bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 1
1 Long title:
2 Risk of soil-transmitted helminthiasis among agrarian communities of Kogi
3 State, Nigeria: Evaluated in the context of The Soil-Transmitted
4 Helminthiasis Advisory Committee recommendation 2016
5 Short title:
6 Soil-transmitted helminthiasis in Kogi State
7
8 Joy T. Anunobi1, Ikem C. Okoye2*, Ifeanyi Oscar N. Aguzie2*, Yvonne E. Ndukwe2 and
9 Onyekachi J. Okpasuo2
10 1 Science Laboratory Technology Department, Federal Polytechnic, Idah, Kogi State, Nigeria.
11 2Parasitology and Public Health Unit, Department of Zoology and Environmental Biology,
12 University of Nigeria, Nsukka, Enugu State, Nigeria.
13 *Corresponding authors:
14 E-mail: [email protected] (IONA)
15 E-mail: [email protected] (ICO)
16 Authors’ contributions
17 Conceptualization and Methodology: Joy T. Anunobi and Ikem C. Okoye
18 Investigation: Joy T. Anunobi, Yvonne E. Ndukwe and Onyekachi J. Okpasuo
19 Data curation, formal analysis & software: Ifeanyi Oscar N. Aguzie
20 Writing of first draft: Joy T. Anunobi and Ifeanyi Oscar N. Aguzie
21 Supervision: Ikem C. Okoye
22 Final draft: All the authors approved the final draft.
23 Funding
24 The study did not receive external funding
1 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 2
25 Long title:
26 Risk of soil-transmitted helminthiasis among agrarian communities of Kogi
27 State, Nigeria: Evaluated in the context of The Soil-Transmitted
28 Helminthiasis Advisory Committee recommendation 2016
29 Short title:
30 Soil-transmitted helminthiasis in Kogi State
31
32 Abstract
33 Soil-transmitted helminths (STH) have remained a major threat to human especially children
34 in developing countries including Nigeria. Interventions have always been geared towards
35 school-aged children, neglecting preschool-aged children and occupational risk adults. The
36 Soil-Transmitted Helminthiasis Advisory Committee (STHAC) recently suggested
37 incorporating other at-risk groups. In the context of this recommendation, this study assessed
38 the associated risk of STH infection among agrarian communities of Kogi State, Nigeria. A
39 total of 310 individuals of all ages participated in the cross-sectional survey. Stool samples
40 were analyzed using standard Kato-Katz method. A total of 106 (34.2%) individuals were
41 infected with at least one STH. Hookworm was the most prevalent (18.1%); followed by
42 Ascaris lumbricoides (16.8%). Worm intensity was generally light. Prevalence of infection
43 was similar between four age groups considered (preschool, school, ‘women of reproductive
44 age’ and older at-risk group). Poor socio-economic status (SES) was a major risk for STH
45 infection. Using a 20-assets based criteria, 68 (23.1%) and 73 (24.7%) of 295 questionnaire
46 respondents were classified into first (poorest) and fifth (richest) wealth quintiles respectively.
47 Risk of infection with STH was 60% significantly lower in the richest wealth quintile
48 compared to the poorest (Prevalence Ratio (PR) = 0.4843, 95% CI = 0.2704 – 0.8678, p =
2 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 3
49 0.015). Open defecators were more likely to harbour STH than those who did not (PR =
50 1.7878, 95% CI = 1.2366 – 2.5846, p = 0.00201). Pit latrine and water closet toilet each
51 approximately reduced STH infection by 50% (p < 0.05). Preventive chemotherapy for all age
52 groups, health education and provision of basic amenities especially toilets are needed in
53 order to achieve the goal toward the 2020 target of STH control.
54 Keywords: KAP; socio-economic; soil-transmitted helminths; Ascaris lumbricoides;
55 hookworm; Trichuris trichiura; neglected tropical diseases; wealth quintiles.
56
57 Author summary
58 Soil-transmitted helminths (STHs) are major cause of morbidities globally, especially among
59 children in developing countries such as Nigeria. Present World Health Organization
60 recommended control strategy solely require preventive chemotherapy targeting preschool-
61 aged children (PSAC) and school-aged children (SAC), and the recently included women of
62 reproductive age (WRA). The Soil-Transmitted Helminthiasis Advisory Committee (STHAC)
63 which is saddled with responsibility of evaluating STHs status and providing appropriate
64 recommendations proposed that preventive chemotherapy be extended to other at-risk groups.
65 This study evaluates this and some other recommendations of STHAC 2016 using sections of
66 a state in Nigeria where soil-transmitted helminthiasis is endemic.
67 Findings from this study supports recommendations for extension of preventive chemotherapy
68 to other at-risk groups apart from PSAC and SAC. It supports WASH (water, sanitation and
69 hygiene) as integral part of STH control. This finding emphasizes the need for health
70 education and change in attitude which could promote tenets of WASH. And very
71 importantly, the study emphasizes the role of poverty in the persistence of STH transmission.
72 It is the belief of the authors that there is the need for improved socio-economic status for
73 sustainable gains of control efforts.
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74 Introduction
75 Soil-transmitted helminths (STH) are intestinal worms whose immature stages require a
76 period of incubation in the soil before becoming infective [1]. The most common are Ascaris
77 lumbricoides, Trichuris trichiura, the hookworms (Ancylostoma duodonale and Necator
78 americanus) and Strongyloides stercoralis [2]. They are transmitted by eggs present in
79 infected human faeces, which contaminate the soil in areas where sanitation is poor. STH
80 infections are included in the list of the world’s neglected tropical diseases, NTDs [3], and are
81 the most common infections among the poorest and most deprived communities [2].
82 Transmission of A. lumbricoides and T. trichiura is primarily through oral-faecal route
83 (usually by ingestion of parasite eggs in faeces), whereas hookworm species and S. stercoralis
84 are through active skin penetration of infective larva.
85 STH infections are among the most common chronic human infections in most regions of the
86 world; with approximately 1.5 billion people infected globally [2]. It accounts for a global
87 burden of 3.3 million of disability-adjusted life years [4]. Approximately 270 million
88 preschool-aged children (PSAC) and 600 million school-age children (SAC) are at risk of
89 infection. They live in areas where transmission of these parasites is intense and are in need of
90 treatment and preventive interventions [2,5].
91 Intestinal helminthiasis prevalence in Nigeria has remained unchanged since the 1970s [6].
92 Nigeria has the highest burden and endemicity [3,7]. A larger fraction of those affected are
93 young children of ages 5 to 14 years living in rural areas and urban slums [6-9]. The major
94 contributors to persistence of infections are cultural, socio-economic and environmental
95 factors [6,7]. Unhygienic and common practice of indiscriminate defecation or dumping
96 excrement have persisted in Nigeria [7,10,11]. There has been little success in the
97 introduction of latrines to rural Nigeria [12]. A temporal data available from 1990 through
98 2015 indicate a marginal decrease in the use of improved sanitation facilities from 38% to
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99 29%, and small increase in open defecation from 24% to 25% [13]. Currently, Nigeria is
100 ranked as one of the nations in the world with the highest number of people practicing open
101 defecation, estimated at over 46 million people [14].
