Association Between Water, Sanitation, and Hygiene Access and the Prevalence of Soil-Transmitted Helminth and Schistosome Infections in Wolayita Zone, Ethiopia

Abstract

Background The Geshiyaro project is a five-year intervention to assess the impact of community and school-based water, hygiene, and sanitation (WaSH) interventions on reducing infection with soil-transmitted helminths (STH) and schistosome parasites, in combination with deworming in Wolayita zone, Ethiopia. Methods Data on baseline STH and schistosome prevalence and the association with household and community access to improved drinking water, latrines, and handwashing facilities were obtained during a population based, cross-sectional (by age and gender) survey conducted between 2018 and 2019. Results Prevalence of STH was found to be 15.5% for any STH species, 9.5% for Ascaris lumbricoides, 1.8% for Trichuris trichiura, and 7.2% for hookworm. Intestinal schistosomiasis (Schistosoma mansoni) infection prevalence was 0.85% by Kato Katz, 21.6% by POC-CCA trace positive and 13.3% trace negative. Microhaematuria was 2.8%, with only 0.13% S. haematobium eggs detected in urine filtration. Increased (>30 min) time taken to collect drinking water, sharing a latrine, and lack of handwashing facilities were all associated with a greater risk of Ascaris, hookworm, and S.mansoni infection. Not disposing of infant stool at the household was significantly associated with increased risk of schistosomiasis infection. Aggregating WaSH data at the community level, showed odds of Ascaris and Trichuris infection significantly decreased as both community sanitation coverage and access to improved drinking water improved. Hookworm had reduced odds of infection as community access to drinking water expanded but there was no effect of community sanitation, however, there was a significant impact of improved household sanitation. Conclusions These findings demonstrate the quality of, and specific behaviours related to an individual’s use of household WaSH infrastructure are likely to augment potential protection latrines can provide. Furthermore, considering an individual household’s access to WaSH alone is insufficient to demonstrate association and risk with STH/schistosomiasis infection. Increased access to improved sanitation and drinking water within the whole community significantly influences exposure and gains made at the household level.