uwani local govermnent area, it is not

generally believed that the nianifestations are caused by gods or enemies and so

people do not resort to appeasing gods and enemies as reported by Edungbola

(1982); Edungbola et al (1983), Edungbola and Asaolu (1984) and Nwoke et al

(1992). Yet, due to ignorance of the aetiology of onchocerciasis, people with such

manifestations do not take the right treatment for their infection. In Uzo-Uwani local

government area, as well as other endemic areas in the nation, the Ministry of Health

in collaboration with World Health Organization (WHO) and Non-governmental

Developmental Organizations (NGDO), have been distributing ivermectin

(Mectizan) since 1996 under the Community Directed Distribution Programme

(CDC) of African Programme for Onchocerciasis Control (APOC). Inspite of this programme, most people of Uzo-Uwani local government area, apart from few teachers, health officers and the Community Directed Distributors, have no idea of any drug used for treating onchocerciasis or its manifestations. Even those taking the ivennectin doCODESRIA-LIBRARY not know the disease for which they are taking the drug. Although ivermectin is supposed to be taken for about 10 years without break, many people in this area refused to take it after the first experience because of some observed side : ·1 effects. As far as such people are concerned the drug causes disease. They feel more at home with the manifestations of onchocerciasis than with the side effects resulting 127

from the treatment. The side effects are such that in two communities (Adaba and

Nkpologu), few people (I and 3 respectively) died from excessive swelling after

taking the drug as a result, many people prefer to live with the disease than to die for

treating it. It should be noted, however, that the root cause of the deaths is

ignorance. Some people, such as those with respiratory problems like tuberculosis

and asthma, who are not supposed to take the drug take it and others drink alcohol

(which should not be taken) after taking the drug, all due to ignorance. In one

community (Uvuru), there is propaganda that the aim of the drug is to reduce the

population of their community and so many people refuse to take it.

As mentioned earlier, one other problem that hinders people from taking the

right treatment for onchocerciasis is poverty. Many people cannot afford to go to

good hospitals to be treated even when they know that they can be treated. Most

people testify of people that went to good hospitals and were cured of their

manifestations, especially onchodermatitis which is most dreaded but there are other

people suffering from the same manifestation in the same locality. Some of such

people, due to poverty, go to herbalists and patent medicine dealers who are not in a

good position toCODESRIA-LIBRARY help them.

4.5 Summary and Recommendations

From the results reported in this Chapter, the people of Uzo-Uwani local

government area know the black.fly but do not associate the bites with any disease.

· They also know the manifestations of onchocerciasis but they do not know the cause. 128

They attribute them to various causes such s poor hygiene, inheritance, old age and

sometimes charm. Because of ignorance and poverty, the people do not take the right treatment for these manifestations. Even the choice drug for onchocerciasis treatment, ivermectin, that is being distributed free of charge in the local govenunent area is not taken by many people because of fear and misconceptions.

From their responses, it is obvious that the people are aware of both the diurnal rhythm and seasonality of the black.fly/human contact. Their major problem is inability to associate the bites of these black.flies with the various manifestations of onchocerciasis, probably as a result of the long period between infection and manifestation of the various effects of the disease (1-3 years). With this knowledge, it appears that the most relevant intervention strategy required in this area at the moment is enlightenment. This enlightemnent programme can be planned to educate them on the following:

(i) The association between blackfly bites and infection with Onchocerca

volvulus.

(ii) The length of time taken for the infection to produce the vanous

CODESRIA-LIBRARYobservable manifestations.

(iii) The fact that onchocerciasis manifestations are not contagious. This

will remove the social stigma associated with such manifestations

especially rashes. 129

(iv) The importance of taking iverrnectin once a year for at least ten years

in order to eliminate the reservoir in man. This will mean that even

when the black.fly bites man, there will be no transmission of the

parasites.

(v) The safety of ivermectii1 if taken according to the laid down

guidelines (e.g. no alcohol intake, no previous history of respiratory

or heart disease etc ).

To encourage them to take the drug, emphasis should be laid on the apparently insidious manifestations of the disease but on the ultimate effect which is blindness and on the fatal effect of blindness on their future generations.

To implement this enlightemnent programme, use will be made of the already existing Community Directed Distributors (CDDs) who are selected members of the individual communities, mostly teachers, trained by World Health Organization

(WI-10) under the African Programme for Onchocerciasis Control (APOC) for the distribution of ivermectin. These people will work hand in hand with the primary health care units in the various communities. It is recommended that WHO, in collaboration CODESRIA-LIBRARYwith the Ministry of Health· and Non-governmental Development

Organizations (NGDO) remunerate these CDDs who have, hitherto, been left to be remunerated by their individual communities. It was found out during the study that most communities do not give them even transport money to go to the headquarters and collect drugs. As a result, most of them, though willing to work, are frustrated, 130 and may often skip the opportunity to continue the service. Cost recovery as suggested by Amazigo et al (1998) and Hopkins (1998) may also be a way of helping to sponsor these CDDs. This involves payment of a token amount by each treated family.

It is also recommended that in addition to the distribution of ivermectin and the enlightenment campaign, WHO should encourage and sponsor nodulectomy as treatment method for the Onchocerca nodule in this local govenm1ent area. The only known hindrance is the cost of removal. When the researchers sponsored the exc1s10n of nodules at Ukpata community, many people were willing to submit themselves.

CODESRIA-LIBRARY 131

CHAPTERS

STUDIES ON THE EFFECTS OF HUMAN ONCHOCERCIASIS ON

PRODUCTIVITY AND .. SOCIAL LIFE IN UZO-UWANI LOCAL

GOVERNMENT AREA OF ENUCU STATE

5.1 introduction

H has been severally reported that the socio-economic impact of human onchocerciasis is very serious (Hamon and Kartman, 1973; WHO, 1973; Bradley,

1976; Vajime, 1982; Nwoke, 1992). Onchocerciasis is a debilitating disease. It rarely leads to death directly but when it results in death, the infection cuts off the individual's supply of labour years in the future (WHO, 1973). As a result of debilitation and blindness, the infected person is unable to maintain for long any type of productive activity. Incidentally, onchocercal blindness is mostly found among

Ao the working age groups and so such permanent disability through blindness. or visual impairment withdraws the affected individual's potential supply of labour years requiring vision (Nwoke, 1992). In the study by Bradley (1976) in the middle Hawal valley of Northern Nigeria, he reported that many villages around River Hawal were deserted and theCODESRIA-LIBRARY villages lie very close to the River Hawal which serves as breeding sites for Simulium flies. He reported that the role of onchocerciasis in this desertion of the villages seemed to be through attrition. Normal village life and development are slowly reduced and although onchocerciasis is responsible for some emigration, the principal effect appeared to be in deterring immigration. Those outside the most 132

severe areas loathe to live, farm or even visit the villages within the riverine zone.

Young people move to nearby villages in search of better health and educational

facilities. Village diminution thus continues until a critical stage in ecological

. ~ balance is reached when the remaining inhabitants mostly the older age groups with

varying degrees of incapacitation are no longer able to protect their farms and

domestic animals from the ravages of wild animals (Bradley, 1976). The implication

of this is that community productivity is seriously affected. Records show that in

areas of high prevalence rates, there also occurs visual impairment often resulting in

blindness. The blind are usually poverty stricken and have a lower life expectancy

than normal people (Vajime, 1982). Hamon and Kartman (1973) summarized the

socio-economic impact of onchocerciasis as follows: blindness in 20 % of the adult

males reduces fanning capacity below survival level, fertile river valleys become

overcrowded with accompanying socio-economic consequences, fishing in infested

rivers is avoided leading to loss of protein and the cost of protecting personnel

engaged in developmental activities such as building dams becomes very high.

The itching and rashes associated with onchocerciasis can cause senous scratching whichCODESRIA-LIBRARY can be so severe as to cause loss of sleep. The various skin changes associated with the disease such as papular eruption, hypopigmentation and scaling, oedema and depigmentation have distressing effects on the life style of infected individuals, ·sometimes constituting destitute (Nwoke, 1986; Nwoke et al,

1987). In some severe cases, malformations of the genitalia occur. These dreadful 133 malformations nearly always result in the affected individual's unwillingness and shyness towards a free social interaction within his or her locality. In the affected patients with pendulous sacs, sexual life is greatly affected if not completely hindered (Nwoke, 1986). Amazigo and Obikeze ( 1991) in their study of effects of onchocerciasis manifestations among adolescent girls at Ette reported that there is social stigma attached to the presence of these manifestations especially rashes. In a study by Hagan ( 1998), he also reported that reactive onchocercal dermatitis and troublesome itching were an important cause of stigma in most endemic communities, those affected suffering from poor self-esteem. These rashes lead to severe itching and scratching which cause absent-mindedness in some infected individuals and sometimes may lead to complete absenteeism from work. This severe itching that often accompanies onchocercal dermatitis may reduce the period lactating mothers breast-feed their babies (Amazigo, 1994). Non-ocular onchocerciasis has a serious negative impact on work productivity (Workneh et al,

1993).

In this study, various ramifications of the effects of human onchocerciasis on productivity wereCODESRIA-LIBRARY investigated. These include the effect of disease on academic performance of the secondary schools in Uzo-Uwani local ·government area in standardized external examinations using Junior Secondary School Certificate

Examination (JSSCE) as an example and the effect of the disease on the productivity of farmers in terms of input (i.e. work time or number of working hours put in) and 134 labour output (i.e. labour efficiency or the amount of work done per working hour).

An attempt was also made to quantify the economic losses as a result of the disturbance by Simulium flies with the associated itching and scratching at work.

Also different aspects of the effects of onchocerciasis on the social life of the people of Uzo-Uwani local government area were studied. These include the effects of the manifestations of the disease on social interactions between infected and uninfected individuals, the effects on the age at which infected young individuals get married and the effects on manied life, if any.

5.2 Materials ai1d Methods

5.2.1 The Study Area and Study Population

The study area is Uzo-Uwani local government area as described earlier. For the study on the effects of the disease on pro.ductivity, the study population consists of all the twelve secondary schools in the local government area namely Boys'

Secondary School, Akiyi Unrnlokpa; Girls' Secondary School, Umulokpa; Attah

Memorial High School, Adaba; Community Secondary School, Ukpata; Uvuru

Secondary School, Uvuru; Adada Secondary School, Nkpologu; Uzo-Uwani

Secondary School,CODESRIA-LIBRARY Adani; Community Secondary School, lgga; Community

Secondary School, Ogurugu; Community Secondary School, Nimbo; Community

Secondary School, Abbi-Ugbene and Community secondary School, Nrobo. Also elders from one of the most endemic communities in the local government area,

Nkpologu, formed part of the study population. ii'.

135

For the studies on the effects of onchocerciasis on social life, the study

population consists of the inhabitants of the 16 communities that make up Uzo- . . Uwani local government area also described in Chapter 2.

5.2.2. Data Collection Methods

For the study on the effects of onchocerciasis on academic performance of

secondary schools, five-year (1994 -1998) Junior Secondary School Certificate

results for the twelve secondary schools in Uzo-Uwani local government area were

collected from Examinations Development Centre (EDC) Enugu, for analysis to

check for any dependence of school academic performance on prevalence of various

manifestations of onchocerciasis namely pr~sence of rashes, presence of palpable

nodules and presence of visual impairment. In addition, a few students and teachers

were interviewed on their perception of the effects of the various manifestations

investigated on the performance of school children.

For the studies on the effects of human onchocerciasis on the productivity of

farmers, twenty .farmers comprising eleven males and nine females showing signs of

onchocerciasis were interviewed using a semi - structured interview schedule for the various ways CODESRIA-LIBRARYSimulium flies and manifestations of onchocerciasis disturb their farm work in terms of labour input (amount of work time) and labour output (amount of work done per unit time). 136

For the studies on the effects of onchocerciasis on social life, the data

collection methods were the same as for the studies on local disease perception and

treatment (Chapter 4).

5.2.3 Data Analysis.

For the analysis of the data on the effects of human onchocerciasis on school

academic performance (i.e. the JSSCE results), a weighted average performance was

calculated for each school for the 5 - year period under consideration using seven

core subjects namely English Language, M,athematics, Integrated Science, Social

Studies, Religious and Moral Education, lgbo and Agricultural Science (see

Appendix 3). The examination scores for each of these subjects were weighted as follows: A was assigned 6 points, C had 4 points, P had 2 points while F had zero point. Graphs of school performance against the various indices of onchocerciasis mentioned above were plotted to check if there was any general trend. For a more quantitative result, a linear regression analysis was performed for the relationships between performance and the different variables - rashes, palpable nodules and visual impairment.

For theCODESRIA-LIBRARY effects of onchocerciasis on the productivity of farmers, the responses to the various questions on the interview schedule were analysed using siri1ple percentages. An estimation of the economic losses incurred as a result of Simulium bites and associated itching and scratching was attempted. 137

For the effects of onchocerciasis on social life the opinion of the majority both from the questionnaire and the interviews was taken as the opinion of the people.

5.3. Results and Observations

5.3.1. Studies on the Effects of Human Onchocerciasis on Academic Performance

The effects of human onchocerciasis on academic performance of students in the study area are shown in figure 5.1. From these, it is obvious that some and not all aspects of onchocerciasis affects academic performance in this study area. For example the scatter diagram in figure 5.1 shows that the presence of rashes is not correlated with performance with correlation coefficient r - 0.014. On the other hand, the figure shows a mild positive correlation (r - 0.36) between performance and prevalence of palpable nodules. However there is a strong negative correlation between performance and visual impairment with r - -0.72.

5.3.2. Effects of Human Onchocerciasis on Productivity of Farmers

Out of twenty elders between the ages of 30 and 70 years comprising 11 males and 9 females interviewed, all were married and all except one woman

(teacher), hadCODESRIA-LIBRARY farming as their major economic activity. The teacher also farms. Out of the sample, 9 people (45%) comprising 4 men and 5 women had palpable nodules while 10 people (50%) made up of 8 men and 2 women, had visual impairment but none was totally blind; 2 women (10%) had rashes while 7 people (35%) comprising

6 men and 1 woman had leopard skin. All the people with leopard skin were above 45

• Rashes X1 40

• Visual impairment X2 6. VISUAL IMPAIRMENT 35 b. Nodules X3 · y = -52.751x + 130.03 R2 = 0.5221 ,,, c: 30 0 : NODULES :.:; ro y = 46.633x - 88.058...... 2 1/) R = 0.133 ....~ 25 s:: ·' I ra I E I ......

;• r, ~· • • / • ...... , 10 / / • - CODESRIA-LIBRARY------Ii - . \ 5 -- ; '.',,.; 6 • • ~ 0 I · --- ··- ·-,-- --···-- ·--,···.-•----,------•. ,--- .. ·,--· 2 2.05 2.1 2.15 2.2 2.25 2.3 ---- ,·--. -' --•~J 2.35 2.4 2.45 2.5

Performance ., ':';,.

Figure 5.1 Performance against onchocercal " ... '; manifestations 139

50 years. Almost all the respondents (75%) claimed to go to farm for 6 days in a

week (only Sunday excluded) while the others go to farm between 3-5 days in a

week; 85% of the respondents start work in their farms between 7.00 and 8.00 in the

morning. Most of the people (75%) leave the farm between 1.00 and 3.00 p.m.

especially women (89%). Those who stay till evening (up to 6.00 p.m.) usually go

on break between 12.00 and 1.00 p.m. and stay for about 30 minutes to one hour

resting under a shade or in a farmhouse. Concerning the period of maximum bite of

Simulium flies, most men (90%) believe that it is during bush clearing while most

women (78%) think that it is during weeding of the farms. While in the farms, most

men (73%) cope with the bites of the blackfly by killing them or chasing them away

while most women (89%) cope with the bites by wearing clothes that cover their

bodies. On how many hours lost during farming as a result of disturbance fro1n

Simulium flies and the associated itching and scratching all the respondents agreed

that they usually lost about one hour. They believe that they cultivate less than their

full capacity as a result of such disturbance. Consequently it is expected that their crop yields willCODESRIA-LIBRARY also be reduced, other factors being constant. On the effects of the manifestations of onchocerciasis on their work output, they reported that the most

disturbing manifestation is impaired vision. Other forms of disturbance include body pains, for example one of the male respondents who had multiple nodules on the hip complained of waist pain which had almost demobilised him from fannwork. The other disturbing manifestations are itching and scratching, arising from either rashes, 140

leopard skin or Simulium bites, which make them lose some work time. However,

except one is blind, the disease does not stop them from going to farm but reduces

the amount of work they can do within their work time (work output or work

efficiency) and the quality of work done such as mistakenly uprooting crops in place

of weeds as a result of impaired vision.

The average daily wage for hired labour at Nkpologu is W300.00 and the

hired labour works in the fatm for about 6 hours. This brings the wage to W50.00 per

man-hour. Assuming one hour is lost per working day as a result of disturbances

from blackfly bites, itching and scratching, this amounts to W50.00 a day. For the

farming season which spans through a minimum of 5 months in a year, there will be

a minimum loss of 26 man-hours every t'nonth and 130 man-hours in the farming

season per individual. This will amount to an average loss of 21.7 man-days (at 6 hours/man-day) equivalent to W6, 500.00 for a farmer in a year. When this is projected for all the farmers in the community, if will be seen that the loss is really . ' enormous. 5.3.3 EffectsCODESRIA-LIBRARY of Human Onchoccrciasis on Social Life The results of the studies on social life of people of Uzo-Uwani local government area are presented in this section. It was found that although some beliefs and attitudes were similar, there were slight differences between communities. Majority of the communities were found to show slight discrimination against people with onchocerciasis manifestations especially rashes. Other 141 manifestations did not attract such social stigmatization. Young girls, in particular, with rashes do not many early and they are limited in their choice of marriage partners to old men, divorced, widowed, childless men etc. The discrimination against these young girls result in their being timid and whenever they must come out to the public, they cover their bodies well with their clothes. If they are fortunate to cure themselves of these rashes early in life; the stigma on them is totally removed. For infected men, the effects are not as much because of the belief that the wealth of a man is his beauty. In general, in every community, it was found that the development of onchocerciasis manifestations after marriage had no serious effect on the marriage. The preoccupation of the couple is usually how to cure the ailment.