102 In Nigeria, there are still states where there are limited to no epidemiological information on
103 STH infections; Kogi State is one of those with limited information. Majority of the
104 communities in Ibaji and Igalamela-Odolu Local Government Areas (LGAs) of Kogi State are
105 farming communities where children and adults are fully exposed to risks of helminth
106 infection. In agrarian communities, practices such as walking on bare feet, open defecation,
107 eating of fallen fruits and raw unwashed vegetables with unwashed hands in farmlands could
108 predispose individuals to STH infections [9,15]. Majority of the agrarian communities are
109 warm and moist for most of the year creating a good environment for the parasites to develop
110 all year round.
111 Therefore the aim of the present study was to ascertain the associated risk factors of STHs
112 among the agrarian communities of Ibaji and Igalamela-Odolu LGAs. Specifically the
113 objectives were to assess, the prevalence and intensity of soil-transmitted helminthiasis;
114 proportion of individuals with low, moderate and high worm intensity; age-related
115 distribution of STHs infection; socio-economic status as risk for STHs infection; and risks
116 associated with knowledge, attitude an practices (KAP). These objectives were pursued in
117 view of the year 2016 recommendations of The Soil-Transmitted Helminthiasis Advisory
118 Committee (STHAC) in relation to the revision of the 2012 Strategic Plan for STH control
119 [16,17]. The prevalence and intensity of soil-transmitted helminthiasis in the LGAs were
120 assessed in view of WHO 2020 milestones number 3 that all countries requiring PC for STH
121 have less than 1% prevalence of moderate to high intensity [16,17]; though this study was
122 localized to agrarian communities of Kogi State as arbitrary ‘sentinels sites’ (milestone
123 number 2). Kogi State was included in the recent epidemiological mapping of
124 schistosomiasis and soil-transmitted helminthiasis by the Federal Government of Nigeria [18]; 5 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 6
125 but the mapping was only school based, leaving out vulnerable adults. The WHO 2012
126 Strategic Plan for STH control recommends preventive chemotherapy for SAC and PSAC,
127 and has now included deworming of women of reproductive age. STHAC and some other
128 authors have suggested inclusion of other at risk groups [17]. In order to evaluate the
129 relevance of this recommendation, considering the additional cost incurred from additional
130 drug provision, this study partitioned our study population into four age groups: PSAC (0 –
131 4yr), SAC (5 – 18 yrs, though 14yrs was not used as the upper limit), ‘women of reproductive
132 age and men of same age bracket’ (19 – 45 yrs), and older at risk group (> 45yrs). This
133 enabled comparison of STHs infections among the age groups. It is believed that where
134 prevalence of STH infection is similar between the age groups, it would support a need for
135 inclusion of all age group in preventive chemotherapy interventions. The choice of agrarian
136 community was due to the persistent risk of infection in such settings, which may justify need
137 for localized mass drug administration (MDA) strategies. Though current WHO STH control
138 strategy depend solely on preventive chemotherapy, the role of socio-economic status and
139 KAP cannot be ignored. The authors believed that the relevance of STHAC re-affirmation of
140 the importance of water, sanitation and hygiene (WASH) in control of STH could be assessed
141 in relation to socio-economic status and KAP. Therefore, socio-economic status of the study
142 population was assessed using asset-based approach, which involved classification of
143 individuals into wealth quintiles in relation to possession of arbitrary but systematically
144 chosen assets.
145 Findings from this study supports STHAC recommendations for extension of preventive
146 chemotherapy to other at-risk groups, as prevalence of STH infection was not different
147 between the four age groups considered. It similarly supports intergradation of WASH into
148 STH control effort. The finding emphasizes the need for health education and change in
149 attitude which could promote tenets of WASH. And very importantly, the study emphasizes
6 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 7
150 the role of poverty in the persistence of STH transmission. There is the need for improved
151 socio-economic status for sustainable gains of control efforts.
152
153 Methods
154 Study design
155 The study employed a household-based, explorative, cross-sectional study design.
156 Study area
157 The study area comprises Ibaji and Igalamela-Odolu LGAs of Kogi State, Nigeria. In Ibaji
158 LGA, six communities were sampled. They are Ejule-Ojebe, Onyedega, Aneke, Inyano,
159 Ichalla-Ajode and Otiaka. Five communities were sampled in Igalamela-Odolu LGA. They
160 are Ogbagba, Okpachala, Ofuloko, Ogbogbo and Aikpele.
161 Ibaji LGA is located on the Eastern flank of Kogi State. The north easterly line of equal
162 latitude and longitude passes through the LGA. Ibaji LGA has an area of 1,377 km2 and a
163 population of 128,129 [19]. Geographically, it is located between longitudes 6°45'E and
164 7°00'E and latitudes 6°45' and 7°00'N. Its inhabitants are primarily Igala speaking tribe [20].
165 High volume of rainfall and warm temperature result in lush vegetation and good conditions
166 for cultivation of food crops such as rice, vegetables, yam, cassava, sorghum, maize, millet,
167 cowpea, and groundnut which predominate the agricultural practice in the LGA. The major
168 occupation is crop farming with some of them taking to fishing activities to supplement their
169 meals and earn income for themselves. Only few of them are civil servants. The area suffers
170 from poor infrastructural facilities such as absence of good road networks, electricity, pipe-
171 borne water, health centres and communication network [21]; and houses in these
172 communities are mainly made of mud walls and thatched roofs.
173 Igalamela-Odolu LGA has its headquarters in the town of Ajaka (7°10′16″N and 6°49′35″E).
174 The northeasterly line of equal latitude and longitude passes through the LGA. It has an area
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175 of 2,175 km² and a population of 148,020 [19]. Majority of the communities in the LGA are
176 made up of crop farmers while few others are civil servants. Basic amenities such as pipe-
177 borne water, electricity, toilets and accessible roads are lacking in most rural communities in
178 the LGA.
179
180 Study Participants and study size
181 Communities sampled were selected randomly. The study population consisted of both male
182 and female adults and children who are resident in the selected communities.
183 Sample size was estimated using the sample size estimation formula by Yamane [22].
N 184 n = (1 + Ne2)
185 Where, n = sample size, N = total number of study population (based on 2006 census). e =
186 probability level (P = 0.05). The estimated sample size was 399. Though 310 people
187 consented to the study.
188 Within each chosen community, selection of the first households was by a systematic random
189 sampling. Thereafter alternate households were enlisted. Within each enlisted household, all
190 members were sampled to avoid the usual displeasure of those omitted [23]. Sample
191 collections took place between February and April 2017, though the study duration was
192 between August 2016 and May 2017.
