Animal Exposure and Its Seasonal Influence on Drinking Water Quality and Child Enteric Infection in Urban Mozambique

Abstract

Exposure to animals and their feces has been linked to zoonotic infections and fecal contamination of the household environment, including stored drinking water. Inadequate separation between animal and human living environments can facilitate enteric pathogen transmission through the fecal-oral route. We investigated associations between animal exposure and (1) stored water contamination, (2) zoonotic enteric pathogen infections among 12-month-old children in a low-income, urban setting. We used data from 630 participants at 12 months enrolled in the PAASIM Study in Beira, Mozambique, from 2022-2023, including household surveys, E. coli contamination measured from sampled stored water, and enteric pathogens analyzed from stool samples using Taqman array cards. We developed a score to characterize animal exposure in the household using Principal Component Analysis. We used generalized estimating equations with robust standard errors to assess associations between animal exposure and 1) household drinking water contamination and 2) child zoonotic enteric infection. We further evaluated the interaction between the animal exposure score and intervention and the presence of a direct household connection. The PAASIM study enrolled 898 pregnant women, and 642 (71%) completed the 12-month visit. We found that animal exposure was associated with a higher prevalence of contamination [prevalence ratio (PR): 1.07 per 1-unit increase; 95% CI: 0.99, 1.160]. Seasonality modified this association; during the rainy season, each one-unit increase in animal exposure score was associated with a 13% higher risk of stored water contamination (PR: 1.13; 95% CI: 1.042, 1.224). Animal exposure was associated with a 5% higher risk of any zoonotic enteric infection (PR: 1.05; 95% CI: 1.00, 1.10). We also found that a one-unit increase in animal exposure score was associated with a 14% higher risk of Campylobacter infection (PR: 1.14; 95% CI: 1.01, 1.29), and the risk is significantly higher in the dry season (PR: 1.21; 95% CI: 1.04–1.40). The association between intervention and zoonotic pathogen infection did not differ meaningfully by animal exposure level. Our study demonstrates that exposure to animals and animal feces can increase the risk of stored-water contamination and Campylobacter infections in low-income urban settings.