BCG Efficacy in Children Aged 1-7 Years in a Rural Area in East Nile Province

University of Khartoum Faculty of Medicine Medical & Health Studies Board

BCG Efficacy in Children Aged 1-7 years In A rural Area in East Nile Province

By Dr. Mai Mohamed El Hassan Mustafa M.B.B.S (University of Khartoum)

A thesis submitted in partial fulfillment for the requirements of the Degree of Clinical MD in Paediatrics and Child Health, February – 2004

Supervisor Dr. Salah Ahmed Ibrahim Associate Professor, Department of Paediatrics and Child Health Faculty of Medicine, U of K

TToo ……

MMyy lloovveellyy ppaarreennttss ……

MMyy hhuussbbaanndd ……

MMyy ssiisstteerrss,, bbrrootthheerrss

TToo aallll wwhhoo lloovvee && ttaakkee ccaarree ooff cchhiillddrreenn ……

MMaaii

ﻗﺎل ﺗﻌﺎﻟﻰ:

ﺻﺪق اﷲ اﻟﻌﻈﻴﻢ ﺳﻮرة اﻟﺮﺣﻤﻦ ﺁﻳﺔ رﻗﻢ (4-1)

CONTENTS

Page

- Acknowledgement i - Abstract (English) ii - Abstract (Arabic) iv - Abbreviations vi - List of tables vii - List of figures ix

CHAPTER ONE 1. INTRODUCTION & LITERATURE REVIEW 1 1.1. History of tuberculosis 3 1.2. Tuberculosis in Sudan 6 1.3. Aetiology 12 1.4. Epidemiology 13 1.5. Pathology 18 1.6. Clinical Manifestations 19 1.7. Laboratory Diagnosis 39 1.8. Tuberculin skin test 44 1.9. Treatment 55 1.10. BCG vaccine 58

JUSTIFICATIONS 80 OBJECTIVES 81

CHAPTER TWO 2. PATIENTS AND METHODS 82 2.1. Nature of the study 82 2.2. Study area 82 2.3. Duration of the study 83 2.4. Study population 83 2.5. Inclusion criteria 84 2.6. Exclusion criteria 84 2.7. Research methodology 84 2.8. Research team 85

4 2.9. Input of the author 85 2.10. Research tools 86 2.11. Diagnosis 88 2.12. Treatment 89 2.13. Data entry and analysis 89 2.14. Funding 89

CHAPTER THREE 3. RESULTS 90 3.1. Socio demographic characteristics of the study population 90 3.2. Certain characteristics of children 91 3.3. Mantoux test results 93 3.4. Factors affecting vaccination state in the study population 95 3.5. Factors affecting BCG scar 95 3.6. Factors affecting tuberculin reaction 95 3.7. TB cases in the study 97

CHAPTER FOUR DISCUSSION 130

CONCLUSION 142

RECOMMENDATIONS 144

REFERENCES 147

APPENDIX (Questionnaire)

5 ACKNOWLEDGEMENT

I am deeply grateful to my supervisor Dr. Salah

Ahmed Ibrahim, Department of Paediatrics and Child

Health, Faculty of Medicine, University of Khartoum for his continuous supervision, constructive criticism, support, encouragement and guidance.

I wish to express my thanks to the children and their parents in El Tukunab, Banant & El Rahana areas who were the core of the study.

Thanks are also extended to the working staff at El

Tukunab Health Centre for their generous cooperation.

My special thanks to my husband for his patience, kindness and encouragement.

I am also thankful to Miss Shereen Yousif for her great effort and typing.

I am grateful to my lovely sister Nasreen and to all my family for encouragement and support.

ABSTRACT

Tuberculosis remains the most common single cause of death.

Although BCG vaccination was introduced in 1920, yet its protective role remains contraversial.

This study was conducted in three rural areas in East Nile

Province, during the period from 1st of June to 31ist of August 2003. It was community-based study done through house-to-house survey.

The main objectives of this study were to evaluate the efficacy of

BCG vaccine and to correlate the efficacy to presence or absence of scar and some social factors. A total of 398 children (50.3% Males and 49.7%

Females) aged 12 months to seven years were studied. All relevant informations on medical, social history, history of BCG vaccination including age of vaccination, symptoms suggestive of tuberculosis, physical examination including checking BCG scar and measurement of scar size, were noted on a pre-coded questionnaire. Mantoux test was done and the induration was measured 72 hours later.

The study showed that the predominant age group was 12-36 months, which represents 42.7% of the study population; 95% were BCG vaccinated (documented by BCG scar, vaccination card or both). 73.9% of them were vaccinated in the first 3 months of age and 72% of the vaccinated had BCG scar, 39.1% of the scars measured from 2 to 5 mm, reflecting good efficacy of BCG vaccine given.68.85% of children

7 showed tuberculin reaction less than 5mm while only 2.5% showed reaction more than 10 mm.

It was found that there is significant association between the size of the scar and

tuberculin measurement supporting the fact that BCG scar is a strong indicator for

vaccine efficacy.

During the study 2(0.5%) cases of TB were diagnosed, their ages were 14 and

18 months and both were BCG vaccinated as documented by BCG scar (in the range

of 2-5 mm), infected TB cases represent (0.1%) of the vaccinated children, which

reflect high protection although the number of non vaccinated group was small in

comparison with the vaccinated group. Social factors such as family income and

number of persons per room did not significantly affect TB infection.

The study concluded that BCG vaccination was efficient reflected in the good

immunity documented by BCG scar and just (0.1%) TB cases among the vaccinated

group.

ﺧﻼﺻﺔ اﻷﻃﺮوﺣﺔ

ﻳﻌﺘﱪ ﻣﺮﺽ ﺍﻟﺴﻞ ﺃﻛﺜﺮ ﺍﻷﻣﺮﺍﺽ ﺍﳌﺴﺒﺒﺔ ﻟﻠﻮﻓﻴﺎﺕ ﻟﻺﻧﺴﺎﻥ ، ﺑﺎﻟﺮﻏﻢ ﻣﻦ ﺍﻛﺘﺸﺎﻑ ﻣﺼﻞ ﺍﻟﺴﻞ ﰲ ﻋﺎﻡ 1920ﻡ ﺇﻻ ﺃﻥ ﺩﻭﺭﻩ ﰲ ﺍﳊﻤﺎﻳﺔ ﻣﻦ ﺍﳌﺮﺽ ﱂ ﻳﻌﺮﻑ ﺣﱴ ﺍﻵﻥ.

8 ﲤﺖ ﻫﺬﻩ ﺍﻟﺪﺭﺍﺳﺔ ﰲ ﺛﻼﺛﺔ ﻣﻨﺎﻃﻖ ﺭﻳﻔﻴﺔ ﰲ ﳏﺎﻓﻈﺔ ﺷﺮﻕ ﺍﻟﻨﻴﻞ ﰲ ﺍﻟﻔﺘﺮﺓ ﻣﻦ 1 ﻳﻮﻧﻴﻮ ﻭﺣﱴ 31 ﺃﻏﺴﻄﺲ ﻋﺎﻡ 2003ﻡ. ﻣﻦ ﺃﻫﻢ ﺃﻫﺪﺍﻑ ﺍﻟﺪﺭﺍﺳﺔ ﺗﻘﻴﻴﻢ ﻣﺪﻯ ﻓﻌﺎﻟﻴﺔ ﻣﺼﻞ ﺍﻟﱯ ﺳﻲ ﺟﻲ ﻭﻣﻘﺎﻭﻣﺔ ﻓﻌﺎﻟﻴﺘﻪ ﺑﻨﺪﺑﺔ ﺍﻟﱯ ﺳﻲ ﺟﻲ ﻭﺑﻌﺾ ﺍﻟﻌﻮﺍﻣﻞ ﺍﻻﺟﺘﻤﺎﻋﻴﺔ. ﲤﺖ ﺍﻟﺪﺭﺍﺳﺔ ﰲ ﺣﻮﺍﱄ 398 ﻃﻔﻞ (50.3% ﺫﻛﺮ ﻭ 49.7% ﺃﻧﺜﻰ) ﺗﺘﺮﺍﻭﺡ ﺃﻋﻤﺎﺭﻫﻢ ﻣﻦ ﺳﻦ 12 ﺷﻬﺮ ﻭﺣﱴ 7 ﺳﻨﻮﺍﺕ. ﰎ ﺗﺴﺠﻴﻞ ﻛﻞ ﺍﳌﻌﻠﻮﻣﺎﺕ ﺍﳌﺘﻌﻠﻘﺔ ﺑﺘﺎﺭﻳﺦ ﺃﻱ ﻣﺮﺽ ، ﺍﻟﺘﻄﻌﻴﻢ ﺑﺎﻟـ ﰊ ﺳﻲ ﺟﻲ ﻭﺍﻟﻌﻤﺮ ﻋﻨﺪ ﺍﻟﺘﻄﻌﻴﻢ ﺃﻱ ﺃﻋﺮﺍﺽ ﳌﺮﺽ ﺍﻟﺴﻞ ﻭﺍﻟﻜﺸﻒ ﺍﻟﻌﺎﻡ ﻋﻠﻰ ﻛﻞ ﺍﻷﻃﻔﺎﻝ ﰲ ﺍﻟﺪﺭﺍﺳﺔ ﻭﻳﺘﻀﻤﻦ ﺫﻟﻚ ﺍﻟﻜﺸﻒ ﻋﻦ ﻧﺪﺑﺔ ﺍﻟﱯ ﺳﻲ ﺟﻲ ﻭﻗﻴﺎﺳﻬﺎ ، ﻭﰎ ﺗﺴﺠﻴﻞ ﺫﻟﻚ ﰲ ﺍﺳﺘﺒﻴﺎﻥ. ﻛﻞ ﺍﻷﻃﻔﺎﻝ ﰲ ﺍﻟﺪﺭﺍﺳﺔ ﰎ ﳍﻢ ﺇﺟﺮﺍﺀ ﺍﺧﺘﺒﺎﺭ ﺍﻟﺘﻴﻮﺑﺮﻛﻠﲔ ﻭﰎ ﺍﻟﻜﺸﻒ ﻋﻦ ﺍﻻﺧﺘﺒﺎﺭ ﺑﻌﺪ 72 ﺳﺎﻋﺔ ﻣﻦ ﺇﺟﺮﺍﺋﻪ. ﺗﻮﺿﺢ ﺍﻟﺪﺭﺍﺳﺔ ﺃﻥ ﺍﻟﻌﻤﺮ ﺍﻟﺴﺎﺋﺪ ﻫﻮ ﺳﻦ 12 ﺷﻬﺮ ﻭﺣﱴ 36 ﺷﻬﺮ ﻭﻫﻲ ﲤﺜﻞ ﺣﻮﺍﱄ 42.7% ﻣﻦ ﲨﻠﺔ ﺍﻷﻃﻔﺎﻝ ﰲ ﺍﻟﺪﺭﺍﺳﺔ. 95% ﻣﻦ ﲨﻠﺔ ﺍﻷﻃﻔﺎﻝ ﺍﳌﺪﺭﻭﺳﲔ ﺗﻠﻘﻮﺍ ﻣﺼﻞ ﺍﻟﱯ ﺳﻲ ﺟﻲ ، 73.9% ﻓﻴﻬﻢ ﺗﻠﻘﻮﺍ ﺍﳌﺼﻞ ﰲ ﺍﻟﺜﻼﺛﺔ ﺷﻬﻮﺭ ﺍﻷﻭﱃ ﺑﻌﺪ ﺍﻟﻮﻻﺩﺓ ، 72% ﻓﻴﻬﻢ ﳍﻢ ﻧﺪﺑﺔ ﺍﳌﺼﻞ ﻭ %39.1 ﻣﻦ ﺍﻟﻨﺪﺏ ﺣﺠﻤﻬﺎ ﻳﺘﺮﺍﻭﺡ ﺑﲔ 2 ﺇﱃ 5 ﻣﻠﻢ ﳑﺎ ﻳﺪﻝ ﻋﻠﻰ ﺍﻟﻔﻌﺎﻟﻴﺔ ﺍﻟﻌﺎﻟﻴﺔ ﻟﻠﻤﺼﻞ ﺍﳌﺄﺧﻮﺫ. ﰲ 68.85% ﻣﻦ ﺍﻷﻃﻔﺎﻝ ﰲ ﺍﻟﺪﺭﺍﺳﺔ ﻛﺎﻥ ﻗﻴﺎﺱ ﺍﺧﺘﺒﺎﺭ ﺍﻟﺘﻴﻮﺑﺮﻛﻠﲔ ﺃﻗﻞ ﻣﻦ 5ﻣﻠﻢ ﻭﰲ 2.5% ﻛﺎﻥ ﻗﻴﺎﺱ ﺍﺧﺘﺒﺎﺭ ﺍﻟﺘﻴﻮﺑﺮﻛﻠﲔ ﺃﻛﺜﺮ ﻣﻦ 10ﻣﻠﻢ. ﻭﻗﺪ ﻭﺟﺪ ﺃﻥ ﻫﻨﺎﻙ ﻋﻼﻗﺔ ﺑﲔ ﺣﺠﻢ ﻧﺪﺑﺔ ﺍﻟﱯ ﺳﻲ ﺟﻲ ﻭﺍﺧﺘﺒﺎﺭ ﺍﻟﺘﻴﻮﺑﺮﻛﻠﲔ ﳑﺎ ﻳﺪﻝ ﻋﻠﻰ ﺃﻥ ﻧﺪﺑﺔ ﺍﻟﺘﻄﻌﻴﻢ ﻣﺆﺷﺮ ﻫﺎﻡ ﻟﻔﻌﺎﻟﻴﺔ ﺍﳌﺼﻞ. ﰎ ﺗﺸﺨﻴﺺ ﺣﺎﻟﺘﲔ ﻣﻦ ﺍﻟﺪﺭﻥ ﺃﻋﻤﺎﺭﻫﻢ 14 ﺷﻬﺮ ﻭ 18 ﺷﻬﺮ ﻭﻫﻲ ﲤﺜﻞ %0.5 ﻣﻦ ﲨﻠﺔ ﺃﻃﻔﺎﻝ ﺍﻟﺪﺭﺍﺳﺔ ﻭﺣﻮﺍﱄ 0.1% ﻣﻦ ﲨﻠﺔ ﺍﻷﻃﻔﺎﻝ ﺍﳌﻄﻌﻤﲔ ﰲ ﺍﻟﺪﺭﺍﺳﺔ ﻣﻦ ﻣﺎ ﻳﺪﻝ ﻋﻠﻰ ﺍﳊﻤﺎﻳﺔ ﺍﻟﻌﺎﻟﻴﺔ ﻟﻠﻤﺼﻞ ﻣﻦ ﺍﳌﺮﺽ ﺑﺎﻟﺮﻏﻢ ﻣﻦ ﺃﻥ ﺍﳌﻘﺎﺭﻧﺔ ﻟﻴﺴﺖ ﻋﺎﺩﻟﺔ ﺑﲔ ﺍﻤﻮﻋﺘﲔ.

9 ﻭﺟﺪ ﺃﻥ ﺍﳊﺎﻟﺔ ﺍﳌﺎﺩﻳﺔ ﻟﻸﺳﺮﺓ ﻭﻧﺴﺒﺔ ﺍﻻﺯﺩﺣﺎﻡ ﰲ ﺍﻟﻐﺮﻑ ﻻ ﺗﺆﺛﺮ ﻋﻠﻰ ﺍﻹﺻﺎﺑﺔ ﲟﺮﺽ ﺍﻟﺪﺭﻥ. ﺩﻟﺖ ﺍﻟﺪﺭﺍﺳﺔ ﻋﻠﻰ ﺃﻥ ﻣﺼﻞ ﺍﻟﱯ ﺳﻲ ﺟﻲ ﻋﻨﺪ ﺍﻷﻃﻔﺎﻝ ﰲ ﺍﻟﺪﺭﺍﺳﺔ ﻟﻪ ﲪﺎﻳﺔ ﻋﺎﻟﻴﺔ ﻣﺘﻤﺜﻠﺔ ﰲ ﺍﻟﻨﺴﺒﺔ ﺍﻟﻌﺎﻟﻴﺔ ﻟﻮﺟﻮﺩ ﻧﺪﺑﺔ ﺍﻟﱯ ﺳﻲ ﺟﻲ ﻭﻭﺟﻮﺩ 0.1% ﻓﻘﻂ ﻣﻦ ﺣﺎﻻﺕ ﺍﻟﺪﺭﻥ.