193 Ethical Approval
194 The study protocol was approved by the Ethical Committee of the Kogi State Ministry of
195 Health, Lokoja, Kogi State. The ethical approval was assigned the reference number
196 MOH/KGS/1376/1/79.
197 Advocacy and community sensitization
198 Prior to commencement of the study, advocacy visits were made to designated communities.
199 The traditional rulers of each of the LGAs were visited and briefed on the study objectives.
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200 Written permissions were obtained from each of the traditional rulers indicating their consent
201 on behalf of the entire communities. The community and household heads were also well-
202 briefed on the objectives of the study. Verbal permissions were obtained from both the
203 community heads and heads of each household visited. Each member of a household was
204 given a consent form on which interest to participate in the study was indicated. Consent for
205 children was obtained from their parents/care-givers.
206 Stool Sample collection and processing
207 Fresh stool samples for helminth screening were collected from each of the subjects into a
208 coded, dry, leak proof and sterilized sample container, each participant having been briefed to
209 ensure that no urine, water, soil or other contaminants entered the container. The samples
210 were received early in the morning, recorded appropriately and processed immediately.
211 Samples which were not processed in the field were kept refrigerated using a portable cooler
212 and later transported the same day to the laboratory for processing within a maximum of three
213 hours.
214 Stool specimen was processed using the Kato-Katz technique [24]. Kato-Katz stool
215 examination kit (Vestergaard Fradson, Switzerland) was used. Stool specimen was processed
216 within three hours of collection and examined microscopically within one hour of preparation
217 to avoid over clearance of hookworm eggs [25]. The presence of STH parasites eggs in any of
218 the stool samples was noted as positive. Microscopic examination was repeated days after the
219 slide preparation for the confirmation of the presence of Trichuris trichiura and Ascaris
220 lumbricoides eggs as a quality control procedure.
221 Assessment of demographic and socio-economic status
222 Use of questionnaires
223 A well-structured, pre-tested questionnaire was administered to each participant. The
224 questionnaire was interview-based since most participants had no formal education and could
225 not read nor write. However, those that could read and write provided the information at their 9 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 10
226 convenience. Responses for 0 – 4 year old participants comprising 18.6% (n = 55) of the
227 study population were provided by their parents/guardians.
228 The questionnaire was sectioned into nine: (i.) basic information, (ii.) perception and
229 knowledge about intestinal helminths, (iii.) community and household characteristics, (iv.)
230 hygiene practices, (v.) farm/home activities, (vi.) use of shoes or sandals, (vii.) use of health
231 services, (viii.) history of deworming, and (ix.) possession of domestic animals.
232 Visual inspection of compounds
233 Complementary information to questionnaire responses was obtained by visual inspections.
234 Inspection of compounds was made and the sanitary condition and presence or absence of
235 sewage disposal system noted. Wearing of shoes at home was assessed by visual observation.
236 Water supply for drinking and washing of hands after using the toilets or urinals was noted.
237 Children playing on sand were noted as well as those walking around the compound without
238 shoes.
239 Quantitative variables
240 Prevalence of infection was computed as proportion of individuals infected to total number
241 examined and presented in percentages. Mean intensity was obtained based on number of
242 eggs per gramme of faeces (epg) of infected individual and categorized into light, moderate
243 and heavy as established by WHO [26]. The number of eggs obtained was multiplied by 24
244 which is the standard for the Kato-Katz technique. Mean intensity was obtained as average
245 number of parasite eggs per infected individuals. Infection status and questionnaire variables
246 were dummy-coded for statistical analysis purpose. All 310 participants responded to
247 questionnaire. Incomplete response led to exclusion of 15 (4.8%) questionnaires, leaving 295.
248 Prevalence and infection intensity report on the 310 participants was provided while socio-
249 economic status and risk estimates used the 295 properly completed questionnaires.
250 Data analysis
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251 Prevalence of infection was compared using chi-square analysis or Fisher’s exact test. Asset-
252 based approach was used to group study participants into different socio-economic status
253 [27,28]. Possession of different assets considered indicators of socio-economic status (SES)
254 was used to develop a single composite variable SES. Twenty assets were used (S1 Table).
255 Principal component analysis (PCA) extracted the key components. Seven principal
256 components were extracted and the first component which explained 24.9% of total variation
257 served as SES; its factor score loading helped group individuals into quintiles [27](S1 Table).
258 Quintile 1 (Q1) represented the poorest who possessed assets associated with lowest extreme
259 of SES, or who did not possess most assets associated with wealth. Quintile 2 (Q2) were poor,
260 Q3 were average (neither poor nor rich), Q4 were rich while Q5 were the richest. The five
261 quintiles were dummy-coded and used for further analysis. Some assets were either combined
262 or excluded; possession of tiled floor was combined with cement floor and both retained as
263 “cement floor” because only 8 persons used tiles. Possession of dog, pig and cow were
264 removed from the PCA because of their scarcity in the population. Possession of these assets
265 and other attributes were compared between the different SES by chi-square analysis.
266 Risk of infection associated with SES, knowledge and perception, attitude and practices are
267 presented as prevalence ratio (PR). Poisson regression model with robust variance was fitted
268 to estimate the PR, 95% confidence interval and associated p-values [29]. Data was analyzed
269 using RStudio [30] and SPSS version 20.0 (IBM Corporation, Armonk, USA). Level of
270 significance was set at 95% probability level.
271
272 Results
273 Prevalence and intensity of soil-transmitted helminthiasis in Ibaji and Igalamela-Odolu
274 LGAs
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275 Prevalence of STH in Ibaji and Igalamela-Odolu LGAs was 34.2%, 106 out of 310 persons
276 examined were infected with at least one of the STH, Ascaris lumbricoides, hookworm and
277 Trichuris trichiura. Hookworm was the most prevalent (18.1%) and T. trichiura the least
278 (5.2%) (Table 1). Difference in prevalence of the three STH was significant (χ2 = 27.097, p <
279 0.0001). STH infections were recorded in the two LGAs. Out of 167 and 143 participants, 58
280 (34.7%) and 48 (33.6%) respectively were infected in Ibaji and Igalamela-Odolu LGAs; the
281 difference was not significant (χ2 = 0.046, p = 0.829). Prevalence of STH infection
282 collectively and specifically was similar between the four age groups considered, namely
283 PSAC (0 – 4yr), SAC (5 – 18 yrs), ‘women of reproductive age and men in similar age
284 bracket’ (19 – 45 yrs), and older at-risk groups (> 45 yrs; Fig 1).
285
0 - 4yr 5 - 18yr 19 - 45yr > 45yr 40 p = 0.912
35
30
25 p = 0.627 20 p = 0.745
15 Prevalence (%) Prevalence
10 p = 0.885 5
0 286 STH Ascaris lumbricoides Hookworm Trichuris trichiura
287 Fig 1. Prevalence of soil-transmitted helminths by age groups.
288
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289 Mean egg count for hookworm was highest (373.71 ± 318.10 epg, range 48 – 2232) followed
290 by A. lumbricoides (216.92 ± 129.81 epg, range 48 – 600) (Table 1). In Fig 2 intensity of the
291 three STH based on WHO [26] standard categories is shown. Intensities of the three
292 helminths were largely light. Collectively, prevalence of moderate and heavy intensity of STH
293 infection was < 1%, though moderate intensity of infection only occurred for hookworm.