These manifestations at this stage do not lead to either separation or divorce. In a few cases, however, it may lead to a second marriage. Communities in the same health district tend to have similar beliefs and attitudes. The effects of onchoocerciasis on social life are presented below according to health districts.

5.3.3.1 Umulokpa Health District: made up of Umulokpa (headquarters), Nkume,

Adaba and Ukpata.

A. Effects CODESRIA-LIBRARYon Social Interactions

There is no general consensus as to whether or not there is social discrimination against people with onchocerciasis manifestations in this zone. Two of the communities (Umulokpa and Adaba) believe that persons with oncho-rashes, in particular, are discriminated against while Nkume and Ukpata people believe that 142 there is no such discrimination. The four communities, however, accept that such people feel ashamed and try to cover themselves in public gatherings.

B. Effects on Age of Marriage

The four communities in this zone agree that onchocerciasis manifestations, especially rashes, affect the age at which infected persons get married. This is particularly so with girls. Although such manifestations do not hinder them completely from getting married, it limits their choice of marriage partners to elderly men, poor and illiterate men, polygamous men, disabled men etc. However, if the rashes clear before man"iage the girl still has a chance of marrying any man of her choice

C. Effects on Manried Life

Once married before the incidence of onchocerciasis the couple resorts to treatment of the infected partner. It does not affect their marital relationship and never leads to separation or divorce. Sometimes, however, a young man may marry another wife for purposes of social outings. The priority of such couples is to seek medical treatment for the infected partners. Clearing of the rashes removes all temporary problemsCODESRIA-LIBRARY arising from their presence.

5.3.3.2 Nkpologu Health District: consisting of Nkpologu, Uvuru and Akpugo.

A. Effects on Social interactions

Apart from the youth in Nkpologu community all the people of this district believe that there is no discrimination against persons with onchocerciasis <" r 143 I manifestations. All the people, however, generally believe that such infected people

feel ashamed and do not freely associate closely with non-infected persons. They try to cover their bodies whenever they appear in public.

B. Effects on Age of Marriage

The majority of the people of Nkpologu district believe that persons with onchocerciasis manifestations, especially rashes, marry later than their non-infected counterparts. This is worse with girls than with men. Although such girls are not completely hindered from getting married, they marry old men, married men and disabled men. This disadvantage lasts as long as the rashes are present, but once the rashes clear, the limitation is removed. The elders of Akpugo, however, believe that such effect does not exist. According to them, marriage is ordained by God and who one marries is a matter of desti11y.

C. Effects on Married Life. The married people believe that onchocerciasis manifestations have no significant effect on marital relationships. They do not result in separation, divorce or polygamy. The priority of the couple is usually to get a cure for the infected partner.

5.3.3.3 Ogboli CODESRIA-LIBRARYHealth District: comprising Adani, Asaba, Igga, Ojjor and Ogurugu.

A Effects on Social Interactions

Majority of the people of Ogboli district believe that there is social discrimination against individuals with onchocerciasis manifestations, especially rashes. People tend to avoid close contact with such infected persons thereby making 144

them ashamed and withdrawn. The people with ashes either avoid appearing in

public or try to cover their bodies with long-sleeved clothes and long wear. However,

elders from Adani and Ojjor communities think that there is no such discrimination.

B Effects on Age of Marriage

The people of Ogboli health district generally believe that onchocerciasis manifestations, especially rashes, affect the age at which men and ladies get married.

Girls are paiticularly delayed. The presence of rashes can eventually stop a girl from getting married but even where it does not,· it affects their option of life partners.

They tend to marry partners that would otherwise have been unsuitable for them such as elderly men, childless men, widowers and divorcees.

C Effect on Married Life

The people of Ogboli district generally believe that the presence of onchodermatitis and nodules do not affect marriage to the extent of separation or divorce. They can however, sometimes affect marital relationships and lead to marrying a second wife. The couples usually seek treatment for the infected partner.

5.3.3.4 Nimbo Health District: made up of Nimbo, Abbi, Ugbene-Ajima and

Nrobo. CODESRIA-LIBRARY

A Effects on Social Interactions

The people of Nimbo health district believe in general that individuals with onchocerciasis manifestations are socially discriminated against. The elders of

Nimbo community, however, believe that there is no such discrimiriation. Such 145

infected persons, according to majority of the people, feel ashamed and hide their

bodies with their wears and seek for a cure.

B Effects on Age of Marriage

All the communities in this district agree that people with onchocerciasis manifestations do not marry early. Girls are particularly affected. Although it does not stop such girls from getting married eventually, it limits their choice of marriage partners to elderly men and previously married men.

C Effects on Married Life

The four communities that make up this health district agree that onchocerciasis manifestations can limit the level of relationship between married partners but do not usually lead to separation or divorce. It can, however, lead to an out-going man marrying a second wife for social outings. Nevertheless, the main preoccupation of the couple is to seek treatment for the infected partner.

5.4 Discussion

Different aspects of the socio-economic impact of onchocerciasis have been previously rep01ied such as male sterility (Hughes, 1954 cited by Budden, 1956), habitual abortionCODESRIA-LIBRARY (Ikejiani, 1954), desertion of fertile riverine areas and overpopulation of less fertile uplands (Hamon and Kartman, 1973; Bradley, 1976), distorted population distribution as a result of emigration from endemic areas jeopardizing family life and the usual division oflabour (Vajime, 1982), lowering of farming capacity below survival level due to blindness, difficulty of fishing in 146

infected rivers (Hamon and Kartman 1973), high cost of caring for the disabled and

perso1rnel involved in developmental activities such as building of dam (Vajime,

1982) and social discrimination against infected persons (Amazigo and Obikeze,

1991 ). According to Vajime (1982), the socio-economic consequences of chronic ill health, depopulation and loss of fertile, agricultural land are of fundamental importance.

In the present work, two aspects of the effects of the disease on productivity have been studied. These include the effects on productivity of farmers and the effects on academic performance. Also three aspects of the effects of onchocerciasis on social life have been investigated. These include the effects on social interactions between infected and uninfected individuals, effects on the age at which infected individuals get married and possible effects on married life.

5.4.1 Effects of Human Onchoccrdasis on Academic Performance

In this study, it is assumed that performance of school children in the study area depends largely on the prevalence of onchocerciasis in their various communities. CODESRIA-LIBRARYThis is a reasonable assumption considering the debilitating effects of the disease especially as it relates to itching/rashes and ocular impairinent in the highly endemic areas. It can be acknowledged also that socio-economic environment, quality of teachers/students and available infrastructure such as laboratory, library and boarding facilities are other potential factors which may affect school performance. However, the communities in the study area are largely rural 147 communities whose major economic activity is farming. They have rivers, streams and/or springs as their major source of water, and with the exception of Adani, all the communities have no electricity. It can thus be said that these communities have similar socio-economic environment which is likely to influence school performance in approximately the same way. For teachers, the minimum qualification for teaching in secondary schools is Nigerian Certificate of Education (NCE). Subject specialization is important at the Senior Secondary level but not critical at the Junior

Secondary School (JSS) level being used for this study (except for Introduction

Technology and elective courses such as Business Education, Fine Arts, Home

Economics which were not included in the sh.1dy). The quality of teachers, therefore, should be considered very similar in the communities. On the availability of infrastructure, aU the schools are day schools without boarding facilities. Other facilities such as laboratories are of siniilar standards. It should be expected that these infrastructures would affect students' performance in a more or less similar way. It should be noted also that the JSS results used in the present analysis spanned

5 years and provided as large a sample size as possible so that dispersion of the distributions wouldCODESRIA-LIBRARY be smoothened out as much as possible. Besides, the standardization of the results is expected to i·educe further any residual dependence of performance on individual student's ability.

The results of the studies on the effccts of onchocerciasis on school academic performance in a standard examination (JSSCE) showed that onchocerciasis 148 manifestations, especially visual impairment, have profound negative effect on school performance. The results of the regression analysis showed strong inverse correlation (r = -0. 72) between performance and visual impairment. The implication of this is that the higher the prevalence of visual impairment in a school, the poorer the performance. On the one hand, the presence of rashes (onchodennatitis) had a weak negative effect on performance (r = -0.014). The presence of palpable nodules, on the other hand, had no adverse effect at all on the school performance (r=0.36).

The result of this study is very significant because it has been reported by many authors (Hamon and Kartman, 1973; WHO, 1973; Bradley, 1976; Vajime,

1982; Nwoke, 1990, Nwoke, 1992) that visual impairment and blindness are the most serious manifestations of onchocerciasis but the reports have been mostly on their effects on farming in particular. The present result has shown that the problem of impairment of vision is as important in academic performance as in other occupations. The result is also supported by the responses from school children and teachers interviewed during the study that the most serious manifestation of human onchocerciasisCODESRIA-LIBRARY as far as the teaching/leaming process is concerned is visual impairment. The presence of rashes gives some discomfort through itching and scratching which can result in lack of concentration while the presence of palpable nodules is not directly disturbing except through the resultant rashes followed by itching and scratching. 149

5.4.2 Effects of Human Onchocerciasis on the Productivity of Farmers

Human onchocerciasis seriously hinders economic activity especially in areas that are mainly agricultural (Hamon and Kartman, 1973; Bradley, 1976; Nwoke,

1990; Nwoke, 1992). According to Nwoke ( 1990), onchocerciasis affects the effective supply of labour in three ways (i) as a cause of death, it removes the individual's supply of labour years in the .future (ii) as a result of permanent disability through blindness and serious visual impairment onchocerciaiss withdraws the individual's potential supply of labour years to activities requiring vision and (iii) paiiial visual impairment and/or other non-disabling manifestations may also reduce the efficiency of labour days worked. Aiso WHO ( 1973) reported that as a result of so many people suffering from onchocercal blindness, there is loss of a huge number of potential working days. The present study on the effects of human onchocerciasis on the productivity of farmers confirms these observations. Kim et al (1997) reported that the human toll of the disease is devastating due to high numbers of blind and the constant itching which affects productivity. Infected persons have difficulty tending to their jobs. CODESRIA-LIBRARYAccording to the report, a recent study at Ethiopia's second largest coffee plantation revealed that those infected with onchocercal skin disease (OSD) were 15% less productive than those not infected. Additionally, when the head of a household has severe OSD, the risk for a child to stop attending school is twice as high. People who become blind due to onchocerciasis die 12 years prematurely, on average. Studies on the effects of other diseases such as malaria on productivity 150

(Eboh and Okeibunor, 1997) also showed that the work time and efficiency of labour

are adversely affected by such disease as a result of both morbidity (complete

disability) or debility (partial disability).

Onchocerciasis hinders economic actf vity especially farming in Uzo-Uwani

local government area in various ways such as disturbance by the blackfly vector of

the disease during farmwork, through itching and scratching caused by the blackfly

bites or by the presence of rashes alone or resulting from the presence of palpable

nodules, through body pains especially waist pain and through visual impairment and

blindness. According to the farmers interviewed, the most disturbing aspect of

onchocerciasis is impaired vision and blindness. Blindness hinders a person

permanently from agricultural activities and makes the person an economic liability.

This leads to loss of the affected individtial's potential supply of labour years

requiring vision as Nwoke (1992) reported. Serious visual impairment, on the other

hand, does not lead to complete disability (morbidity) from fannwork as blindness

but reduces the working efficiency of such a person and at times leads to counter­ production asCODESRIA-LIBRARY when a farmer removes crops in an attempt to remove weeds especially in rice-cultivating areas. Onchocerciasis therefore leads to both morbidity and debility resulting in complete loss of productive years and reduction in labour input (work time) and labour output or labour efficiency (amount of work per unit time) respectively. 151

As rep01ied in the results, the average daily wage for hired labour in the

studied community, Nkpologu, is W300.00 and the hired labour works for about 6

hours. The average wage comes to WS0.00 per hour. From the responses during

interviews, it can be estimated that most farmers lose an average of 1 hour per

working day as a result of disturbance from Simulium flies, itching and scratching of

the bites and the rashes. It means, therefore, that they lose on the average about W

50.00 every working day and for the 5 months of fanning within the year, each

farmer may be losing about 26 man-hours a month and 130 man-hours for the 5

months. This implies a loss of about 21.7 man-days equivalent to about W 6,500.00

per farmer per year. When this is calculate1 fo~ all the farmers in the community,

the economic losses from Simulium bites, itching and scratching could be enormous.

5.4.3 Effects of Human Onchocerciasis on Social Life

The results of the studies on the effects of human onchocerciasis on social life

showed that there is social discrimination against people with manifestations of

onchocerciasis especially rashes. This is similar to the results obtained at Ette also in Enugu State byCODESRIA-LIBRARY Amazigo and Obikeze (1991) in which they studied the effects of the disease on the social life of adolescent girls. In the present study, the results show that the effects are more serious on young girls and this is reflected in the fact that these young girls do not get married as early as their non-infected counterpmis because men tend to avoid them. The young men with rashes are less seriously affected because of the common belief in almost every community in Uzo-Uwani 152

local government area that the wealth of a man is his beauty. If a young man is

wealthy therefore, his wealth tends to overshadow his disabilities. These infected

young girls are subjected to perpetual unhappiness in life. This is due to the fact that

they are subjected to social discrimination while unmarried and because of this social

stigma, they are limited in their choice of marriage partners to men- that they would

ordinarily not have liked to marry such as elderly men, divorced, widowed, disabled

and childless men. Most likely, these men would treat them as second class citizens.

So throughout life, they suffer socially and emotionally for a problem that is no fault

of theirs and a disease that has a known treatment. The effects of the disease on

married life is not serious. The presence of onchocerciasis in one partner never leads

to separation or divorce but can lead to an outgoing man marrying another wife for

social outings. Onchocerciasis is, therefore, a disease that has many indirect effects

that may not be obvious at first sight, although these effects have long lasting

consequences.

5.5 Summary and Recommendations

Onchocerciasis is a disease of public health importance. In addition, it has

far-reaching socio-economicCODESRIA-LIBRARY implications. The results of the studies on the effects of

onchocerciasis on productivity show that the disease affects the productivity of

infected persons through its various manifestations. These effects show in terms of reduction in labour input or work time, labour efficiency or work output and consequently labour productivity of farmers. These reductions amount to huge (

153 econonuc losses when quantified. There is also a senous negative effect on academic performance. The manifestations of ondiocerciasis with the most profound negative effects on productivity of farmers and students alike are visual impairment and blindness. · Blindness completely withdraws the individual from any productive activity and serious visual impairment reduces the efficiency of work done. Other manifestations such as itching and scratching as a result of rashes or nodules or leopard skin together with Simulium bites and the subsequent itching and scratching also affect productivity and lead to some economic losses though to a lesser degree.

In terms of social effects, the most important manifestation is the presence of rashes which results in social discrimination against the infected persons. This discrimination leads to a feeling of shame on the part of the infected persons and prevents them from free social interactions within their locality.

Due to the enormous effects of onchocerciasis on the economic and social lives of rural communities which are mainly agricultural, it is important that more efforts be made in these endemic communities so as to reduce the adverse effects on the productivity of these rural dwellers who produce most of the food resources used to sustain the urbanCODESRIA-LIBRARY dwellers. It is notable that the World Health Organization under the African Programme for Onchocerciasis Control (APOC) in collaboration with

Non-governmental Development Organizations (Global 2000 for Uzo-Uwani local government area) has been undertaking free distribution of ivennectin in the area smce 1996 in order to reduce the reservoir in man. More effective distribution of I' 154 ~ ! this drug of choice against the disease will help to save many students and farmers from visual impairment which is the major factor that leads to low productivity. In addition, it is recommended that vector control be undertaken in order to reduce the disease prevalence and the economic losses resulting from their bites. It is also recommended that nodulectomy which is a generally accepted treatment procedure in the area should be sponsored by World Health Organization in collaboration with the Federal Ministry of Health and Non-Governmental Developmental Organizations

(NGDO) so that the disease can be attacked from all fronts and eradicated. As mentioned in Chapter 4, there is need for public enlightenment campaign on the effective use of ivermectin drug so that more people will accept the drug. In addition, people should be enlightened on the disease aetiology stressing the fact that the manifestations of onchocerciasis especially rashes are not contagious. These strategies will help to stem further damages on the health of the people, increase their productivity in agriculture and academics and free young people, particularly girls, from social stigmatization which ends them in perpetual frustration. CODESRIA-LIBRARY ... ,.._ ......

155

CHAPTER6

STUDIES ON THE EFFECTS OF MECTIZAN TREATMENT ON THE

HISTOLOGY OF THE NODULE

6.1 Introduction

The appearance of subcutaneous nodules is a conspicuous feature of human

infection with Onchocerca volvulus. The nodule contai11s the coiled up adult worms

amid a mass of chronic i1iflammatory tissue (Israel, 1959). Subcutaneous nodules

containing several mature filariae are found mostly on the hips, the iliac crest, the

ribs and other places where the skin and the underlying bone are close together. The

mature worms are usually trapped in these places during their subcutaneous

migration after which a fibrous nodule forms around them (Oomen, 1967).

According to Oomen, in some localities, all or nearly all infected subjects have

onchocercomas (nodules). Nodule formation is thought to be a result of

inflammatory reaction around migrating worms in subcutaneous tissue (Nnochiri,

1964b, Oomen, 1967). This may happen in some patients but not in others and it

may involve some but not all mature worms present. It may depend on various

factors such asCODESRIA-LIBRARY individual sensitivity to filarial antigen and the intensity and duration

of the infection (Oomen, 1967). Some nodules have been reported to be too deeply

located to be palpable and so escape detection (Nnochiri, 1964b ). Although nodules have been recorded within the first year of life, they begin to appear more commonly

in children of three years (Onuigbo, 1975; · WHO, 1999). With reference to the 156

location of nodules, Choyce (1972) reported that 2/3 of the nodules are found above

the waist in Central America and below that line in Africa and British Isles.

