Human fecal contamination of the domestic environment and child enteric infection in urban Maputo, Mozambique

Abstract

Background: Children living in settings with poor sanitation infrastructure are commonly infected by a range of enteric pathogens that can be transmitted through multiple pathways in the domestic environment. Host-associated microbial source tracking (MST) markers are increasingly used to identify fecal contamination, but the relationship between MST markers and infection risk remains poorly characterized.Methods: We assessed fecal contamination in samples of water, soil, and food preparation surfaces from household clusters (compounds) in low-income neighborhoods of urban Maputo, Mozambique through two cross-sectional surveys conducted approximately 12 months apart. Child stool was analyzed for 23 enteric pathogens from four classes: nine bacteria, three viruses, and three protozoan parasites by multiplex reverse-transcription polymerase chain reaction (RT-PCR) and eight soil transmitted helminths (STH) by Kato-Katz. Human fecal contamination was determined by real-time PCR (qPCR) targeting two human-associated MST markers, HF183/BacR287 and Mnif, and Escherichia coli was assessed by culture and qPCR to indicate non-specific fecal contamination. We estimated associations between fecal indicators in each sample type and infection by pathogen class and number of co-infections using multilevel logistic and negative binomial regression, respectively, with compound-varying intercepts.Results: Samples were collected from 193 children and 71 compounds, with 112 children contributing stool in both survey rounds. Prevalence of enteric infection was high, with 86-92% of children in each survey round shedding at least 1 pathogen, but most were asymptomatic with 8-12% reporting diarrhea in the preceding 7 days. Contamination of drinking water source demonstrated weak associations with bacterial (aOR: 2.2; 95% CI: 1.0-4.4) and viral (aOR: 1.9; 95% CI: 1.0-3.6) infections for increasing E. coli density, while detection of human-associated HF183 in latrine soil was weakly associated with reduced odds of protozoan infection (aOR: 0.7; 95% CI: 0.4-1.0).Conclusions: Measures of fecal contamination were largely unassociated with enteric infection prevalence or number of co-infections.