294 Moderate intensity of hookworm infection only occurred in 1.8% of individuals infected.
295
296 Table 1. Overall prevalence of soil-transmitted helminths. (N = 310)
No. Infected (%) Egg count (epg)
STH 106 (34.2) Intensity (Mean ± SD) Min. – Max.
Ascaris lumbricoides 52 (16.8) 216.92 ± 129.81 48 – 600
Hookworm 56 (18.1) 373.71 ± 318.10 48 – 2232
Trichuris trichiura 16 (5.2) 156.00 ± 143.73 48 – 576
297 N = number examined. Epg = egg per gram. SD = standard deviation
298
299
Trichuris trichuria
Light Hookworm 98.2% Moderate Heavy
Ascaris lumbricoides
300 0% 20% 40% 60% 80% 100% 13 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 14
301 Key [26]:
Soil-transmitted Standard intensity degrees (epg)
helminths Light Moderate Heavy
Ascaris lumbricoides 1 – 4,999 5,000 – 49,999 ≥ 50,000
Hookworm 1 – 1,999 2,000 – 3,999 ≥ 4,000
Trichuris trichiura 1 – 999 1,000 – 9,999 ≥ 10,000
302 Fig 2. Intensity of soil transmitted helminths in agrarian communities of Ibaji and
303 Igalamela-Odolu Local Government Area, Kogi State.
304
305 Demographics and socio-economic status of questionnaire respondents
306 All 310 participants responded to questionnaire. Incomplete response led to exclusion of 15
307 (4.8%) questionnaires, leaving 295. Demographics and SES of respondents are summarized in
308 Tables 2 and 3. Ichalla-Ajode (24.4%) and Ogbagba (4.7%) had the highest and least number
309 of respondents respectively. Majority of the respondents were students (38.6%), farmers
310 (36.9%) and PSAC (21.4%; Table 2). Majority of the participants lived in houses made of
311 mud (50.5%) and cement (46.8%) floors (Table 3). Over 41% of respondents had electricity
312 and 51.9% had pipe-borne water.
313
314 Table 2: Overall demographics of questionnaire respondents of agrarian communities in
315 Ibaji and Igalamela-Odolu Local Government Areas, Kogi State. (n = 295)
Characteristics Frequency (%)
LGA
Ibaji 154 (52.2)
Igalamela-Odolu 141 (47.8)
Community
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Onyedega 19 (6.4)
Ejule 15 (5.1)
Inyano 15 (5.1)
Aneke 15 (5.1)
Ichalla-Ajode 72 (24.4)
Otiaka 18 (6.1)
Ogbagba 14 (4.7)
Okpachala 28 (9.5)
Ofuloko 18 (6.1)
Ogbogbo 53 (18.0)
Aikpele 28 (9.5)
Sex
Male 153 (51.9)
Female 142 (48.1)
Age (year)
0 – 4 55 (18.6)
5 – 18 107 (36.3)
19 – 45 89 (30.2)
> 45 44 (14.9)
Marital Status
Single 173 (58.6)
Married 122 (41.4)
Occupation
Pre-school 63 (21.4)
Student 114 (38.6)
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Farming 109 (36.9)
Fishing 1 (0.3)
Civil Servant 6 (2.0)
Others 2 (0.7)
n = number of respondents
316
317 Table 3. Socio-economic status of questionnaire respondents of agrarian communities in
318 Ibaji and Igalamela-Odolu Local Government Areas, Kogi State. (n = 295).
Characteristics Frequency (%)
House floor type
Mud 149 (50.5)
Cement 138 (46.8)
Tiles 8 (2.7)
Electricity and Appliances
Electricity 123 (41.7)
Radio 170 (57.6)
Television 78 (26.4)
Refrigerator 21 (7.1)
Source of Water
Tap 153 (51.9)
River 135 (45.8)
Well 15 (5.1)
Rain 11 (3.7)
Toilet facility 128 (43.4)
Types of Toilet
16 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 17
Pit 84 (28.5)
Water closet 32 (10.8)
Bucket 6 (2.0)
Others 6 (2.0)
Wipe Used after Toilet
Toilet paper 28 (9.5)
Water 172 (58.3)
Plant leaf 95 (32.2)
319 n = number examined
320
321 Knowledge, perception, attitude and practices
322 Summary of knowledge, attitude and practices of the questionnaire respondent are presented
323 in Tables 4. Almost half (48.8%) of the respondents think they could get infected by worms
324 but only 8.8% know how they could get infected; and only 16.6% try to prevent infection. A
325 high proportion of respondents defecate in the open (59.3%). Though 64.7% eat food with
326 bare hands (without cutleries), 88.5% washed their hands after using the toilet.
327
328 Table 4. Knowledge, perception, attitude and practice of questionnaire respondents in
329 agrarian communities of Ibaji and Igalamela-Odolu Local Government Area, Kogi State.
330 N = 295.
Characteristics Frequency (%)
Knowledge and Perception
Know parasitic worm 115 (39.0)
Think could get worms 144 (48.8)
Know how to get worm 26 (8.8)
17 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 18
Ever had worm infection 109 (36.9)
Attitude and Practices
Try to prevent worm infection 49 (16.6)
Hygiene
Defecate in open 175 (59.3)
Wipe after toilet
Toilet paper 28 (9.5)
Water 172 (58.3)
Leaf 95 (32.2)
Wash hand after toilet 261 (88.5)
Wash hand with soap 169 (57.3)
Eat meal with bare hands (without cutleries) 191 (64.7)
Home/farm activities
Eat in the farm 265 (86.8)
Wear shoe to farm 272 (92.2)
Wear shoe while working in farm 170 (57.6)
Wear shoe at home 219 (74.2)
Child/ward play in sand 276 (93.6)
Have animal(s) at home 209 (70.8)
Types*
Dog 19 (6.4)
Pig 6 (2.0)
Goat 146 (49.5)
Chicken 162 (54.9)
Cow 5 (1.7)
18 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 19
Others 2 (0.7)
Use of health services
*have medical centre near home 262 (88.8)
*been sick one or more times in past year 242 (82.0)
Visited the doctor one or more times in the past year 184 (62.4)
*have received medicine for worm 93 (31.5)
*When received medicine for worm?
None 203 (68.8)
Months ago 40 (13.6)
Years ago 53 (18.0)
331 *Included in the section for convenience. n = number examined.
332
333 Socioeconomic Status (SES) in Ibaji and Igalamela-Odolu LGAs
334 A total of 68 (23.1%) of the respondents were classified as poorest based on the 20-assets
335 criteria. Those in richest category were 73 (24.7%) while poor, average and rich were slightly
336 fewer (Table 4). Homes with mud floor was mainly associated with poverty, 68 (45.6%) and
337 49 (32.9%) of those that used mud floor were poorest and poor respectively. Majority of the
338 people who had cement floors at home where in the fourth and fifth quintiles. There was very
339 high significant difference in the distribution of floor types by wealth quintile (p < 0.0001).
