Impact of community piped water coverage on re-infection with urogenital schistosomiasis in rural South Africa.

Polycarp Mogeni,Frank Tanser,Alain Vandormael,Christopher Appleton,Diego Cuadros

doi:10.7554/elife.54012

Polycarp Mogeni, Frank Tanser + Show 3 more

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https://doi.org/10.7554/elife.54012

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Abstract

Previously, we demonstrated that coverage of piped water in the seven years preceding a parasitological survey was strongly predictive of Schistosomiasis haematobium infection in a nested cohort of 1976 primary school children (Tanser, 2018). Here, we report on the prospective follow up of infected members of this nested cohort (N = 333) for two successive rounds following treatment. Using a negative binomial regression fitted to egg count data, we found that every percentage point increase in piped water coverage was associated with 4.4% decline in intensity of re-infection (incidence rate ratio = 0.96, 95% CI: 0.93-0.98, p=0.004) among the treated children. We therefore provide further compelling evidence in support of the scaleup of piped water as an effective control strategy against Schistosoma haematobium transmission.

Highlights

About 243 million people are infected with schistosomiasis worldwide, of whom ~ 93% reside in subSaharan Africa where children carry the greatest burden of the disease
We previously used novel geostatistical methods, annual population-based surveillance data, and a parasitological survey to quantify the risk of Schistosoma haematobium infection in a nested cohort of 1976 primary school children (Tanser et al, 2018). In this baseline parasitological survey, we showed that every percentage increase in community piped water was associated with a 2.5% decrease in the odds of Schistosoma haematobium infection
During the baseline parasitological survey, a total of 2105 children from all 33 primary schools located in a contiguous geographical area in rural KwaZulu-Natal consented to participate in the study

Summary

Introduction

About 243 million people are infected with schistosomiasis worldwide, of whom ~ 93% reside in subSaharan Africa where children carry the greatest burden of the disease. Infection occurs when trematodes of the genus Schistosoma shed by infected freshwater snails (an intermediate host) penetrate the skin upon contact with infested water (Colley et al, 2014). Intensity of infection in the human host is a function of the parasite load and can indirectly be quantified by the number of eggs excreted. Most human infections in sub-Saharan Africa (SSA) are due to Schistosoma mansoni, which causes intestinal schistosomiasis and Schistosoma haematobium responsible for urogenital schistosomiasis (Lai et al, 2015). Schistosoma haematobium has the widest geographical coverage in SSA and is the main cause of infection in the Hlabisa sub-district, where our study is based (Saathoff et al, 2004)

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