LIST OF ABBREVIATIONS

AIDS Acquired Immuno Deficiency Syndrome BCG Bacilli Calmete Guérin CD4 Cluster Differentiation

10 CNS Central Nervous System CSF Cerebrospinal Fluid DNA Deoxy Ribonucleic Acid EPI Expanded Programme of Immunization HIV Human Immunodeficiency Virus IUATLD International Union Against Tuberculosis and Lung Diseases NTP National Tuberculosis Programme OT Old Tuberculin PCR Polymerase Chain Reaction PPD Purified Protein Derivative RFLPs Restriction Fragment Polymorphisms RNA Ribonucleic Acid SPSS Statistical Package for Social Science T12 Thoracic Vertebra Number 12 TB Tuberculosis TU Tuberculin Unit UNICEF United Nation of Children Emergency Fund

USA United States of America WHO World Health Organization ZN Ziehl Neelsen Stain

LIST OF TABLES

Page

Table 1: Age in month in relation to BCG vaccination of children

11 in the study population 99 Table 2: Fathers’ education in relation to BCG vaccination in children of the study population 100 Table 3: Mothers’ education in relation to BCG vaccination of children in the study population 101 Table 4: Mothers’ education in relation to age when BCG vaccinated of children in the study population 102

Table 5: BCG scar in relation to age when BCG vaccinated (in months) in children of the study population 103

Table 6: BCG scar in relation to sex in children of the study population 104

Table 7: Age in month in relation to tuberculin reaction in children of the study population 105

Table 8: Age when BCG vaccinated (in month) in relation to Tuberculin reaction in children of the study population 106 Table 9: Tuberculin reaction in relation to sex in children of the study population 107

BCG scar in relation to tuberculin reaction in children Table 10: 108 of the study population Age in month in relation to TB cases in children of the Table 11: 109 study population Table 12: TB cases in relation to age when BCG vaccinated in children of the study population 110

Table 13: TB cases in relation to family income (in Sudanese Dinars) in children of the study population 111

Table 14: TB cases in relation to number of persons per room in children of the study population 112

Table 15: BCG scar in relation to TB cases in children of the study population 113

12 Table 16: TB cases in relation to tuberculin reaction in children of the study population 114

Table 17: TB cases in relation to BCG vaccination of children in the study population 115

LIST OF FIGURES

Page

Figure 1: Age distribution of children in the study population 116

13 Figure 2: Sex distribution of children in the study population 117 Figure 3: Tribe distribution of children in the study population 118 Figure 4: Parents education of children in the study population 119 Figure 5: Fathers' occupation of children in the study population 120 Figure 6: Mothers' occupation of children in the study population 121 Figure 7: Family income of children in the study population in Sudanese Dinars 122 Figure 8: Number of persons per room of children in the study population 123 Figure 9: BCG vaccination state of children in the study population 124 Figure 10: Age of studied children (in months) when 125 BCG vaccinated Figure 11: Size of BCG scar in children of the study population 126

Figure 12: Contact with TB cases in children in the study 127 population Figure 13: Clinical cases of TB in children in the study 128 population Figure 14: Tuberculin reaction in children in the study 129

14 population

15 1. Introduction & Literature Review

Tuberculosis is an ancient disease, which

was recognized centuries before the Christian

era by physicians in many areas including

Greece, the Middle East and India. It has always been the scourge of the malnourished poor who

live in overcrowded, insanitory conditions and

was described by Dickens as ‘The disease

which medicine never cured, wealth never warded off’. At the present time, medicine when

properly applied can cure the disease, and

money, properly used, can prevent it, but even

in the developed countries of the world

tuberculosis still causes more deaths than any other notifiable communicable disease, while in

the developing countries it is, without

16 exception, the most prevalent chronic

inflammatory disease accounting for untold

human misery(1).

The extent of the world tuberculosis problem is not accurately known but it has been

estimated that some 10-12 million people are

infected perhaps 50-100 million of their fellows

with tubercle bacilli every year, and that six

people die of the disease every minute of the

day. The annual incidence of new cases of

tuberculosis per 100.000 of the population has

been estimated to be 20 in the industrialized world, 200 in Africa and 500 in South East Asia.

In some communities up to 5 percent of the

population may have pulmonary tuberculosis.

The disease affects all age groups, but

infants and adolescents have a heightened

17 susceptibility, as do women in pregnancy and

the puerperium.

These facts, plus the adverse influence of

malnutrition, which is endemic in childhood in

the tropical developing countries, determine

that tuberculosis constitute one of the most serious and intractable problems in Paediatrics

in the tropics.

Some important land marks in the history of tuberculosis include Robert Koch’s description

of the organism in 1882, the development of

BCG (Bacillus of Calmette and Guērin) vaccine in 1920, the introduction of streptomycin in 1948 as the first effective anti – tuberculosis drug and the subsequent introduction of isonicotinic acid

hydrazide (INAH or INH) in 1952, which

18 transformed the clinical management of the

disease(1).

1.1. History of tuberculosis:

Robert Koch was the first to establish the causal relationship of the tubercle bacillus to the disease tuberculosis. The organism was named mycobacterium tuberculosis in 1886, presumably because the organism resembles the fungi in its slow growth and colony morphology.(2)

In 1868 Villemin published his masterly study on the epidemiology of tuberculosis, and succeeded in transmitting the disease to animals by direct inoculation. Koch in 1882, after an investigation that will always remain a classical example of thorough and accurate bacteriological technique, showed conclusively that the tubercle bacillus was the one essential cause of tuberculosis. The bacillus was resistant to all ordinary stains; but Koch succeeded in staining it by alkaline solutions of methylene blue, kept in contact with the tuberculous tissue for 24

19 hours. The bacillus would not grow on any ordinary medium; but he devised a new medium - inspissated blood serum – on which, after a delay of 10 days or so, growth first became apparent.

Finally by a large series of inoculations with pure cultures of the bacillus, several generations removed from the primary one, he transmitted the disease to numerous animals of different species.

Henceforward the demonstration of the bacillus afforded the sole infallible criterion for the diagnosis of all lesions of tuberculosis(3).

At the London congress on tuberculosis in 1901, Koch’s

asserted, on the basis of inadequate experimentation, that bovine

bacilli were virtually non-pathogenic to human beigns. His views

were attacked by M’ fadyean (1901) on the basis of strong,

circumstantial, evidence. As the result of considerable opposition,

Koch modified his views at the Washington congress in 1908, to the extent of admitting that human beigns might be infected with bovine

tubercle bacilli, though to maintained that serious disease due to

these organisms was very rare, and that protective measures to

protect the human population against tuberculosis of bovine origin

were quite unnecessary.

The extensive labours of the Royal commission on tuberculosis

Great Britain, and of continental and American workers, revealed

20 the fallacy of Koch’s teaching, and showed that non-pulmonary

tuberculosis in childhood was frequently caused by the bovine bacillus. The subsequent work of Griffith, Munro, Lange, and others

drew attention to the occurrence of bovine bacilli in pulmonary

tuberculosis; and infections of bovine origin as a whole must be

regarded as a serious menace to the human population in those

countries where tuberculosis of cattle is common. The evidence

suggests that the bovine bacillus is quite as virulent for man as the

human bacillus, and possibly even more so. The result of Koch’s

teaching was of more than academic importance.

The pulmonary form was described by Hippocrates, and spinal

caries has been observed in the mummies of ancient Egypt(3).

21 1.2. Tuberculosis in Sudan:

For many years after the establishment of a modern health service in 1899, little information was available about the amount of tuberculosis in the Sudan. Pioneer work on the subject was carried out by Cummins (1908, 1911), when engaged in a study of tuberculosis in the Egyptian army.

Cummins was struck by the fact that the incidence of the disease was much higher amongst the Sudanese than the

Egyptian. During the five years from 1902 to 1908 he reported an average annual incidence of 3.7 per 1,000 in Sudanese and 1.5 per

1,000 in Egyptian soldiers. In contrast to this observation, Balfour

(1904) and Archibald (1922) referred to the susceptibility of

Sudanese tribes to respiratory diseases in general and their particular predisposition to tuberculosis(4).

During the 1920s and 1930s the Sudan Medical Service conducted a number of surveys with a view to obtaining some information about the extent of the infection in different parts of the country(4).

The first tuberculin test survey was conducted in 1925 on 700 school boys, soldiers and hospital patients in Blue Nile province.

22 The technique was that devised by Von Pirquet in 1907. Positive results ranging between 7 and 27 percent were obtained. The age distribution of the positive tests ranged between 8 and 35 years.

By the late 1920s, there was some evidence to show that the disease was gaining ground in the northern and central parts of the country; but there was an air of satisfaction that the detrimental effects of town growth and population movement were being counter – balanced by better nutrition and control of debilitating disease. In the south, however, the situation was different(4).

The isolated rural population had little chance of acquiring immunity and there was evidence to show that pulmonary tuberculosis was gaining a foothold among some tribes in Upper Nile Province because of their proximity to central and northern Sudan. In the period 1928 to 1931 about 181,000 people in Upper

Nile Province were examined and 39 were found to be positive for pulmonary tuberculosis, a prevalence rate of 0.2 per 1,000.

The extensive tuberculin test surveys, which were carried out during the period 1929 to 1932 threw more light on the problem of tuberculosis in the Sudan. A survey performed in 1929 among Nuer prisoners of Upper Nile Province revealed that about

33 percent were tuberculin positive(4).

23 With the outbreak of the Second World War in 1940 there was every reason to expect an increase in the incidence of tuberculosis as a result of unsettled conditions and lack of food in eastern Sudan following a temporary Italian occupation. More over, the disease appeared to be very common in Eritrea and western Ethiopia, which they had more contact with the Sudan than before the war(4).

By 1945 there was evidence that tuberculosis was slowly increasing among the civil population of the Sudan.

Tuberculosis was, therefore, considered by the Sudan

Medical Service to be the most important health problem to be tackled immediately after the war.

By the 1950s some important development in the history of tuberculosis control in the Sudan were well underway.

A start was made towards the formation of a pilot tuberculosis service in Khartoum, the aims of which to secure hospitalization of cases for a minimum effective period, to start a scheme of domiciliary treatment and supervision and to under take the investigation and supervision of contacts of known cases.

24 In 1950s a chest physician was appointed to lead the organization of the pilot tuberculosis scheme in Khartoum and three female tuberculosis visitors were trained to carry out domiciliary supervision. By the end of 1950 the Sudan Association for the prevention of tuberculosis was formed to render some voluntary assistance in domiciliary care.

An advisor in tuberculosis from the WHO Eastern

Mediterranean Region visited Sudan in 1953 to arrange for the initiation of a pilot project of Mantoux testing and B.C.G. vaccination. The pilot scheme, which to operate in March 1954, showed that nearly 50 percent of the population under 25 years of age were mantoux negative and therefore required B.C.G vaccination.

The rate of infection was evenly spread over all provinces and younger age groups gave less positive results than the older groups(4).

In a tuberculin survey carried out by Haseeb (1954) in

Khartoum province, similar results were obtained. In the urban population of Khartoum province from 21.9 to 26.4 percent became infected by the age of 10 years and from 36.2 to 44.4 by the age of

25 20 years. In the rural population, on the other hand, 34.4 percent became infected by the age of 10 years and 69.4 percent by the age of 20 years.

By 1954, the Chest Diseases Unit in Khartoum became staffed with two chest physicians and seven tuberculosis visitors with the necessary auxiliary nursing and laboratory staff. The unit had 175 beds but an appreciable expansion in domiciliary treatment was made(4).

A rehabilitation centre for convalescents was opened in

Khartoum as a joint venture of the Red Cross, the Red Crescent and the Sudan Association for the prevention of tuberculosis. The centre proved popular and convalescent tuberculosis patients were train suitable trades to earn their living.

In 1957-1958 a mass compaign with Mantoux testing and

B.C.G. vaccination was carried out in the southern provinces and by the end of 1960 about 622,000 had been tested and 250,000 vaccinated. Centres were established in Wau, Malakal and Juba to continue the work. In the north permanent B.C.G. centres were established and the tuberculosis demonstration and training centre

26 at Wad Medani, Khartoum Chest Hospital, El Obeid, Kassal,

Atbara and Port Sudan(4).

In 1963, mass campaigns were lunched in Wadi Halfa before movement of its population to their new resettlement area at Khashm El Girba and in Blue Nile Province. In the period 1940 to 1958 the number of cases of tuberculosis admitted to hospitals showed a threefold increase, then started to show signs of decline. Most of the cases reported were due to pulmonary tuberculosis (60 to 75 percent). Cases of non-pulmonary tuberculosis kept swinging fairly constantly at an incidence rate of about 10 per 100,000 populations. In order of importance, the sites of non pulmonary lesions are bone

(30 percent), gland (30 percent), joint (15 percent) and about 15% for rarer sites, i.e., skin, genitourinary tract and meninges(4).

The earliest report of TB cases among children in Sudan reported in 1905(5). In 1939 TB accounted for 1% of total hospitals admission(4).

In the period (1941-1945) children represent less than 2% of hospitals admission due to TB, this figure rose to 12% in the period

(1949-1954) and most were of glandular type(6).

From (1971-1979) 1453 children with TB were reported in

Khartoum hospital(7). Tuberculin survey was carried in 1976 and in

27 1986 in children under 14 years old and annual rate of infection found to be 109, 108 per 100.000 respectively(8).

Hospital based study in Khartoum showed that 70% of children admitted with TB had pulmonary TB and case fatality rate of 70%(5).

1.3. Aetiology:

The agents of tuberculosis, mycobacterium tuberculosis, mycobacterium bovis, and mycobacterium africanum, are members of the order actinomycetales and the family mycobacteriaceae.

The tubercle bacilli are non-spore forming, non motile, pleomorphic, weakly gram positive curved rods about 2-4µm long.

They may appear beaded or clumped in stained clinical specimens or culture media containing glycerol as the carbon source and ammonium salts as the nitrogen source. These mycobacteria grow best at 37-140c, produce niacin, and lack pigmentation. A lipid rich cell wall accounts for resistance to the bacteriocidal actions of antibody and complement. A hall mark of all mycobacteria is acid- fastness. The capacity to form stable mycolate complexes with arylmethane dyes such as crystal violet, carbolfuchsin, auramine,

28 and rhodamine. Once stained, they resist decoloration with ethanol and hydrochloric or other acids(5).

M. tuberculosis has atypical colony morphology, produces niacin but no pigment, is able to reduce nitrates, and produces catalase(9).

1.4. Epidemiology:

Mycobacterium tuberculosis is responsible for more deaths around the world than any other infectious agent, accounting for almost 3 million death annually(10).

These fatalities are mostly from a pool of more than 7 million new cases of tuberculosis per year and a prevalence of almost 16 million persons with active tuberculosis, half of whom have significant disability as a result of their disease(11).

The global epidemiologic patterns of tuberculosis have changed as a result of the AIDS epidemic and development and spread of multiple –drug – resistant strains of M. tuberculosis.

New strategies to control tuberculosis, especially directly observed therapy, raise the potential to affect tuberculosis epidemiology in a positive way(12).

29 In the developed countries of the world, illness and death from tuberculosis declined dramatically throughout much of the

20th century. These declines predated the availability of anti tuberculosis drugs, beginning in the 1940s with streptomycin, and probably were a result of improved living conditions and decreasing opportunity for exposure(13).

Anti tuberculosis therapy increased the slope of the decline, which in the United States averaged 6% per year until the mid-

1980s to a nadir of 22,201 new cases in 1985(14).

Tuberculosis incidence then began to increase, primarily because of the dismantling of the tuberculosis control infrastructure, the impact of HIV infection, and multiple drug resistance of M. tuberculosis by 1992(14).

Similar trends were observed in western European countries

(Spain, 28% increase between 1990 and 1992; Italy, 27% increase between 1988 and 1992; Netherlands, 19% increase between 1987 and 1992(15).

Implementation of directly observed therapy has substantially increased therapeutic compliance and reduced the occurrence of disease transmission(16).

30 During this period, the epidemiologic patterns of tuberculosis were also in transition. Between 1986 and 1993, the number of new cases in the United States that occurred in persons born out side the country increased from 22% to 30%; by 1997, this proportion had increased to 40%(16).

In many locations, one third or more of the population is infected with tuberculosis (compared with 6% in the United

States), and incidence rates of newly diagnosed tuberculosis are higher than 300 cases per 100,000 population in parts of Africa(15,17).

HIV infection is known to be the strongest risk factor for the progression of tuberculosis infection to active disease. In non HIV- infected persons infected with tuberculosis, the cumulative life time risk of active disease ranges between 5% and 10%(14).

In contrast, HIV infected persons have a 10% annual risk of progression to active tuberculosis(18).

In areas of the world with rapid escalation of HIV prevalence, the impact on the occurrence of active tuberculosis has been dramatic. One study of data from sub-Saharan Africa demonstrated that tuberculosis rates were declining by 1.6% per year before 1985 but since then have increased by 7.7% annually(19).

31 In one city in Thailand, the proportion of tuberculosis patients who were HIV positive increased from 1.5% to 45.5% in only 4 years(20).

Estimates suggest that there are more than 5 million persons co-infected with tuberculosis and HIV in the developing world, largely in sub-Saharan Africa (3.8 million persons) and Asia

(1.15 million persons)(11,12).

Because HIV infection rates are rising rapidly in some areas of Asia, these numbers are likely to be underestimates today.

Tuberculosis rates are also rapidly rising in areas of the former Soviet Union. Between 1990-1991 and 1993, the notification rate in Russia increased from 34 to 42.9 cases per 100,000 population(21).

In some population in Russia, the rate of active disease is estimated to be as high as 10%. Because HIV infection is not currently wide spread in this region, other explanations, including deterioration in the public health infrastructure and economic disruption, have been suggested to account for the increases in tuberculosis(21).

32 Molecular sub typing of M. tuberculosis isolates using restriction fragment length polymorphisms (RFLPs) has contributed to the understanding of patterns of tuberculosis transmission(22).