Many authors have described extensively the histology of the nodule. These

include Diaz (1957), Israel (1959), Nnochiri (1964b), Palomar et al (1976); Burchard

et al (1979), Omar et al (l 979), Buttner and Racz ( 1983) and Ezeasor (1986). Out of

these studies, three were carried out in Nigeria. Israel (1959) studied the histology of

Onchocerca nodules collected from onchocerciasis patients in Kaduna (savanna

zone); Nnochiri (1964b) studied onchocercal lesions including nodules in autopsy

specimens in Ibadan (rainforest zone) and Ezeasor (1986) studied the histology of

nodules from Achi (forest-savanna-mosaic zone).

In a cut nodule, many transverse and oblique sections of worms are seen.

The coelomic cavity of the female worm is filled with capacious uterine and ovarian

sacs full of developing embryos but in the male, the genitalia are less evident.

Around the worm segments are seen cellular fibrous tissue containing lymphocytes, plasma cells, eosinophils and other polymorphs. One of the most prominent features of nodules is the accumulation of large numbers of macrophages. Disintegrating worm segmentsCODESRIA-LIBRARY are covered by endothelioid histiocytes. Foreign body giant cells are also commonly found. In nodules with viable worms, the connective tissue usually contains variable numbers of microfilariae which appear to be derived from the living worms since they are absent in nodules with only necrotic mass (Israel, 1959;

Nnochiri, 1964b; Buttner and Racz, 1983). 157

Generally, without chemotherapeutic treatment, patients studied by

histopathology had nearly all the microfilariae intact. The reaction to dying and dead

microfilariae could only be investigated around those occasionally observed

microfilariae which probably died because they had reached the end of their span.

More frequently, the killing and the cellular reaction to the dead microfilariae was

studied in biopsies from patients treated with drugs especially diethylcarbamazine

citrate (Banocide) (Buttner and Racz, 1983). Mectizan (ivermectin) treatment results

in an initial unexplained increase in skin mic1:ofilariae (Richards et al, 1989; A wadzi

et al, 1989), but unlike in the treatment with diethylcarbamazine, the microfilariae do

not disintegrate in the skin but appear to migrate into the deep layers (Richards et al,

1989). Skin and ocular microfilaria counts are kept at very low levels for up to one

year. Mectizan though ineffective against the adult worms has a serious effect on the

adult female worms. Treatment with ivermectin (Mectizan) results in reduction in

the reproductive activity of female worms. This action is characterized by an intra­

uterine sequestration with subsequent degeneration of normally formed microfilariae,

resulting in their failure to reach the skin or eye (Awadzi et al, 1985).

ExcisionCODESRIA-LIBRARY of the onchocercal nodule is usually undertaken for three reasons.

Firstly, mass nodulectomy may be undertaken as a method of controlling the disease; secondly it can serve as a treatment method or in case of excision of head nodules as a precaution for reducing the risk of blindness in the individual patient (Anderson et 158

al, 1975; Fulsang et al, 1976; Kale, 1982a). Thirdly nodules can also be excised for

histopathological examination for evidence of drug activity against the adult worms.

In this study, the excision of the nodules is to aid histopathological studies in

order to assess the effect of ivermectin (Mectizan) treatment on the histology of the

nodules from onchocerciasis patients from Uzo-Uwani local government area of

Enugu State. Mass treatment with ivermectin has been on yearly basis in this area

since 1996 under the African Programme for Onchocerciasis Control (APOC).

6.2 Materials and Methods

6.2.1 The study Area

The study area is Uzo-Uwani local government area described in Chapter 2.

6.2.2 Nodule Collection and Processing

A total of thirty-four nodules were excised from Mectizan-treated

onchocerciasis patients from Ukpata in Uzo-Uwani local government area in March,

1999, by a health superintendent in the town's health centre. The sex and age of

each patient as well as the site of the excised nodules were recorded (Table 6.1 ). The

nodules were fixed in 10% formol saline. Twelve of the nodules were randomly

selected andCODESRIA-LIBRARY processed (see Appendix 4). Portions of the nodules were dehydrated

using absolute alcohol and embedded in paraffin wax. Sections of the embedded nodules were cut using microtome and stained with Ehrlich's haematoxylin and eosin for preparation of permanent slides (Israel, 1959; Palomar et al, 1976,). The slides were examined under the light microscope for histological studies. The results 159 were compared with previous work done in Achi (in the same vegetational zone) with nodules from non-Mectizan treated individuals. These sets of nodules were processed using the same method .

.6.3 Results and Observations

From Table 6.1 it is observed that most adults in Uzo-Uwani local government area harbour multiple nodules in sites around and below the waist. Only three persons out of 12 (25%) had nodules above the waist while the rest (75%) had nodules around and below the waist. Also, out of the 34 nodules excised, only 7

(20.6%) were from sites above the waist while 27 (79.4%) were from sites around and below the waist.

The nodules varied in sizes but were generally oval in shape but with protuberances and milky in colour (Plate 6.1): On examination, the sectioned nodule showed an outer and inner zone. The outer zone consists of loose connective tissue of collagen type containing fibroblasts. A lot of congested blood vessels containing only red blood cells as a result of outflow of other cell types from the vessels were also seen in this zone (Plate 6.2). The inner zone was marked by accumulation of infiltrated cellsCODESRIA-LIBRARY most of which were polymorphonuclear leucocytes. Also common were macrophages and foreign body giant cells (Plate 6.3). The centres of the nodule sections were occupied by worm sections cut transversely or longitudinally

(Plate 6.4). r · 160. r . I· . . I Table 6.1: Age-sex distribution and location of excised nodules in Mectizan- · ..

treated onchocerciasis patients. in Uzo-Uwani local government area .

S/No Sex Age Site of Excised Nodule . No. of Nodules

Male 22 Pubic area and thigh .4

2 Male 38 Waist 4

3 Male 23 .Waist 4

,, ,· i 4 Male 55 Waist 1 i ! ' 5 Male 26 Waist 4

6 Female 42 Waist . 1

-~ ' . 7 Female 40 Waist 4 !

8 Female · 22 Knee 1· .. " ·9 Female 43 Knee (2 ), chest (3) · 5

10 Female 50 Chest 1

11 Female 50 Hip 4

12 Female 44 Chest 3 CODESRIA-LIBRARY 161

CODESRIA-LIBRARY

Plate 6.1 The external appearance of nodules. 162

CODESRIA-LIBRARY

Plate 6.2 A section of nodule showing part of outer and inner zones. 163

CODESRIA-LIBRARY

Plate 6.3 A section of nodule showing congested blood vessel. 164 .

CODESRIA-LIBRARY

Plate 6.4 A section of nodule from untreated patient showing macrophages and foreign body giant cells. 165

These worm sections were completely surrounded by the infiltrated cells (Plate 6.5).

Interestingly, most of the uteri of the female worm sections from Mectizan-treated

I individuals were found to be empty containing no egg packets or microfilariae unlike the nodules from non-treated patients which had the uteri filled with egg packets and microfilariae at various stages of development (Plate 6.6 a & b, and Plate 6. 7 a & b ).

Another interesting difference between the sectioned nodules from Mectizan-treated and non-treated individuals was that many intact microfilariae were found within the connective tissue of non-M~ctizan treated individuals while these were completely absent in sectioned nodules from tl'eated individuals (Plate 6.8 a & b).

6.4 Discussion

The study of nodules from onchocerciasis patients in Uzo-Uwani local government area confirms earlier reports. In terms of nodule location, most of the patients (75%) harboured nodules at sites below the waistline while 25% harboured nodules at sites above the waistline. Greater number of nodules (79.1 %) was removed from sites below the waistline. This confirms the report of Choyce (1972) that 2/3 of nodulesCODESRIA-LIBRARY are found below the waistline in Africans. Similar observations have been reported in many parts of West Africa.

For the study of the histology of the nodule, there were obvious differences between Mectizan-treated and non-treated individuals. Generally, it was observed 166

CODESRIA-LIBRARY

Plate 6.5 A section of nodule from treated patient showing sections of worms surrounded by infiltrated cells. 167

CODESRIA-LIBRARY Plate 6.6a A section of nodule from untreated patient showing sections of worms containing egg packets and microfilariae.

Plate 6.6b A section of nodule from treated patient showing empty sections of worms. 168

CODESRIA-LIBRARY

Plate 6.7a A section of nodule from untreated patient showing sections of worms with egg packets and microfilariae.

Plate 6. 7b A section of nodule from treated section of worms. 169

CODESRIA-LIBRARY

Plate 6.8a A section of nodule from untreated patient showing free microfilariae in the connective tissue.

Plate 6.8b A section of nodule from treated patient showing no microfilariae in connective tissue. 170

that the uteri in nodule sections from Mectizan-treated individuals were empty in

contrast to uteri filled with egg packets and microfilariae in nodule sections from

non-treated individuals. In addition, intact microfilariae were observed in the

connective tissue of nodules from non-treated individuals while these were absent in nodules from Mectizan-treated individuals. These are pointers to the effectiveness of ivermectin (Mectizan) against the worms in the treated individuals. In trials of ivermecti,1 drug, Awaclzi et al (1989), Richards et al ( 1989) and Remme et al

( 1990b) reported that ivermectin treatment results in the disappearance from the skin of up to 90 - 97% of the microfilarial load. Skin and ocular microfilaria counts Were kept at very low levels for up to one year. It had also been reported that ivennectin, although ineffective against the adult worms has a serious effect against the adult female worms. The drug results in reduction of the reproductive activity of female worms and this action is characterized by an intrauterine sequestration with subsequent degeneration of normally formed microfilariae 1'esulting in their failure to reach the skin or eye (Awadzi et al, 1985). Buttner and Racz (1983) had earlier reported thatCODESRIA-LIBRARY without chemotherapeutic treatment, patients studied by histopathology had all the microfilariae nearly intact. Similar observations had been made by other researchers that studied the histology of the Onchocerca nodule. There were always a great number of microfilariae found near the adult worms and inside the uteri of the female worms (Israel, 1959; Nnochiri, 1964; Burchard et al, 1979; Omar et al, 1979;

Buttner and Racz, 1983 and Ezeasor, 1986). 171

In severe localized onchocerciasis, Buttner and Racz ( 1983) rep01ied that many dead and degenerating microfilariae were found in the nodule with few microfilariae in the skin. The frequency of dead microfilariae in the patients without any microfilaricidal treatment indicated that many microfilariae were killed by the host in the nodule. They suggested that these patients possibly possessed microfilaricidal activity and most of the dead microfilariae in the nodules were killed by an immune response of the host. In the present study, microfilariae were not found in the connective tissues of the sectioned nodules indicating the possibility that the microfilariae were actually killed inside the uteri of the female worms and degenerated there before coming into the connective tissue of the nodules.

6.5 Summary and Recommendations

A look at the distribution o_f the excised nodules showed consistently that a greater number of nodules were found on locations around and below the waist line in the people of Uzo-Uwani local government area. The study on the histology of the nodule showed that in Mectizan-treated individuals, microfilariae are absent both in the connective tissues of the nodules and within the uteri of the female worms pointing to the possibilityCODESRIA-LIBRARY that Mectizan attacks microfilariae within the uteri of the female worms. This strengthens the recommendation of ivermectin (Mectizan) as a control measure in onchocerciasis. 172

CHAPTER 7

STUDIES ON THE DAILY AND SEASONAL BITING PATTERNS OF

SlfifUL/UM DAMNOSUA1 {BLACKFL Y) (DIPTERA: SIMULUDAE) IN UZO­

UWANI LOCAL GOVERNMENT AREA OF ENUGU STATE

7.1 Introduction

Human onchocerciasis is a debilitating disease caused by the filarial parasite,

Onchocerca volvulus. The manifestations of the disease are mainly dermal, lymphatic and ocular, the most severe of which is blindness, hence the common name 'river blindness'. Dipterous insects of the family, Simuliidae transmit the parasite, Onchocerca volvulus. In West Africa, transmission is by members of the

Simulium damnosum (Theobald) species complex (Boakye; 1999). Simulium damnosum is made up of a complex of sibling species described on the basis of cytotaxonomic identification which depends on variations of the larval polytene chromosomes (Dunbar, 1966). The members of the Simulium damnosum complex can be classified into savanna and forest species according to their relative abundance in the climatic zones of West Africa and this largely depends on their preferred habitats.CODESRIA-LIBRARY Within each species, chromosomal variants or forms exist but only very few have been described (Boakye, 1999). Vajime and Dunbar (1975) recognized eight species within this complex from West Africa. Since the description of the members of the Simulium damnosum complex in West Africa by

Vajime and Dunbar (1975), there have been revisions of the specific status of some 173

of the species as well as the cytotaxonomy of various species. Currently nine species

of the Simulium damnosum complex have been ide11tified from the area covered by

the Onchocerciasis Control Programme from 1984 to 1993 and so far twelve

cytological segre&ates included in the nine species are recognized as members of

Simulium damnosum complex in the OCP area. The savanna group of Simulium

damnosum complex include S. damnosum s.s, S. sirbanum and S. dieguerense while

the forest group includes S. yahense, S. squamosum and S. sanctipauli subcomplex

consisting of S. sanctipauli, S. soubrense, S. leonense and S. konlwurense (Boakye et

al, 1998; Boakye, 1999). Changes in the distribution patterns, however, occur

annually in association with the pronounced seasonal climatic variations manifested

in West Africa by the dry and wet seasons. The seasonal change is accompanied by

shifts in wind direction and by the drying out or flooding of rivers which provide the

S. damnosum s.l breeding sites (Boakye et al, 1998). During the main rainy season,

prevailing (monsoon) winds blow from the Southwest to the Northeast, there is

heavy precipitation, and enhanced flow in the river results in many more potential breeding sites.CODESRIA-LIBRARY The opposite happens during the dry season. Other factors influencing species distribution include the hydro-chemical and physical

characteristics of rivers (Grunewald, 1981) and human activity leading to changes in the fly's habitat e.g. deforestation (Boakye, 1999).

The savanna· species of the Simulium damnosum complex have been known to be efficient vectors of the severely blindi~g savanna strain, vice versa for forest 174

species (Duke, 1990). Toe et al (1997) reported that the vector-parasite complex

does not exist in the transition zones between forest and savanna. However, invasion

of deforested areas by savanna flies can introduce the savanna strain of 0. volvulus

into these areas and carry forest strains into savanna areas.

Severe human onchocerciasis in West Africa with blindness as its most

dangerous manifestation results from continuous exposure to the bites of the

Simulium damnosum_ vector flies. Those with the most serious manifestations are those that are continuously exposed to the bites of the vector. Blackflies are daytime and outdoor biters. This is why males who carry out more outdoor activities such as farming, fishing, swimming etc. usually have more severe manifestations than females whose activities are more of indoor activities such as cooking. When females are involved in outdoor activities, they are usually for sho1ier periods e.g. fetching water, firewood or vegetables etc. The variation in the biting activities of the flies and in particular of the old, parous individuals delimits the hours of maximum or minimum danger of transmission of onchocerciasis (Nwoke, 1988). To interruptCODESRIA-LIBRARY the transmission of onchocerciasis or to reduce it to a minimum, man-fly contact must be reduced to a very low level and to be able to reduce man-fly contact, the daily and seasonal biting patterns of the flies need to be studied and understood.

Many researchers have studied the daily biting activities of different species of Simulium in different parts of the world. Lacey and Charlwood ( 1980) studied the 175 biting activities of some anthropophilic Ama,zonian Simuliidae in Brazil. Alverson and Noblet (1976) studied the response of female blackflies to selected meteorological factors in Southern Carolina while Renz (1987) studied the seasonal and diurnal changes in the biting densities of Simulium damnosum in Sudan-savanna area of North Cameroon. Boakye (1999) carried out distributional, cytotaxonomic and genetic studies of Simulium damnosum complex in the OCP area of West Africa in relation to insecticide resistance.

In Nigeria, some studies have also been carried out on the biting activities of

Simulium damnosum. Gemade and Dipeolu ( 1983b) studied the daily biting activities of blackfly at Manor (Benue State) while Nwoke (1988) investigated the effects of climatic factors on flies on the Jos Plateau. Much work has not been carried out on the biting activities of the black.fly in the eastern parts of Nigeria.

Ezike and Iwuala (1979) had studied the occurrence and distribution of blackflies

(Simulium species) in Cross River State while Ezike (1979) worked on the biting densities of Simulium damnosum complex in Oji River area. In Uzo-Uwani local government areaCODESRIA-LIBRARY of Enugu State there is no previous record of any study on the Simulium vector of onchocerciasis.

In the present study, the daily biting patterns of these Simulium vector flies were studied with the aim of relating the biting habits of the flies with the daily working habits of farmers in this. area. Seasonal variations in biting densities were also investigated. The results of the study it was hoped should enable appropriate 176

recommendations to be made on how best to reduce man-fly contact and

consequently reduce the transmission of onchocerciasis by the vector in this area.

7.2 Materials and Methods

7.2.1 The Study Area

One community (Nkpologu) in Uzo-Uwani local govenm1ent area was

chosen for the study. This community is traversed by one of the perennially flowing

rivers (River Adada) which belong to the A1rnmbra River System which had been

reported to form the breeding sites for Simulium damnosum in the eastern part of the

country (Crosskey, 1981 ). All the communities crossed by this river in this local

government area are highly endemic for onchocerciasis e.g. Nkpologu, Akpugo,

Uvuru, Ukpata, Adaba and Nkume. River Adada is continuous with River Duu at

Umulokpa which flows to join River Anambra at Ogurugu, all in Uzo-Uwani local

government area. A farmland about 500 metres from River Adada at Nkpologu was

selected for the study. The use of a farmland stemmed from the responses by

members of every community during intervfows on local disease perception in the study area thatCODESRIA-LIBRARY the blackfly is most abundant in the farms. 7.2.2 Fly Collection

Fly collection was carried out for 28 days within different seasons of the year

(April, 1999 - March, 2000). The seasons covered include early rainy season (April

- May, 1999), late rainy season (September - October, 1999) and dry season

(November, 1999 - March, 2000). Within the dry season, the hannattan season was 177

studied as a separate sub-season. Human baits were used for the fly collections and

two sites in the farmland separated by a distance of about 100 metres were selected

for the study. On each fly catching day, two human baits sat in the two locations

exposing their lower legs (WHO, 1966). Blackflies that landed on the baits for

bloodmeal were killed, collected and stored in specimen bottles containing I 0%

formal saline for preservation. Fly catching generally took place from 6.00 a.m. to

7.00 p.m. on each fly - catching day. Sampling of flies was done 30 minutes every

· hour and the number of flies caught per man per hour recorded. At the end of the

day, the average number of flies per man per hour and the total number of flies per

man for the day were calculated. Within each fly-catching hour, measurements of

temperature and light intensity were made using mercury in glass thermometer and a

model S511 photometer respectively. Readings of each factor were taken at the

beginning and end of each sampling period and an average taken to represent the

measurements for the hour.