340 Electricity and electrical appliances such as radio, television and refrigerators were common
341 in homes of the rich and richest members of the communities. Usage of toilet paper was not
342 dependent on wealth quintiles. The poorest and poor were relatively more likely to practice
343 open defecation and constituted 39.4% and 25.1% respectively of 175 who practiced it. This
344 contrasts strongly with 12.0% and 6.3% of the rich and richest people respectively. Majority
345 of people in Igalamela-Odolu LGA had better wealth status than those in Ibaji LGA (Fig 3).
346 19 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 20
347
348
349 Table 5. Wealth quintiles and relative possession of assets among agrarian communities
350 in Ibaji and Igalamela-Odolu Local Government Areas, Kogi State.
Wealth Quintiles (%)
Descriptors Q1 Q2 Q3 Q4 Q5 Total P**
(Poorest) (Poor) (Average) (Rich) (Richest)
Total 68 (23.1) 52 (17.6) 58 (19.7) 44 (14.9) 73 (24.7) 295
Floor type
Mud 68 (45.6) 49 (32.9) 30 (20.1) 2 (1.3) 0 (0.0) 149 < 0.0001
Cement 0 (0.0) 3 (2.1) 28 (19.2) 42 (28.8) 73 (50.0) 146 < 0.0001
Electricity & Appliances
Electricity 2 (1.6) 13 (10.6) 17 (13.8) 28 (22.8) 63 (51.2) 123 < 0.0001
Radio 9 (5.3) 28 (16.5) 34 (20.0) 29 (17.1) 70 (41.2) 170 < 0.0001
Television 10 (12.8) 6 (7.7) 14 (17.9) 17 (21.8) 31 (39.7) 78 < 0.0001
Refrigerators 1 (4.8) 0 (0.0) 4 (19.0) 6 (28.6) 10 (47.6) 21 0.005
Source of water
Pipe-borne 3 (2.0) 16 (10.5) 37 (24.2) 27 (17.6) 70 (45.8) 153 < 0.0001
River 67 (49.6) 35 (25.9) 18 (13.3) 15 (11.1) 0 (0.0) 135 < 0.0001
Well 1 (6.7) 3 (20.0) 3 (20.0) 6 (40.0) 2 (13.3) 15 0.052
Rain 0 (0.0) 0 (0.0) 0 (0.0) 7 (63.6) 4 (36.4) 11 < 0.0001
Have toilet 2 (1.6) 10 (7.8) 24 (18.8) 28 (21.9) 64 (50.0) 128 < 0.0001
Toilet types
Pit 0 (0.0) 5 (6.0) 12 (14.3) 17 (20.2) 50 (59.5) 84 < 0.0001
Water closet 1 (3.1) 0 (0.0) 10 (31.2) 7 (21.9) 14 (43.8) 32 < 0.0001
20 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 21
Bucket 0 (0.0) 1 (16.7) 1 (16.7) 4 (66.7) 0 (0.0) 6 0.007
Others* 1 (16.7) 3 (50.0) 2 (33.3) 0 (0.0) 0 (0.0) 6 0.149
Wipes
Toilet paper 9 (32.1) 4 (14.3) 3 (10.7) 1 (3.6) 11 (39.3) 28 0.096
Water 23 (13.4) 28 (16.3) 40 (23.3) 27 (15.7) 54 (31.4) 172 < 0.0001
Plant leaf 36 (40.0) 20 (22.2) 14 (15.6) 14 (15.6) 6 (6.7) 90 < 0.0001
Possess animals
Chicken 30 (18.5) 27 (16.7) 32 (19.8) 26 (16.0) 47 (29.0) 162 0.175
Goat 38 (26.0) 16 (11.0) 37 (25.3) 25 (17.1) 30 (20.5) 146 0.003
Defecate in open† 61 (34.9) 44 (25.1) 38 (21.7) 21 (12.0) 11 (6.3) 175 < 0.0001
351 Q1 to Q5 are first to fifth socio-economic status quintiles; values are presented as number of 352 respondent possessing the asset (%). *other unspecified toilet types. †Open defecation was 353 not included as asset in the PCA but was include here for ease presentation. **p – value from 354 chi-square comparison of possession of asset between quintiles. 355
356
Ibaji Igalamela-Odolu 100% 90% 17.6 28.8 80% 39.7
70% 63.6 60% 86.3 50% 40% 82.4 71.2 Individuals (%) 30% 60.3
20% 36.4 10% 13.7 0% 357 Q1 (Poorest) Q2 (Poor) Q3 (Average) Q4 (Rich) Q5 (Richest)
21 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 22
358 Fig 3. Distribution of wealth among individuals in Ibaji and Igalamela-Odolu Local
359 Government Areas.
360 A summary of how STH infection was distributed in relation to the 20 assets is provided in
361 supplementary file 2. Four assets were each significant determinant of STH infection. The
362 single most important determinant was possession of toilet (χ2 = 13.469, p < 0.0001),
363 especially pit toilet (χ2 = 10.222, p = 0.0001). The other two were ‘having water to wash after
364 toilet’ (χ2 = 3.854, p = 0.050) and ‘using plant leaf as toilet paper’ (χ2 = 4.759, p = 0.029), and
365 both more likely are associated with use of toilet and open defecation respectively. As was
366 expected, people who had cement floor, electricity, television and tap water had lower cases
367 of infection compared to those who did not (S2 Fig). Surprisingly, refrigerator as an indicator
368 of wealth was associated with greater infection.
369
370 Risk for infection with soil-transmitted helminths in Ibaji and Igalamela-Odolu LGAs
371 Risks of STH infection due to SES, knowledge, attitude and practices are presented in Tables
372 6 and 7. Risk of STH infection was similar between the first four wealth quintiles, poorest,
373 poor, average and rich. However, risk of infection was significantly lower by 60% in the
374 richest wealth quintile compared to the poorest quintile (PR = 0.4843, 95% CI = 0.2704 –
375 0.8678, p = 0.015). People that claimed to know parasitic worms, that think they could get
376 worm, know how to get worm, and believed they had previously been infected by worms had
377 little to no reduction in risk of STH infection when compared to those whose knowledge and
378 perceptions were otherwise (Table 6). Open defecation was one major factor associated with
379 significant increase in STH risk. People who practiced open defecation were two times more
380 likely to harbor STH compared to those who did not (PR = 1.7878, 95% CI = 1.2366 –
381 2.5846, p = 0.00201). Compared to non-possession of toilet facilities, pit latrine and water
382 closet toilet each reduced STH infection by approximately 50% (p < 0.05). Washing hands
383 after toilet use, and wearing shoes while working in farms each also significantly lowered the 22 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 23
384 risk of STH infection. Though washing of hands after toilet significantly lowered risk of
385 infection, using soap for this purpose had no to little effect (Table 6).