Studies in hospital and community settings in developed countries have shown surprisingly consistent findings. The ratio of individual RFLP patterns to enrolled patients 0.66:1 (range, 0.59:1 to 0.8:1), with one “cluster” of patterns for every 10.4 persons enrolled (range, 8.7 to 13.8 persons). A cluster was defined as at least two matching RFLP patterns during the study period.

Despite different settings and enrollment methods, these studies concluded that between 29% and 40% of all newly diagnosed cases of tuberculosis were caused by recent transmission. These figures are higher than had previously been suspected for locations thought to have effective control programmes(23,24).

They can be used as baselines to monitor the impact of improved tuberculosis control.

Studies conducted in developing countries have shown less diversity of RFLP patterns than in developed countries(23,24).

33 1.5. Pathology:

The first infection with M. tuberculosis is known as primary tuberculosis. It is usually subpleural, often in the mid to upper zones. Within an hour of reaching the lung, tubercle bacilli reach the draining lymphnodes at the hilum of the lung and a few escape into the blood stream.

The initial reaction comprises exudation and infiltration with neutrophil granulocytes. These are rapidly replaced with macrophages that ingest the bacilli. These interact with

T lymphocytes with the development of cellular immunity that can be demonstrated 3-8 weeks after the initial infection by the development of a ppositive reaction in the skin to an intradermal injection of protein from tubercle bacilli (tuberculin)(25).

At this stage the classical pathology of tuberculosis can be seen. Granulomatous lesions consist of a central area of necrotic material of a cheesy nature, called caseation, surrounded by epithelioid cells and Langhan’s giant cells with multiple nuclei, both cells being derived from the macrophage. Lymphocytes are present and there is a varying degree of fibrosis. Subsequently the caseated areas heal completely and many become calcified. It is

34 now known that at least 20% of these calcified primary lesions contain tubercle bacilli, initially lying dormant but capable of being activated by depression of the host defense system.

Reactivation leads to typical post-primary pulmonary tuberculosis with cavitation, usually in the apex or upper zone of the lung. ‘Post primary tuberculosis’ refers to all forms of tuberculosis that occur after the first few weeks of the primary infection when immunity to the mycobacterium has developed(25).

1.6. Clinical Manifestations:

Primary Pulmonary Disease:

The primary pulmonary complex includes the parenchymal focus and the regional lymph nodes. About 70% of lung foci are subpleural, and localized pleurisy is common. The initial parenchymal inflammation usually is not visible on chest radiograph, but a localized, non-specific infiltrate may be seen before the development of tissue hypersensitivity. All lobar segments of the lung are at equal risk of initial infection. Two or more primary foci are present in 25% of cases.

The hall mark of primary tuberculosis in the lung is the relatively large size of the regional lymphadenitis compared with the relatively small size of the initial lung focus. In most cases, the parenchymal infiltrate and adenitis resolve early. The common sequence is hilar adenopathy, focal hyper inflation and then

35 atelectasis. The resulting radiographic shadows have been called collapse – consolidation or segmental tuberculosis. These radiographic findings are similar to those seen with foreign body aspiration but are different from typical cases of bacterial pneumonia in children(9).

Rarely inflamed caseous nodes attach to the endobronchial wall and erode through it, causing endobronchial tuberculosis or a fistula tract. The caseum causes complete obstruction of the bronchus, resulting in extensive infiltrate and collapse.

Most cases of tuberculosis bronchial obstruction in children resolve fully with appropriate treatment. Occasionally, there is residual calcification of the primary focus or regional lymph nodes. The appearance of calcification implies that the lesion has been present for at least 6-12month(9).

Healing of the segment is rarely complicated by scarring or contraction associated with cylindrical bronchiectasis.

Children may have lobar pneumonia without impressive hilar adenopathy. If the primary infection is progressively destructive, liquefaction of the lung parenchyma can lead to formation of a thin – walled primary tuberculosis cavity. Rarely,

36 bullous tuberculosis lesions can occur in the lungs and lead to pneumothorax if they rupture. Enlargement of the subcarinal lymph nodes can cause compression of the esophagus and, rarely, a bronchoesophageal fistula.

The symptoms and physical signs of primary pulmonary tuberculosis in children are surprisingly meager considering the degree of radiographic changes often seen. More than 50% of infants and children with radiographically moderate to sever pulmonary tuberculosis have no physical findings and are discovered only by contact tracing. Infants are more likely to experience signs and symptoms. Non productive cough and mild dyspnoea are the most common symptoms(9).

Systemic complaints such as fever, night sweats, anorexia, and decreased activity occur less often. Some infants have difficulty gaining weight or develop true failure –to– thrive syndrome that often does not improve significantly until several months of effective treatment have been taken. Pulmonary signs are even less common. Some infants and young children with bronchial obstruction have localized wheezing or decreased breath sounds that may be accompanied by tachypnoea or, rarely,

37 respiratory distress. These pulmonary symptoms and signs are occasionally alleviated by antibiotics, suggesting bacterial super infection(9).

Progressive primary pulmonary disease:

A rare but serious complication of tuberculosis in a child occurs when the primary liquefaction may cause formation of a primary cavity associated with large numbers of tubercle bacilli.

The enlarging focus may slough necrotic debris into the adjacent bronchus, leading to further intra pulmonary dissemination.

Significant signs or symptoms are frequent in locally progressive disease in children. High fever, sever cough with sputum production, weight loss, and night sweats are common. Physical sings include diminished breath sounds, rales, and dullness or egophony over the cavity. The prognosis for full but usually slow recovery is excellent with appropriate therapy(9).

Reactivation Tuberculosis:

Pulmonary tuberculosis in adults usually represents endogenous reactivation of a site of tuberculosis infection established previously in the body. This form of tuberculosis is rare in childhood but may occur in adolescence. Children with

38 a healed tuberculosis infection acquired before age 2yr. rarely develop chronic reactivation pulmonary disease, which is more common in those who acquire the initial infection after 7yr. of age.

The most frequent pulmonary sites are the original parenchymal focus, lymph nodes, or the apical seedings (Simon foci) established during the hematogenous phase of the early infection. This form of disease usually remain localized to the lungs because the established immune response prevents further extrapulmonary spread. The most common radiographic presentation of this type of tuberculosis is extensive infiltrates or thick – walled cavities in the upper lobes(9).

Older children and adolescents with reactivation tuberculosis are more likely to experience fever, anorexia, malaise, weight loss, night sweats, productive cough, hemoptysis and chest pain than children with primary pulmonary tuberculosis.

However, physical examination findings usually are minor or absent, even when cavities or large infiltrates are present. Most signs and symptoms improve within several weeks of starting effective treatment, although the cough may last for several months.

39 Therefore tuberculosis may be highly contagious if there is significant sputum production and cough. The prognosis for full recovery is excellent when patients are given appropriate therapy(9).

Pleural Effusion:

Tuberculosis pleural effusions, which can be local or general, originate in the discharge of bacilli into the pleural space from a subpleural pulmonary focus or caseated lymph node. A symptomatic local pleural effusion is so frequent in primary tuberculosis that is basically a component of the primary complex. Larger and clinically significant effusions occur months to years after the primary infection. Tuberculous pleural effusion is in frequent in children <6yr. of age and rare in those <2yr. of age. Effusions are usually unilateral but can be bilateral. They are virtually never associated with a segmental pulmonary lesion and are rare in disseminated tuberculosis. Often the radiographic abnormality is more extensive than would be suggested by physical findings or symptoms.

Clinical onset of tuberculous pleurisy is often sudden, characterized by low to high fever, shortness of breath, chest pain on deep inspiration, and diminished breath sounds. The fever and other symptoms may last for several weeks after the start of anti tuberculous chemotherapy(9).

The tuberculin skin test is positive in only 70-80% of cases.

The prognosis is excellent, but radiographic resolution often takes

40 months. Scoliosis is a rare complication from a long-standing effusion(9).

Pericardial Disease:

The most common form of cardiac tuberculosis is pericarditis. It is rare, occurring in 0.5-4% of tuberculous cases in children. Pericarditis usually arises from direct invasion of or lymphatic drainage from subcarinal lymph nodes.

The presenting symptoms are usually non specific, including low-grade fever, malaises and weight loss. Chest pain is unusual in children. A pericardial friction rub or distant heart sounds with pulsus paradoxus may be present. The pericardial fluid is typically serofibrinous or hemorrhagic(9).

Lymphohematogenous (Disseminated) disease:

Tubercle bacilli are disseminated to distant sites, including liver, spleen, skin, and lung apices, in all cases of tuberculosis infection. The clinical picture produced by lymphohematogenous dissemination depends on the quantity of organisms released from the primary focus and the adequacy of the host immune response.

Lymphohematogerous spread is usually asymptomatic(9).

41 Rare patients experience protracted hematogenous tuberculosis caused by the intermittent release of tubercle bacilli as a caseous focus erodes through the wall of a blood vessel in the lung. Although the clinical picture may be acute, more often it is indolent and prolonged, with spiking fever accompanying the release of organisms into the blood stream. Multiple organ involvement is common, leading to hepatomegally, splenomegally, lymphadenitis in superficial or deep nodes, and papulonecrotic tuberculoids appearing on the skin. Bones and joints or kidneys also may become involved. Meningitis occurs only late in the course of the disease. Early pulmonary involvement is surprisingly mild, but diffuse involvement becomes apparent with prolonged infection(9).

Occult lymphohematogenous spread:

Occult lymphohematogenous spread is the most common form, and it occurs in all cases of asymptomatic tuberculosis infection. This event may lead to the development of extrapulmonary tuberculosis months or years after the initial infection(26).

42 Miliary tuberculosis:

Miliary tuberculosis arises when massive numbers of tubercle bacilli are released into the blood stream, resulting in simultaneous disease in two or more organs. It usually is an early complication of primary infection, occurring within 2 to 6 months after the initial infection.

This disease is most common in infants and young children.

Adults may develop miliary tuberculosis as a result of the breakdown of a previously healed or calcified lesion that formed years earlier.

The pathologic picture of miliary tuberculosis is caused by tubercle bacilli entering the blood stream from a caseaus focus that erodes through a blood vessel.

The organisms lodge in small capillaries in various sites and form tubercles of relatively uniform size, ranging from 2mm to several centimeters. Different tissues have different susceptibilities to infection. Lesions are larger and more numerous in the lungs, spleen, liver and bone marrow than in other tissue. This difference may be explained by blood supply and by the numbers of reticuloendothelial cells and tissue phagocytes. The patients

43 general immune status may play a role, as suggested by findings that this form of tuberculosis is more common in infants and in malnourished or immunosuppressed hosts(26).

The clinical manifestations of miliary tuberculosis are protean and depend on the actual load of organisms that disseminates. Rarely, the onset is explosive, with the patient becoming gravely ill over several days. Most often, the onset is insidious, with weight loss, anorexia, malaise, and low-grade fever. Early in the course, few a bnormal physical signs are present. Within several weeks, hepatosplenomegally and generalized lymphadenopathy develop in approximately one-half of patients. At approximately this time, fever as high as 39°-40°c may be present. Initially, chest radiograph may be normal or show evidence only of a primary complex; few respiratory signs or symptoms are observed. Within 3 to 4 weeks after symptom onset, the lung fields usually become filled with tubercles(26).

The child may develop respiratory distress and diffuse rales or wheezing. Pneumothorax, pneumomediastinum, and pleural effusion also can complicate miliary tuberculosis.

44 Signs and symptoms of meningitis or peritonitis are found in

20% to 30% of these patients. In a patient with miliary tuberculosis, headache almost always indicates the presence of meningitis, and the presence of abdominal pain or tenderness usually signals tuberculous peritonitis. Cutaneous lesions, including papulonecrotic tuberculids, nodules, or purpuric lesions, may occur in crops. Choroid tubercles appear several weeks after the onset of the disease in 13% to 87% of the patients(26).

Central nervous system tuberculosis:

Involvement of the central nervous system (CNS) is the most serious complication of tuberculosis in children. Before the development of effective therapy, CNS tuberculosis was uniformly fatal. Several different forms of CNS tuberculosis, including meningitis, tuberculoma, and brain abscess, exist.

The pathogenesis of CNS tuberculosis results from formation of a metastatic caseous lesion in the cerebral cortex or meninges during the occult lymphohemagenous dissemination of the initial infection. This lesion (Rich focus) may increase in size and discharge tubercle bacilli into the sub arachnoid space. A thick gelatinous exudate infiltrates the cortical or meningeal blood

45 vessels, producing inflammation, obstruction, or infarction. The brain stem usually is the site of greatest involvement, which account for the frequent involvement of the cranial nerves III, VI and VII. The basal cisterns usually become obstructed, leading to hydrocephalus. This is a communicating hydrocephalus because all four ventricles are open to the flow of cerebrospinal fluid (CSF), but the flow to the spinal column is obstructed(26).

Tuberculous meningitis

complicates 1 in 300 untreated

tuberclousis infections in children.

This disease is almost unheard in

infants younger than 4 months

because it takes a long time for the

inciting pathologic events to develop.

It is most common in children younger

46 than 4 years and usually occurs within

3 to 6 months of the initial infection.

The clinical onset of tuberculous meningitis may be abrupt or insidious. The more rapid progression of disease tends to occur in young infants, who may experience symptoms for only several days before the onset of acute hydrocephalus, brain infarction, or seizures.

More commonly, the onset is gradual, occurring over several weeks. The usual course can be divided into three stages. The first stage, which may last 1 to 2 weeks, is characterized by non-specific symptoms such as fever, headache, irritability, drowsiness, and malaise. No focal neurologic signs are present, but infants and young children may experience a loss or stagnation of developmental milestones. The second stage usually begins abruptly, with lethargy, convulsions, nuchal rigidity, positive

Kernig or Brudzinski sings, increased deep tendon reflexes, hypertonia, vomiting, and cranial nerve palsies. The appearance of this clinical picture correlates with the development of hydrocephalus and increased intracranial pressure, combined with

47 meningeal irritation but show signs of encephalitis, such as disorientation, abnormal movements, and speech abnormalities.

The third stage is marked by coma, irregular pulse or respiration, hypertension, hemiplegia or paraplegia, decerebrate posturing, and eventually death(26).

Skeletal tuberculosis:

Skeletal tuberculosis results from lymphohematogenous dissemination of tubercle bacilli early in the course of the initial infection. Occasionally, bone infection is initiated by direct extension from contaguous lymph node or by extension from a neighbouring infected bone.

Involvement of bone complicates 1% to 2% of untreated infections in childhood, usually occurring within 12 to 24 months of formation of the primary complex. The pathologic process begins in the metaphysis because of its rich blood supply.

Granulation tissue and caseation develop, destroying bone by direct infection and pressure necrosis. Cold soft tissue abscesses and extension of the infection through the epiphysis into the joint often accompany the primary bone lesion(26).

48 The most commonly affected bones are the vertebrae, causing tuberculosis of the spine (i.e. Pott’s disease). Although any vertebral body can be infected, a predilection for the thoracic vertebrae, especially T12, exists. Involvement of two or more vertebrae is fairly common, and skip areas between lesions may occur. Usually, the body of the vertebra is affected, causing destruction and collapse. The progression to tuberculous spondylitis viewed on radiographs is from narrowing of a disc space to collapse and wedging of the vertebral body, with subsequent angulation of the spine (i.e. gibbous) or sever kyphosis. Para spinal abscess, psoas abscess, or retropharyngeal abscess may develop from the bone lesion.

The most frequent clinical signs and symptoms of tuberculous spondylitis include low-grade fever, restlessness, pain and abnormal positioning or gait. Rigidity of the spine is caused by muscle spasm, often initiated by the patient’s effort to minimize pain by immobilization. Intermittent referred pain caused by associated radiculitis may occur(26).

49 Abdominal and gastrointestinal Tuberculosis: Tuberculosis of the oral cavity and

pharynx is quite unusual today; most

cases in the past were associated with

bovine tuberculosis acquired from

infected milk. The usual lesion is a

painless ulcer on the mucosa, palate, or tonsil, accompanied by swelling of a

regional lymph node. Tuberculosis of

the larynx may cause hoarseness.

Tuberculosis of the esophagus is

exceedingly rare in children.

50 Tuberculous enteritis is caused by ingestion of infected milk, super infection of the mucosa caused by swallowed tubercle bacilli discharged from a patient’s own lungs, or hematogenous spread.

The most commonly affected regions are the jejunum and ileum, especially near the peyer patches or appendix. Shallow ulcers are the most common lesions that cause pain, diarrhea or constipation, and weight loss. Mesenteric adenitis accompanying the enteritis may cause intestinal obstruction or may erode through the omentum and cause peritonitis. The clinical presentation of tuberculous enteritis mimics many other conditions.

Tuberculous peritonitis occurs mainly in young men and is more in childhood. Generalized peritonitis may occur as a result of hematogenous dissemination. Localized peritonitis is caused by direct extension from a lymph node, intestinal focus, or tuberculous salpingitis. The lymph nodes, omentum, and peritoneum often are matted together and are palpated as a doughy irregular mass that is relatively non tender. Ascites may occur, usually accompanied by fever(26).

Renal Tuberculosis:

51 Renal tuberculosis is fairly rare in childhood because it doesn’t develop for several years after the initial infection.