7.3 Results and Observations 7.3.1 DailyCODESRIA-LIBRARY Biting Patterns The results of the studies on the biting activities of the blackflies in Uzo­

Uwani local government area are shown in tables 7.1 - 7.5 and figures 7.1 - 7.5.

The results show that generally the blackflies are bimodal in their daily biting

activity patterns. Flies started biting as early as between 6.00 and 7.00 a.m.

depending on the season and continued until between 6.00 and 7.00 p.m. Biting does 178

Table 7.1 Summary of fly collections in Uzo-Uwani local government area during the study period.

.our ~------DAYS ------~ Total No. Aver -age of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 No.of of llay flies days No. of flies ' -7.00 2 2 6 0 0 0 0 0 0 0 0 0 0 0 0 0 10 16 0.63 •1.m. II -8.00 0 3 4 6 2 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20 22 0.91 1.m. ' - 9.00 3 2 4 2 7 3 4 0 0 2 0 5 3 3 0 0 0 2 0 49 28 1.8 1.m. -10.00 7 4 4 5 4 5 2 0 0 0 3 2 4 6 2 8 0 0 0 0 0 0 0 61 28 2.17 1.m. J -11.00 9 0 3 3 14 0 4 2 0 0 2 0 0 2 0 0 3 0 0 0 0 0 2 0 2 0 48 28 1.71 1.m. o(} -12.00 3 0 0 9 0 2 0 0 0 0 0 0 3 0 0 0 0 2 0 0 0 0 25 28 0.89 IIQOO ~o -1.00 4 2 11 2 0 0 0 0 0 2 0 0 0 0 2 4 0 0 0 0 2 36 28 1.29 ~.m. 0-2.00 3 5 9 0 2 0 2 0 0 0 0 0 5 0 0 3 0 4 3 0 0 0 0 0 40 28 1.43 111.m. ,0-3.00 5 3 6 3 ll 3 4 0 J 0 0 6 2 0 2 12 0 3 0 0 0 0 0 68 28 2.43 J.m. r0-4.00 2 3 6 5 24 3 3 8 11 7 0 3 4 2 4 0 6 3 6 0 0 0 0 0 104 28 3.71 1.m. 1()-5.00 4 7 3 23 6- 2 7 6 6 2 9 4 J. 7 8 9 27 30 15 9. 14 0 0 0 4 0 207 · 28 7.39 lf.m. l-0-6.00 5 3 9 6 12 12 6 4 6 3 0 2 11 3 11 50 32 8 43 9 16 6 2 0 8 2 270 27 10.00 ~.m. l-0-7.00 3 2 9 3 0 0 0 0 0 0 0 5 14 4 10 18 12 0 0 0 0 0 82 24 3.38 ~.m. ?~ oral 33 24 53 38 128 50 30 28 34 14 9 22 22 6 --> 32 31 105 99 16 85 49 57 8 4 0 16 4 1020 28 36.4 CODESRIA-LIBRARY . ,, . .179.

Table7.2 Daily Biting Pattern in Early·RainySeason.

Day Day Day Total No. Average_· HourofDay 1. 2 3 4. 5 6 7 No.-of f -- of. No·;' of· lies days - . flies 6.00-7.00 a.m. 2. 2 6 lO 3 3.33-

7 .00-8.00 a.n:i. 0 3 4. 6 2 · 15 5 3.00 s.oo:.9.00 a.m~ 3 2 r 4 2 7 3 22 7 3.14 9.00~l0.00 a~m. 1 1 7_ 4 4 5 4- 26 .7 3.71 10.00-11.00 a.m. 9 0 3 3 14 0 1 30 7 - 4.28 · 11.00-12.00. noon 3 0 1 0 9 0 2 15 7 2.14 .- 12.00-1.00 p.m. 1 4 1 2 11 1 1 21 -7 · 3.00

1.00-2.00 p.m. "I,:, 1 5 1 9 0 2 21 7 3.00 _2.00-3.00 p.m. 5 ' 3 6 3 11 3 4 35 .7 5.00 3.00-4.00 p.m. 2 3 6 5 24 1 3 44 7 6.29 - 4.00-5.00 p.m. _ 1 4 7 3 23 6 2 46 7 6.57. 5.00-6.00 p.m. 5 3 9 6 12 12 6 53 7· 7.57

6.00-7.00 -p.m. ,:,"I 2 ~ 1 9 9 0 18 6 3.00 TOTAL 33 ·24 53 28 128 50 30 356 7 50.851 CODESRIA-LIBRARY 180

Table 7~3 UaiJy,Biting Pattern iii Late Rainy Season.· • • • • • ~ • • • •• > - • ' ,. •

·.Day_ .... -l)ay ·Total No. ··No~ Average Ho.ur of:Oay . -1 ·. 2 . . 3· 4 ·.··s ... 6 : ·off , . of .No. of .. ·' , . lies days . . flies . 6.00-7 ~00 a.m. - .. - -· Q, . 0' .• 0 0 3 o.oo· 7 .00-8.00 a~m. -- 3 1 o·. 0 4 4 1.00 8.00.,9.00 a.m. 4 1 0 1 l 1 '8 6 1:33 9.00-10.00 a~m. 5 . 1 1 2 0 1 8 6 1.33 10.00-11.00 a.m. 4 2 0 1 0 2 9 6 1.50 11.00-12.00 noon 0 0 1 0 0 1 2 6 0.33 12.00:-1.00 p.m. 1 2 1 0 0 0 4. 6 0.67 ,., 1.00-2.00 p.m. ·O 2 0 0 1 ·, 0 .) 6 0.50 ,., · 2'.00.,3.00 p.m. 0 .) 1 0 0 6 10 6 1.67 3.00-4.00 p~m. 3 8 1 1 11 7 31 6 5.17

· 4~00-5.00 p.m: 7 - 6 6 2 9 4 ., 30 6 5.00 5.00-6.00 p.m. 4 6 3 1 0 14 5 2.80 · ... 6.00-7.00 p.m. 0 0 0 ·_ .o 0 4 0.00 TOTAL ~i )'f- l'f q 11. 2.2. 29 6 21.5 CODESRIA-LIBRARY 181

. Table 7.4 Daily Biting Pattern in the Dry Season (Without Harmattan).

. J Day Day Day7 Total No. of Average .· Hour of Day. l 2 3 4 5 6 No. of days. · No. of flies flies

6.00-7.00 a.m. 0 0 . 0' 2 0.00 7.00"'."8.00 a.m. 0 0 0 0 o· 0 5 0:00 8.00-9.00 a.m. 0 3 0 0 0 2 0 5 7. 0.71 · 9.00-10.00 a.m. 0 .2 0 0 0 0 0 2 7 · . 0.28 ·. 10.00~11.oo a.m .. 0 0 0 2 0 2 .o 4 7 0.57 11.00-12.00 noon 0 2 0 0 0 0 3 7 0.42 · 12.00-1.00 p.m. 0 0 0 0 0 0 2 2 7 0.27 1.00-2.00 p.m. 0 0 0 0 0 0 o- 0 7 0.00 . 2.00-3.oo p.m~ . 1 0 0 0 .0 0 0 1 7 0.14 3.00-4.00 p.m. 0 0 0 0 0 0 0 o- 7 0,00. 4.00-5.00 p.m. ·3 1 .. _O 0 0 4 0 8 7 .. 1.14 5.00-6.00 p.m~ 2 8 6 2 0 8 2 . 28 7 - 4.00 ··. .. 6.00-7.00 p.m. 0 . 1 0 0 0 0 0 1 ·7 0.14

.. TOTAL -6 16 CODESRIA-LIBRARY8 - 4. 0 16 4 54 ·. - . 7 - 7.71

..

.. -- -- Yi"-··-, ·-· .. --~ -·-?.-.. . ---- .. - ... · -, ... : - ,.,.:..-'. - - _- ·' ··--. --.- '·: ____ ; ... · ·-·- - ..• - ....> .~ .. - ···- .· .... : •.--.·.· ·._ . ___ . --~ ... · - . ----- .. ·---. <,·--···· . ---·-~< . . -;;.'. ·····- --~ ---·-,· .. - 182

Table 7.5 Daily Biting Pattern in the Dry Season with Harmattan.

Hour Day Day Day Total No. Average of 1 -2· 3 4 5 6 ·7 8 No.of of days No.of Day flies :(lies

6.00-7.00 a.m. 0 0 0 0 0 0 0 0 0 8 0 7.00-8.00 a.m. 0 0 0 0 0 0 0 1 8 0.13 8.00-9.00 a.m. 0 2 0 5 3 1 -· 1 1 13 8 . 1.63 _ 9.00-10.00 a.m. ·o 3 2 4 . 6 8 0 0 23 8 . 2.88

10.00-11.00 a.m. 0 2 0 0 :,"· 0 0 0 5 8 0.63 11.00-12.00 noon 0 3 0 1 1 0 0 0 5 8 0.63 12.00-1.00 p.m. 0 2 0 0 0 2 4 9 8 1.13

1.00-2.00 p.m. 0 . 5 0 0 :,'I 1 4 3 16 8 2.00 2.00-3.00 p.m. 2 0 2 12 l 3 22 - 8 2.75 3.00-4.00 p.m. 3 ,. 1 4 .. 2 . 4_ 6 3 6 29 8 3.63 4.00-5~00 p.m. 7 8 9 27 30 15 9 14 119 8 14.88 5.00-6.00 p.m. 11 J 11 50 32 43 9 16 175 8 21.87 6.00-7.00 p.m. 0 . 5 14 4 - 10 18 12 63 7· 9 31 -_ ·. 480 TOTAL 22 CODESRIA-LIBRARY32 105 99 85 .49 57 8 60

.·.- . ,.,~--. ,: I r 183

\I

12 ------.....------'----,

10 .

8 .

~ ....~ !+:: ~ 0 I,., ~ . ..Q 6 8 =Cl ~ bJJ ~ . I,., ~ "' ~ 4 1· I

', "j I I 2 CODESRIA-LIBRARY

6.00- 7.00- 8.00- 9.00- 10.00- 11.00- 12.00- 1.00- i.00- 3.00- 4.00, 5.00- 6.00- 7.00 8.00 9.00 10.00 11.00 12.00 1.00 2.00 3.00 4.00 5.00 - 6.00 _- 7.00

A.M. Hours of the day P.M.

Figure 7.1: Daily biting pattern of black fly (Simulium) in Uzo­ Uwani Local Government Area of Enugu State, Nigeria~ rI. 184 I Ir- 1

· ii:' .- r IL . /: 1. 1· I I-- ,. 1 t-:

i I.

CODESRIA-LIBRARY

6.00- 7.00- 8.00- 9.00- I0.00- 11.00- 12.00- 1.00- 2.00- 3.00- 4.00, 5.00- 6.00- 7.00 8.00 9.00 I0.00 11.00 12.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 A.M. NOON .... P.M .

Hour of the day

Figure 7.2: Daily biting pattern of Blackfly (Simulium) in Uzo~ Uwani Local Government Area of Enugu State, Nigeria, during early rainy season. I

185 f I I 6 -i ·1! l ;j' i ! l I I .I 5 f J

[ . ,-, -, 4 -- A ·t . i '

v.i ....~ i:;::::: c.., 0 t3 I~ ..ca m = 'I = I\ty"'.~ ~ ! blJ 11 ~ ~J.? ""~ ·~,~ I ·I ~2 I f1ft i ~! IV: I

tr~ ~' ~ ) 1 _,

CODESRIA-LIBRARY • I

6.00- 7.00- 8.00- 9.00~ 10.00- 11.00- 12.00- l.00- 2.00- 3.00- 4.00- 5.00- 6.00- '·lI 7.00 8.00 9.00 10.00 11.00 12.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 A.M. _Hour of the day P.M. Figure 7.3: Daily Biting Pattern of Black fly (Simulium) in Uzo-Uwani Local Government Area of Enugu State, Nigeria, .. during late Rainy Season i86

4.5 ··.....------~------,

4 -

3.5 -

3 - rn ....Cl.I ....!+:: 0 ~ 2.5 - Cl.I ,.Qe = =Cl.I bJ) 2· ~ Cl.I ~ ~ 1.5 -

1 .

CODESRIA-LIBRARY

6.00- 7.00- 8.00- 9.00- 10.00- 11.00- .12.00- 1.00- 2.00- 3.00- 4.00- 5.00- 6.00- . 7.00 8.00 9.00 10.00 11.00 12.00 1.00 2.00 3.00 · 4.00 5.00 6.00 · 7.00

A.M.----- Hour of the day

Figure 7.4: Daily Biting Pattern of Blackfly (Simulium) in Uzo Uwani Local Government Area of Enugu State, Nigeria, · during the dry season (without harmattan) 187

25 -.------,------:-----'-----i

20

./ ~ ....~ ' 15 - =~ 0 i.. ~ ,.Qe = ~ bl) ~ i.. <~ 10 -

.! 5 - 1 CODESRIA-LIBRARY

6.00- 7.00- 8.00- 9.00- 10.00- 11.00- 12.00- 1.00- 2.00- 3.00- 4.00- · 5;00- 6.00- · 7.00 8.00 9.00 10.00 11.00 12.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 A.M. H our of t h e d ay P.M.

· Figure 7.5: Daily Biting Pattern of Blackfly (Simulium) in Uzo Uwani Local Goverment Area of Enugu State, Nigeria; during 1- the dry season with harmattan 188 not, however, go on at the same ~ate throughout the day. There were usually two peak biting periods within the day, one in the morning and the other in the evening, with the evening peak higher than the morning peak by a factor of about 5. There is usually a decline towards the afternoon (Table 7.1, Figure 7.1). Biting rates increased steadily from morning and on the average peaked between 9.00 and 10.00 a.m., then there was a drop in biting activity towards the mid-clay between 10.00 a.m. and 12.00 noon. Biting activity started rising again and peaked on the average between 5.00 and 6.00 p.m. On humid days (e.g. day 5) when sunlight was not intense and temperature was not high throughout the day, it vvas observed that the fly density was higher than other days which were generally sunny and dry. The bimodal activity pattern was still evident although the evening peak shifted from the usual 4.00 - 6.00 p.m. to between 3.00 - 5.00 p.m.

The daily biting pattern of the black.flies appeared to be governed by changes m climatic conditions. Temperature increased gradually from morning until it reached the peak between 11.00 a.m. and 3.00 p.111. depending on the prevailing climatic conditionsCODESRIA-LIBRARY for the day and gradually decreased until evening. Light intensity increased very fast in the morning hours until a maximum was reached between 12.00 noon and 3.00 p.m. and then dropped sharply until evening. The minimum temperature recorded during the study was I 5°C and this was during the harmattan period within the dry season while the highest temperature recorded was

38°C and this was during the late dry season (January - March). The minimum 189 temperature at which blackflies were caught on man was I 8°C while the maximum temperature at which flies were caught biting man was 36°C. Blackflies in this area mainly attacked man between temperatures of 24-32°C, but the optimal range of temperature was between 26~30°C. On the other hand, the minimum light intensity at which blackflies were caught on man was 80 lux while the optimum light intensity recorded when the highest number of flies were caught was 3,000 - 10,000 lux.

On the average the biting rates for the period of study were 3 flies/man/hour

(3FMH) and 36 flies/man/day. The probability of catching a fly on man at any given hour was found to be 0.59 (201/341 ). Casual checks on preferred sites for fly bites showed that the blackflies in this area bit on any exposed part of the body but there was no record of bites on the face. There was however, preference for the lower legs especially the heels.

Observations on the working habits of farmers in the area during the period of fly collection showed that farmers arrived in the farms between 6.00 and 7.00 a.m., went on break in the afternoon between 1.00 and 3.00 p.m., resting in farm houses (Plates 7.1 a & b) or tree shades, and resumed fanning from around 3.00 p.m., till aroundCODESRIA-LIBRARY 6.00 p.m. It was also observed that men stayed longer in the farms than women and worked in the farms bare bodied wearing only shorts or rolled up trousers while women left the farms earlier and worked with clothes on exposing only their legs and hands. 190

CODESRIA-LIBRARY

Plate 7.1 a Front view of a farm bouse.

Plate 7.1 b Side view of a farm bouse. 191

7.3.2 Seasonal Variations in Biting Densities

During this study, seasonal variations were observed in the biting densities of

Simulium damnosum species complex in Uzo-Uwani local government. area of

Enugu State.

7.3.2.1 Early Rainy Season

During the early rainy season, the blackflies were observed to bite from dawn to dusk. The biting pattern was clearly bimodal with a low morning peak between

10.00 and 11.00 a.m. and a higher evening peak between 5.00 and 6.00 p.m. The evening peak 'Yas found to exceed the morning peak by a factor of about 2 (Figure

7.2). The lowest number of flies/man/day was 24 while the highest number of flies/man/day was 128 and this was collected on a humid and overcast day. The lowest number of flies/man/hour was zero while the highest number of flies/man/hour was 24. The average number of flies/man/day was about 51 while the average number of flies/man/hour was about 4( 4.18). The probability of finding a blackfly at any given hour was found to be 0.91(76/84).

7.3.2.2 Late Rainy Season

DuringCODESRIA-LIBRARY the late rainy season, the biting densities were generally lower than during the early rainy season. The season was marked by sudden fluctuations in climatic factors, rainstorms often threatening with sudden decrease in light intensity and temperature with a corresponding rise in relative humidity. The lowest number of flies/man/day was 9 while the highest number of flies/man/day was 34. The 192 lowest number of flies/man/hour was zero while the highest number of flies/man/hour was 11 and this was recorded when there was sudden drop in light intensity and temperature and a corresponding increase in relative humidity due to threatening rainfall. The average number of flies/man/day was about 22 while the average number of flies/man/hour was about 2. The probability of finding a blackfly at any given hour was found to be 0.60 (42/70).

