Rwanda has made remarkable progress on many sustainable development goals (SDGs), including reducing infant, child, and maternal mortality. However, the prevalence of child stunting has remained high, impacting 33% of children under the age of five in 2020. Stunting is a complex global health challenge that can be associated with diverse individual, family, and community factors as well as environmental risk factors such as water quality. Limited clean drinking water in dry seasons and reliance on surface water sources shared with livestock and wildlife can expose people to chemical and biological contaminants. Cohabitation of people and livestock in rural areas increases the risk of zoonotic pathogen sharing and human illness. Pathogen exposure and resulting diarrheal diseases are also linked to child stunting.
To examine the relationships among stunting, water quality, and zoonotic pathogen sharing, we used primary data collected in Karongi district in western Rwanda, an area with high stunting prevalence, as well as secondary national survey data. We linked data from the 2019-2020 Rwanda Demographic and Health Survey (DHS) with national water quality testing data. We used generalized linear regression to identify demographic, socio-economic, livestock ownership, and water quality factors associated with stunting. Child factors (birth order, age, gender) and household factors (wealth status, mother’s education, rural or urban location, number of children in the household) were associated with increased stunting. Water quality (pH) was also marginally associated with stunting.
In our Karongi district field study, we paired household surveys with biological sample collection from children, livestock, and drinking water in upstream and downstream communities in the Musogoro River watershed. Water samples from surface water, public taps, and household drinking water storage containers were tested for basic physical water quality parameters, bacterial contamination (total coliform bacteria and E. coli), and potential hazardous elements (As, Cd, Cr, Cu, Fe, Pb, Mn) with public health importance. We cultured and isolated potentially zoonotic pathogens (Campylobacter, E. coli, and Salmonella) from child stool samples, livestock fecal samples, and drinking water. Surface water sources and household drinking water containers had high levels of biological (total coliform/E. coli) and chemical contaminants (iron and manganese). The prevalence of Campylobacter was high (>60%) across child, livestock, and water samples in upstream and downstream communities. High levels of E. coli were also detected across samples (>40%), with significantly higher prevalence in upstream children and livestock. Salmonella was less commonly detected, but the prevalence was significantly higher in upstream livestock. Whole genome sequencing analyses of cultured pathogens are planned to define population structures and assess pathogen sharing at the child-livestock-water interface. Our results highlight the need for further research to assess environmental factors associated with child stunting and to facilitate development of more holistic household- and watershed-based intervention strategies to improve human, animal, and ecosystem health outcomes.