|Year : 2017 | Volume
| Issue : 4 | Page : 201-204
Urinary schistosomiasis in school children of a southern nigerian community 8 years after the provision of potable water
Emmanuel Eyo Ekanem, Francis Michael Akapan, Michael Eteng Eyong
Department of Paediatrics, University of Calabar, Calabar, Nigeria
|Date of Web Publication||18-Jan-2018|
Prof. Emmanuel Eyo Ekanem
Department of Paediatrics, University of Calabar, Calabar
Source of Support: None, Conflict of Interest: None
Background: Urinary schistosomiasis, one of the neglected tropical diseases, is a major infection of public health importance in Nigeria. Control measures include the provision of potable water as the main strategy, population-based chemotherapy and health education. Aims and Objectives: The aim of this study was to determine the effect of the provision of potable water on the prevalence and intensity of infection with Schistosoma haematobium in Adim community, Cross River State, Nigeria. Subjects and Methods: A cross-sectional survey was carried out among school and children aged 5–14 years in Adim community in Cross River State using the polyamide millipore filter technique and ova detection and count compared with the situation that obtained 8 years earlier before the provision of potable water. The prevalence and intensity of haematuria and proteinuria by reagent strips were also compared between the two eras. Results: The prevalence of schistosomiasis was 14.5% compared to 51% in the prepotable water era (P = 0.001). The intensity of the infection was also significantly reduced between the two eras with 1.3% of the children having a severe intensity compared to 4.5% in the prepotable water era. Conclusions/Recommendations: The prevalence and intensity of S. haematobium have significantly reduced in this community though not yet eliminated. More boreholes need to be provided to make the water more accessible. This could be combined with other measures to eradicate S. haematobium from this community.
Keywords: Childhood, 8 years, impact, potable water, schistosomiasis
|How to cite this article:|
Ekanem EE, Akapan FM, Eyong ME. Urinary schistosomiasis in school children of a southern nigerian community 8 years after the provision of potable water. Niger Postgrad Med J 2017;24:201-4
|How to cite this URL:|
Ekanem EE, Akapan FM, Eyong ME. Urinary schistosomiasis in school children of a southern nigerian community 8 years after the provision of potable water. Niger Postgrad Med J [serial online] 2017 [cited 2019 Jan 20];24:201-4. Available from: http://www.npmj.org/text.asp?2017/24/4/201/223460
| Introduction|| |
Urinary schistosomiasis is one of the major infections of public health and socio-economic importance in the developing world. It is also one of the neglected tropical diseases. Infection is widespread with a relatively low mortality but high morbidity rate in millions of people. Transmission is largely enhanced by human behaviour and in this case, water use practices such as urination and defecation onto water bodies. Control of schistosomiasis requires an integrated approach with the provision of potable water as the main strategy. Other measures are as follows: population-based chemotherapy, health education, the use of molluscicides, agricultural engineering, sanitation and vaccination.,
Several studies have shown a high prevalence of schistosomasis in Adim Community in South-South Nigeria with a range of 43%–51%.,, The earliest was in 1991 by Ejezie et al. (43.5%), followed in 1996 by Useh and Ejezie  (53.8%) and recently by Eyong et al. (51%) in 2003. Efforts at controlling the disease in this community have been in the form of intermittent chemotherapy with praziquantel and health education during research activities., Inspite of these measures, the prevalence of the disease was still found to be high in 2003.
It was at the end of 2003 that this typical Nigerian rural community was provided with potable water, though commercialised (at a fee of N 2.00–N 5.00 (1–3 cents) per 20 L). With access to potable water, the burden of the disease is expected to decline. This study was conducted 8 years after the provision of water in this community, and it is aimed at determining the possible effects of this provision on the prevalence of the disease.
| Subjects and Methods|| |
This was a cross-sectional study of the prevalence of Schistosoma haematobium infection in school children aged 5–14 years in Adim community, South-South Nigeria, from October to December 2011. The village is located in the rainforest belt of South-South Nigeria, 110 km to the North of the Atlantic Ocean. Before the provision of bore-hole water, the community used one big stream for the supply of her water needs, washing and recreation such as swimming. Children attending the only primary school in the community were recruited into the study. The school has a population of 1012 pupils. Stratified random sampling was employed to select participants. In the first stage, the population was categorised into classes. The number of children to be recruited was proportionately allocated among the classes. In the second stage, the number of children to be recruited was again subdivided according to a number of streams in each class such that all streams were involved. In the third stage, children were selected from each stream using a table of random numbers.
Each selected child was asked about the frequency of contact with the community stream and given a wide mouth screw-capped container into which to void urine after a mild exercise (running to-and-fro across the school field). This was carried out between 10.00 am and 2.00 pm when ova count of S. haematobium is expected to be at its peak. A semi-quantitative estimation of blood and protein was done in the voided urine using combi – 9 strips (Macheray – Nagel, Germany). Ova count was done using Nytrel (polyamide) millipore filter as described by Mott.
In this study, urinary schistosomiasis was defined as the presence of ova of S. haematobium in the urine and the intensity of infection graded as light (1–49 ova per 10 ml), moderate (50–100 ova per 10 ml) and heavy (>100 ova per 10 ml). Children with ova were treated with praziquantel at a single dose of 40 mg/kg.
The prevalence and intensity of haematuria and proteinuria by reagent strip were also determined. The prevalence and intensity of haematuria, proteinuria and ova of S. haematobium in the study were compared with the values in 2003 study (which used the same methods) in the same school just before potable water was provided.