7.3.2.3 Dry Season (Without Harmattan)

During the dry season, the weather was generally sunny, hot and dry. The highest temperature of 38°C was recorded within this period and the lowest fly densities were also recorded within this selson. The lowest daily fly collecti~n/man was zero while the highest number of flies/man/day was 16. The lowest number of flies/man/hour was zero while the highest number of flies/man/hour was 8. The average number of flies/man/day was about 8 while the average number of flies/man/hour was less than 1 (0.64). The probability of finding a fly at any given hour was 0.21 (19/84). 7.3.2.4 Dry SeasonCODESRIA-LIBRARY (With Harmattan) The harmattan season was marked by cold mornings with temperatures of as low as 15°C on some days, sunny, dry, windy and hot afternoons and warm evenings. The biting pattern was clearly bimodal with a low peak in the morning between 9.00 and 10.00 a.m. and a much higher evening peak between 5.00 and 6.00 p.m. The evening peak was found to be higher than the morning peak by a factor of 193

about 7 (figure 7.5). The daily fly densities were on the average found to be highest

within the hannattan season but concentrated mostly in the evenings. The lowest

number of flies/man/day was 22 while the highest number of flies/man/day was 105.

The lowest number of flies/man/hour was zero while the highest number of

flies/man/hour was 50. The average number of flies/man/day was 60 while the

average number of flies/man/hour was about 5( 4.66). The probability of finding a

fly at any given hour was 0.61 (63/103).

7.4 Discussion

The results of the studies on the daily biting activities of Simulium damnosum

complex in Uzo-Uwani local government area of Enugu state show that the flies are

bimodal in their daily biting habits. Biting occurs throughout the day but there are

peak biting periods in the morning (9.00 - 10.00 a.m.) and in the evening (5.00 -

6.00 p.m.) with the evening peak higher than the morning peak by a factor of about

5. There is usually a decline in the midday. Factors that appear to govern the daily

biting activities of the blackflies include light intensity, temperature and relative humidity. ItCODESRIA-LIBRARY is, however, obvious from the variations in biting activities, even when · external factors appear to be more or less similar, that there is likely an innate factor that regulates biting activity within the day.

Crosskey (1990) reported that the cause of biting activity peaks is still little understood, but believes that some kind of innate clock rhythm is involved.

According to him, peaks do not seem explicable solely on the basis of external 194 factors and hunger, nor is it likely that in twin-peak rhythms one peak is caused only by an innate rhythm and the other only by external stimuli. In essence, the biting activity rhythm appears to be internally timed but readily modifiable by the environment. According to Saundets (1982), the biting activity rhythm resembles any of the innate physiological clock mechanisms that regulate the repetitious activities of insects. Blackflies bite and suck blood every few days according to the gonotrophic egg producing cycle so the biting cycles loosely speaks of a circadian rhythm. After the first bloodmeal, flies clock-on to take more blood at intervals of three or four days, biting again when eggs matured with the aid of blood taken at the previous meal have been laid. However, the approximate timing of the innate biting will be fine-tuned according to the suitability of the weather for flying and the availability of hosts. Daily biting activity is also affected by the physiological age of flies in the biting population. Flies seem to bite at different times of day when they are nulliparous, taking their first blood, from when they are parous taking blood, after having already laid eggs at least once. The resultsCODESRIA-LIBRARY of the studies on the biting activity patterns of Simulium damnosum complex in Uzo-Uwani local govenunent area are similar to those obtained by earlier researchers on the daily biting activities of different species of

Simulium in different parts of the world.

WHO (1976) reported that daily biting cycles are mainly governed by air temperature and humidity. At high temperatures during the dry season, the daily 195

biting curve shows two peaks, one in the morning and one in the evening separated

by a midday trough. At low temperatures during the rainy season, the daily biting

curve is unimodal with a single afternoon peak.

On the biting patterns of Simuliwn damnosum, Crosskey ( 1990) reported that

blackflies bite from dawn to dusk but not at the same sustained level throughout the

day. Biting tends to b.e concentrated into activity peaks with lulls in-between. The

peak pattern can be readily disrupted by a variety of environmental and innate

causes, for example, after a heavy rainfall, a time of normal low activity can be

transformed into one of high activity and biting activity characterized by two peaks

(morning and evening) can be smoothed out into general all day activity on dull and

humid days. Biting activity is usually bimodal with early morning and late afternoon

peaks separated by a long i:nidday lull in activity or unimodal with mid-afternoon

peak. In warm and humid tropics, there is a morning peak and all day plateau.

Crosskey (1955) had earlier reported that in Simulium damnosum complex, flies tend ./ to bite more actively on humid days than when the sun is shining unobscured. The studyCODESRIA-LIBRARY by Lacey and Charlwoocl (1980) on the biting activities of some anthropophilic Amazonian Simuliidae in Brazil shO\,ved that the species of Simulium

which included S. simplicicolor, S.guinanse and S. sanguinem were bimodal in their

biting activities. The factors that influenced biting activities included light intensity,

temper~ture and humidity. Rapidly increasing illumination resulted in sharp increase

in activity after the initial onset of biting activity with only a barely perceptible rise 196

in temperature or decrease in relative humidity apparent. They reported that beyond

the optimum illumination, an inverse relationship between light and activity was

observed with an abrupt drop in activity. Between 10.00 and 16.00 hours when light

intensity and temperature were highest and relative humidity lowest, little or no

feeding activity was observed. The late afternoon peak of biting activity occurred when light and temperature were decreasing and humidity increasing.

In the study by Anderson and Noblet (1976) in Southern Carolina, they reported that the biting activity of Simulium flies was generally influenced by cloud types, light intensity and time of day provided the temperature was above 50°F

(10°C). Most species were found to maintain peak activity in both morning and afternoon with a midday decrease in activity.

Renz (1987) in his study of the seasonal and diurnal changes in the biting densities of Simuliwn flies in North Cam~roon reported that the highest biting densities were recorded between 16.00 and 17.00 hours and the lowest densities were found between 11.00 and 12.00 hours. Generally, however, there were two peaks, a morning peakCODESRIA-LIBRARY that occurred before 11.00 hours and an evening peak between 16.00 and 17.00 hours with a midday decline. He linked the daily variations in biting densities to daily variations in temperature but believed that the afternoon variations in the biting densities were probably governed by other innate parameters.

In the study by Nwoke (1988) on the effects of climatic factors on the biting pattern of Simulium damnosum on the Jos Plateau, he reported that the fastest 197 changing climatic factor relative to increasing biting activity was illumination. He found that under shade, there was no remarkable fluctuation in light intensity and no obvious peaks in the biting activity of the flies but in sunny places, biting activity was bimodal, with a small morning peak and a pronounced afternoon peak with a decline in the midday. According to him, the morning activity peak occurred between 9.00 and 11.00 hours with increase in illumination and only a barely perceptible rise in temperature and decrease in relative humidity. The midday decline occurred between 12.00 and 15.00 hours when light intensity and temperature were highest and relative humidity lowest. The afternoon peak occurred between 16.00 and 18.00 hours when light intensity and temperature were decreasing and relative humidity increasing.

The study by Gemade and Dipeolu (1983b) at Manor also showed that daily biting activities of Simulium damnosum had bimodal curves with peaks between 7.00 and 9.00 a.m. and between 3.00 and 5.00 p.m., the morning peak being higher. In their opinion, the daily biting activity of S. damnosum at Manor was influenced mostly by temperature.CODESRIA-LIBRARY The fly preferred to be active during the cool periods of the clay as reflected by the bimodal curve with peaks of activity during periods of low temperature. They also reported that sudden changes in climatic conditions e.g. rainfall, influenced the hourly catches. On shady and overcast days, there was no marked morning or evening peaks observed. The study by Ezike (1979) on the vector 198 of onchocerciasis in Oji River area showed that the female S. damnosum had a peak biting period of I 0.00 - 11.00 a.m.

Biting patterns have been most studied in the tropics where season has the least effect on day length. In tropical species the biting activity is presumably limited to about 12 hours each day only because day length and night length are about equal in equatorial latitudes. Arctic blackflies bite more or less throughout the

24 hours of continuous mid-summer daylight, and in temperate areas, where daylight lengthens or shortens with the time of year, the timing of the early and late activity peaks shifts accordingly (Crosskey, 1990). From the various reports, it appears that the level of illumination, particularly the morning and evening rise and fall in light intensity, is the most important external factor influencing biting activity pattern.

Roberts and Irving-Bell (1985), however, reported that in savmma species of

Simulium studied in Nigeria by using a trapping net mounted on a moving car driven after dark, a little flight activity will continue for as much as 2Yz hours after darkness falls, but since sight plays a big part in orientation of blackflies to their hosts, a fly dependent on seeing its host is unlikely to bite in the dark (Crosskey, 1990).

The observationsCODESRIA-LIBRARY on the biting activity patterns of blackflies in Uzo-Uwani local government area confirm the observations of most of the above mentioned researchers. Uzo-Uwani local government area is in the forest-savanna-mosaic zone of Nigeria lying between the northern savannas and the southern rainforests

(Crosskey, 1981). Most of the rivers were observed to flow perennially e.g. River 199

Adada, River Duu, River Obina, River Eshi and River Anambra into which others flow. Biting activities of the Simulium flies occur throughout the year but with variations in intensity of biting in different seasons. As reported above, it was observed that biting activities occurred from morning until evening with morning and evening peaks, the evening peak being higher than the morning peak. There is usually a decline in the midday. The biting appears to be governed by light intensity, temperature and relative humidity. Biting occurs most at a combination of moderate light intensity of 3,000 - I 0,000 lux, moderate temperatures of 26 - 30°C and high relative humidity. At low and high temperatures, low and high light intensities and low relative humidity, biting activity is minimal. The biting activity of Simulium in this area occurs in the cool periods of the clay and these occur in the mornings and evenings resulting in the bimodal biting pattern observed. On a humid clay after rainfall in the night and drizzling in the morning, with relatively low light intensity and low temperature throughout the day, fly densities per hour were higher than on dry, sunny days, but again the bimodal biting pattern was still observed. The evening peak,CODESRIA-LIBRARY however, shifted up to an earlier time (3.00 - 5.00 p.m.). It is important to note that it is not so much the time of day that matters but the prevailing climatic conditions. Whatever time of day suitable conditions prevail, biting activity is intense.

As mentioned earlier, Cross key ( 1990) reported that the biting activity peaks involve some kind of innate clock rhythm, the biting activity rhythm being internally 200

timed but readily modifiable by the environment. . He recorded also that light

intensity appears to be the main controlling factor in the blackfly diurnal rhythm, provided the temperature remains high enough not to inhibit flight completely, and that flies differ in the range of temperature they prefer. Temperatures below 10°C

usually inhibit biting activity. Host seeking and other flight activity of tropical

species occur at temperatures of up to 30 -- 40°C. In any species, biting occurs within a narrow range of temperature of about 8°C. Attacks of S. damnosum complex on man in the tropics occur mainly at 22-31 °C (Crosskey, 1990). In Uzo­

Uwani local government area, as long as there was sunlight biting activity continued provided other climatic conditions were suitable. The minimum illumination recorded for biting activity was 80 lux. Also it was observed that the blackflies bite mainly at temperatures of 24-32°C. However, few bites occur at temperatures as low as l 8°C. On the effect of relative humidity, Crosskey (1990) believes that it is not a critical factor in determining whether flies will bite or not so long as the moisture content of the air is sufficient to obviate any risk to flies of rapid desiccation. Times of maximum biting,CODESRIA-LIBRARY however, are often associated with rather high humidity. In the present study, the highest number of flies was collected on a humid day.

This biting activity pattern of Simulium damnosum complex in Uzo-Uwani local government area is significant in the transmission of onchocerciasis because it corresponds almost exactly with the working hours of farmers in the area. Generally, farmers stmt working in their farms as early as between 6.00 and 7.00 a.m. go on 201

break between 1.00 and 3.00 p.m. and go back to work until evening between 6.00

and 7.00 p.m. On cool, humid days, farmers may work in the farms throughout the

morning and afternoon periods with a very s.hort break since they are not disturbed

by the heat of the sun. They rather leave the farms earlier. Coincidentally, on such

cool, humid days, the flies are more abundant than on hot, sum1y days and the

evening peak occurs earlier in the day. Also during their break periods when the

farmers rest in farm houses or under tree shades, the blackflies also withdraw from

direct sunlight into shady places to avoid desiccation with the result that the man-fly

contact continues even during the break periods. This correspondence between the

daily biting patterns of blackflies and working hours of farmers ensures close man­

fly contact and hence continued transmission of onchocerciasis.

On the seasonality of biting, Crosskey ( 1990) reported that biting can be highly seasonal in tropical regions with a prolonged dry season which eliminates, or at least severely reduces, the available breeding habitat. According to him, in West

Africa, biting activity of S. damnosum complex ceases for several months in the long dry season ofCODESRIA-LIBRARY the northern savannas when rivers stop flowing or are reduced to trickles, resuming only when the rivers run again in the rains. On the contrary, where the climate is almost uniform through the year and the rivers run perennially, biting activity occurs year round in association with continuous breeding (though not necessarily always at the same intensity). In Uzo-Uwani local government area, the rivers run perennially and continuous breeding can be assumed. Biting activity was 202

observed to occur throughout the year but the biting densities varied with seasons

with the dry season (without harmaltan) having the lowest densities and the rainy

season having higher densities. It was, however, observed that the highest fly

densities were recorded during the hannattan season. The recording of higher fly

densities in the rainy season than in the dry season (without harmattan) can be

attributed to the provision of better breeding sites for the blackflies as a result of

increase in water levels and attachment objects. However, the reason for the

observation of highest fly densities during the harmattan season may lie in the

addition to local flies of migrating savanna flies carried down into the area with the help of the north-south harmattan winds blowing from the Sahara to the coasts. The savanna species of blackflies (S. damnosum s.s and S. sirbanum) have been recorded to migrate up to about 500 km on the wind (Garms and Walsh, Ganns et al, 1989,

Boakye, 1999). The savanna - forest - ri1osaic species, S. squamosum migrate up to about 100-150 km, while the forest and forest-savanna-mosaic species, S. sanctipauli subcomplex are short-range migrants which seem rarely to move more than about 50 km from theirCODESRIA-LIBRARY emergence sources. The true forest species (S. yahense) is more or less non-migratory (Crosskey, 1990). Walsh et al (1993) observed that there is a strong indication of a relationship between deforestation and onchocerciasis - deforested areas could be invaded by savanna species. Boakye (1999) had shown that the effect of deforestation on the biting population could only be found at the severely deforested site in the dry season. Ganns and Vajime (1975) also reported 203

that S. damnosum s.s. which breeds predominantly in savanna areas extend its range

into the forest zone, especially in dry season. These savanna species not only invade

deforested areas but also establish breeding populations that would persist (Post and

Crosskey, 1985; Baker et al, 1990; Boakye, 1999). Uzo-Uwani local government

area is in the forest-savmma-mosaic vegetational zone and so should have species of

blackflies that are short-range migrants. Addition of migrating savanna flies to these

local flies during the hannattan season would. most likely be responsible for swelling

the biting populations of the blackflies within this season. Forest-savanna mosaic vegetation can also be likened to severely deforested sites which are usually invaded

during the dry season by migrating savanna flies.

On the rates of biting, it has been shown (Crosskey, 1990) that the biting rates of blackflies on man in tropical Africa are low compared to the rates in tropical

Americas. He reported that in S. damnosum complex, the peak biting rates occur in the wet season and are rarely sustained at more than about 3-60 flies/man-hour

(FMH) in savanna regions and 200 FMH in forested regions. In some Central American speciesCODESRIA-LIBRARY e.g. S. ochraceum, the biting rates lie between l 00-1 OOO FMH and with the heaviest biting in the drier part of the year. In Uzo-Uwani local government area, the peak and average biting rates were highest (50 FMH and ~5 FMH respectively) during the hm·mattan season mid lowest (8 FMH and ~ 1 FMH respectively) during the dry season without hannattan. During the early rainy season the peak biting rate was 24 FMH while the average biting rate was~ 4 FMH. On the 204

other hand, during the late rains, they were 11 FMH and~ 2 FMH respectively. It is, however, noteworthy that the probability of man-fly contact at any given hour of the

clay was highest during the early rainy season (0.91) and lowest during the dry

season without harmattan (0.21 ). For the late rainy season and harmattan, the probability of man-fly contact at any given hour was 0.60 and 0.61 respectively.

This implies that even though the harmattan season had the highest FMH, the early rainy season is more dangerous in terms of onchocerciasis transmission because the biting fly populations are spread tlu·ough almost all the hours of the day ensuring a higher possibility of man-fly contact. During the harmattan season, on the other hand, the biting flies are concentrated within the evening period. This observation that the highest probability of man-fly contact at any given hour of day was recorded during the early rainy season has serious implications. This is because this season happens to be the season when the most intense farming activities (clearing and cultivation) occur and when greater number of people work in the farms. The implication of this observation is that there is continuous man-fly contact and the highest possibilityCODESRIA-LIBRARY of transmission of onchocerciasis within the early rainy season. Nwoke et al ( 1987) pointed out that some human factors affecting disease distribution in onchocerciasis include village proximity to breeding sites of vectors, disease prevalence and intensity, accessibility to hospitals/ clinics and awareness of the disease aetiology. From observations during the present study, another factor that enhances onchocerciasis transmission is the mode of dressing of farmers during 205

farming. Men usually worked in the farms wearing only shorts and rolled up

trousers thereby exposing most parts of their bodies. Casual checks on biting sites

showed that the Simulium flies in this area bite on all exposed parts of the body

especially on the legs (the heels in particular). As a result, blackflies suck blood

from these males some of who are infected and transmit the disease to uninfected

individuals. On the other hand, it was observed that women work in the farms

covering most parts of their bodies except their hands and legs. So, generally, men

should have higher man-fly contact and hence higher rate and intensity of infection than women and this is what results of studies on onchocerciasis_ prevalence have shown in every paii of the world where the disease is endemic. It is possible, therefore, that the higher rate and intensity of onchocerciasis observed in males in agricultural areas do not occur only as a result of occupational differences between males and females as commonly reported but also as a result of differences in the mode of dressing during fannwork.