Tubercle bacilli reach the kidney during lymphohematogenous dissemination. Organisms can be recovered from the urine in many cases of miliary tuberculosis and in some cases of pulmonary tuberculosis before renal parenchymal disease develops. Small caseous tubercle develop in the renal parenchyma and discharge tubercle bacilli into the tubules. Occasionally, a large mass develop near the cortex and discharge large numbers of organisms through a fistulous tract into the renal pelvis. Infection can spread locally to involve the ureter, gallbladder, prostate, or epididymis(22).

Usually no symptoms are present early in the course of renal tuberculosis. The development of “sterile” pyuria, hematuria, dysuria, or vague flank pain first suggests the infection. Super infection with other bacteria may cause delay in diagnosing the underlying tuberculosis(26).

Superficial Lymph Node Tuberculosis:

Tuberculosis of the superficial lymph nodes (i.e., scrofula) probably the most common form of extra thoracic disease,

52 complicating 3% to 6% of infections. In most cases, it is an early manifestation of lymphohematogenous dissemination, occurring within 6 to 9 months of the primary infection. Some cases arise years after the initial infection and may herald a reactivation of infection.

Regional lymphadenitis is part of the primary complex of tuberculosis. The nodes most commonly involved are in the tonsilar and submandibular regions because of extension of a primary lesion in the upper lung field or the abdomen. Enlarged nodes in the inguinal, epitrochlear or axillary regions result from skin or skeletal infections in the extremities(26).

In the early stage of infection, the lymph nodes are firm, discrete and non tender. Multiple nodes in one region often are involved. Scrofula in the neck usually is unilateral, but because of the drainage patterns of lymphatics from the chest, it may be bilateral. Other than low-grade fever, systemic signs and symptoms usually are absent.

The lymph nodes may enlarge gradually. Occasionally, rapid enlargement, associated with high fever, tenderness, and fluctuation, occurs.

53 The picture can be caused by tuberculosis or a bacterial super infection.

The initial presentation rarely is a fluctuant mass with overlying cellulites

or discoloration of the skin(26).

Perinatal tuberculosis:

True congenital tuberculosis caused by the spread of infection through the placenta or amniotic fluid has been reported in only 300 infants. Transplacental transmission occurs through the umbilical vein from a mother with primary hematogenous or genital tuberculosis. This hematogenous “inoculation” of the fetus leads to miliary tuberculosis. The major site of the disease is the liver, which is enlarged. Pulmonary disease usually has amiliary pattern but may be more localized. Generalized lymphadenopathy and meningitis occur in approximately 50% of these patients. The exact clinical manifestations depend on the infecting “dose” of bacilli and the time of transmission.

Stillbirth has been associated with tuberculosis in the fetus.

Although the onset of symptoms may be delayed for several weeks, symptoms most commonly begin around the second week of life and include lethargy, decreased feeding, nasal discharge,

54 jaundice, respiratory distress, and abdominal distention from hepatosplenomegally.

Several cases of congenital tuberculosis have been caused by aspiration of amniotic fluid infected with M. tuberculosis from a mother with tuberculous endometritis. Pulmonary symptoms and signs dominate the clinical picture, but hepatomegally usually is present.

Perinatal tuberculosis caused by inhalation of tubercle bacilli expelled by an adult who handles the infant is much more common than is true congenital tuberculosis. More than 50% of untreated infants infected with M. tuberculosis at or near birth can be expected to develop clinically significant disease, usually in the lungs or cervical lymph nodes. The newborn infant should be separated from any adult known or thought to have pulmonary tuberculosis until the disease is no longer contagious(26) .

Tuberculosis in HIV infected children:

Most cases of tuberculosis in HIV infected children have been described in developing countries. Tuberculosis in HIV infected children is often more sever, progressive, and likely to occur in extra pulmonary sites. Non-specific respiratory

55 symptoms, fever, and weight loss are the most common complaints. Rates of drug-resistant tuberculosis are higher in HIV- infected adults and, probably, are also higher in HIV infected children.

The mortality rate of HIV infected children with tuberculosis

(9) is high, especially as the CD4 lymphocytes numbers fall .

1.7. Laboratory Diagnosis:

The definitive diagnosis of tuberculosis is based on the detection of acid-fast bacilli in clinical specimens by microscopy, cultural techniques or by the polymerase chain reaction (PCR) and its various derivatives. Numerous attempts have been made to develop serological tests for the disease with little success(26).

Specimens:

The most usual specimen for diagnosis of pulmonary tuberculosis is sputum, but if non-is produced, bronchial washings, brushings or biopsies and early morning gastric aspirates (to harvest any bacilli swallowed overnight) may be examined. Tissue biopsies are homogenized by grinding for microscopy and culture. Cerebrospinal fluid (CSF), pleural fluid,

56 urine and other fluids are centrifuged and the deposits are examined(27).

Microscopy:

Use is made of the acid- fast property of mycobacteria to detect them in sputum and other clinical material. In the Ziehl-

Neelsen (ZN) staining technique, heat-fixed smears of the specimens are flooded with a solution of carbol fuchsin

(a mixture of basic fuchsin and phenol) and heated until steam rises. After washing with water, the slide is flooded with a dilute mineral acid (e.g. 3% hydrochloric acid) and, after further washing, a green or blue counter stain is applied. Red bacilli are seen against the contrasting background colour. In some methods, the acid is diluted in 95% ethanol rather than water. This gives a clearer background but, contrary to a common belief, it does not enable tubercle bacilli to be distinguished from other mycobacteria. Fluorescence microscopy, based on the same principle of acid-fastness, is increasingly used and is much less tiring to the microscopist. Modifications of the various staining techniques are used to examine tissue sections(27).

Cultural Methods:

57 As sputum and certain other specimens frequently contain many bacteria and fungi that would rapidly overgrow any mycobacteria on the culture media, these must be destroyed.

Decontamination methods make use of the relatively high resistance of mycobacteria to acids, alkalis and certain disinfectants.

In the widely used Petroff method, sputum is mixed well with 4% sodium hydroxide for 15–30min, neutralized with potassium dihydrogen orthophosphate and centrifuged. The deposit is used to inoculate LJ or similar media. Specimens such as

CSF and tissue biopsies, which are unlikely to be contaminated, are inoculated directly onto culture media. As an alternative to chemical decontamination, mixtures of antibiotics that kill fungi and all bacteria other than mycobacteria may be added to the culture media. These are used principally in the automated culture systems described below(27).

Inoculated media are incubated at 35–37c° and inspected weekly for at least 8 weeks. Cultures of material from skin lesions should also be incubated at 33c°. Any bacterial growth is stained

58 by the ZN method and, if acid- fast, it is sub cultured for further identification.

Amore rapid bacteriological diagnosis is achievable by use of commercially available automated systems. Systems that detect colour changes in dyes induced by the release of carbon dioxide, or the unquenching of fluorescent dyes on the consumption of oxygen by metabolizing bacilli, have replaced the earlier radiometric method.

The first step in identification is to of the M. tuberculosis complex.

These organisms:

• Grow slowly.

• Do not produce yellow pigment.

• Fail to grow at 25 and 41 c°.

• Do not grow on egg media containing P- nitrobenzoic cid

(500 mg/L).

Strains differing in any of these properties belong to other species(27).

Nucleic acid technology:

Nucleic acid probes for the identification of the M. tuberculosis, and also for certain other species are commercially

59 available. They are not sensitive enough to detect mycobacteria in clinical specimens and are used to identify mycobacteria cultivated by conventional techniques.

Amplification of specific nucleic acid sequences specimens is achievable by PCR and related techniques, some of which are commercially available. Problems of low sensitivity, ‘false – positive’ reactions and cross contamination have largely been over come by the introduction of closed – system, isothermal techniques for amplification of species – specific 16S ribosomal RNA.

Most members of the M. tuberculosis complex contain 1 – 20 copies of the insertion sequence 1S6110, which has been used to develop DNA ‘Finger printing’ methods for epidemiological purposes. Alternatively, detection of spacer oligonucleotides, short

DNA sequences found around the sites of the insertion sequences, is useful for typing isolates (‘spoligotyping’) (27).

1.8. Tuberculin skin test:

Historical background:

About 6–8 weeks after the initial infection, the phenomenon of tuberculin

conversion occurs. This altered reactivity was discovered by Robert Koch

while attempting to develop a remedy for tuberculosis. When tuberculous

guinea - pigs were injected intradermally with living tubercle bacilli, the

60 skin around the injection site became necrotic within a day or two and was

sloughed off together with the bacilli. Koch then found that the same

reaction occurred when the injected old tuberculin– a heat- concentrated

filtrate of about in which tubercle bacilli had been grown. This reaction

became known as the Koch phenomenon, and its characteristic feature is

extensive tissue necrosis.

Although Koch’s tuberculin proved unsuccessful as a therapeutic agent, it formed the basis of the widely used tuberculin test(27).

Although Robert Koch’s attempts to use old tuberculin as a remedy for tuberculosis failed, an Austrian physician, Clemens

Von Pirquet, used the Koch phenomenon as an indication of bacterial ‘allergy’ resulting from pervious infection. Individuals with active tuberculosis were usually tuberculin positive, but many of those with disseminated and rapidly progressive disease were negative. This led to the wide spread but erroneous belief – that tuberculin reactivity is an indicator of immunity to tuberculosis.

Old tuberculin caused non-specific reactions and it has been replaced by purified protein derivatives (PPD) (27).

61 Robert Koch first described the tubercle bacilli in 1882. It was derived by evaporation from filtrate of cultures of M. tuberculosis at first in glycerol broth, later in synthetic media.

Despite its failure as a therapeutic aid, Koch’s solution which is now called old tuberculin (OT), was soon put to practical use. In

1907, Clemens Von Pirquet named the local skin reaction to (OT) an allergy and proposed that OT be used in the diagnosis of tuberculosis(27).

In 1908, Charles Mantoux introduced an intra-cutaneous method that has subsequently become the standard procedure for administration of tuberculin(28).

In 1950s, multiple puncture applicators were introduced and gained popularity because of their ease of use(28).

In 1934, Florence Seibert announced the discovery of a purified protein derivative (PPD) tuberculin obtained from ammonium sulphate – precipitated infiltrates of OT.

The purity is only relative as small quantities of lipids, polysaccharides and nucleic acids are also present(28,29).

In 1939, she produced a large batch of this substance, lot

49608,which was designated PPDS (standard) tuberculin(30).

62 In 1968, the World Health Organization redefined the international unit of tuberculin as 0.000028mg of standard PPD.

A large batch of standardized PPD (PPD-Rt23) has been prepared in Denmark of international use. In phosphate buffered solution

0.00002mgof Rt23 is equivalent to the international standard but unfortunately solutions prepared in buffer alone are very unstable owing adsorption on to glass. The solution can be stabilized with

0.005% tween 80, a detergent, but this is about three times, as powerful as the standard PPD, though the reactions are softer.

Nevertheless it was divided by the WHO to call this 1 tuberculin unit (TU) of R T23; it is important to remember that this is equivalent to three standard tuberculin units(29).

The dose originally recommended for epidemiological work was 1 TU of Rt 23 but now it is changed to 2 TU of Rt 23(29).

New patches of PPD are standardized by bioassay against

PPDS tuberculin. The standard dose of 5 tuberculin units (TU) used in intermediate strength PPD tuberculin should elicit a reaction equivalent to that produced by 0.1µg of PPDS tuberculin. First and second strength PPDS containing one and

250(TU) respectively, are not bioassayed against PPDS tuberculin.

63 Instead these products contain one fifth and 50 times respectively, the concentration of the antigen in intermediate strength PPD tuberculin. Both have limited value in diagnosing tuberculosis infections(28).

Uses of the tuberculin test:

1- To investigate the prevalence of TB in the community.

2- To investigate the effectiveness of control measures.

3- To examine the prevalence of opportunistic mycobacteria.

4- Differential diagnosis of TB.

5- To identify those who may require BCG.

6- To identify those who may require chemoprophylaxis.

7- Differential diagnosis in conditions associated with

depression of type IV (delayed – type) hypersensitivity(1).

Types of tuberculin test:

Three types of tuberculin test are in common use.

1- Mantoux test:

Tuberculin is injected intradermally (0.1ml) into the

volar aspect of the forearm and the reaction is read at 72-96

hours. The reading is based on the size of the transverse

induration only and ignores any associated erythema.

64 In Europe and America induration of 5mm or more is

regarded as positive, but in many developing countries 9mm

of induration is regarded as the minimal criterion for

a positive reaction.

The amount of tuberculin injected on routine testing

varies in different countries and institutions. Initial testing

may be carried out using 1 or 2 tuberculin units (TU)

(1/10000 or 1/5000) of tuberculin, but in many countries

1/1000 (10TU) is used as the standard Mantoux test(1).

A negative Mantoux reaction with a low dose of

tuberculin should be followed by tests of greater strength

when tuberculosis is suspected, especially in subjects who

may be immunosuppressed by malnutrition or disease(1).

2- The Heaf test:

This is performed using a six pronged, spring loaded

‘Heafgun’ which has settings for the depth of penetration of

the skin. A 1mm setting is usually used for infants and 2mm

setting for older children.

Undiluted PPD or OT is applied to the skin of the

forearm after cleaning (avoid using alcohol which is slow

65 drying and can denature the tuberculin) and the gun is

firmly applied to the skin and ‘Fired’. The six points of

penetration should be visible. The test is read 72-96 hours

later as follows:

Grade I: Palpable induration a round four or more

puncture points.

Grade II: Induration around the six puncture points

joined up to form a ring of induration.

Grade III: Induration that fils the centre of the ring to

form a solid plaque.

Grade IV: As in III but associated with ulceration of the

skin.

The Heaf test is as strong as, or stronger than, a mantoux using 10 TU (1/1000). If the Heaf test is negative, tuberculin sensitivity is weak or absent and further testing, if indicated, should be done using Mantoux 100 TU (1/100)(1).

3-The tine test:

This multiple puncture skin test was introduced by

Rosenthal in 1950s. The test is carried out with disposable

units each one comes 4 prongs or tines 2mm in length

66 mounted on a disc. The tines have been dipped in OT and

subsequently sterilized. The sterile times are mounted on a

plastic base from which they are removed immediately

before use. The tines are pressed on the stretched skin of the

volar surface of the forearm to form 4 puncture sites. The test

is read 48-72 hours and 2mm or greater palpable induration

around one or more of the puncture sites is said to be

approximately equivalent to 5mm reaction to the 5 TU

Mantoux test. It is thus weaker than the Heaf test. In details

it is graded from I to IV, a positive test is 5mm or more

(around one or more of the puncture sites). Doubtful 2-4mm

and negative less than 2mm. The advantage of this test is

that it is rapid, convenient, and acceptable. Its disadvantage

are that it is expensive if used on a large scale and because it

has a lot of false –ve reaction, it is not recommended now for

epidemiological purpose(29,31,32).

Interpretation of the tuberculin test:

A strongly positive tuberculin test is the rule in active post – primary infections but a negative reaction does not exclude the

67 possibility of active disease. The tuberculin test may be negative in the presence of active disease in the following circumstances:

1- The test is carried out in the pre-allergic phase of infection,

i.e. early.

2- The patient is immunosuppressed by:

a. Drugs: Most commonly prednisolone which is widely

and often indiscriminately used, but also by other

immunosuppressive drugs.

b. Malnutrition: Children with Kwashiorkor are

frequently allergic and the tuberculin test is of limited

value to establish a diagnosis of tuberculosis in these

children. Other forms of malnutrition may also reduce

or ablate the tuberculin response.

c. Disease: Measles, pertusis and kala-azar are infections

which commonly reduce or abolish the response to

tuberculin, as do various forms of malignant disease.

3- Faulty technique and denatured PPD or OT used in the test

may give false negative results especially in units where

tuberculin testing is only occasionally used and medical staff

are in experienced in its use.

68 Tuberculin tests in children who have had BCG:

The widespread use of BCG vaccination in infancy in developing countries has posed clinicians with some difficulty in interpreting the results of tuberculin tests. The following points help to reduce this difficulty:

1- BCG induced tuberculin sensitivity is usually not

demonstrable using Mantoux 1/10000.

2- The size of induration in response to Mantoux 1/1000

following BCG is usually <10mm and almost never exceeds

15mm wane.

3- The response to tuberculin tends to wane following BCG but

is much more persistent following tuberculosis, waning

handily at all in most, even after the eradication of the

infection(1).

Most of tuberculous patients who have reversible host factors that lead to false negative results like fulminent tuberculous infection, malnutrition, use of immunosuppressive drugs, viral infection etc…, react to tuberculin once their general health has been restored. However, small number of patients with tuberculosis have allergy to tuberculin even while able to manifest

69 positive reactions to other antigens, therefore, a negative tuberculin test even when coupled with a positive control skin test, does not justify excluding the diagnosis of tuberculosis(29).

In persons already sensitized to mycobacterial antigen, a false positive Mantoux test may result from cross reactions with non tuberculous mycobacteria. This is a particular problem in geographic areas where non-tuberculous mycobacteria are prevalent. There is considerable geographical variation in the prevalence of non-tuberculous mycobacteria(33). It is, as studied by the WHO, less than 10% in Denmark and North USA to over 90% in the Philippines, Sudan and Vietnam(34). It is 70 to 80% in some parts of India(35).