386
387 Table 6. Risk of soil-transmitted helminths infection associated with socio-economic status
388 (SES), knowledge, perception, attitude and practices among agrarian communities in
389 Ibaji and Igalamela-Odolu Local Government Area, Kogi State. N = 295.
Determinants PR (95% CI) p
SES
Q1 (Poorest) 1
Q2 (Poor) 0.9938 (0.6182 – 1.5979) 0.97967
Q3 (Average) 1.2193 (0.7990 – 1.8608) 0.35789
Q4 (Rich) 1.1127 (0.6937 – 1.7849) 0.65773
Q5 (Richest) 0.4843 (0.2704 – 0.8678) 0.01483
Knowledge and Perception
Know parasitic worms 0.7943 (0.5654 – 1.1159) 0.18425
Think could get worms 0.8095 (0.5876 – 1.1150) 0.19580
Know how to get worm 0.7705 (0.4006 – 1.4817) 0.43446
Ever had worm infection 0.9451 (0.6784 – 1.3166) 0.73850
Attitude and Practices
Try to prevent worm infection 1.0160 (0.6666 – 1.5487) 0.94104
Hygiene
Defecate in open 1.7878 (1.2366 – 2.5846) 0.00201
*Toilet types
No toilet 1
Pit 0.4694 (0.2967 – 0.7428) 0.00123
23 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 24
Water closet 0.5074 (0.2577 – 0.9991) 0.04968
Bucket 0.7731 (0.2460 – 2.4294) 0.65962
Others** 1.1597 (0.5113 – 2.6303) 0.72285
Wash hand after toilet 0.6437 (0.4404 – 0.9407) 0.02288
Wash hand with soap 0.9278 (0.6755 – 1.2744) 0.64360
Eat meal with bare hands (without cutleries) 1.2295 (0.8674 – 1.7429) 0.24578
Home/farm activities
Eat in the farm 1.1299 (0.6855 – 1.8625) 0.63202
Wear shoe to farm 1.6235 (0.7354 – 3.5843) 0.23039
Wear shoe while working in farm 0.7209 (0.5264 – 0.9872) 0.04130
Wear shoe at home 0.9048 (0.6383 – 1.2825) 0.57396
Use of health services
Have medical centre near home* 0.9342 (0.5769 – 1.5125) 0.78177
Been sick one or more times in past year* 1.0822 (0.7052 – 1.6606) 0.71780
Visited the doctor one or more times in the 0.8474 (0.6166 - 1.1646) 0.30751
past year
Have received medicine for worm* 0.8331 (0.5813 – 1.1940) 0.32000
When received medicine for worm? *
None 1
Months ago 0.7544 (0.4418 – 1.2880) 0.30178
Years ago 0.8441 (0.5402 – 1.3189) 0.45664
390 N = number examined. PR = prevalence ratio; CI = confidence interval. *Included in the 391 section for ease of result presentation. **other toilet types apart from the ones listed. Except 392 SES, types of toilet and “when medicine was received for worm” which has 1 indicated as 393 reference, the reference value for all other determinants is 1 and represent the group that 394 responded “no” to each of the questions concerned. 395
396
24 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 25
397 Risk of A. lumbricoides infection was similar between the first four quintiles. Though people
398 in the fifth wealth quintiles had about 40% reduced risk compared to first quintile, but this
399 was not significant (p = 0.36850). People who responded affirmatively to making effort at
400 preventing worm infection unfortunately had more than 2 times greater risk of A.
401 lumbricoides infection (Table 6). The greater risk among those who “try to prevent worm
402 infection” compared to those who did not ranged from 30% to 360%, and was significant (p =
403 0.00397). Wearing shoes while working in farms also significantly lowered the risk of A.
404 lumbricoides infection by over 50% (p = 0.00278). Those that practiced open defecation were
405 at 30% greater risk of A. lumbricoides infection as those who did not (Table 7).
25 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license.
26
Table 7. Risk of infection with Ascaris lumbricoides, hookworm and Trichuris trichiura associated with socio-economic status (SES), knowledge, attitude and practices (KAP) among agrarian communities in Ibaji and Igalamela-Odolu Local Government Area, Kogi State. (N = 295).
Ascaris lumbricoides Hookworm Trichuris trichiura
Determinants PR (95% CI) P PR (95% CI) P PR (95% CI) P
SES
Q1 (Poorest) 1 1 1
Q2 (Poor) 0.8322 (0.3465 – 1.9986) 0.68108 1.3077 (0.6634 – 2.5779) 0.43851 1.3077 (0.2750 – 6.2173) 0.73593
Q3 (Average) 1.7053 (0.8613 – 3.3765) 0.12564 1.4430 (0.7589 – 2.7436) 0.26333 1.1724 (0.2460 – 5.5878) 0.84175
Q4 (Rich) 1.1240 (0.4911 – 2.5725) 0.78207 0.8322 (0.3603 – 1.9218) 0.66702 2.0606 (0.4843 – 8.7683) 0.32780
Q5 (Richest) 0.6775 (0.2899 – 1.5830) 0.36850 0.4299 (0.1732 – 1.0672) 0.06880 0.3105 (0.0331 – 2.9137) 0.30591
Knowledge and Perception
Know parasitic worms 0.9593 (0.5698 – 1.6151) 0.87549 0.5870 (0.3402 – 1.0126) 0.05501 0.6261 (0.2020 – 1.9492) 0.41900
Think could get worms 0.9679 (0.5838 – 1.6050) 0.89952 0.4691 (0.2777 – 0.7925) 0.00467 1.8875 (0.6480 – 5.4980) 0.24419
Know how to get worm 1.4108 (0.6651 – 2.9928) 0.36969 0.5969 (0.2003 – 1.7788) 0.35433 0.7959 (0.1084 – 5.8440) 0.82239
Ever had worm infection 0.5996 (0.3337 – 1.0773) 0.08709 0.9006 (0.5446 – 1.4893) 0.68334 3.0716 (1.0564 – 8.9312) 0.03933
Attitude and Practices
Try to prevent worm infection 2.1516 (1.2774 – 3.6241) 0.00397 0.5020 (0.2110 – 1.1944) 0.11915 1.3692 (0.3965 – 4.7279) 0.61920
26 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license.