7.5 Summary and Recommendations The resultsCODESRIA-LIBRARY of the studies on the biting activities of Simulium flies in Uzo­ Uwani local government area of Enugu State, Nigeria, show that the flies are bimodal in their daily biting patterns. Although these blackflies bite throughout the clay, there are peak biting periods within the. day. One peak occurs in the morning between 9.00 and 11.00 a.m. and another peak occurs in the evening between 4.00 and 6.00 p.m. with a decline in the midday. Three external factors appear to control 206

the biting activities namely light intensity, t~mperature and relative humidity. The

flies prefer moderate light intensities of 3,000 - I 0,000 lux, moderate temperatures

of 26-30°C and high relative humidity. It seems that in addition to these external

factors, there is an internal clock that controls their daily activities. This is because

under similar climatic conditions, the biting densities still vary. A factor that is not

observable may be responsible.

The implications of the bimodal daily biting pattern are obvious and serious.

This bimodal pattern coincides almost exactly with the working hours of farmers in this area and as a result ensures continuous -man-fly contact and hence continuous transmission of onchocerciasis in the area. The most dangerous hours to work in the farms are the peak biting periods of 9.00 to 11.00 a.m. and 4.00 to 6.00 p.m.

On the seasonal variations in the fly densities, it was observed that the highest average number of flies/man/day (60) and the highest average number of flies/man/hour (~5) were found during the harmattan period but the fly densities were concentrated in the evenings. The next highest of the two indices (~s 1 and ~ respectively)CODESRIA-LIBRARY were recorded during the early rainy season. The lowest of the two indices (;::::;8 and ;:::,J) were recorded during the dry season without harrnattan followed by late rainy season (;::::;22 and ~2 respectively). It is however, important to note that the highest probability of man-fly contact in the farm at any given hour of day was highest (0.91) during the early rainy season. Coincidentally, this season happens to be the period when farmers are mostly in the farms clearing and cultivating almost 207

throughout the day. Farming activities are not as intense at other seasons of the year

especially the harmattan season (November to January) when only few people are

involved in any farmwork. The implication of this observation is that there is more

continuous man-fly contact during the early rainy season than in other seasons of the

year. The season with the lowest possibility of man-fly contact in this area is dry

season without harmattan (0.21 ).

To break the man-fly contact and hence the continuous transmission of

onchocerciasis, these rural farmers should be made aware of the biting patterns of the

Simulium flies and the most dangerous hours of the day to work in their farms.

When they become aware of these, the farmers can be advised to adjust their working hours, taking their break and leave during the peak biting periods. Another alternative is for the farmers to try and cover their bodies as much as possible while working in their farms especially during the peak biting periods. Thirdly, the farmers can use insect repellents to prevent fly bites especially at the peak biting periods. These three strategies will help to reduce the man-fly contact and hence the transmission CODESRIA-LIBRARYlevel of onchocerciasis in this important agricultural area. 208

CHAPTERS

GENERAL DISCUSSION

Onchocerciasis commonly known as "River blindness" 1s a senous debilitating and disabling disease of public health importance and is one of the diseases that the World Health Organization is making every effort to control because of its socio-economic importance. WHO (1996) ranked onchocerciasis as the second leading infectious cause of blindness in the world. Onchocerciasis is a cumulative disease whose severity in an infected person increases with age as long as the infected individual stays in the endemic community. The disease hinders socio­ economic development in rural communities where it is endemic. Agricultmal communities living around the breeding sites (fast-flowing rivers) of the Simulium vectors are the worst affected areas. (OCP/WHO, 1997). The socio-economic impo1iance of the disease is mainly as a result of blindness and serious visual impairment which are the major and most dangerous disabilities associated with the disease (WHO, 1980) Males have been reported to show higher infection rates than females dueCODESRIA-LIBRARY to differences in occupation ( e.g. Oomen, 1967, Wyatt, 1971). Also adults show higher prevalence and intensity of infection than children because of the cumulative nature of the disease. Onchocerciasis leads to desertion of fe1iile river valleys where the vector, Simulium flies, are a serious nuisance to farmers (Bradley,

1976) and the disease leads to serious economic losses as a result of reduction in the 209 productive ability of infected individuals as men and women in the most productive age groups are the worst affected (Nwoke, 1992).

The studies carried out in this research work are on different aspects of onchocerciasis in Uzo-Uwani local government area which forms the most agriculturally productive area of Enugu state and the major source of food supply in

Enugu State and environs. The aspects of onchocerciasis studied include the prevalence of the disease in the area, the local disease perception and treatment of the disease by the people of the area which involves their knowledge of the disease aetiology, their attitude towards infected persons and common treatment methods.

The effects of the disease on productivity of both farmers and students as well as the effects on social interactions, age of marriage of infected persons and married lives were examined. The effects of I vennectin drug on the onchocercal nodule were studied and finally, the daily and seasonal biting activity patterns of the Simuliium vector flies were monitored using human baits. The results obtained from the studies on the prevalence of onchocerciasis in Uzo-Uwani local govenunent area show that the entire communitiesCODESRIA-LIBRARY that make up the area are endemic for the disease although the level of endemicity varies from one community to another. Of the three indices examined, the most common manifestations of the disease in the area are impaired vision (20.2%) and palpable nodules (20.0%) followed by leopard skim (5.9%).

Uzo-Uwani local government area belong to the forest-savanna - mosaic vegetational zone of Nigeria and lies between the northern savanna and the southern 210

forest zones (Crosskey, 1981). During this study, it was observed that areas closer to

the savanna vegetational zone have higher prevalence rate of visual impairment

while areas closer to the forest vegetational zone have higher prevalence rate of

palpable nodules. This observation is in line with previous reports (Budden, 1963,

Anderson et al, 1974, Nwoke and Ikonne, 1993) that the savanna strain of

Onchocerca volvulus invades the eyes more readily than the forest strain which cause more of skin manifestations such as skin depigmentation, palpable nodules, rashes, scrotal elephantiasis and hanging groin while savanna strain results more in impaired vision and blindness.

The present results show that differences exist in the prevalence rates of vanous symptoms of onchocerciasis between males and females and between children and adults. Males were observed to have higher prevalence rates than females as repo1ied by many authors, for example Oomen (1967); Wegesa (1970);

Wyatt (1971); Nwoke and Ikonne (1993). This can be attributed mainly to occupational difference between males and females. In Uzo-Uwani local government area,CODESRIA-LIBRARY it was observed that these occupational differences start very early in life when males are involved more in outdoor activities such as playing ball, fishing, hunting, swimming etc while females are more occupied in the house than outdoors. At adult stage, these differences tend to continue when men mostly become farmers, hunters, fishermen etc and women become mostly home keepers, part-time farmers, petty-traders etc. In addition to the differences in occupation, the 211

length of time spent outdoors even by males and females of the same occupation

varies. Male farmers, for example, spend longer periods in the farms than female

farmers and when females visit the streams and rivers mainly for fetching water,

washing clothes, processing cassava or swimming, it is usually for shorter periods

than the males. Another factor that could lead to differences in onchocerciasis

prevalence and manifestatioi1S of males and females is their mode of dressing while

working outdoors. During the studies, it was observed that males and females have

different modes of dressing while working in the farms or near the rivers. Males

tend to expose greater parts of their bodies than females while working. They wear

only shorts or rolled up trousers while women wear clothes that cover most parts of

their bodies exposing only their hands and legs. These differences in occupation, in the length of time spent outdoors even by males and females of the same occupation and the mode of dressing while working outdoors lead to differences in the length and level of exposure to the bites of female blackflies which are the vectors of onchocerciasis in various parts of the world and subsequently to differences in the prevalence rates and intensity of infection in males and females. Oomen ( 1967) in his study ofCODESRIA-LIBRARY onchocerciasis in Ethiopia reported that a possible explanation of the observed marked difference in the infection rates of men and women might be that all work done in the fields was carried out by the men who spend roughly 85% of their working time in this way, whereas the women mostly stay at home. According to him, as the soil near the rivers is the best, the cultivated fields usually lie as near to 212

them as possible whereas the houses stand on higher ground (Oomen, 1967).

Brinkmann (1980) in his own study reported that in Togo, the infection was most

intense near the rivers but at the same time only very few areas were really free from

onchocerciasis except for the coastal region that was void of suitable breeding places

for the vector. According to him, the location of farms with respect to Simulium

breeding sites and the resulting differences in exposure create onchocerciasis

patterns related to occupation, habits and age as much as geography. The higher

prevalence and intensity of infection in adults than in children is a clear indication of

the cumulative nature of onchocerciasis. The longer the exposure to Simulium bites,

the higher the intensity of infection. Wegesa (1970) also reported that the distribution

of onchocerciasis, like other vector-borne diseases, is closely linked with the distribution of its vectors, the vectors themselves being limited in their distribution

by their ecological requirements.

The studies on the local disease perception and treatment revealed the people of Uzo-Uwani local government area are not aware of the aetiology of onchocerciasisCODESRIA-LIBRARY and Nwoke et al (1987) included awareness of disease aetiology as one of the human factors affecting disease distribution in onchocerciasis. The people are aware of the presence and nuisance value of the blackfly,_ Simulium, especially the disturbance by the fly bites during farmwork but they do not associate the bites of these flies with the manifestations of onchocerciasis which are also very corhmon in their communities. This ignorance leads to the mismanagement of onchocerciasis 213

manifestations, which they attribute to different causes, majorly lack of hygiene, old

age or family traits. The various manifestations e.g. rashes are treated with different

methods by different people. Some go to native doctors to treat them for rashes with

herbs, some to patent medicine dealers while others go to health centres and general

hospitals. There were reports of people that went to "good" hospitals and were

completely cured of their dermatitis. Generally, treatment of nodules is by

nodulectomy. Some people go to local excisors for nodule removal, some go to

health centres/government hospitals while others go to private hospitals. Usually, for

the different manifestations, what detenhines where different people go to receive

treatment is the availability of funds. One can, therefore, say that the two major

factors that lead to lack of proper treatment of onchocerciasis manifestations in these

rural communities are ignorance and poverty. In this local government area, there is

at present, free distribution of ivermectin (Mectizan) drug under the WHO/African

Programme for Onchocerciasis Control (APOC) in collaboration with the Federal

Ministry of Health and non-governmental development organizations (NGDO), in this case GlobalCODESRIA-LIBRARY 2000. After the first experience of the drug in the area in 1996, there were casualties of the side effects to the extent that few people (about 4) died as a result of excessive swelling of the body. Because of these, many people refused to take the drug again and prefer to live with the apparently non-disturbing disease, to them, than to die from its treatment. 214

Another area of problem in these rural communities is the misconception by the people, especially the youth, that the onchocercal rashes are infectious. This erroneous belief is at the root of social stigmatization on people with oncho-rashes.

These people are avoided by non-infected individuals. This social stigmatization manifests itself mainly in the age of marriage of young people, particularly girls.

These girls marry later than their non-infected counterparts· and unfortunately, they are limited in their choice of marriage partners to elderly men, divorcees, disabled men, childless men and men that want multiple wives. If before marriage the rashes are completely treated, such stigmatization and limitation no longer hold. In that case, the girl is free to marry any man of her choice just like other non-infected girls.

Men are not affected as much as girls in this social stigmatization. Popular opinion on why infected men are not socially stigmatised as much as infected ladies is the general belief in the area that "wealth is the beauty of a man." Marriages that have been contracted before the onset of the manifestations are not significantly adversely affected. The priority of the couple is to get treatment for the infected partner. Only few people,CODESRIA-LIBRARY especially men, tend to marry second .wives when their first wives get infected. According to the elders of the communities, the second wife is for social outings. These results on local disease perception and effects on social life are similar to those obtained by Amazigo and Obikeze (1991) at Ette also in Enugu

State. They reported ignorance of the people of Ette of the aetiology of onchocerciasis followed by some misconceptions about the cause, symptoms and \f 215 I

treatment methods of the disease. They also reported the presence of social

discrimination against the adolescent girls with oncho-rashes together with their

family members.

On the effects of onchocerciasis on productivity of farmers, it was observed

that the farmers suffer losses in work time and work output or efficiency as a result

of Simulium bites and the subsequent itching resulting from these bites. The manifestations of onchocerciasis, pa1iicularly serious visual impairment and

blindness also contribute to the economic losses. Serious visual impairment leads to loss in labour input and work efficiency. Periods of dizziness reduce the man-hours put in while counter productivity such as uprooting of crops in place of weeds reduce the efficiency of work done. Blindness, on the other hand completely disables the farmers from fmiher farm work hence resulting in complete withdrawal of the farmer from any productive activity. Blindness also makes the individual a socio-economic liability who should be cared for and led about by young children who are forced to drop out from their schools. Other manifestations such as itching arising from rashes or leopardCODESRIA-LIBRARY skin also affect productivity. Severe itching has been reported (Nwoke, 1990) to result in insomnia, lack of concentration and at times complete absenteeism from work.

For the students, it was found that various manifestations of onchocerciasis ex,.,,:lincd, namely, presence of rashes, palpable nodules and visual impairment had

,,:,i ,cJ effects on academic performance of the students. From analysis, it was 216 discovered that visual impairment had the most profound negative effect on academic performance. The presence of rashes also had a slight negative effect on academic performance while the presence of palpable nodules had no negative effect. These results were confirmed by interviewed teachers and school children who agreed that the impact of visual impairment on academic performance was the most serious manifestation of the disease as. far as the teaching/learning process is concerned. Students with impaired vision find it difficult to copy things written on the chalkboard. Most of the tiine, the teachers keep them in the front seats, yet they have difficulty seeing written things on the board. Students with rashes are disturbed through itching and scratching which result in lack of concentration while those with palpable nodules are not apparently as disturbed.

On the effects of ivermectin treatment on the Onchocerca nodule, it was observed in sectioned nodules that ivermectin treatment has a great effect on the micro:filariae within the nodule. The drug resulted in the absence of microfilariae in the connective tissues of the nodules and also within the uteri of the female worms within the nodules. The presence of microfilariae in the skin and eyes has been reported (KershawCODESRIA-LIBRARY et al, 1954) to be the cause of the various manifestations observed in onchocerciasis. There have been reports (Awadzi et al, 1985, 1986, and

1989) that ivermectin reduced skin microfilariae by over 97%, cleared ocular microfilariae and in addition the skin and ocular microfilarial counts were kept at very low levels for up to one year. According to these reports ivermectin was not 217 macrofilaricidal for Onchocerca volvulus and this long lasting effect was attributed to a novel mode of action on adult female worms characterized by an intrauterine sequestration with subsequent degeneration of normally formed microfilariae resulting in their failure to reach the skin or eye. The observation in this study that microfilariae were absent in the connective tissues of the nodules and in the uteri of the female worms within the nodules indicates that these microfilariae have been killed and degenerated within the nodules from where they mostly emanate. This observation is a pointer to the effectiveness of ivennectin in the treatment of onchocerciasis.

During the studies on the daily and seasonal biting activity patterns of

Simulium damnosum complex in Uzo-Uwani local government area, it was observed that these blackflies bite from morning till evening but the biting densities vary at different hours of the day. These variations result in a bimodal biting pattern within the day with two peak biting periods, one occurring in the morning between 9.00 and

11.00 am and the other occurring in the evening between 4.00 and 6.00 p.m. A close look at the CODESRIA-LIBRARYworking habits of the farmers in this area also revealed that there is a close correspondence between their working habits and the biting activity patterns of the flies. The farmers, particularly men, work in their farms from morning till evening especially during the early rainy season. They however, go on break in the midday between 1.00 and 3.00 p.m. Therefore, it implies that when the flies are most abundant in the farms (morning and evening), the farmers are also working in 218

the farms. When the flies escape from the farms to avoid desiccation as a result of

high light intensity, the farmers are also out from the farms to rest. Coincidentally,

the flies and the farmers tend to meet either in the farmhouses or under tree shades at

such resting times. The implication of this close correspondence is that throughout

the farming day, the flies and farmers are in close contact. This continuous man-fly

contact results in continuous transmission of onchocerciasis in the study area.

On seasonal variations in fly densities it was found that the highest fly

densities with the highest peak biting and average biting rates (50 FMH and ;:::: 5

FMH respectively) were recorded during the harmattan season. The early rainy

season had a peak biting rate of 24 FMI-I and an average biting rate of ;:::: 4 FMH

while the late rainy season had a peak biting and average biting rates of 11 FMH and

;:::: 2 FMH respectively. The lowest peak biting and average biting rates of 8 flies per

man-hour and ;:::: 1 FMH respectively were recorded during the dry season without hannattan. The recording of the highest fly densities during the harmattan season

can be attributed to the addition of migrating savanna flies to the local fly populations CODESRIA-LIBRARY(Garms and Walsh, 1987; Garms et al, 1989; Boakye, 1999) while the recording of the lowest fly densities during tl;ie dry season without harmattan can be as a result of reduction in the breeding sites due to lower levels of waters in the rivers

(Crosskey, 1990). It was observed that although the highest fly densities were recorded during the hmmattan period, these fly densities were concentrated within the evening periods with very low biting activities during the morning and afternoon 219 periods. The early rainy season, on the other hand, had slightly lower fly densities and biting rate, but the fly densities were spread tlu·oughout the day. This gives a higher probability (0.91) of man-fly contact at any given hour of day compared with a lower probability of 0.61 for harmattan season. This makes the early rainy season more dangerous in terms of possibility of continuous man-fly contact and possible transmission of onchocerciasis. Coincidentally, this early rainy season is the clearing and cultivating season when most farmers stay in the farms for the greater part of the day. This implies that there is a continuous man-fly contact and hence possible continuous transmission of onchocerciasis during this period.

CODESRIA-LIBRARY 220

CHAPTER9

SUMMARY AND RECOMMENDATIONS

9.1 Summary

The research work reported in this thesis is parasitogical, histological,

entomological, ecological and economic in nature covering varied aspects of human

onchocerciasis. The studies revealed that the whole of Uzo-Uwani local

government area is endemic for the disease. They also revealed the effects of this

debilitating disease on the productivity and social lives of these rural communities.