In the United States evidence from a detailed study of navy recruits suggests that such cross reactions may be especially prevalent in South East and a long the Mexican border(36).

Cross-reactions with non tuberculous mycobacteria produce smaller reactions in comparison with mycobacterium tuberculosis, and they are a major problem in interpretation of the skin test results. Although larger reactions >15mm almost always indicate infection by mycobacterium tuberculosis, smaller reactions don’t

70 always help to discriminate between exposure to non-tuberculous mycobacteria and tuberculosis infection(28). Another problem with the interpretation occurs when a patient with an initial small reaction manifest a larger reaction when retested, usually within

10 days to 12 month(37).

1.9. Treatment:

The Anti tuberculosis drugs are divisible into three groups:

• Bactericidal drugs that effectively sterilize tuberculosis

lesions.

• Bactericidal drugs that only kill tubercle bacilli in certain

situations. Streptomycin is in effective against bacilli

within macrophages and acidic inflammatory tissue, and

isoniazid kills bacilli only if they are replicating.

• Bacteriostatic drugs, which are of limited usefulness and

are not included in standard drug regimens.

Mutation to drug resistance occurs at a rate of about one mutation every 108 cell divisions. Successful therapy requires the prevention of the emergence of drug resistant strains by the simultaneous use of at least two drugs to which the organism is sensitive(27).

71 The earlier 2-year regimen of streptomycin, isoniazid and p-aminosalicylic acid has been replaced by much more acceptable orally administered regimens based on an initial intensive 2-month phase and a 4-6-month continuation phase depending on the world health organization (WHO) treatment category.

Most patients are in category 1 when diagnosed and the most widely used regiment

therefore consists of an intensive phase of rifampicin, isoniazid, pyrazinamide and

ethamputol for 2month, followed by the first two drugs for a total of 6 months.

Ideally, the drugs are given daily, but to ensure compliance they may be given

thrice weekly during the continuation phase or throughout.

The response to therapy of drug –susceptible tuberculosis is divisible into three

phases:

• During the first week or two, the large numbers of

actively replicating bacilli in cavity walls are killed,

principally by isoniazid, but also by rifampicin and

ethambutol. The patient rapidly ceases to be infectious,

and hospitalization with barrier nursing is non rarely

necessary.

• In the following few weeks the less active bacilli within

macrophages, caseous material and dense, acidic,

72 inflammatory lesions are killed by rifampicin and

pyrazinamide.

• In the continuation phase any remaining dormant bacilli

are killed by rifampicin during their short bursts of

metabolic activity. Any rifampicin resistant mutants that

start to replicate are killed by isoniazid.

Short course regimens are usually well tolerated by the patient. Isoniazid, rifampicin and pyrazinamide are all potentially hepatotoxic, and rifampicin may cause an influenza – like syndrome, which paradoxically, is more likely to occur when the drug is given intermittently. Contraceptives - an important point to be considered when treating young women. There is also mutual antagonism between rifampicin and the antiretroviral drugs used for HIV infection substituting rifabutin for rifampicin reduces this problem. Isoniazid may cause mild psychiatric disturbances and peripheral neuropathy, particularly in alcoholics, but these usually respond to treatment with pyridoxine (vit B6).

Ethamputol is toxic for the eye and, although this is rare with standard dosages, care is required and the patient should be informed of this possibility(27).

73 The emergence of drug-resistant strains (acquired resistance) during adequately supervised short – course chemotherapy is uncommon- most relapses are due to drug- sensitive bacilli.

Multi drug-resistant strains (acquired resistance) during adequately supervised short –course chemotherapy is uncommon

– most relapses are due to drug- sensitive bacilli. Multi drug- resistant strains are defined as those resistant to isoniazid and rifampicin; they are sometimes also resistant to other drugs and pose serious problems. The regimens for multi drug- resistant tuberculosis are based on in-vitro drug susceptibility tests; useful agents include the newer fluoroquinolones and macrolides and amoxicillin with a B-lactamase inhibitor such as sulbactam. The mortality rate is high, but with a high level of care this can be reduced to around 15% although HIV seropositivity is a poor progonstic factor(27).

1.10. BCG vaccine:

History of BCG vaccine:

For all mycobacterial diseases, only one vaccine, based on M. bovis, exists. In 1908, Calmette and Guérin at the Pasteur Institute of Lille, began a series of 230 passages of the virulent M. bovis. The

74 original virulent strain was grown for 13 years on potato slices cooked in beef bile supplemented by glycerol. The resulting culture was stable to reversion to virulence but retained limited invasiveness. The first human vaccination with this attenuated strain, named Bacille Calmette – Guérin (BCG), was applied in

1921 in Paris. After acceptance by the league of nations in 1928,

BCG vaccine was widely used(38).

For prevention of tuberculosis BCG vaccination is accepted as one of the most important measures. It is compulsory in 64 countries and is officially recommended in an additional 118 countries and territories. BCG is the most effective known adjuvant in animals and humans. It is also cheap, stable, and safe.

As BCG came into general use, a number of different substrains were generated in a number of production laboratories.

Some of these substrains, derived from the original strain by additional culture passages, lost residual invasiveness and were devoid of efficacy. Therefore, any strain used for vaccine production should be documented and approved by WHO.

At present, the four most widely used strains are derivatives of the Pasteur –

1173P2, Tokyo – 172, Copenhagen – 1331, and Glaxo – 1077 strains(38).

75 There is considerable evidence that heterogeneity exists among the different isolates of M. tuberculosis, though the impact of these differences on the antigenic properties is not clear.

Despite the fact that BCG is a strain of M. bovis and tuberculosis is caused by M. tuberculosis, studies indicate that

BCG protects against tuberculosis and leprosy. Recent data confirm the assignment of BCG as M. bovis, but also show great antigenic variation among BCG strains.

In 1966, the WHO Expert Committee on Biological standardization established the first requirements for BCG vaccine.

These requirements have subsequently been revised. They out line procedures for production of BCG vaccine to ensure potency, safety, efficacy, and describe certain tests which should be done on the vaccine seeds, and on the final vaccine it self. The WHO requirement were designed to reduce the variability among BCG strains, seen in clinical and animal trials, by requiring each manufacture to correlation laboratory test results with clinical efficacy data(38).

The age of vaccination:

76 Most countries (except for the united states of American and the Netherlands) recommend the use of BCG. The schedule differs from country to country. WHO recommends one dose at birth or at the first contact of the infant with the health system. Other countries use other schedules(38).

Children born in Asia, or those born in Britain with parents from the Indian subcontinent, however, have a higher risk of infection and this should be taken into account when immunization policies are considered. These children should be given BCG after birth.

In some areas of Britain BCG is given to children in their ten age years after a tuberculin skin test has been performed and shown to be negative.

Heaf or Mantoux testing before giving BCG at birth is obviously not required, but when BCG is given after the age of 3 months, it is probably wise to do so, particularly if tuberculosis is common in the community(39).

Routes of administration:

The route of administration and dosing schedules for the

BCG vaccines are important variables for efficacy(40).

77 Early attempts were made to give BCG by mouth using the fluid, not the lyophilized, form of the vaccine, but that route gave little success because of the low dosages used. Better response was seen with massive (hundreds of milligram) doses.

A number of different injection methods were tried. BCG administration by jet injector was found to deliver less than the full dose and give a variable vaccination lesion. Attempts to increase the dose gave rise to large ulcers and the method was discarded. For this reason, BCG administration by jet injector is not advised.

Intradermal injection is the method of choice. This method was introduced in 1927. For intradermal injection, the injection site is the lower deltoid area so as to involve the axillary instead of the upper clavicular lymph nodes. This is to minimize complications from post vaccination lymphadenopathy(38).

Multiple puncture is an alternative technique for BCG administration, which is not recommended by WHO. Several drops of BCG are rubbed on the same site as for intradermal injection, and an appropriate device with multiple points is used to introduce the vaccine under the skin. To obtain a result similar

78 to intradermal injection, 40 punctures are needed. This requires a large volume of vaccine, and it is operationally difficult. Use of a bifurcated needle has been studied, but this was also found to be inferior to intradermal injection(38).

Mee and Thwaites (1977) have studied the response to the tuberculin test in neonates given BCG by intradermal injection or by multiple puncture with a Heaf gun or a bifurcated needle. They found minimal difference in the conversion rates of the three groups. However, other authors have found that uniformity of dose is more readily assured by intradermal injection, a long with a superior level of tuberculin sensitivity and lower cost. For this reason, intradermal injection is the WHO recommended method for administration of BCG(38).

The dose of the vaccine:

The vaccine is injected intradermally in a dose of 0.05ml, after 3-6 weeks a small red papule appears, which in most cases, breaks down to a shallow ulcer after 4 weeks. Healing is slow and may take as long as a year leaving a small puckered scar(39).

Immune response to BCG vaccine :

79 Clinical trials have confirmed that infection with mycobacteria other than M. tuberculosis, including the BCG vaccine, may induce some protection against tuberculosis.

Artificial infection with BCG spreads from the inoculation site via the lymphatic system to local lymph nodes and produces immunity equivalent to that produced by natural primary infection with virulent bacilli. As in the case of natural tuberculosis infection, the resistance is cell mediated and is largely attributable to activated macrophages. BCG induced immunity develops about six weeks after vaccination(38).

BCG scar:

Immediately after the BCG vaccine there is a small swelling at the injection site, which persists for 6–8 hours. After that the swelling disappears and the injection site looks normal, after 6–8 weeks a swelling reappears which looks like a mosquito bite. It grows in size and forms a nodule, which breaks open and discharges some fluid and forms and ulcer. The ulcer heals by forming a scar. The whole process takes 2-5 weeks. Sometimes this process of ulceration and healing recurs 2-3 times. Ultimately the typical puckered scar is formed which remains for life time(40).

80 The presence of such scar in the appropriate place has been used as evidence for prior BCG vaccination. With multiple puncture inoculation, there are many small papules which disappear more quickly and often without scarring(38).

Size of the scar:

Although the size of the scar follows a simple dose – response, various others factors have been shown to influence the size and shape of the scar:

1- The technique of administration of vaccine (intradermal

administration is more likely to leave a uniform scar,

while in proper, i.e. subcutaneous, administration may

not).

2- Characteristics of the recipient (keloid formation may be

associated with race).

3- The strain of BCG used.

Fine et al. (1989) found that of children vaccinated in infancy fewer than 60% retained a recognizable scar after two years. Thus, scars are poor indicators of BCG vaccination in infancy. This may be due to : 1- The lower dose used.

2- Difficulty of administering vaccine truly intradermally.

3- An immature immune response, although cell-mediated

immunity is normal at birth.

81 Other studies have shown more than a 10% loss of scars in

Algeria, Botswana, Tunisia and Zambia(38).

Poor immunization technique or loss of vaccine integrity might explain the failure to retain a scar.

It has been suggested that immunization programme manager might use a systematic assessment of the variability of scar size in BCG recipients to evaluate the proficiency of vaccinators, since a uniform scar of a certain minimum size would indicate a consistency of vaccine administered. However, this suggestion may not be feasible when BCG is given over a wide range of ages or if different strains of BCG are administered, since there is known variability in scar size with vaccine strain used and with age at which the vaccine is administered.

It is possible that there is association between the tendency for vaccination to leave a scar and its protective efficacy. This may be because in properly administered vaccine may not be efficacious. Another explanation could be that if the vaccine recipient did not mount an adequate immune response to the vaccine, no scar would be seen, and the vaccination would not be protective. It is worth noting, however, that misclassification of

82 vaccination status because of lack of scar formation would tend to reduce the apparent vaccine efficacy. For this reason, studies on

BCG vaccine efficacy should rely on documentation of immunization by immunization card(38).

A BCG scar is highly sensitive and repeatable indicator of vaccination status when:

1) The vaccine is properly handled.

2) Delivered appropriately.

3) Given at or over 3 months of age, but not

vaccination given within one month of birth.

Given that most vaccinations in the world are given soon after birth, this low sensitivity will lead to both vaccine coverage and vaccine efficacy being underestimated in studies in which vaccination status is inferred from the presence or absence of a distinctive BCG scar(41).

Most of authorities believe that BCG vaccination should result in along standing scar in more than 90% of the cases(42).

Contraindications:

Although BCG vaccine is contraindicated in HIV – infected children in the United States, the World Health Organization

83 (WHO) recommends giving BCG to asymptomatic HIV – infected children in areas with a high incidence of tuberculosis.

Live virus vaccines should be administered with caution to children receiving corticosteroids. Children receiving physiological doses of corticosteroids, or less than 2mg/kg/24hrs of prednisone or its equivalent or less than 20mg/24hr if they weigh more than 10kg, can be immunized while on treatment.

Contraindications to BCG include active tuberculosis, sever malnutrition, other sever illness and immunosuppression.

A fatal ‘BCG’ infection has been reported in adults with

AIDS and therefore HIV-positive children should not be immunized(39).

Adverse side effects:

Since BCG is a live attenuated vaccine, it can be expected that occasionally its use will result in complications.

The BCG vaccines are extremely safe in immunocompetent hosts. Local ulceration and regional suppurative adenitis occur in

0.1-1% of vaccine recipients. Local lesions do not suggest underling host immune defects and do not affect the level of

84 protection afforded by the vaccine. They usually resolve spontaneously, but chemotherapy is needed occasionally. Osteitis is rare complication of BCG vaccination that appear to be related to certain stains of the vaccine that are no longer in wide use.

Systemic complaints such as fever, convulsions, loss of appetite, and irritability are extraordinary rare(40).

Profoundly immunocompromised patients may develop disseminated BCG infection after vaccination. Children with HIV infection appear to have rates of local adverse reactions to BCG vaccines that are comparable to rates in immunocompetent children. However, the incidence in these children of disseminated infection month to years after vaccination is currently unknown(40).

Vaccine storage and handling:

A freez – dried vaccine is now available which maintains its activity for a year, if kept in a refrigerator, and obviate the problem of the short life of the liquid preparation(40).

BCG vaccine stocks can be stored frozen in freezer compartment. Working stock can be stored in the chiller

85 compartment. Even diluents should be stored in the refrigerator’s lower racks at 2-8c°(40).

BCG vaccine ampoules should be cut with a file very slowly and not snapped open because it has vacuum inside, the glass will splinter and fly if cut very suddenly. It may be safer to hold the ampoule in a cloth to avoid injury. Once prepared, BCG vaccine should be used within 2-3 hours and discarded there after(40).

Monitors of the vaccine:

The cold chain monitor is used to show exposure to temperature during transportation and storage. It has an indicator that responds to two different temperatures. The first part responds to two different temperatures(43).

The first part responds to temperature above +10 c°(43). When the indicator exposed to temperature+10 c°, a blue colour starts to appear. The higher temperature, the faster the blue colour spreads, when the indicator exposed to temperature above +34c°, the blue colour appears within two hours. When the colour changes to blue it will never change back to white.

86 The vaccine vial monitor is around disc of heat sensitive material placed on a vaccine vial to register cumulative heat exposure. A direct relationship exists between the rate of colour change and temperature, the lower temperature, the slower colour change. The higher temperature the faster colour changes. VVM can be used on vaccine vial or ampoules(43).

Protective efficacy of BCG:

BCG vaccination has worked well is some situation but poorly in others. Clearly BCG vaccination has had little effect on the ultimate control of tuberculosis throughout the world because over 8 billion doses have been administered but tuberculosis remains common in most regions.

BCG vaccination does not substantially influence the chain of transmission because those cases of contagious pulmonary tuberculosis in adults that can be prevented by BCG vaccination constitute a rather small fracture of the sources of infection in a population.

The best used of BCG vaccination appears to be prevention of life threatening form of tuberculosis in infants and young children(31).

87 Trials of the vaccine have been undertaken since it was first developed in the 1920s. The results have been variable. About a third of the total trials have shown no protective effect. The remainders have shown protection of up to 80% at best lasting a maximum of 15 years. No trials on second or subsequent vaccinations have shown any protective effect(44).

Experimental studies indicate that the mechanism of protection consists in reduction of the hematogenous spread of the bacilli from the site of primary infection mediated by memory T lymphocytes induced by the first exposure to BCG(38).

There is no evidence that BCG reduces the risk of becoming infected with tuberculosis bacilli, but it prevents forms of tuberculosis depending on hematogenous spread of the bacillus, thus reduces the risk of immediate disease and of disease due to reactivation(38).

Myint et al. (1987), in studies in newborns, showed a wide range of protective efficacy (that is, the measure of protection against tuberculosis afforded by BCG vaccination), depending on the form of tuberculosis. The highest efficacy seen in this study was 80% for disseminated tuberculosis, 52% for tuberculous

88 meningitis, 39% for tuberculosis of the bone, 32% for lymphadenitis, 32% for primary complex with local extension and

20% for primary complex formed in the lung(38).

Causes of variability in BCG effectiveness:

The reason for variability are not fully understood. There have been a number of theories put forward, non of which seem to provide a total explanation:

1- Methodological. All studies varied slightly in the way they

were designed.

2- Different vaccines. The development of BCG has meant that

strains vary according to the time at which each has been

developed. Different vaccine strains were used in the trials

and are in use across the world today.

3- Tuberculin status of subjects. Within trials some individuals

in both control or vaccinated group may have been

tuberculin positive and therefore had natural protection.

