The prevalence of schistosomiasis in Uganda: A nationally representative population estimate to inform control programs and water and sanitation interventions.

Natalie G Exum,Edridah M Tukahebwa,Simon P S Kibira,Fredrick E Makumbi,Alexandra K Shannon,John C Ssempebwa,Julien Nobili,Ronald Ssenyonga,Kellogg J Schwab,Scott Radloff,Adam Akullian

doi:10.1371/journal.pntd.0007617

Natalie G Exum, Edridah M Tukahebwa + Show 9 more

Open Access

https://doi.org/10.1371/journal.pntd.0007617

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Abstract

BackgroundTo improve schistosomiasis control programs in Uganda, where intestinal schistosomiasis is a widespread public health problem, a country-wide assessment of the disease prevalence among all age ranges is needed. Few studies have aimed to quantify the relationships between disease prevalence and water and sanitation characteristics across Uganda to understand the potential to interrupt disease transmission with an integrated package of interventions.Methodology/Principal findingsA nationally representative survey was undertaken that included a household and individual questionnaire followed by disease testing based on detection of worm antigens (circulating cathodic antigen–CCA), diagnosis and treatment. A comprehensive set of questions was asked of randomly sampled individuals, two years of age and above, to understand their water and sanitation infrastructure, open defecation behaviors, exposure to surface water bodies, and knowledge of schistosomiasis. From a set of 170 randomly sampled, geographically diverse enumeration areas, a total of 9,183 study participants were included. After adjustment with sample weights, the national prevalence of schistosomiasis was 25.6% (95% confidence interval (CI): 22.3, 29.0) with children ages two to four most at risk for the disease with 36.1% infected (95% CI: 30.1, 42.2). The defecation behaviors of an individual were more strongly associated with infection status than the household water and sanitation infrastructure, indicating the importance of incorporating behavior change into community-led total sanitation coverage.Conclusions/SignificanceOur results highlight the importance of incorporating monitoring and evaluation data into control programs in Uganda to understand the geographic distribution of schistosomiasis prevalence outside of communities where endemicity is known to be high. The high prevalence of schistosomiasis among the youngest age group, ineligible to receive drug treatment, shows the imperative to develop a child-appropriate drug protocol that can be safely administered to preschool-aged children. Water and sanitation interventions should be considered an essential investment for elimination alongside drug treatment.

Highlights

Schistosomiasis is a neglected water-based, vector-borne disease transmitted indirectly through freshwater snails, estimated to affect more than 240 million individuals worldwide with 700– 800 million people living at risk of infection [1,2,3]
Schistosomiasis is a neglected tropical disease in sub-Saharan Africa that has remained intractable despite efforts to eliminate it through mass drug administration
In Uganda, where fresh water bodies are abundant and intestinal schistosomiasis is endemic, very little is understood about the disease prevalence at a national level

Summary

Introduction

Schistosomiasis is a neglected water-based, vector-borne disease transmitted indirectly through freshwater snails, estimated to affect more than 240 million individuals worldwide with 700– 800 million people living at risk of infection [1,2,3]. The lack of sanitation infrastructure to adequately collect and treat human waste, along with the common behaviors and activities that involve frequent contact with open waters, has made schistosomiasis a challenging disease to control in sub-Saharan Africa. In 2018, coverage of either annual or biennial mass drug treatment, coupled with health education, was achieved across all 82 districts where schistosomiasis is common. Despite this progress, there is doubt that the targets set by the World Health Organization will be met to control morbidity by 2020 and achieve elimination by 2025 [15]. Few studies have aimed to quantify the relationships between disease prevalence and water and sanitation characteristics across Uganda to understand the potential to interrupt disease transmission with an integrated package of interventions

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