27
Hygiene
Defecate in open 1.3311 (0.7780 – 2.2774) 0.29659 2.0082 (1.1465 – 3.5173) 0.01476 4.1143 (0.9377 – 18.0529) 0.06084
*Toilet types
No toilet 1 1 1
Pit 0.5772 (0.2883 – 1.1557) 0.12078 0.3699 (0.1823 – 0.7506) 0.00587 0.4418 (0.0976 – 1.9991) 0.28890
Water closet 0.8417 (0.3542 – 2.0002) 0.69643 0.2473 (0.0619 – 0.9518) 0.04227 1.1597 (0.2627 – 5.1190) 0.84490
Bucket 1.7957 (0.5544 – 5.8168) 0.32897 - - -
Others** 2.6935 (1.1388 – 6.3712) 0.02408 1.2946 (0.4056 – 4.1319) 0.66281 3.0926 (0.4631 – 20.6505) 0.24380
Wash hand after toilet 0.6839 (0.3513 – 1.3316) 0.26373 0.6658 (0.3587 – 1.2360) 0.19748 0.4777 (0.1402 – 1.6270) 0.23735
Wash hand with soap 1.2164 (0.7215 – 2.0510) 0.46226 0.8316 (0.5164 – 1.3391) 0.44806 0.9941 (0.3538 – 2.7931) 0.99102
Eat meal with bare hands (without cutleries) 0.9680 (0.5722 – 1.6376) 0.90351 1.2171 (0.7239 – 2.0465) 0.45861 1.9965 (0.5697 – 6.9970) 0.27988
Home/farm activities
Eat in the farm 1.1172 (0.5103 – 2.4460) 0.78165 1.0446 (0.5096 – 2.1416) 0.90508 0.9141 (0.2126 – 3.9303) 0.90389
Wear shoe to farm 0.9724 (0.3841 – 2.4618) 0.95295 2.2408 (0.5831 – 8.6106) 0.24009 1.0993 (0.1504 – 8.0333) 0.92750
Wear shoe while working in farm 0.4507 (0.2673 – 0.7598) 0.00278 0.7625 (0.4739 – 1.2268) 0.26382 0.7353 (0.2646 – 2.0430) 0.55350
Wear shoe at home 1.2304 (0.6644 – 2.2784) 0.50957 0.9254 (0.5431 – 1.5769) 0.77561 0.3470 (0.1258 – 0.9573) 0.04091
Use of health services
27 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license.
28
Have medical centre near home* 0.9237 (0.4267 – 1.9996) 0.84030 0.8637 (0.4265 – 1.7489) 0.68392 - -
Been sick one or more times in past year* 0.9977 (0.5170 – 1.9254) 0.99453 1.5018 (0.7200 – 3.1324) 0.27830 0.8030 (0.2320 – 2.7792) 0.72911
Visited the doctor one or more times in the 0.9049 (0.5410 – 1.5136) 0.70337 0.8393 (0.5187 – 1.3581) 0.47559 0.8043 (0.2866 – 2.2575) 0.67923
past year
Have received medicine for worm* 0.9309 (0.5356 – 1.6179) 0.79950 0.7417 (0.4259 – 1.2917) 0.29105 1.2067 (0.4159 – 3.5014) 0.72958
When received medicine for worm?*
None 1 1 1
Months ago 1.1600 (0.5823 – 2.3109) 0.67296 0.4833 (0.1836 – 1.2724) 0.14096 1.1278 (0.2531 – 5.0252) 0.87467
Years ago 0.7808 (0.3680 – 1.6565) 0.51901 0.8365 (0.4357 – 1.6061) 0.59176 1.3013 (0.3652 – 4.6367) 0.68458
406 N = number examined. PR = prevalence ratio; CI = confidence interval. *Included in the section for ease of result presentation. **other toilet types 407 apart from the ones listed. Except SES, types of toilet and “when medicine was received for worm” which has 1 indicated as reference, the reference 408 value for all other determinants is 1 and represent the group that responded “no” to each of the questions concerned. 409
410
411
28 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 29
412 Risk of hookworm infection dropped in the fourth and fifth wealth quintiles compared to the
413 first (Table 7). The drop was more obvious among the richest people, though it was not
414 significant (p = 0.06880). Those who were conscious of the possibility of getting infected by
415 worms had lower chances of infection with hookworm; risk of infection dropped significantly
416 by over 50% (p = 0.00467). Open defecation increased risk of hookworm infection by 200%
417 (PR = 2.0082, 95% CI = 1.1465 – 3.5173, p = 0.01476). Pit latrine and water closet toilets
418 compared to non-toilet owners reduced risk of infection by 65% and 70% respectively, the
419 differences were significant (p < 0.05).
420 People who acknowledged being previously infected by worm were at over 300% greater risk
421 of T. trichiura infection. The actual range of this estimate was 5% to 800%, and was
422 significant (PR = 3.0716, 95% CI = 1.0564 – 8.9312, p = 0.03933). Open defecation also
423 increased the risk of infection by about 400% though this was not significant (p > 0.05; Table
424 7). Those that wore shoes at home were 70% less likely to get infected by T. trichiura (p =
425 0.04091).
426
427 Discussion
428 Overall prevalence of STH was 34.2%. STH isolated were Ascaris lumbricoides, hookworm
429 and Trichuris trichiura, and at prevalence 18.1%, 16.8% and 5.2% respectively. Intensities of
430 the three helminths were largely light. Collectively, prevalence of moderate and heavy
431 intensity of STH infection was < 1%. A total of 68 (23.1%) of the respondents were classified
432 as poorest based on the 20-assets criteria. Those in richest category were 73 (24.7%) while
433 poor, average and rich were slightly fewer. Mud floor at homes was mainly associated with
434 poverty. Majority of the people who had cement floors at home where in the fourth (rich) and
435 fifth (richest) quintiles. There was very high significant difference in the distribution of mud
436 and cement floors by wealth quintile (p < 0.0001). The poorest and poor were relatively more
29 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 30
437 likely to practice open defecation and constituted 39.4% and 25.1% respectively of 175 who
438 practiced it; which contrasts strongly with 12.0% and 6.3% of the rich and richest people
439 respectively. Majority of people in Igalamela-Odolu LGA had better wealth status than those
440 in Ibaji LGA. Risk of infection was significantly lower by 60% in the richest wealth quintile
441 compared to the poorest quintile. People who practiced open defecation were two times more
442 likely to harbor STH compared to those who did not. Compared to non-possession of toilet
443 facilities, pit latrine and water closet toilet each significantly reduced the risk STH infection.
444 Washing hands after toilet use significantly lowered the risk of STH infection; though using
445 soap for this purpose had no to little effect.
446 Overall prevalence of STH in Ibaji and Igalamela-Odolu LGAs was moderate (34.2%). This
447 falls within the 16.2% – 39.0% range among LGAs of Kogi State as earlier reported by the
448 Nigerian Federal Ministry of Health [18]. However, FMOH survey was only school-based.
449 Most STH prevalence surveys in Nigeria were carried out among school children: Sowemino
450 and Asaolu [31] obtained prevalence of 34.4% in Ile-Ife, Osun State; 26.66% was reported in
451 Rivers State [32], 80.9% among Almajiri children in northern Nigeria [33], and 30.3% in Imo
452 state [9]. Differences in prevalence obtained in various parts of the country relative to the
453 present study may be attributable to environmental, ecological and anthropogenic factors that
454 prevailed in each area. Moreover, methodological differences between studies could also be
455 an issue; while floatation techniques were applied in most of these surveys, the standard Kato-
456 Katz technique was employed in this study. Comparative studies on floatation and Kato-Katz
457 techniques have reported both similar and disparate performance depending on the helminth
458 of interest [34-36]. Despite the 34.2% prevalence, mean intensity of STH was low; moderate
459 to high intensity was below 1% in the study population. This finding holds a promise in terms
460 of possibilities of control of STH in the population.