This may not have been accounted for in some of the trials.

4- Different strains of M. tuberculosis. New molecular

techniques have demonstrated that there are a large number

of different strains of the bacterium. It is possible that

89 different areas of the world have different strains, which

may vary in virulence.

5- Genetic differences in population. There is variation in

individual susceptibility to tuberculosis. This could have

caused disparity in results.

6- Intensity of infecting dose. Infection and susceptibility to

disease may be affected by the quantity of bacteria inhaled.

7- Nutritional differences. It is known that different nutritional

states can affect susceptibility to disease. The poorly fed

individual is more susceptible.

8- Protection of control by environmental mycobacteria. These

free living mycobacteria which resemble M. tuberculosis

sometimes cause disease. They may be responsible for

infecting individuals therefore providing partial immunity to

M. tuberculosis(44).

Although dozens of BCG trials have been reported in various human populations, the most useful data have come from several controlled trials. The results of these studies have been disparate.

Some demonstrated a great deal of protection from BCG vaccines, but others showed no efficacy at all.

90 A recent meta-analysis of published BCG vaccinations trials suggested that BCG is 50% effective in preventing pulmonary tuberculosis in adults and children. The protective effect for disseminated and meningeal tuberculosis appears to be slightly higher with BCG preventing 50-80% of cases(44).

BCG administered during infancy has little effect on the ultimate incidence of tuberculosis in adults, suggesting that the effect of the vaccine is time limited(19).

In 1994 a “metanalysis” of all the trials was published. This looked at a total of 1264 articles. 70 in depth, 14 prospective trials and 12 case-control studies. The authors found that seven trials show a protective effect from death of 71%, five trials showed protection from meningitis of 64%, three, protection from disseminated disease of 78% and three, protection from laboratory

– confirmed disease of 83%.

The authors concluded that geographical site of study explained 66% of variability. They also found that on average BCG reduces risk of infection leading to disease by 5%. This is probably an erroneous conclusion, as the efficacy of BCG cannot be

91 averaged. Trials show it to be 80% protective in one place and 20% in another, an average efficacy should not be taken(45).

Sequential studies from the U.K show that the 75% efficacy has been maintained.

Studies carried out by the British Medical Research Counsel in 1950s showed that BCG, when given to teenage school children gave about 75% for 15 years(46).

Some workers believe that BCG efficacy waning with time because it is continually being reproduced as part of the manufacturing process and in common with other life organisms, which undergo this process, may be becoming less virulent and therefore less able to provide immunity to those who are vaccinated(47).

Future prospects (and needs):

The discussions above indicate some needs in BCG vaccinology. They are summarized as follows, in decreasing order of likelihood:

92 • A decreased number of BCG preparations. At present

they are many, which may not be well characterized in

terms of their tuberculin response and reactogenicity.

Efforts are being made, primarily through the UNICEF tender, to decrease this number, by imposing limits on the tuberculin response and reactogenicity.

Programme managers can help by assuring continuity of supply of their BCG vaccine and by discouraging proliferation of strains in local production(38).

• Development of an in vitro assay, which would relate to

human tuberculosis immunity.

As more is being learned about the structure of the M. tuberculosis bacillus and the components of the immune response, this possibility looks increasingly more probable.

• Development of a vaccine, which is well defined in terms

of its molecular structure, so that it can be tested in a

quantitative manner. Such a vaccine will become feasible

as studies on the molecular structure of the organism and

on the cellular immune response are completed.

93 • Development of a vaccine, which will work against

exogenous reinfection, that is, will prevent implantation

of the tubercle bacillus from outside the host organism.

This will probably necessitate a vaccine which works at

the level of the respiratory tract. Only by designing a

vaccine which will fulfill this characteristic will a

tuberculosis vaccine be able to be truly protective(38).

Implications for Immunization Programme:

Since cell mediated immunity is life long, there may be little advantage in giving a booster dose, even if there is an increase in tuberculin sensitivity on revaccination.

The EPI Global Advisory Group recommends the following.

BCG should be given to newborns as protection against the most severe forms of childhood tuberculosis. BCG should be given as early in life as possible in all population at risk of tuberculosis infection. Research should be initiated or continued on the long term effectiveness of BCG given in infancy(38).

It is best to allow an interval of one month between BCG vaccination and vaccinations against measles and other similar

94 vaccines such as Mumps vaccine because they may temporarily depress the cellular immune response(38).

BCG as a diagnostic test:

There is considerable evidence that children who fail to show reaction to the standard Mantoux test or even to PPD or O T 1/100

(100 TU) may have a cellular immune response provoked by BCG.

Such children show an accelerated BCG reaction with induration within 48 hours, a pustule on the third day and a scab by 5-6 days leading to a scar formation within 2 weeks. BCG vaccination may therefore be employed as a final test of tuberculin sensitivity in children suspected of the disease.

It has been advocated that BCG be routinely used as a diagnostic and protective measure. Children who show an accelerated reaction require further investigation for active disease, while those with a normal BCG response can be assumed to be tuberculosis free and have been immunized against the disease(1).

JUSTIFICATIONS

1- Tuberculosis is still a leading cause of death in many

countries in spite of wide spread use of BCG vaccine.

2- BCG efficacy widely differs from population to

another; some demonstrated a great deal of

protection but others showed no efficacy at all.

OBJECTIVES

1- To evaluate the protective efficacy of BCG

vaccination in children aged 1-7 years

2- To correlate the efficacy with:-

i- BCG scar .

ii- Social factors

97 2. PATIENTS AND METHODS

2.1. Nature of the study:

Descriptive cross sectional community based study.

2.2. Study area:

The study was conducted in three rural areas in East Nile

Province (El Tukunab, Banat, El Rahana).

These areas were selected because they were labeled as high risk area of tuberculosis in 1997 by Dr. Hind Omer El Nour with annual risk of infection which was estimated as 2.35 with an estimated incidence of 234 per 100,000 population(48). The estimated number of the total population is 5000 families and the average number of children per family is 5.

The climate is hot and dry with short rainy season. It is inhabited mainly by tribes branched from Gaaleen tribe according to Oan Elshareef Gasim classification(49).

Health care is provided through one health centre which staffed mainly by one medical assistant, Health visitors, vaccinators, midwives, assistant pharmacist and lab technician.

98 BCG vaccination is the direct responsibility of the vaccinator in the health centre, she is a female from near by area working as vaccinator for the last 6 years, she attended courses that were regulated by the Federal Ministry of Health on how to apply the six immunizable childhood disease vaccines.

There are two specialized days weekly for vaccination in specialized room (for all services of the primary health care), it is given by intradermal injection with a disposable syringe in the lateral aspect of the upper one third of the left forearm. Sometimes

BCG vaccine is given to the newborn during the regular home visits. The type of vaccine, which is available there now, is S

Artillerivel 2300 cph.s Denmark. The vaccine is stored in a special refrigerator for all vaccine, which works with gas with two-gas cylinder.

2.3. Duration of the study:

This study was conducted during the period from 1st of June

2003 to 31st of August 2003.

2.4. Study population:

The study population was composed of 398 children aged one year to seven years.

99 The study population was calculated according to the following formula:

N = (z)2pq/(d)2 = 385

N = sample size z = statistical certainty p = prevalence where p = 0.05 q = 1 – p d = desired margin of error

2.5. Inclusion criteria:

All children aged 1 – 7 years who live in the study area.

2.6. Exclusion criteria:

Children whose parents refuse to participate in the study.

2.7. Research methodology:

All children aged 1 to 7 years in the study areas (Three near by villages – El Tukunab, Banat & El Rahana) were studied. The houses at those areas were already numbered, so the work was organized from house number one onwards.

The tuberculin solution is PPD 23 Tween80. It was carried in a vaccine carrier and was given by a well-trained vaccinators, the questionnaires and clinical examination were the responsibility of

100 the author, 72 hours later the tuberculin reactions were measured by both the author and the vaccinators by transparent flexible ruler as will be mentioned below.

2.8. Research team:

The research team is composed of:

1- Author.

2- Two vaccinators.

3- Four volunteers. They are four females from the study area,

their age range from 18 to 22 years and they are already

attached to the health centre to assist the main staff in

registration and to share in the home visits to facilitate the

work for the vaccinator and dietitian.

2.9. Input of the author:

Input of the author was to:

1- Design the study and the questionnaire.

2- Supervise the process.

3- Make necessary contacts and obtain permission from

authorities.

4- Interview the parents and complete the questionnaire.

5- Obtain informed consent.

101 6- Conduct physical examination of the children.

7- Measure the tuberculin reaction.

8- Reside in the study area for many days for supervision,

doing the tuberculin test and measuring the reactions

72 hours later.

2.10. Research tools:

2.10.1. Consent:

Written approvals were taken from the EPI programme and

Ministry of Health and informed consents were obtained from the parents and/or guardians in each case.

2.10.2. Questionnaire:

A pre-coded questionnaire was completed for all children in the study group. It included detailed history: Individual age, gender, health status, tribe, family members per room, parents education and occupation, history of contact with TB case, history of BCG vaccination, age of vaccination and history of symptoms suggestive of tuberculosis. Thorough clinical examination was also done. The BCG scar size and tuberculin reactions were measured to the nearest millimeter using flexible transparent ruler and measurement of the tuberculin reaction.

102 2.10.3. Mantoux test:

Special disposable 1ml syringes graduated in hundredth of milliliters were used, 10mm long, disposable needles.

The test was given on the volar aspect of the forearm. The needle point is inserted in the superficial layer of the skin of the forearm while the skin is slightly stretched in the direction of the needle. The 0.1ml volume is slowly injected to form a blister and the finger is removed from the end of the plunger before the needle is withdrawn.

2.10.4. Measurements of reactions (Mantoux test):

The reactions were examined after 72 hours. The reading was limited to a single aspect of the reaction, the induration. The test sites were carefully palpated and when indurations were present its limits were determined and its transverse diameter

(transverse relative to the arm) is measured in millimeters.

Measurements were made by a small transparent flexible ruler calibrated in millimeters. The widest transverse diameter of the induration is recorded in millimeters, when there is no palpable induration, “0” is recorded.

103 2.11. Diagnosis:

Children were diagnosed as tuberculosis according to the scoring criterion developed by the MRC National Tuberculosis

Research Programme and centre for epidemiological research in

Southern Africa, Pretoria, South Africa and the International

Union Against Tuberculosis and Lung Diseases (IUATLD)(50).

Criterion Age group <5 years Age group >5 years

History of contact 2 2

Skin test 2 2

Cough 2 1

Weight loss 3 3

Fever 1 2

Total ≥5 ≥5

104 2.12. Treatment:

Children suspected of having TB according to this score were referred to Ahmed Gasim Hospital for further management. 2.13. Data entry and analysis:

Data was entered and analyzed using the SPSS (Statistical

Package for Social Sciences). Cross tabulation between the variables was done. The X2 test was used and the P value at 95% confidence level was used as the test of significance, probability value of ≤0.05 was considered significant.

2.14. Funding:

This research is funded by the author with a contribution from the EPI programme.

3. RESULTS

105 A total of 398 children aged 12 months to seven years in three rural areas in East Nile Province were prospectively studied during the period from the 1st of June to 30th of August 2003. Full records were analyzed.

3.1. Sociodemographic characteristics of the study population:

3.1.1. Age and sex distribution:

Figure 1 shows the age distribution of the children; 170

(42.7%) children were from 12 months to 36 months, 132 (33.2%) were more than 36 to 60 and 96 (24.1%) were more than 60 to 84 months.

Sex distribution of the children is shown in Figure 2. About

200 (50.3%) of the children were males and 198 (49.7%) were females. The ratio of males to females is 1.01 : 1.00.

3.1.2. Tribe:

392 (98.5%) of children in the study were from Gaaleen,

4 (1%) descended originally from other tribes and 2 (0.5%) from

Bagara tribe, as shown in Figure 3.

3.1.3. Parents’ education:

106 About 42(10.6%) of the fathers and 52 (13.1%) of the mothers were illiterate; 204 (51.2%) of the fathers and 308 (77.4%) of the mother completed 8 years primary school; 148 (37.2%) of the fathers and 38 (9.5%) of the mothers completed the secondary school and only 4 (1%) of the fathers completed university

(Figure 4).

3.1.4. Parents’ occupation:

The majority of the fathers i.e. 258 (64.82%) were unskilled labourers, whereas 351 (88.4%) of the mothers were housewives as seen in Figure 5 and 6 respectively.

3.1.5. Family income:

The income of 10 (2.51%) of the families was less than 10,000

Sudanese Dinars per month; 258 (64.82%) between 10,000 to 30,000 and 130 (32.67%) more than 30,000 Sudanese Dinars (Figure 7).

3.2. Certain characteristics of children:

3.2.1. Number of persons per room:

The predominant group was 1-3 persons per room, which was 202 (50.8%), the other groups which were 4-6 and 7-9 persons per room were 180 (45.2%) and 16 (4%) respectively (Figure 8).

3.2.2. BCG vaccination state:

107 About 378 (95%) of children were BCG vaccinated, 33% of them documented by BCG scar, 32% have no scar but documented by vaccination card, 30% of them have both vaccination card and BCG scar, 5% gave no history of BCG vaccination (Figure 9). 3.2.3. Age of children in months when BCG vaccinated:

Most of the children (73.9%) were vaccinated in the 1st 3 months of age, 24.6% between 3 to 6 months and only 1.5% were vaccinated at more than six months of age as shown in (Figure 10).

3.2.4. Size of BCG scar:

Figure 11 shows that 148 (39.1%) of the vaccinated children were having scar measuring from 2-5mm, in 106 (28%) there was no scar seen, in 38 (10.1%) it was faint, in 20 (5.3%) less than 2mm and in 66 (17.5%) it was more than 5mm.

3.2.5. Contact with TB cases:

Most of the children 392 (98.5%) gave no history of contact with TB case, while the contact was unknown in 1.5% as shown in

(Figure 12).

3.2.6. Clinical cases of tuberculosis:

During the three-month study period there were 2 (0.5%) cases of tuberculosis detected out of the total 398 children surveyed (Figure 13).

108 3.3. Mantoux test results:

Figure 14 shows that most of the children 274 (68.85%) of children shows reaction less than 5mm, 114 (28.64%) between

5-10mm and 10 (2.51%) more than 10mm.

3.4. Factors affecting vaccination state in the study population:

3.4.1. Age:

3.4.1.1. Correlation of BCG vaccination with age:

Table 1 shows that most of the children vaccinated in the study population age 12-36 months while 12 (60%) of the non vaccinated aged more than 36 to 60 months. and this was found to be statistically significant (P<0.001). 3.4.2. Parents education:

3.4.2.1. Parents education in relation to BCG vaccination:

Table 2 shows that, 40 (10.6%) out of the 42 (10.6%) of children whose fathers were illiterate received BCG vaccine, while 188 (49.7%) out of 204 (51.2%) of children whose fathers completed primary school, 78 (20.6%) out of 8 (20.1%) of children whose fathers completed secondary schools, 68 (18%) out of 68 (17.1%) of children whose fathers completed higher secondary school and 4 (1.1%) out of 4 (1%) of children whose fathers graduated from university receive BCG vaccine. BCG vaccine was given to 42 (11.11%) out of 52 (13.1%), 298

(78.84%) out of 308 (77.4%), 24 (6.35%) out of 24 (6%) and 14 (3.7%) out of 14 (3.5%) of children whose mothers were illiterate, completed primary, completed secondary and completed higher secondary school respectively, as shown in (Table 3).

Table 4 shows that 260 (77.4%) out of 280 (74.1%) of children whose mothers were educated received their BCG vaccine from birth to 3 months while 74 (22%) out of 92 (24.3%) and 2 (0.6%) out of 6 (1.6%) receive their BCG vaccine at more than 3 to 6 months

109 and more than 6 months respectively. This was statistically significant (P<0.001), so children whose mothers, were educated received the BCG vaccine earlier than those whose mothers were not educated.

3.5. Factors affecting BCG scar:

3.5.1. Age when BCG vaccinated:

3.5.1.1. BCG scar in relation to age when BCG vaccinated:

BCG scar was not present in 76 (71.7%) out of 280 (74.1%) of children who were vaccinated from birth up to 3 months while it was not present in 28 (26.4%) out of 92 (24.3%) and 2 (1.9%) out of

6 (1.6%) of children who were vaccinated at more than 3 to 6 months and more than 6 months respectively. These findings were found to be statistically highly significant (P< 0.001), as shown in

Table 5.

3.5.2. Correlation of sex and BCG scar:

Table 6 shows that 64 (50.8%) of males had no BCG scar compared to 62 (49.2%) of females. There was significant

110 difference between males and females (P<0.001), so females had higher chance of scar than males.

3.6. Factors affecting tuberculin reaction:

3.6.1. Age:

3.6.1.1. Correlation of tuberculin reaction and age:

Table 7 shows that 122 (44.5%), 42 (36.8%) and 6 (60%) out of

170 (42.7%) of children aged 12-36 months had Mantoux test measuring less than 5mm, between 5 and 10mm and more that

10mm respectively compared to 64 (23.4%), 28 (24.6%) and 4 (40%) out of 96 (24.1%) children aged more than 60 to 84 months who showed reactions less than 5mm, from 5 to 9mm and equal or more than 10mm respectively. These findings were statistically not significant (P=0.052), so tuberculin reaction is not affected by age.

