WASH (Water, Sanitation, and Hygiene) Deficits and Infectious Disease Burden in Urban Slums: A Cross-sectional Survey of Households in Nigeria

Abstract

Background: Urban informal settlements frequently experience inadequate water, sanitation, and hygiene (WASH) services, increasing exposure to enteric and environmentally mediated infections. Multi-city primary data linking household WASH conditions with disease outcomes in Nigerian slum communities remain limited. Objectives: To describe WASH access and water quality in selected slum communities in Lagos, Kano, and Port Harcourt; estimate household-reported 30-day occurrence of selected WASH-related illnesses; describe soil-transmitted helminth positivity among stool-tested participants; and examine associations between selected WASH exposures and disease outcomes. Methods: A multi-site cross-sectional household survey was conducted from January to August 2024. A total of 1,157 households were enrolled through stratified cluster sampling. Drinking-water microbiology was assessed in 580 sampled households, and 648 consenting household members provided stool specimens for Kato-Katz examination. Multivariable logistic regression models adjusted for household income, caregiver education, household size, number of children younger than five years, and city of residence. Results: Household WASH conditions were poor: 37.4% of households practised open defecation, 10.5% had a functioning handwashing station with soap and water, and 63.8% of point-of-use water samples exceeded the study microbiological threshold. Household-reported 30-day diarrhoeal episodes occurred in 35.3% of households, while the combined suspected/confirmed typhoid outcome occurred in 19.1%. Among the 648 stool-tested participants, 478 were Kato-Katz positive for at least one soil-transmitted helminth (73.8%). Unimproved water source was associated with diarrhoea (adjusted odds ratio [aOR] 5.10, 95% CI 3.90-6.70), open drainage within 50 m with suspected cholera (aOR 4.20, 95% CI 3.10-5.70), and absence of household sanitation with the combined typhoid outcome (aOR 3.80, 95% CI 2.60-5.40). Conclusion: In the surveyed communities, multiple WASH deficits co-occurred with substantial burdens of household-reported enteric illness and microbiological contamination. The cross-sectional design supports association rather than causation, but the findings identify potentially actionable deficits in water quality, sanitation, hygiene, and household water handling.