461 An important aspect of the result is the similarity in infection among the four age groups
462 (preschool, school, women of reproductive age and men of same age, and older at-risk 30 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 31
463 groups). This further emphasizes need for extension of preventive chemotherapy to other at-
464 risk groups, especially in settings such as the one covered by this study where majority of the
465 inhabitants are at risk. The finding corroborates STHAC recommendation [16,17]. Though
466 women of reproductive age were considered along with men of similar age group (52.8% vs.
467 47.2%), there are no bases for expecting that helminth burden will be any different between
468 men and women considering the locality in question. Infection was also not significantly
469 different between male and female (unreported). Restricting mass drug administration (MDA)
470 to preschool-aged and school-aged in agrarian communities of Ibaji and Igalamela-Odolu
471 LGAs, and other localities with similar attributes only increases the risk of re-infection after
472 MDA.
473 Factors associated with STH infection were identified in this study. Socio-economic and
474 demographic factors such as poverty, lack of portable water, occupation, age, and attitudes
475 such as poor sanitation and poor sewage disposal have been recognized as determinants of
476 STH distribution in endemic areas [15,37]. From the asset-based approach used in this study,
477 the number of very poor and very rich households was almost equal in the study area. While
478 the asset-based approach employed effectively classified the household into wealth quintiles,
479 number and types of assets considered generally influence classifications [27]. From the
480 present study, people at the fifth wealth quintile (richest) were less likely to harbour STH.
481 Possession of assets indicative of good SES such as cement floor, electricity, radio, television,
482 pipe-borne water and toilet facilities such as pit latrine and water closets reduced risk of STH.
483 Open defecation which was common among people in the first, second and third wealth
484 quintile was a major risk for STH infection. It has been stated previously that improper
485 sewage disposal is a major factor for STH infection [38]. Availability of toilet facilities in a
486 household is a matter of social class proving the saying that poverty breeds diseases. Mud and
487 hut house is associated with increased STH infection [39]. Mud has the tendency of retaining
488 parasite eggs even when it has been apparently cleaned. Mud floor which was assigned strong 31 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 32
489 negative factor score by statistical analysis is one of the strong indicators of poverty in the
490 LGAs. In addition, cement floor alone was one of the SES assets that strongly reduced the
491 risk of infection with STH. Thus, STH infection in the LGAs can largely be blamed on SES.
492 Though it has been suggested by Becker et al. [17], that it is unlikely that significant impact
493 can be made between 2018 and 2020 concerning socio-economic status of people in STH
494 endemic areas. This therefore suggests, that other approaches such as preventive
495 chemotherapy are more important if the WHO 2020 target is to be achieved. The authors
496 share the same view, but would wish to emphasize that in order to sustain gains, a sustainable
497 approach against STH requires improved SES.
498 Knowledge, attitude and practices were other strong determinants of STH infection in the
499 LGAs. Fifty-nine percent (59%) of the respondents admitted defecating in the open mainly
500 due to lack of toilets. Risk of STH infection was generally higher among those who practiced
501 open defecation. This was especially obvious for hookworm and T. trichiuria. This
502 corroborates reports from Nigeria and other parts of the world [39,40]. Regular visits to
503 defecation spots increase chances of hookworm infection because the infective stages of this
504 parasites develop around defecation sites where the eggs were released and are always ready
505 to strike and infect an unsuspecting host. Open defecation can be reduced through health
506 education and by improving the SES of communities affected through provision of amenities
507 such as pit latrines and water closet toilets.
508 Hand washing after toilet use lowered the risk of acquiring STH. Although auto-infection
509 from freshly passed stool is not possible since period of incubation in the soil is required by
510 STH, habitual hand washing after toilet use is an indication of high sense of personal hygiene.
511 More so, individuals, especially children, who use regular open defecation sites are more
512 likely to soil their hands with previously contaminated soil. Therefore hand washing protects
513 against STH. It has been advocated that health education in the aspect of hand washing with
514 soap be intensified among communities where STH infection occurs [41]. Though the present 32 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 33
515 study found no special role played by soap. The importance of water, sanitation and hygiene
516 (WASH) which was re-affirmed by STHAC is emphasized by the present study.
517 Chances of having STH infection were also lowered significantly by wearing shoes while
518 working on the farm. This act provided some level of protection against the three STH, and
519 the effect was significant against A. lumbricoides. Not wearing of shoes was similarly
520 reported as a risk factor for hookworm infection in northwestern Ethiopia [42]. The infective
521 hookworm larvae from soil enter into the host by active penetration of unbroken skin
522 especially the feet that are often in contact with the soil. Shoe wearing therefore, reduces the
523 risk of hookworm infection. Though unrelated to A. lumbricoides infection, shoe wearing
524 prevents contamination of feet which could indirectly lead to infection when individuals touch
525 such contaminated feet and eat with unwashed hands afterwards.
526
527 Conclusion and recommendations
528 In conclusion, this study reports a moderate prevalence and light intensity of STH infection in
529 the study population indicating its endemicity in the study area and therefore a public health
530 problem that requires attention. A number of risk factors associated with STH transmission
531 was identified. These are mainly socio-economic, attitude and practices. Based on the
532 findings, it is hereby recommended that
533 1. Mass preventive chemotherapy against STH infection through the interventions of the
534 Ministry of Health and other health organizations should be extended to all age groups in the
535 affected communities. This is especially important to prevent risk of re-infection by other at-
536 risk adults.
537 2. Health education and awareness on transmission and health impact of STH should be
538 emphasized. The study further affirms water, sanitation and hygiene (WASH) as integral STH
539 control strategy.
33 bioRxiv preprint doi: https://doi.org/10.1101/663237; this version posted June 7, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 34
540 3. Effort should be made at improving SES in places where STH has moderate to high
541 endemicity such as Ibaji and Igalamela-Odolu LGAs through provision of basic amenities
542 such as pit latrine and water closet toilets, pipe-borne water, electricity and good housing.
543
544 Conflict of interest
545 The authors declare no conflict of interest.
546 Acknowledgements
547 We thank the traditional heads in Ibaji and Igalamela-Odolu LGAs, and the households that
548 willing participated in the study.
549
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675 Supporting information Legends
676 S1 Table. Supporting information from the asset-based socio-economic status 677 S2 Fig. Proportion of people positive and negative for soil-transmitted helminthiasis
678 who had different assets. The five key determinants are highlighted in dark-walled
679 rectangles. Possession of toilet was the most important determinant, usage of plant leaf or
680 water is closely associated with possession of toilet (open defecation is not an asset, but was
681 included here for convenience of presentation).
682 S3 Checklist: STROBE Checklist
683
684
685
39