3.6.1.2. Correlation of tuberculin reaction with age of BCG vaccination:

Table 8 shows that 6 (60%) out of 280 (74.1%) children who were vaccinated from birth to 3 months showed tuberculin measurement more or equal 10mm while 4 (40%) out of 92 (24.3%) of children vaccinated in more than 3 to 6 months had measurement more than 10mm. While no children were found to have tuberculin reaction measuring more or equal 10mm in children vaccinated in more than 6 months of age. These findings were found to be statistically not significant (P=0.276), so tuberculin reaction is not affected by age of vaccination provided that it was read after 6 weeks of vaccination.

3.6.2. Correlation of tuberculin reaction with sex:

111 Table 9 shows that 8 (80%) of males had positive tuberculin reaction compared to 2 (20%) of females. There was significant difference between males and females (P=0.001). 3.6.3. Correlation of tuberculin reaction with BCG scar:

BCG scar was not present in 108 (39.4%) of children who showed tuberculin measurement less than 5mm and it was more than 5mm in 8 (80%) of children with tuberculin measured more or equal 10mm. This was found to be statistically significant

(P<0.001), as shown in Figure 10, so children with large BCG scar showed large induration.

3.7. TB cases in the study:

3.7.1. Correlation of TB cases with age:

Table 11 shows that 2(100%) cases of TB were detected out of 170 (42.7%) of children aged 12-36 months. This was found to be statistically not significant (P=0.260).

3.7.2. Correlation of TB cases with age when BCG vaccinated:

Table 12 shows that the 2 (100%) of TB cases detected received their BCG from more than 3 to 6 months.

3.7.3. Correlation of TB cases with family income:

Table 13 shows that the family income of the 2 TB cases detected were in the range of 10,000 to 20,000 SD.

3.7.4. Correlation of TB cases with number of persons per room:

112 Table 14 shows that the number of persons per room in the 2 cases of TB detected were in the range of 4 to 6.

3.7.5. Correlation of TB cases with BCG scar:

The BCG scars of the 2 TB cases detected were measuring

<2mm as shown in (Table 15).

3.7.6. Correlation of TB cases with tuberculin reaction:

Positive tuberculin reaction was found in the 2 TB cases detected as shown in (Table16). 3.7.7. Correlation of TB cases with BCG vaccination:

Table 17 shows that the 2 TB cases detected were BCG vaccinated.

Table 1 : Age in month in relation to BCG vaccination of children in the study population (n=398)

113

Age in months Vaccinated Non vaccinated Total

n % n % n %

12-36 162 42.9 8 40 170 42.7

>36-60 120 31.7 12 60 132 33.2

>60-84 96 25.4 0 0 96 24.1

Total 378 100.0 20 100.0 398 100.0

X2 = 36.862 P < 0.001

Table 2 : Fathers’ education in relation to BCG vaccination in

children of the study population (n=398)

Educational level Vaccinated Non vaccinated Total

n % n % n %

114 Illiterate 40 10.6 2 10 42 10.6

Primary school 188 49.7 16 80 204 51.2

Secondary school 78 20.6 2 10 80 20.1

Higher secondary school 68 18 0 0 68 17.1

University 4 1.1 0 0 4 1

Total 378 100.0 20 100.0 398 100.0

115

Table 3 : Mothers’ education in relation to BCG vaccination of children in the study population (n=398)

Educational level Vaccinated Non vaccinated Total

n % n % n %

Illiterate 42 11.1 10 50 52 13.1

Primary school 298 78.8 10 50 308 77.4

Secondary school 24 6.4 0 0 24 6.0

Higher secondary 14 3.7 0 0 14 3.5 school

Total 378 100.0 20 100.0 398 100.0

116 Table 4 : Mothers’ education in relation to age when BCG vaccinated of children in the study population (n=398)

Age when BCG vaccinated Non Educated educated Total (in month) n % n % n % 0-3 260 77.4 20 47.6 280 74.1 >3-6 74 22.0 18 42.9 92 24.3 >6 2 0.6 4 9.5 6 1.6 Total 336 100.0 42 100.0 378 100.0

X2 = 30.401 P < 0.001

Table 5 : BCG scar in relation to age when BCG vaccinated (in months) in children of the study population (n=378)

117

Age when BCG BCG scar Total vaccinated in months Not present Faint <2mm 2-5mm >5mm

n % n % n % n % n % n % 0-3 76 71.7 36 90 18 81.8 110 75.3 40 62.5 280 74.1 >3-6 28 26.4 4 10 4 18.2 36 24.7 20 31.3 92 24.3 >6 2 1.9 0 0 0 0 0 0 4 6.2 6 1.6 Total 106 100.0 40 100. 22 100. 146 100. 64 100. 378 100. 0 0 0 0 0

Table 6 : BCG scar in relation to sex in children of the study population (n=398)

118

+v -v

Sex BCG scar BCG scar Total n % n % n % Males 136 50.0 64 50.8 200 50.3 Females 136 50.0 62 49.2 198 49.7 Total 272 100.0 126 100.0 398 100.0

Table 7 : Age in months in relation to tuberculin reaction in children of the study population (n=398)

119

Age in months Tuberculin reaction in mm Total <5 5-9 ≥10 n % n % n % n % 12-36 122 44.5 42 36.86 60 170 42.7 >36-60 88 32.1 44 38.60 0 132 33.2 >60-84 64 23.4 28 24.6 4 40 96 24.1 Total 274 100.0 114 100. 10 100. 398 100. 0 0 0

Table 8 : Age when BCG vaccinated (in months) in relation to Tuberculin reaction in children of the study population (n=378)

120 Age when BCG Tuberculin reaction in mm Total vaccinated <5 5-9 ≥10 n % n % n % n % 0-3 196 76.6 78 69.6 6 60 280 74.1 >3-6 58 22.6 30 26.8 4 40 92 24.3 >6 2 0.8 4 3.6 0 0 6 1.6 Total 256 100.0 112 100.0 10 100.0 378 100.0

Table 9 : Tuberculin reaction in relation to sex in children of the study population (n=398)

+ve -ve Sex Tuberculin Tuberculin Total reaction reaction n % n % n % Males 8 80 198 51 206 51.8 Females 2 20 190 49 192 48.2 Total 10 100.0 388 100.0 398 100.0

121

Table 10 : BCG scar in relation to tuberculin reaction in children of the study population (n=398)

BCG scar Tuberculin reaction in mm Total <5 5-9 ≥10 n % n % n % n % Not present 108 39.4 18 15.9 0 0 126 31.7 Faint 26 9.5 12 10.5 0 0 38 9.5 < 2mm 20 7.3 0 0 2 20 22 5.5 2-5mm 96 35 50 43.90 0 146 36.7 > 5mm 24 8.8 34 29.8 8 80 66 16.6 Total 274 100 114 100 10 100 398 100

X2 = 89.077 P < 0.001

122

Table 11 : Age in months in relation to TB cases in children of the study population (n=398)

+v -v Age in months TB cases TB cases Total n % n % n % 12-36 2 100 168 42.4 170 42.7 >36-60 0 0 132 33.3 132 33.2 >60-84 0 0 96 24.3 96 24.1 Total 2 100.0 396 100.0 398 100.0

Table 12 : TB cases in relation to age when BCG vaccinated in children of the study population (n=398)

123 Age when BCG vaccinated in +ve -ve monthss TB cases TB cases Total n % n % n % <3 0 0 98 24.7 98 24.6 >3-6 2 100 278 70.2 280 70.4 >6 0 0 20 5.1 20 5 Total 2 100.0 396 100.0 398 100.0

Table 13 : TB cases in relation to family income (in Sudanese Dinars) in children of the study population (n=398)

+ve -ve Income (is SD) TB cases TB cases Total n % n % n % 10,000-20,000 2 100 168 42.4 170 42.7 >20,000-30,000 0 0 148 37.4 148 37.2 >30,000 0 0 80 20.2 80 20.1 Total 2 100.0 396 100.0 398 100.0

124

Table 14 : TB cases in relation to number of persons per room in children of the study population (n=398)

+ve -ve Number of person per room TB cases TB cases Total n % n % n % 1-3 0 0 202 51 202 50.8 4-6 2 100 178 45 180 45.2 7-9 0 0 16 4 16 4 Total 2 100.0 396 100.0 398 100.0

125

Table 15 : BCG scar in relation to TB cases in children of the study population (n=398)

+v -v BCG scar TB cases TB cases Total n % n % n % Not present 0 0 126 31.8 126 31.7 Faint 0 0 38 9.5 38 9.5 <2mm 2 100 20 5.1 22 5.5 2-5mm 0 0 146 36.9 146 36.7 >5mm 0 0 66 16.7 66 16.6 Total 2 100.0 396 100.0 398 100.0

Table 16 : TB cases in relation to tuberculin reaction in children of the study population (n=398)

126 +ve -ve TB cases Tuberculin Tuberculin Total reaction reaction n % n % n % Yes 2 20 0 0 2 0.5 No 8 80 388 100 396 99.5 Total 10 100.0 388 100.0 398 100.0

Table 17 : TB cases in relation to BCG vaccination of children in the study population (n=398)

Non TB cases Vaccinated vaccinated Total n % n % n % Yes 2 0.5 0 0 2 0.5 No 376 99.5 20 0 396 99.5 Total 398 100.0 0 0 398 100.0

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141 DISCUSSION

Surveillance of the immediate and long-term effects is an important component of any vaccination strategy. This usually entails monitoring immune response to the vaccine as well as trends in disease morbidity and mortality in the vaccinated community.

The most recent BCG vaccination coverage data for East Nile

Province as stated by the Expanded Programme for Immunization (EPI) was coverage of 75%(51).

The present study was carried out in three rural areas in East Nile

Province studying BCG efficacy in children aged one to seven years and to correlate the efficacy to some social factors and presence or absence of scar during the period of 1st of June to 31st of August 2003. The study included a total of 398 children aged 1-7 years with no records lost. The study group is a crude representation of the rural community in the East

Nile Province. The selection of the study group was community based that is house-to-house survey for all children aged 1 to 7 years. It showed that the predominant age group was from 12-36 months, which account for 42.7% of the total of the study population.

142 The sex distribution of the children showed male to female ratio of

1.01 : 1.00, this is in contrast to findings in other study done in the same area in 1997 which showed a ratio of 1.00 : 1.03(48).

About 98.5% of the families descended from tribe belong to the

Gaaleen tribe(49), so they share many genetic factors which may affect

BCG efficacy.

Family history of the children showed that more than half of the mothers and more than two thirds of the fathers had education level at primary school. Two thirds of the fathers were unskilled labourers, where as the majority of the mothers were housewives.

Most of the families had an income between 10,000 to 30,000SD per months (which is Just above the lowest level of El Zaka, which is

10.000SD).

Half of the families have a range of 1 to 3 persons per room, which reflects a reasonable environment.

About 378 (95%) of the children gave definite history of BCG vaccination (documented by vaccination card, BCG scar or both), more than two thirds of them received their vaccine in the 1st 3 monthss of age in consistent with the WHO recommendation to vaccinate all babies with BCG as soon after birth and preferably within the first year(52),

143 while three fifth of the non vaccinated aged more than 36 to 60 months, this is in contrast to the findings by El Nour in the same area in 1996, she reported that 82.6% of children had definite history of BCG vaccination which was mainly given after the 1st year(48), this was less than the figure given by the EPI at that time(48). This is may be due to that vaccination was given through irregular visits by the EPI mobile teams but now they have health centre with full services including a well-trained vaccinator with two specialized days for vaccination.

Most of the vaccinated children in the study were from educated parents and three quarters of children whose mothers were educated received their BCG vaccine in the 1st three months of age.

BCG scar is highly sensitive and good indicator of vaccination status when the vaccine is properly handled, delivered appropriately and given at or over 3/12 of age but not vaccination given within one months of age(41). Most authorities believe that BCG vaccination should result in along standing scar in more than 90% of cases(42).

State of BCG scar among the vaccinated children showed that 72% had scar reflecting good efficacy consistent with the finding in the study of El Nour, which reported three quarter of vaccinated children had scar(48). Similar studies done in Gambia, India and Sri Lanka, which

144 showed percentage of BCG scar among children who received BCG vaccination was 71, 83 and 97, respectively(53,54,55).

In a study done by Ahmed in children aged 0-14 years in Aroma and Kassala in 1988, the rate of BCG scar was 22% and 17% in children aged 0-6 and 7-14 years respectively(56). While Zaki found 129 (8.7%) scar positive among (1489) children in Tokar, Haya and Port Sudan(57).

Usually BCG vaccination gives rise to a scar within three months of vaccination but sometimes scar formation is poor indicating either bad technique or host factors affecting immunity at the time of vaccination or scars may fade with time in some people. It is clear that older studies done in Sudan showed low percentage of BCG scars this may be attributed to bad technique and less trained personnel.

BCG scar measuring more than 5mm is considered as abnormal or complicated according to the WHO classification of BCG scars(58).

Complicated scar are usually due either to improper technique

(e.g. Subcutaneous administration, over dose), strongly antigenic vaccine or due to host factors(59,60). In this study 17.5% of children had complicated scar consistent with 17% reported by El Nour(48). The persistence of this complicated scar with similar percentage in this community is most probably due to host factors. Zaki attributed his

145 findings to poor technique by the untrained newly launched EPI programme(57), and El Nour believed that the causes are multiple(48).

BCG scar was not present in 76 (71.7%) out of the 280 (74.1%) of children who were vaccinated in the 1st 3 months of age and in 28

(26.4%) out of the 92 (24.3%) of those who were vaccinated in more than

3 to 6 months; this is similar to a study done on 149 Asian children who received BCG shortly after birth, who were reviewed at the age of 22 months, many of them had an apparently in adequate response to the vaccine, a quarter had no scar, and half of the children with a scar had a negative response to 10TU (Mantoux 1/1000) and these children showed only limited lymphocyte transformation in vitro in response to tuberculin. It seemed more likely that the high incidence of poor response was due to some factors operating in the perinatal period.

There was circumstantial evidence implicating perinatal nutrition, and there is a possibility of interference with vaccination by maternal antibody(42).

Fine et al in 1989 found that less than 60% of children vaccinated in infancy retained a recognizable scar after 2 years, this may be due to lower dose used, difficulty of administering vaccine truly intradermally

146 and immature immune response other studies have shown more than of scars in Algeria, Botswana, Tunisia and Zambia(38).

Variability of scar size in BCG recipients has been suggested to be used to evaluate the proficiency of vaccinators but this may not be feasible when BCG is given over a wide range of ages or if different strains of BCG is administered(34), and the size of the scar is affected by technique of administration, characteristic of the recipients and the strain of BCG used(38).

In this study the tuberculin test and readings were done by a well trained vaccinator, the author practiced and grasped the technique under her supervision and conducted the survey in the house-to-house survey, this is to minimize the interobserver error, 72 hours later the largest indurated areas were palpated and measured in millimeters by transparent flexible ruler.

Evaluation and interpretation of tuberculin readings has been and remains contraversial because it is affected by ethnic environmental and host factors and technique of administration. In this study indurations of

10mm or more were regarded as positive according to National

Tuberculosis Research Programme and IUATLD recommendations(50).

147 In Sudan 93% of tuberculous children studied by Kamal Eldin were Mantoux positive(61) and 80% of adult with tuberculosis studied by

N. A. Dongola were tuberculin positive(62).

In this study about 68.85% of the children studied (both vaccinated and non vaccinated) showed reactions less than 5mm while 28.64%, showed reactions from 5-9mm and 2.51% showed positive reactions

(more or equal 10mm), this is in contrast to El Nour findings which were

49% less than 5mm and 51% more than 5mm, 1% > 15mm and 10% from

10-14mm(48). This high percentage of reactions less than 5mm in our study may be due to the fact that BCG effect waned 2-3 years in children(42) and the majority of children in this study received their vaccine in the 1st 3 months of age while the majority of children studied by El Nour received their vaccine from the second to seventh birthday(48).

Ibrahim Z. E. In 1954-1955 prior to introduction of BCG vaccination found that 76% of the study population showed negative reactions and 24% showed positive reactions(63).

In a study done in Peru where 87% of the study population were vaccinated there was significant increase in the 5-9mm reactions but did not cause significant increase in 10mm and more reactions, the

148 prevalence of 10mm reaction and more was 24%(64) in our study was

2.51%.

In our study (44.5%) of children aged 12-36 months showed tuberculin reactions less than 5mm and 24 (36.8%) reactions from 5-9mm and 6 (60%) reactions equal or more than 10mm, while 88 (32.1%) of children aged more than 36 to 60 months and 64 (23.4%) of children aged more than 60 to 84 months had reaction less than 5mm.

In Sri Lanka and Gambia significant waning of the tuberculin reactions was observed, at 5-7 years of age in BCG vaccinated children in

Sri Lanka and at 5 years of age in Gambia(53,55).

In Gambia, positive tuberculin reactions were independent with age(53), in study done in India, the prevalence of 5mm and more tends to increase with age(65) and the same was found in study done in

Somalia(66).