One of the major problems revealed in these studies is that of ignorance. Majority of

the inhabitants of these communities are aware of the presence of blackflies in their

localities but are not aware of any disease caused by the bites of these insects which

are very common in their communities and as a result, there is no serious effort to

prevent the bites. Again, they believe that the oncho- rashes are contagious. This

belief is at the root of discrimination against individuals with rashes in particular and

leads to the late marriage of such people with rashes especially young girls. Such girls are left CODESRIA-LIBRARYwith the option of marrying unsuitable partners such as elderly men, divorced men, childless men, disabled illiterate _and pom men. This type of marriage

is likely to be a frustration for such girls for life and they may not be happy to contribute their best both to their families and communities.

Another area of ignorance is in the treatment of the disease. Majority of the people do not take the right treatment for the disease. Although there is not the 221

general belief that the manifestations are caused by charm, so people do not resort to

appeasing of gods and enemies, the available drug (Mectizan) being distributed

freely in the entire local government area is not taken by most of the rural people

because of misconception.

In terms of productivity there is reduction in labour input as a result of blackfly

bites, itching, emotional disturbance, visual impairment and some other effects of

onchocerciasis such as muscle or skeletal pain. Many rural people (especially

farmers) stop farming as a result of oncho-blindness and these are mainly men and

women in their most productive age. There is also a reduction in labour output in

terms of the amount of work done within a working day due to visual impairment,

fly disturbances and itching. According to the people, the most disturbing problem of

onchocerciasis is blindness which withdraws the individual's labour years requiring

vision. Those with serious visual impairment who manage to go to farm at times end up being counter-productive because, according to them, they mistakenly remove their crops (especially rice) in place of weeds. These can lead to low production returnsCODESRIA-LIBRARY since those that get blind in any year resort to hiring labour to complete the year's work.

The results of the studies on the effects of lvermectin on nodules showed that ivermectin treatment resulted in destruction of microfilariae within the nodules. The studies on the biting patterns of the blackfly showed that there were daily and seasonal variations in the biting patterns. The daily variations result in a bimodal 222 pattern with one peak - biting period in the morniilg and another in the evening. For the seasonal variation the hannattan season was found to be the period with the highest biting densities but these bites were concentrated in the evenings. The highest probability of hrnn - fly contact was, however, found to occur within the early rainy season. Generally, therefore, th~ morning and evening periods and the early rainy season were found to be the most dangerous periods in terms of onchocerciasis transmission.

9.2 Recommendations

Major recommendations to be made from the results of the studies are shown in

Figure 9 .1. These include

1. Strengthening the Ivermectin Distribution Programme

Since 1996, WHO under the African programme for Onchocerciasis Control m collaboration with the Federal Ministry of Health and non-governmental development Organizations (NGDO) has been undertaking free distribution of ivermectin in Uzo-Uwani local government area. There is need to make the distribution CODESRIA-LIBRARYmore effective by supplying enough drugs to the area and monitoring its distribution to the various communities. Also, a more effective training of the

Community Directed Distributors (CDDs) selected from the individual communities for the drug distribution is required. 223

2. Nodulectomy

Nodulectomy (nodule excision) is a common and generally accepted

treatment procedure in Uzo-Uwani local government area. From interactions with

the people of the area, they are willing to remove the nodules. Their only hindrance

is the cost of the removal. In the health centres and health posts, the personnel to do

the removal are available but the materials to use are not readily available. The

people with nodules are expected to provide these materials and many of the people

cannot afford them. They, therefore, either go to quacks for the removal or leave the

nodules. It is recommended that nodulectomy be sponsored in these communities in

addition to the on-going drug distribution. The Ministry of Health should provide

these materials to the health personnel in the affected communities.

3. Enligbtemne:nt Campaign

The people of Uzo-Uwani local government area are largely ignorant of

the basic facts concerning the causative agent, vector and common manifestations of

onchocerciasis. This ignorance leads to misconceptions of both the cause· and symptoms ofCODESRIA-LIBRARY the disease. One of the misconceptions with serious implications is that oncho-rashes are caused by poor hygiene and are contagious. This belief leads

to social discrimination against people with rashes and culminates in the late

marriages and limited choice of marriage partners of infected people, especially girls.

The enlightemnent campaign recommended here will make use of the

Community Directed Distributors (CDDs) selected from each community for 224 lvermectin distribution in collaboration with the staff of primary health care (PHC) units e.g. health centres and/or health posts in each community. In the existing set up, APOC trains the CDDs centrally who go back to their communities to distribute drugs but the various communities are supposed to remunerate these CDDs serving them. From reports gathered from these CDDs, most of them are discouraged from doing the work because their communities were not as much as giving them transport fare to travel to the local government headquarters to collect the drugs. It is recommended that there should be further training on the cause, vector, manifestations and effects of onchocerciasis and that these CDDs be given token allowances by the Ministry of Health to encourage them to carry out the assignments effectively.

From the little enlightenment carried out during the studies, it is obvious that the communities are willing to learn. Some of the areas of enlightenment suggested include the aetiology of the disease, onchocerciasis, including what causes it

(Onchocerca volvulus), the vector (Simuliwn damnosum) and the symptoms (itching, i·ashes, palpableCODESRIA-LIBRARY nodules, visual impairment, ,eopard skin, lizard skin, hanging groin, scrotal elephantiasis, body pains etc ). Also to be included here is where and how they get the infection (mostly near rivers and in farms and through Simulium bites), the socio - economic effects of onchocerciasis, the fact that the manifestations, especially rashes, are not contagious. Finally, they should be encouraged to try and prevent the bites particularly during the peak biting periods through covering 225 themselves properly while working outdoors, usmg insect repellents or changing their working habits, taking their break and leave from the farms during the peak biting periods especially the evening peaks (between 5.00 and 6.00 p.m.) which are usually higher.

Another area of the enlightenment should be on the effective use of the choice drug, lvermectin. Some people, for example little children and people with respiratory diseases are not allowed to take the drug and the drug should be taken as a single dose ( 4 tablets for an adult) once a year. These should be made known and stressed to the CDDs during the training before drug distribution. The effect of not taking the drug by the entire community should also be stressed, for example the danger of serious visual impairment and blindness with their long- lasting implications on both the young and old. Again, the rural people have no recorded medical history and this has led to a few tragic cases that discouraged many in the affected communities from taking the drug. It is recommended that the medical history of each individual be traced and recorded before the administration of the drug. ProperCODESRIA-LIBRARY monitoring is also required. 4. Vector Control

Boakye (1999) reported some of the successful results of vector control by

World Health Organization (WHO) in the Onchocerciasis Control Programme

(OCP) areas of West Africa. To be able to eradicate onchocerciasis in Uzo-Uwani local government area, it is recommended that vector control be undertaken in 226

addition to effective distribution of ivennectin drug, nodulectomy and

enlightenment campaigns. These strategies, if well co-ordinated will yield the

desired result in this area and eliminate c1chocerciasis as a public health and socio­

economic problem in Uzo-Uwani local government area as has been reported in the

OCP areas (WHO, 1996).

5. Provision of Social Amenities

It was observed in the course of this study that all the communities in Uzo­

Uwani local government area lack pipe-borne water and therefore depend on streams and rivers as their major source of water supply. Provision of pipe-borne water/ boreholes would help to reduce the man -fly contact arising from going to the river/stream to fetch water for drinking and laundry.

CODESRIA-LIBRARY 227

Effective Drug Nodulectomy using Enlightenment Distribution using Primm;y Health Care Campaigns usmg Community Directed Personnel CDDsandPHC Distributors personnel -·"-·------.----~ ~ " / ~------~------~ World Health Organization, Federal Ministry of Health, Non-governmental Developmental Organizations

Vector Control Provision of Pipe­ usmg borne water and/or WHO/APOC borehole by the

Figure 9.1: Schema.tic Representation of Strategies for Controlling Onchoccrciasis in Uzo-Uwani Local Government Area

CODESRIA-LIBRARY 228

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CODESRIA-LIBRARY 252

APPENDIX 1

Questionnaire Schechde on Epidemiology and Effects of Human Onchoccrdasis on Social Life in Uzo-Uwani Local Government Area.

Section I: Personal Data (For Students)

1. Serial Number:

2. Date:

3. Name of School:

4. Name of pupil/student

5. Sex:

6. Age group:

(1) Below 5 years (2) 6-9 years, (3) 10-14 years

(4) 15-19 years (5) 20 years and above.

7. Class:

(1) Pre-School, (2) Primary 1-3, (3) Primary 4-6,

(4) J. S. 1-3, (5) S.S. 1-3. 8. CODESRIA-LIBRARYHome town: 9. Where do you live?

10. For how long?

(1) Below 1 year, (2) 1-2 years (3) 2-5 years

(4) Above 5 years,

11. Other places you lived in the past: 253

Name of town How iong? Date (fro1m 19 ..... to 19 ... )

1.

2.

3.

4.

12 What other activity do you engage in besides schooling?

Section I: Personal Data (Foll" Workers)

I. Serial No: (2) Date:

3. Name (if you please):

4. Sex:

6. Age range: (1) 5-9 years (2) 10-19 years (3) 20-29 years (4) 30-39 years

(5) 40- 49 years (6) 50-59 years (7) 60 years and above.

5. Home town:

6. Where do you live? 7. For howCODESRIA-LIBRARY long have you lived there? 1. Less than 1 year 2. 1-2 years. 3. 2-5 years 4. Above 5 years.

8. Can't say. (1) No response.

9. Other places you lived in the past. 254

Name of town How long? Date) from 19 ... to 19 ... i. ii. iii. iv

10. What is your regular occupation? ( l) Schooling, (2) School leaver/applicant.

(3) Civil service (specify): (4) Trading. (5) Farming. (6) Fishing (7)

Artisan (Tailor, mechanic, electrician, carpenter, Barber/hair dresser etc.) (8)

· Others (specify) ...... (9) Can't say (I 0) No response.

11. What is your highest educational qualification?

1. No formal education. 2. First School Leaving Certificate. 3.

WASC/GCE

4. OND/NCE 5. First Degree/ I-IND. 6. Higher Degree. 7. Others

(specify) ...... 8. Can't say. 10. No response.

12. Where do you work/trade? 13. How CODESRIA-LIBRARYlong do you normally spend in your place o work/trade in a day? 1. Less than 1-hour (2) 1-5 hours (3) 6-10 hours ( 4) More than 10 hours (9)

can't say. (0) No response.

14. What other activities do you engage in besides your regular occupation? 255

Section U: Community Data

1. Name of community:

2. What is the most common economic activity in this community? (1) Farming

(2) trading (3) fishing (4) wine tapping (5) Road transportation (6) Others

(specify) ...... (9) Can't say (0) No response.

3. Which of these facilities are available in the community?

Facility Present Absent Number Can't No say response i. primary school ii. Secondary School iii. Health Centre iv. Government Hospital v. Private Hospital vi. Mission HospitaR vii. Patent Medicine Store viii. Native doctors ix. Church x. Mosque xi. Market xii. Private company/industry xiii. Government farm/cstab. xiv. Others (specify) 4. Is there any river or stream in the community? (1) Yes (2) No. (9) Can't say (0) NoCODESRIA-LIBRARY response. 5. What are the other water sources in the community?

(1) Tap water (2) Well (3) Spring (4) others (specify)

6. In which of these water sources do people of this community usually go for

the following activities? 256

Activity River/stream Tap Weil Spring Others (sveci(v) 1. Collect drinking water

2. CoHcct water for cooking

3. Taking bath

4. Soaking and washing

5. swimming

6. washing clothes

7. fishing

8. others (specify)

Section HI: Local Disease Perception and Treatment

1. Do you know a small black fly called (local name)?

(I) Yes (2) No. (9) Can't say. (0) No response.

2. How abundant is this fly in your community? (1) NotCODESRIA-LIBRARY seen at all (2) Seen but not abundant (3) Abundant (4) Very abundant (9) Can't say (0) No response.

3. Where is this black fly usually found most?

(1) Everywhere (2) around the house (3) In the fields (4) In the bushes (5)

In the farms (6) Near the river/stream (7) Others (specify) ......

(9) Can't say (0) No response. 257

4. What time of the day is it most abundant?

(]) In the morning (6-10 a.m.) (2) Before noon (10-12 Noon) (3) In the

afternoon 2-4.00p. m.) (4) In the evening (4.00-7.00 p.m.) (5) In the night

(after 7.00 p.m.). (9) Can't say (0) No response.

5. What season of the year is it most abundant?

(1) Dry season (without harmattan) (2) Harmattan (3) Rai11y season (9)

Can't say (0) No response.

6. Where does it breed?

(J) On the trees (2) In the bushes (3) Jn river/stream (4) In ponds (5) Other

(specify) ...... (9) Can't say (0) No response.

7. Have you ever been bitten by this fly?

(1) Yes (2) No (9) Can't Say (0) No response

8. If yes to question 7, how often?

(]) Everyday (2) At times (3) Rarely (9) Can't Say (0) No response.

9. What part of the body does this fly bite most?

(1) All CODESRIA-LIBRARYpart of the body (2) On the head/face (3) On the arms/hands (4) On

the legs (5) On the trunk (9) Can't say (0) No response.

10. Which group of people does it bite most?

(1) Everybody (2) Adult males (3) Adult females (4) young males (5)

Young females (9) can't say (0) No response. '258

11. Is there any disease/illness associated with the bite of this black fly?

(1) Yes (2) No (9) Can't Say (0) No response.

12. If yes to question 11, name the disease/illness.

1.

2.

3.

4.

13. Is there any method used to prevent the bite of this fly?

(1) Yes (2) No (9) Can't say (0) No response

14. If yes to question 13, what are the methods?

(1) Use of broom to kill theri1/clrive them away. (2) Use of palm fronds to kill

them/drive them away. (3) Use of oil/ointment on the body to deep them

away. (4) Any other methods (specify). (9) Can't say (0) No response.

15. Do you know of any skin disease ( onchoclermatitis/rashes) called (1) YesCODESRIA-LIBRARY (2) No (9) can't say (0) No response. 16. How can a person get this skin disease (choose as many. As are applicable).

(1) It is inherited. (2) Through poor hygiene/dirtiness (3) Through the bite

of the small black fly above. (4) Through the bite of any other insect. (5)

Through jqju/charm/evil people (6) Witchcraft (7) Malnutrition (8) Any

other (specify)...... (9) Can't Say (0) No response. 259

17. Can this disease be passed from one person to another?

(1) Yes (2) No (9) Can't Say (0) No response.

18. If yes to question 17, in what ways (choose as many as are applicable).

1. Through direct body contact. 2. Through use of the same materials ( e.g.

Clothes, towels, bed sheets, buckets, soap etc.) (3) Through blood

transfusion/same injection needles. (4) Through sexual contact. (5) Through

bite of the black fly above. (6) Through bite of any other insect. (7) Any other

(specify) ...... (9) Can't say (0) No response.

19. Is there any season of the year this skin condition gets worse?

(1) Yes (2) No (a) Can't say (v) No response.

20. If yes to question 19, what season of the year?

(I) Dry season (Without harmattan) (2) Harmattan (3) Rainy season

(4) Others (Specify) ..... (a) Can't say (0) No response.

21. Can the spread of this skin disease be prevented?

(I) Yes (2) No (a) Can't say (o) No response. 22. If yes to questionCODESRIA-LIBRARY 21, in what ways? 1. Personal hygiene, 2. Avoid contact with infected person, 3. Avoid

blood/it~ection needle from infected person. 4. Avoid use of the same materials

(clothes/bucket/scalp/bed-sheets etc.) with infected person. 5. Avoid bite of the

small black fly (local name) 6. Avoid bite of other insects. 7. Any other

(specify) ... (a) Can't say (o) No response. 260

23. Can't this skin disease be cured?

(l) Yes (2) No (a) Can't say (o) No response.

24. If yes to question 23, in what ways?

1. Use of local herbs, (2) Use of drugs, (3) by rubbing ointment (name) ....

(4) Others (specify) ...... (9) Can't say (0) No response.

25. Where do people of this community usually go to receive treatment for this skin

disease?

(I) They treat it at home, (2) To chemists, (3) To native doctors, (4) To health

centres, government hospitals (5) To private hospitals, (6) Others (specify) ....

...... (9) Can't say (0) No response.

26. Do you know of any drugs used to treat this skin disease?

(1) Yes (2) No, (9)Can't say (0) No response

27. If yes to question 26, name the drugs (1) (2) (3)

28. Do you know of any lump (nodule) in the body called (local name)?

(J) Yes (2) No) (9) (a) Can't say (0) No response 29. What causesCODESRIA-LIBRARY this lump? ( 1) It is inherited (2) Poor hygiene/dirtiness (3) Charm/j t~j u/evil people

(4) Bite of the small black fly above (5) Bite of other insects (6) Malnutrition

(7) Others (specify) (9) (a) Can't say (0) No response.

30. Can nodule be prevented?

(1) Yes (2) No (9) Can't say (0) No response 261

3 I. If yes to question 30, in what ways?

(1) By being clean (2) By avoiding channs/juju/cvil people (3) By avoiding

contact with infected person ( 4) A void use of the same materials with the

infected person. (5) avoid bites of the black.fly (6) avoid bites of other insects (7)

Any other (specify) ...... (9) Can't say (0) No response

32. Can nodule be cured?

(1) Yes (2) No (9) Can't say (0) No response.

33. If yes to question 32, in what ways?

(I) Use of herbs (2) Use of drugs (3) By removing the nodule. ( 4) Any other

(specify) ...... (9) Can't say (0) No response.

34. Where do people of this community usually go for treatment/removal of nodule?

(1) To health centres/government hospitals, (2) To private hospitals, (3) To local

excisors (removers) (4) To chemists/patent medicine dealers (5) To

herbalists/native doctors (6) Any other (specify) ...... (9) Can't say (0)

No response 35. Do you knowCODESRIA-LIBRARY of any drugs used in the treatment of nodules? (1) Yes (2) No (9) Can't say (0) No response

36. If yes to question 35, name the drugs.

(1) (2) (3)

37. Is there any connection between dermatitis (rashes) and nodules?

(I) Yes (2) No (3) (9) Can't say ( 4) No response. 262

38. If yes to question 37, what is the connection?

(1) I cannot explain the connection, (2) Rashes result in nodules, (3) Nodules

results in rashes, (4) They usually go together, (5) They are caused by the same

agents (6) Other (specify) ...... (9) I can't know. (0) No response.