Categorical variables were compared using Chi-square and Fisher's exact test while continuous variables were compared using Student's t-test. Multivariate logistic regression was used to determine independent predictors of infection. The receiver operator characteristic curve (ROC) was constructed to test the validity of the regression model. The values of P < 0.05 were considered statistically significant. Ethical approval was obtained from the University of Calabar Teaching Hospital Ethics Committee by letter dated 5 September, 2011.
| Results|| |
Three hundred and eighty children aged 5–14 years participated in the study. Of these, 203 (53.4%) were male and 177 (46.6%) were female. The mean age of the children was 8.57 ± 2.17 years with a median age of 9 years. [Table 1] shows the prevalence of S. haematobium infection by age group and gender. Fifty-five of the patients were ova positive giving a prevalence of 14.5% (95% of confidence interval [CI] 10.9%–18%). Twenty-eight of the 203 males (13.8%) were infected while 27 of the 177 (15.3%) females were infected. The gender difference was not statistically significant. However, in the 9–11 years old category, more females than males were infected and vice versa in the 12–14 age bracket. Furthermore, children from ages 11–13 years were most affected by the infection going by age distribution.
|Table 1: Prevalence of Schistosoma haematobium infection by age group and gender|
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Eighty-three children (21.84%) never visited the stream, and 79 (95.18%) of them did not have the infection [Table 2]. There was a significant relationship between stream visits and infection (χ2 = 8.28; P = 0.04). The odds ratio (95% CI) of the children having the infection for each stream visit per week was 1.06 (1.005–1.122). Thus, there was a 6.2% increased risk of S. haematobium infection for every extra stream visit. At the multivariate level, gender did not predict the presence of infection but increasing age and number of stream visits did [Table 2]. The area under the curve was 0.65 validating the regression model of the ROC constructed.
|Table 2: Result of logistic regression models for independent predictors of Schistosoma haematobium infection|
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Comparison of infection in the eras of pre- and post-potable water provision
There was a significant reduction in the prevalence of S. haematobium infection (14.5%) in the current study compared to the prevalence of 51% in the era preceding potable water supply (P = 0.001).
[Table 3] shows the comparison of the prevalence of infection by age in the era preceding potable water supply and the current era. At all age groups, the prevalence was lower in the current period. Similarly, [Table 4] shows the reduced intensity of infection in all age groups in the current era compared to the era preceding supply of potable water.
|Table 3: Comparison of the prevalence of Schistosoma haematobium infection in eras of pre- and post-potable water provision|
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|Table 4: Comparison of the intensity of infection in the eras pre- and post-provision of potable water|
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[Table 5] demonstrates reduced prevalence and intensity of haematuria and proteinuria in the current era compared to the era preceding potable water supply.
|Table 5: Comparison of the degree of haematuria/proteinuria in these pre- and post-eras of provision of potable water|
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| Discussion|| |
The present study has demonstrated a remarkable fall in the prevalence of S. haematobium infection in Adim community in 2011 compared to the prevalence in 2003. A 2009 study in the same community reported a prevalence rate of 38.5% among children aged 4–17 years. The difference in the prevalence in the present study may reflect the effect of time after provision of borehole water as our study was done 2 years after this. In addition, that study did not state the sampling technique used, and their quest for children who could self-diagnose schistosomiasis with the history of visible haematuria may have biased the sample studied. The reduction in the prevalence of the disease noted in the study could be attributed to the provision of potable water in the community as there was no other control activity subsequent to this. This intervention has been shown to be an effective approach in the control of the disease in other settings.,,
The marked reduction in the prevalence notwithstanding, availability and utilisation of potable water have not resulted in a complete eradication of the disease in the community. It is obvious that not all children have access to the potable water for their needs at all times. A number still visit the community stream for varying number of times weekly. The prevalence of infection increased with the frequency of visits to the stream. It has been shown that transmission of infection is largely enhanced by human behaviour such as water use practices. This is a large community with only one borehole located centrally. The distance of the facility from homes may discourage efficient use by those living farther away. In addition, the fees charged, though small, may not be affordable at all times by the inhabitants of a typical Nigerian rural community. Molluscicidal activities have never been carried out in this community. Health education and intermittent chemotherapy appear restricted to two earlier periods of research activities (1994 and 2000). In addition, other modalities of control were not applied during both periods.
Children aged 9–11 years were most affected by the infection. This could be explained by the fact that children in this age group are more actively involved in recreational activities and utilise the stream more than others.
The intensity of the infection has shown a remarkable decline since the advent of potable water. Similarly, the prevalence and intensity of haematuria and proteinuria (by reagent strips) showed remarkable decline. A similar low prevalence of haematuria following the provision of potable water has also been reported in other studies.,, Proteinuria and haematuria are important indices of S. haematobium infection. The degrees of haematuria and proteinuria have been demonstrated to be directly related to the intensity of ova count.,
| Conclusion/recommendations|| |
Eight years after the provision of a single borehole in the community, the prevalence of infection is still relatively high. A multi-faceted approach to the eradication of this neglected tropical disease is recommended: intermittent chemotherapy, molluscs control, health education and provision of more boreholes are recommended. It would appear that none of these approaches taken in isolation would eradicate the parasite. They all have to be taken in concert. The borehole in Adim was provided by the assistance of the World Bank. Unfortunately for this community, the borehole broke down in 2016 and there is currently no functional borehole in the community. It is therefore not surprising that recent surveys, despite their lack of clarity about sampling techniques, have reported prevalence rates of S. haematobium among primary school age children ranging from 22.1% to 32.8%. The Local Government Authority has to be persuaded to fulfil her social obligations to the community by providing more boreholes in the community at highly subsidised rates to the inhabitants. Active and sustained molluscicidal activities and enduring health education should commence. Intermittent chemotherapy should be more regular, and not only restricted to periods of research activities.
The obvious limitation of this study is the use of oral interview to extract some of the information. This may not always be reliable, particularly in children.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]