In the three surveys done in Sudan by Zaki in Red Sea Area, by

Ahmed also in the East and by Ibrahim in most of Sudan, it was found that tuberculin sensitivity increases with age which may denote increased exposure to environmental tuberculosis or non tuberculous mycobacteria(56, 57,63).

149 In our study tuberculin reaction is affected by gender where males showed larger reactions than females in contrast to El Nour study who found that gender difference did not affect tuberculin reactivity(48).

It is clear that in this study there is a strong correlation between

BCG scar and tuberculin reaction for example the 5-9mm reactions were found in 18 (15.9%) in children without BCG scar and in 29.8% of those with scar measuring more than 5mm. This result was highly significant, so there is higher positively rates with BCG scar.

Ibrahim ZE conduct a survey in 1954 in Sudan, he found no correlation between the size of BCG scar and tuberculin reaction(63). This was also found in a study done in Sri Lanka where they found also no correlation between BCG vaccination and tuberculin reaction(55).

El Nour found that higher positively rates in children with BCG scar (48).

During the three months study, there were two cases of pulmonary tuberculosis out of the 398 children studied, which account for 0.5% of the study population, they were diagnosed according to the scoring system adopted by the NTP and Centre for Epidemiological

Research in Southern Africa, Pretoria, South Africa and the IUATLD (50).

Both of them were complaining of chronic cough which scores 2, loss of

150 weight which scores 3 and tuberculin reaction more than 10mm, which scores 2, the cut off point for diagnosis is score more or equal 5 in children less than 5 years. One of them aged 14 months and the other 16- months and both of them were males. It was found that among adults two thirds of the patients are males among children females slightly predominate.

Younger children less than five years old are more prone to infection with TB and to develop severe complications. The two cases were vaccinated out of 378 vaccinated children in the study group, which account only about 0.1%. They had BCG scar measuring less than

2mm.

It was found that TB affect both sexes equally but males predominate(67) and in a study done in Netherlands the positivity and risk of infection were higher in boys but after the age of 10 years(68).

The organism can live only 5 minutes under sun light but 5 months in dark(67). The average number of persons per room was 5 for both and it is evidenced that living in an ill ventilated crowded house enhances transmission of TB, they gave no history of contact with tuberculous patient or patient with chronic cough this in contrast to findings by other studies in Sudan, which reported 43.3% out of the 88

151 tuberculous children studied gave strong family history of tuberculosis

(hospital based study).

Kamal Eldin reported that 64% of the children studied by her had history of contact(61). In a study done in India it was found that 33.7% of children with TB had family history of tuberculosis(24).

In our study the contact could be hidden and un noticed by the parents.

It is difficult in this study to correlate between vaccinated and non vaccinated children because the number of the non vaccinated was just

5% of the study population and TB cases accounted just 0.1% of the vaccinated group, and as we know BCG vaccine protects mainly against the sever form of TB i.e. Tuberculous meningitis and miliary tuberculosis.

Clearly BCG vaccination has worked well in some situation but poorly in others, it has had little effect on the ultimate control of tuberculosis through out the world, and although over 8 billion doses have been administered but tuberculosis remains common in most regions(31).

Trials on the vaccine have been undertaken since it was first developed in 1920s, a third of them have shown no protective effect, the

152 remainders have shown protection of up to 80% lasting a maximum of

15 years(44). There is no evidence that BCG reduces the risk of becoming infected with tubercle bacilli but it prevents forms of tuberculosis depending on hematogenous spread(38), this can explain presence of 2 cases of pulmonary TB in the vaccinated group in this study, and it is also supported by a recent meta-analysis of published BCG vaccination which reported that BCG is 50% effective in preventing pulmonary tuberculosis in adults and children(31). Some authors also concluded that on average, BCG reduces risk of infection leading to disease by 5%(45).

Some workers believe that BCG efficacy waning with time(47), but in our study the waning time was not reached so there is other factors affecting efficacy which are many like different vaccine used, different strains of M. tuberculosis, genetic differences, intensity of infecting dose, nutritional differences and protection by environmental mycobacteria(38).

153 CONCLUSION

• The study showed that vaccination coverage was 95% in the

study population, which is comparable to the EPI figure.

• Nearly three quarters of vaccinated children had BCG scars,

two fifth of them measured from 2 to 5mm.

• The study showed that BCG vaccination evoked a good

protection as measured by finding of just 0.1% tuberculous

patient out of the total number of vaccinated children (378),

although the comparability of the two groups is open to some

doubt, because the non vaccinated group was very small in

comparison with the vaccinated group (it was just 5% from the

total population).

• BCG efficacy by evaluation of the scar showed that, the early

age of vaccination particularly the first three months have low

percentage of scar formation which is an strong indicator of

vaccine efficacy. So age of vaccination affect the efficacy of the

vaccine.

• There is a strong relation between scar size and tuberculin

reaction, which reflects that children with BCG scar are more

154 immuned than those without scar (they receive efficient

vaccine).

• Although just 2 cases (0.1%) of the total population studied

were tuberculous during the 3 months study, but this means

that mycobacterium tuberculosis is prevalent in the community.

• Some social factors like family income and number of persons

per room did not affect the efficacy of the vaccine.

155 RECOMMENDATIONS

• For eradication of tuberculosis we need a well integrated

Tuberculosis Control Programme co-operated with the EPI

programme incorporated within the primary health care

system.

• BCG vaccination survey must be encouraged in all areas of low

coverage, and the vaccination policy should be very clear for

both the vaccinators and the community including best age of

vaccination (At birth), contraindications and side effects.

• Better training of staff at health care level on cold chain,

vaccination technique and administration is essential in order to

reduce the incidence of vaccination failure.

• Further studies are needed to evaluate BCG vaccine failure.

• It is important to investigate post vaccination state in BCG

vaccinated infants who did not show the scar within 3-6

months.

• Further evaluation of BCG vaccination especially considering

the duration of immunity is needed in order to decide

156 revaccination or not especially if it is given in infancy

(particularly in the first 3 months of age).

• Development of a new vaccine which is well defined in terms of

its molecular structure, so that it can be tested in a quantitative

manner, such a vaccine will become feasible as studies on the

molecular structure of the organism and on the cellular immune

response are completed.

• Development of a vaccine, which will work against exogenous

re infection, that is will prevent implantation of the tubercle

bacillus from outside the host organism, this will probably

necessitate a vaccine which works at the level of the respiratory

tract. Only by designing a vaccine which will fulfill this

characteristics will a tuberculosis vaccine be able to be truly

protective.

• Development of an in vitro assay, which would relate to human

tuberculosis immunity, as more is being learned about the

structure of M. tuberculosis bacillus and the components of the

immune response, this possibility looks increasingly more

probable.

157 • Reduction of number of BCG preparations. At present they are

many, which may not be well characterized in terms of their

tuberculin response and reactogenicity, effort in this part have

already being made through the UNICEF.

• WHO recommendation regarding BCG vaccination at birth

should be continued because evaluation of its efficacy still

under study with no definite answer.

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Efficacy and applicability of mass BCG vaccination in tuberculosis control. Br Med J 1967; 1: 587-92. 47. Behr MA, Small PM. Has BCG attenuated impotence? Nature 1997; 389: 133-34. 48. ElNour HO. Tuberculin sensitivity in children in arural area in Sharg El Niel Province. MD thesis University of Khartoum, Sudan 1997. ﻣﻮﺳﻮﻋﺔ اﻟﻘﺒﺎﺋﻞ واﻷﻧﺴﺎب ﻓﻲ اﻟﺴﻮدان وأﺷﻬﺮ أﺳﻤﺎء اﻷﻋﻼم واﻷﻣﺎآﻦ ﻣﻦ اﻟﺠﺰء اﻷول ﻟﻠﺠﺰء .49 اﻟﺴﺎدس. ﺑﺮوﻓﻴﺴﻮر ﻋﻮن اﻟﺸﺮﻳﻒ ﻗﺎﺳﻢ. اﻟﻄﺒﻌﺔ اﻷوﻟﻰ 1996م 50. EL Sony AI. Manual of NTP in Sudan. 2nd ed. Khartoum: Federal Ministry of Health Sudan 2000.p. 36-7. 51. Khartoum State, Ministry of Health. Federal EPI. Office. Research and Information Unit. Annual Report on BCG Vaccination. Khartoum : Ministry of Health; 2002. 52. BCG vaccination polices. Report of the study group. WHO Tech Rep Ser 1980 : 652. 53. Elliot A, Bardley AK, Tulloch S, Greenwood BM. Tuberculin sensitivity in rural Gambian children. Ann Trop Paediatr 1985; 5 (4) : 185 – 89. 54. Young TK, Mirdad S. Determinants of tuberculin sensitivity in a child population covered by mass BCG vaccination. Tuberc Lung Dis 1992; 73 (2): 94 – 100. 55. Karalliedde S, Katugaha LP, Uragoda CG. Tuberculin responses of Sri Lanka children after BCG vaccination at birth. Tubercle 1987; 68 (1): 33-38. 56. Ahmed KM. Implementation of regional tuberculosis programme. Eastern region, Kassala Province, Ministry of Health. Tuberculosis Control Programme 1988.

163 57. Zaki AM. A community based study on tuberculosis control at the primary health care level. Red Sea State. Sudan. MD thesis 1995 : 141-58. 58. WHO, EPI information system summary of the WHO Eastern Mediterranean region. WHO/EPI/96.03. 59. WHO/EPI. Tuberculosis: Magnitude of tuberculosis problem in the world 1981. 60. Vallishayee RS, Shashihora AN, Bunch CK, Guld J. Tuberculin sensitivity and skin lesions in children after vaccination with 11 different BCG strains. Bull Wld Hlth Org 1974; 51: 489 – 94. 61. Kamal Eldin MA. A controlled clinical trial of SCC in treatment of childhood pulmonary TB. MD Thesis University of Khartoum, Sudan 1996. 62. Dongola NA. Radiological and clinical pattern of pulmonary TB in selected TB clinics in Khartoum. MD thesis University of Khartoum, Sudan 1997. 63. Ibrahim Z E. Final report on the Internationally Assisted BCG Project in Sudan. 1954 – 1955. Tuberculosis Control Division, Ministry of Health, Khartoum, Sudan 1960. 64. Cetchell WS, Davis CD, Gilman J. Basic Epidemiology of Tuberculosis in Peru: a prevalence study of tuberculin sensitivity. Am J Trop Med Hyg 1992; 47 (6) : 721-29. 65. Ferguson RG, Simes AB. BCG vaccination of Indian Infants in Saskatchewan. Tubercle 1949; 30: 5 – 11. 66. Peltola H, Mohamed ON, Kataja M. Risk of infection with Mycobacterium tuberculosis among children and mothers in Somalia. Clin Infect Dis 1994; 18 (1) : 106 – 11. 67. Crofton J, Douglas A. Tuberculosis Epidemiology, Prevention, Infection and Treatment. In : Respiratory Diseases. 3rd ed. Oxford: Blackwell Scientific Publications; 1981. p. 218 – 301. 164 68. Sutherland I, Bleiker M, Meijerj. the risk of tuberculous infection in the Netherlands from 1967 to 1979. Tubercle 1983; 64 (4): 94 – 100.

165 University of Khartoum Faculty of Medicine Department of Paediatrics and Child Health Postgraduate Study on QUESTIONNAIRE BCG Efficacy in Children Aged 1-7 years in Rural Areas in East Nile Province 1. Serial No. 2. Date: 3. Name : ……………………………………………………… 4. Age (Months) 5. Weight (gms) 6. Height (cm) 7. Head Circumference (cm) 8. Sex: 1) Male 2) Female 9. Tribe: 1) Gaaleen 2) Bagara 3) Shaygia 4) Foar 5) Nilotic 6) Nuba 7) Bija 8) Descended originally from other tribes 10. Age when BCG vaccinated (months) 11. BCG vaccination: 0) No 1) BCG scar 2) Vaccination card 3) Both 12. Father education (No. of school year) 13. Father’s occupation: 1) Professional/Manager 2) Skilled labourer 3) Government employee teacher 4) Unskilled labourer 5) Unemployed 6) Dead 7) Others Cause of death …………………………………………………………… 14. Mother’s education (No. of school years) 15. Mother’s occupation: 1) Professional/Manager 2) Skilled labourer 3) Government employee teacher 4) Unskilled labourer 5) Unemployed 6) Dead 7) Others Cause of death ……………………………………………………………

166

16. History of contact with TB case: 0) No 1) House hold 3) Neighbour 4) School 8) Others 9) Unknown 17. Monthly income (Sudanese Dinars) 18. Number of persons per room: 19. Water source: 1) Pipe in 2) Pipe out 3) Nile 4) Traditional wells 20. Toilet facility: 1) Siphon 2) Pit latrine (private) 3) Communal pit latrine 4) Open space 21. Duration of symptoms (days) 22. Fever: 0) Non 1) Nocturnal 2) Diurnal 3) Continuous chrome 4) Others 23. Cough: 0) No 1) Dry 2) Productive of mucoid sputum 3) Productive of purulent sputum 4) Blood stained 5) Haemoptysis 24. Sweats: 0) No 1) Yes 25. Loss of weight: 0) No 1) Yes Examination: 26. Discharging sinuses: 0) No 1) Yes 27. BCG scar: 0) Not present 1) Faint 2) <2mm 3) 2-5mm 4) >5mm 28. Chest deformity: 0) No 1) Yes 29. Kyphoscoliosis: 0) No 1) Yes 30. Chest signs: 0) No 1) Yes 31. Mantoux test reading: 1) <5mm 2) 5-9mm 3) ≥10mm 32. Necrotic Mantoux: 0) No 1) Yes

167 33. Lymph nodes: 1) No 2) Cervical 3) Axillary 4) Inguinal 5) Combination 6) Epitrochlear 7) Generalized 34. Tuberculous: 0) No 1) Yes

168 169

Figure 1: Age distribution of children in the study population (n= 398)

42.70% 45%45

40% 40 33.20%

35%35

30%30 24.10%

25%25

20%20

116 Percentage 15%15

10%10

55%

00% 12--36 > 36-60 >60-84 Age (in months)

170

Figure 2: Sex distribution of children in the study population (n=398 ) 117

Females Males 49 .7% 50 .3%

171

Figure Fi 3gu :r e Tribe 3: Trib ofe o childrenf children i nin th thee stu studydy population (n= 398) population ( n = 398 )

98 .50 % 100100 %

9090 %

8080 %

7070 %

6060 %

5050 % 118

40 % Percentage 30 %

20 % 1 .00 % 0 .50 % 1010 %

0 0% Gaaleen Descended Bagara originally from other tribes Tribes

172

Figure 4: Parents' education of children in the study population (n=398)

77% 80%80

70%70 60% 60 51% 50%50 37% 40%40

Father 119 30%30 Percentage Mother 13% 20%20 10% 11% 10%10 1% 0% 00% Illiterate Primary schoolSecondary University school Education level

Figure 5 : Fathers' occupation of children in the study population(n=398)

70 64.82% 60

e g 40

30 Percenta 120 20 17.09% 10 4.52% 4.02% 4.02% 5.53% 0

Professional/Manager Gov. employee/teacher Skilled labourer Unskilled labourer Unemployed/dead Others Occupation

Figure 6: Mothers’ occupatiion of chilldren in the Figure 8: Occupation of the mothers of children in the study study population population (n=398) 88.40% 9090%

8080%

7070%

121 6060%

5050%

4040%

Percentage 3030%

2020% 10.10% 1.50% 1010%

0 0% Unskilled labourer Housewives Others

Figure 7 : Family income of children in the study population in Sudanese Dinars “S.D” (n=398)

2.51% 32.67%

122 64.82%

<10000 10000-30000 >30000

Figure 12 : Contact with TB cases in children of the study population (n=398)

1.50%

No contact Unknown 127

98.50%

Figure 13 : Clinical cases of TB in children of the study population (n=398 )

0.50%

128

99.50%

Yes No

Figure 8 : Number of persons per room in children of the study population (n=398)

60%60 50.8% 45.2% 50%50

40%40

30%30 123

Percentage 20%20

10%10 4%

00% 1--3 4--6 7--9 Number of persons per room

Figure 10: Age of studied children (in months) when BCG vaccinated (n=378)

73.90% 8080%

7070%

6060%

5050% 125

4040% 24.60% Percentage 3030%

2020%

1010% 1.50%

0 0% 0--3 > 3-6 >6 Age (in months)

Figure 11: Size of BCG scar iin chilldren of the study population (n=378)

39.10% 40%40

35%35

28.00% 30%30

25%25

17.50% 126 20%20

Percentage 15% 10.10%

10%10 5.3%

55%

00% Not present Faint < 2 mm 2-5 mm >5 mm Size of BCG scar

Figure 14: Tuberculin reaction in children of the study population

68.85%

701

601

129 50 1

40 0 28.64% 30 0 20 Percentage

100

0 0 2.51%

0 < 5 mm 5-9 mm≥ >10 mm Tuberculin reaction in mm

Figure 9 : BCG vacciination state of children iin the study Figure 9 : BCGpopulation vaccination (n=398) state of children in the study population (n=398)

33% 32% 35%35 30%

30%30

25%25

20%20

15%15

124

Percentage 10%10 5%

55%

00% Not vaccinated Vaccinated with Vaccinated with Vaccinated with BCG scar vaccination card both (card+BCG scar) BCG vaccination state