エクアドル北西部における動物の糞便と人獣共通感染症病原体への小児曝露：混合手法研究

In low- and middle-income countries (LMICs), close cohabitation with animals and limited access to water, sanitation, and hygiene (WASH) infrastructure increase the risk of zoonotic enteric pathogen transmission to young children. This mixed-methods study combined (A) microbiological analysis of 120 animal fecal samples, and (B) go-along, semi-structured interviews with 35 mothers of children under two years across urban (n = 10), intermediate (n = 15), and rural (n = 10) communities in Ecuador to investigate: (Q1) What zoonotic enteric pathogens are present in animal feces and at what concentrations? (Q2) How are children exposed to animals and their feces? and (Q3) Which animals may serve as key sources of child exposure? Microbiological analysis revealed high prevalence and concentrations of zoonotic pathogens, most commonly E. coli aEPEC (57%), Salmonella sp. (36%), and E. coli STEC (25%), with frequent co-infections (33%) and concentrations (4.97-9.29 log10 gc/g) often exceeding infectious dose thresholds. Qualitative findings showed risks from free-roaming animals, poor feces management, and frequent child-animal contact, often indirectly through caregivers and siblings. Triangulation identified chickens and dogs as the most likely potential exposure sources due to their behaviors, proximity to children, and pathogen carriage. These findings highlight the need for targeted interventions to limit animal roaming, improve animal feces management, and increase caregiver awareness, while underscoring how mixed-methods approaches can help identify context-specific exposure pathways that should be considered when designing interventions.