39. Is there any connection between these rashes and any other illness/ disease?

(1) Yes (2) No (9) Can't say (0) No response.

40. If yes to question 39, name the illness/disease.

(1) (2) (3)

41. Is there any connection between nodules and any other disease/illness?

(I) Yes (2) (9) Can't say (0) No response

42. If yes to question 43, name the illness/disease.

(1) (2) (3)

Section IV: Effects of Onchoccrciasis on Social Lives

A. Effects of onchodermatitis and nodules_ on social interactions of people with and withoutCODESRIA-LIBRARY them 43. Are people with rashes and/or nodules discriminated against 111 our

school/community?

(1) Yes (2) No (9) can't say (0) No response.

44. If yes to question 43, in what ways? (Choose as many as are applicable)

People avoid (1) Reading/working/trading/farming together with them. . 263

(2) Sitting on the same chair/seat with them

(3) Making friends with them.

( 4) Eating together.

(5) Swimming with them, taking bath with them.

(6) Marrying them. (7) Sleeping with them (9) Can't say (0) No response.

45. How do people regard them in your community?

( l) As normal people, (2) As social outcasts.

(2) As unclean/dirty (4) As people with infectious disease. (5) As people that

· are cursed. (6) As poor and ignorant people (7) Others (specify) ...... :.:.:: ..

(9) (9) Can't say· (0) No response.

46. When they are discriminated against, how do they usually react/feel?

(1) They show noreaction/are bothered. (2) They feel ashamed. (3) They are

moody. (4) They are withdrawn. (5) They are aggressive (6) Others (specify) ...

(9) Can't say (0) No response.

47. How do people with dermatitis and/or nodules cope with their condition? ( 1) TheyCODESRIA-LIBRARY don't bother. (2) They try to hide it with their wears, (3) They do not appear in public places (4) Others (specific) ...... (9) Can't say (0) No

response.

·B. Effects on age of marriage

48. Does the disease affect the age at which the infected persons marry?

(1) Yes (2) No (9) Can't say (0) No response 264

49. If yes to question 48, does it affect girls more than men?

(I) Yes (2) No (9) Can't say (0) No response.

50. Does it eventually stop the girls/men from getting married?

(1) Yes (2) No (9) Can't say (0) No response.

51. Does the disease affect the choice/option of life partners of infected persons?

(1) Yes (2) (9) Can't say (0) No response.

52. If yes to question 51, what options do they have?

(1) Old men/ladies, (2) Widows/Widowers, (3) Divorcees, (4) Disabled

men/girls, (5) Poor men/illiterate girls. (6) Others specify ...... (9) Can't

say (0) No response.

53. If the rashes/nodules clears, does the affected girl/man still get married?

(1) Yes (2) No (3) It depends on his/her age (9) Can't say (0) No

response.

C. Effects on married life (For married people)

54. What is the attitude of a husband/wife when the partner develops dermatitis and/or nodulesCODESRIA-LIBRARY (Choose as many as are applicable). (1) It does not affect their relationship in any way.

(2) I-le/she avoids the partner. (3) Does not go to public places with him/her.

(3) Does not eat what he/she cooks or touches. (5) Others (specify) ......

(9) Can't say (0) No response.

55. Does this disease possibly affect their marital relationship? 265

(1) Always (2) Sometimes 0) Never

(9) Can't say (0) No response

56. Does it usually lead to marrying another wife/husband?

(1) Always (2) Sometimes (3) Never (9) Can't say (0) No response.

57. When the disease clears, do the partners come together again?

(1) Always (2) Sometimes (3) Never (9) Can't say (0) No response.

Section V: Physical Examination for the Manifestation of Ondrnccirdasis

a. Itching - (i) Present (ii) Absent Location:

Severity (i) Mild (ii) Severe (iii) Very severe

b. Rashes - (i) (i) Present (ii) Absent. Location:

Severity (i) Mild (ii) Severe (iii) Very severe c. Nodules (i) Present (ii) Absent. Location: ...... No: ...... d. Lizard Skin (i) Present (ii) Absent. Location:

Severity (i) Mild (ii) Severe (iii) Very severe e. Leopard Skin i) Present (ii) Absent Location:

SeverityCODESRIA-LIBRARY (i) Mild (ii) Severe (iii) Very severe f. Eye Problem (i) Present (ii) Absent Location:

Severity (i) Mild (ii) Severe (iii) Very severe g. Muscle-skeleton pain (i) Present (ii) Absent Location:

Severity (i) Mild (ii) Severe (iii) Very severe 266 h. Hanging groin (i) Present (ii) Absent Location:

Severity (i) Mild (ii) Severe (iii) Very severe

1. Elephantiasis i) Present (ii) Absent Location:

Severity (i) Mild (ii) Severe (iii) Very severe

J. Others (specify) ......

CODESRIA-LIBRARY 267

APPENDIX 2

Interview Schedule on the effects of River blandness on prnductilvity. (For farmers/ other workers)

Na111e: ...... Age: ...... years

Sex: Male/ Female

Onchocerciasis (River Blindness) manifestations present:

(i) Itching: Present/Absent.

(ii) Rashes: Present/Absent.

(iii) Modules: Present/Absent.

(iv) . Lizard Skin: Present/Absent.

(v) Leopard skin: Present /Absent.

(vi) Impaired vision/blindness: Present /Absent.

(vii) Others: ......

1. What is your major occupation?

(i) Fanning (ii) fishing (iii) trading (iv) others CODESRIA-LIBRARY What other outdoor activities do you engage in during the day?

(I) ......

(2) ...... ······ ......

(3) ......

(4) ...... 268

2. How many days in a week do you normally work in your farm? ...... days.

3. What time do you normally start working in your farm in a day?

...... a.in.

4. What time do you normally stop working 111 your farm 111 a day?

...... p.n1.

5. Do you normally go on break within the working hours? Yes/ No.

a. If yes, what time and for how long? ...... a.111./p.m. for

...... hours.

b. Where do you stay during your break time?

6. What farm activity usually takes place at the period of maximum bite of the

blackfly?

(1) Bush clearing (2) Cultivation

(3) Weeding (4) Harvesting.

7. How do you cope with the bite of the blackfly during your working hours?

(1) Kill/chase them away. (2) Cover body during work. (3) PutCODESRIA-LIBRARY fire around. (4) Others: ...... 8. How many hours do you lose out of your working hours as a result of the

blackfly bites? ...... hours.

9. Does the disturbance by blackfly bites cause you to clear/

cultivate/weed/harvest less land area than you should have? Yes/No

10. Does it lead to production of less crop output than you should have? Yes/No 269

11. What is the most disturbing manifestation of river blindness to you?

(1) Itching Yes/No

(2) Rashes Yes/No

(3)Nodules Yes/No

( 4) Lizard skin Yes/No

(5) Leopard skin Yes/No

(6) Impaired vision /blindness. Yes/No

13. Around what age did you notice these manifestations 111 your body?

...... years.

14. In what ways do these manifestations hinder your work?

(1) Through excessive itching/scratching.

(2) Through impaired vision.

(3)

(4) ......

15. Does it stop you entirely from going to work? Yes/No. 16. WhatCODESRIA-LIBRARY are those things other people do in your occupation that you cannot do because of the manifestations?

( 1) ......

(2) ......

(3) ......

(4) ...... 270

How do you make up for the loss of labour supply caused by these manifestations?

(1) ...... (2) ...... (3) ......

(4) ......

What is the average daily wage for

(a) Clearing a farm N= ......

(b) Cultivating a farm =N ......

(c)Weeding a farm N ......

( d) Harvesting a farm N ......

Have you received any treatment for the manifestations of river blindness? Yes/No. a. What type of treatment?

(I) Drug Yes/No. Name of drug: ......

(2) Local Yes/No. b. Who gave the treatment? (1) Doctor/Health Officer (2) Chemist (3) Herbalist.

(4) Others (specify): ...... b. For how long did you take the treatment? (1) ...... CODESRIA-LIBRARY days (2) ...... weeks (3) ...... months (4) ...... years.

20. If you are treated, do you think it will help you increase.

(a) the number of hours worked/day : Yes/No

(b) the amount of work done in a day: Yes/No

(c) the amount of farm products produced: Yes/No. 271 APPENDIX3

· · Weighted Average Performance of Secondary Schools in Uzo-Uwani Local Government Area·

School Years English_ Math Int. · Soc. Religion . Igbo Agric.. Total Average. Weighted Science Studies .. Science. ,Average Performance 1. Adada Sec. Sch. Nkpologu 1994 2.613 2.000 · 2.000 2.065 .·2.065 2.258 2.161 15.162 2.166 2.202 1995 2.046 2.182 3.470. 2.258 . 2.061 2.303 3.576 1:7.896 2.55T 1996 2.200 2.143' 2.200 2.400 1.194 · 2.086 · 2.086 14.309 2.044 1997 2.081 2.081 2.135 2.108 · 2.027 2.029 2.082 14·.543 2.078 .. 1998 2.114 .. · 2.286 2.229 2.000 2.114 2.294 2.118 15.155 2.165

2~ c.s.s. Abbi.. Ugbene 1994- 2.447 2.277 2.617 2.192. 3.000 2.021 2.213 ·. 16.77 · . 2:395 2.273 1995 2.371 3.245 · 2.265 2:318. 2.252 2.662 '.3.576 18.689 2.670 1996 2.156 1.183 1.916 2.169 L916 2.056 2.11.3. 14.199 2.028 1997 2.234 2.263 2.307 2.146 2.117 .. · 2.204 2.000 . 15.271 ~ 2.182 1998 2.032 2.236 2.142 2;110 2.095 1.969 2.063 14.647 2.092

\.·.,'. 3. c.s.s. Nimbo 1994 2.583 3.833. -2.583 ·. ·-2.667 ·3.375 19.875 2.839 2.367 .• . 2.417 2.417 1995 . 2.591 3.113 2.644' 2.539 2.070 2.800 2;765 18.522 2.646 1996 · 2.083 2.167 2.000· 2.183 .· 2.183 2.133 2.200 .• 14.949 2.136 1997 ·2.026 2.442 2.078 .2.234 2.052' 2.079 · · 2~158 · 15.069 .. 2.153. 1998 2.294· .. . 2.185 2:037 1.907 · 1.963 1.982 2.056 .. 14.424 2.06L. -4. ·Uvuru Sec~ Sch~ Uv11ru . . · .· · 1994 .. 2.1.59. 1995 2,.185 2.111 ·. 2.370 ·f.482- 2.'519 2.444- 13. 111 2.185 1996 .. 2.100· 2.333...• 230() .. • : ·2.067. · · .2.000 2.067 2.033' 14.900 2.129· .. . . ·1997· 2.000 . 2.213· 2.298 · 2.298. 2,128 .2;170. 2.085 15.192' . 2.170 1998 · .. : 2:050 . ··. 2.20Q. 2.100 ' 2.150 2.200. 2.100 2.250 '15.050 2.150. ''•"...... 5~ c.s~~~ l,Jkpata. · 1994 2.200 2.00.0.CODESRIA-LIBRARY 2300· · 2.200. J:100. 2~100 · 2.100 · . ·t6.000: - . 2.286_ . 2.185 '• ·. .. 1995c · . 2.320 2.480 2.800. .· 2.920 2;080 2.100· -2.600 1s~·900 · - · 2~211 1996·-· ., . '2;00o' 2.-146 .·· 2;293 . 2.195 ..•. 2.048 -2.244·_ ·2,098. 15.025 2.146 . ~ .. [ J997. 2.080·: -2:000: 2;10 ·2:080 2;I60'-' 2.400 4-.160 15.040 ._ .• 2:.-149 . . .1998 2'.0~'-· 2.091' · 2.136 . • 2.091 .···-2.091 ·2.046··· .2;()00 · 14.501 · 2.072;. · .

.. , .:·, ~ . >,··.·': .

·:.::· .. . ',. 272 · . 6. Atta Mem. Sec. Sch. 1994 · 2.444 3.556 3.67 · 2.778 2.778 2.778 3.000 21.001 · 3.000 2.444 Adaba. . · 1995 2.727 2.667 3.394 2.030. . 3.515 3.091 · 4.182 21.606 3.087 1996 2.182 1.818 1.818 2.061 3.061 2.000 2.000 15.243 . 2.178 1997 3.356 2.267 2.178 2.044 2.133 2.222 2.044 15.244 2.178 1998 2.053 2.316 2.053 · 2.158 2.000 l.895 1.421 · 13.786 1.971 7. G.S.S. Umulokpa 1994 2.546 · 3.758 3.212 2.182 3.515 3.636 2.424. 21.273 3.039 2.285 1995 2.833 2.250 1.583 1.833. 1.625 2.333 1.583 14.040 2.006 · 1996 2.074 · 2.049 2.074 2.099 2.124 2:124 2.074 14.614 2.088 1997 2.000 2.043 · · 2.000 2.087 2.152 2.435 2.261 · 14.978 2.140 1998 2.278 2.278 2.222 · 2.056 2.167 2.000 2.056. 15.057 2.151 8. B.S.S. Akiyi- Umulokpa 1994 2.000 3.067 2.622 2.267 .· 2.044 2.444 ·. 2.267 16.711 . 2.387 2.278 · 1995 2.296 2:333 2.852 · .2.148 3.222 3.037 2.148 18.033 2.576 1996 2.101 . 2.IOr 2.051 2.203 1.899 2.000 2.016: 14.431 2.062 1997 2.346 2.159 2.346 2.392 2.308 2.346 2.235· 16.132 2.305 1998 2.071 2.071 2.179 2.107 2.071 ·. 2.071 1.964 14.434 2.062 9 .. C.S.S. Ogurugu. 1994 2.138 2.483 · 2.483 3.105 2.552 · 2.414 2.483 17.658 2.523 2.300 . 1995 2.125 2.375 2.688 2.188 · 2.188 2.250 1.563 15.377 2.197. 1996 2.146 2.195 2.098 2.195 '.Z:098 1.854 12.586 . 2.098 .1997 2.059 2.235 2.353 2.118 2.177 - . 2.353 13.295 2.216 1998 ·2:000 2.278 2.778 2.167 4.05~ 1.939 . 1.889 17.107 2.444 10. C.S.S. lgga 1994 2.514 •. 3.353 2.824 2.588 2.971 2.514 2.800 16.764 2.395 . 2.230 1995 2.286. 2.476 2.381 1.810 . 2.381 2.095 2.762 16.191 2.313 1996 ·. 2.069 2;000 1.931 .2.345 · 1.931 2.414 .. 2.138 14~828 2.118 1997 .·. 2:192 · 2.423 2.462 2.154, 2.077. 2.275 2.077 15.660 2.237

1998 2.818 2.303 1.818 2:122 · 2.242. .. • 2.000 2.313 .14.616. 2,088 . . 11. Uzo-Uwani Sec. Sch. ·.1994 L380 · 2.155 2.155 · 2.138 2.155 l.948 .· 2.000 13.931 · .· 1.990 · 2.068 ·• Adani · 1995. 2.038 2.115 2.43.6 · 1.734: l.949 1.833 1.423 13.528 i.933 · 1996 · 2.047- 2.019 . 2.047 . 2.015.· ·2.009·. · . •·.L934 2.085 14~216 . . 2.03 r 1997 2.143 2.344. . :2.270 .. 2.064 • ·. 2~175. 2.159 13.15~ · 2.193 ···,,, . . · 1998 2.148 · . 2.'2.75· 2.389 ·.·.2.128: . · 2;220 2.037 2'.l65' ·. · 15.362 2.195 12., CS.S. Nrobo· ·. · ·· 199.4 . · CODESRIA-LIBRARY.. .. . ,. 2~119 - - •. f995·· .. . - .. - - : . .· 1996 •, 2'.067 •. 1.933 2.267. 2.133: i.80()' 2.067 2.133 14.400 2.057 .. · .. : t997 .·· · 2.333 'J.778 2.333. 2:000 ·. 2.000· 2.222. ·: 2.444 -15.110 2.159 . .. ,1998. 2.T43 2.07i, ·: 2.214 ·. · . 2.357: 2:01r.· l.926 .. 2.222. 15.004 .··.·• .. . 2.143''

qr • t~· " " .. ~ ' .. ~:

''. ,_ ..':i: -~-.: >-" ' ,:.: '.,,. 273

APPENDIX

Processing of Nodules a. Maniuu:ai processhag

After collection, the nodules were fixed in formol-saline. The nodules were

then trimmed to smaller sizes using a sharp scalpel blade and put into

specimen bottles containing 70% alcohol for 5-8 hours. The tissues were

transferred into 90% alcohol for one hour each. They were transferred into 2

changes of xylene for one hour each. b. Embedding

The tissues were removed from xylene and packed in a perforated stainless

basket and put into a vacuum oven for 1-2 hours to suck in some melted

paraffin wax. The tissues were fransferred into the embedding machine and

using molds, they were molded into blocks in paraffin wax allowed to cool

and mounted on wooden blocks for cutting. c. Sectioning The embeddedCODESRIA-LIBRARY tissues were cut into 5-micron sections usmg a rotary microtome. The sections were placed on slides smeared with adhesives. d. Staining

The slides were placed in an oven to melt wax. They were then placed in

xylene for 10 -15 minutes to remove wax. The slides wee placed in a series

of alcohol preparation Viz. absolute-)- 90% -)-80% -)o 70% and then washed 274

in tap water. The slides were stained in haematoxylin (30 min - 1 hour) and

washed in tap water. The slides were dipped in acid alcohol and washed in

tap water and then stained in eosin and washed. The slides were dehydrated

using a series of alcohol Viz. 70% -,.80%-~ 90% -,. absolute. They were

then placed in xylene to remove alcohol. e. Mm.mfo1g

Using few drops of mountant (dpx) the tissues were mounted on the slides for

permanent preparations.

CODESRIA-LIBRARY