# Child exposure to animal feces and zoonotic pathogens in northwest Ecuador: A mixed-methods study

## TL;DR

This study in Ecuador finds that chickens and dogs are key sources of zoonotic pathogens in young children due to close contact and poor feces management.

## Contribution

The study combines microbiological and qualitative methods to identify context-specific exposure pathways to zoonotic pathogens in low-resource settings.

## Key findings

- Over 80% of animal fecal samples contained zoonotic pathogens like E. coli and Salmonella at high concentrations.
- Chickens and dogs were identified as the main sources of exposure due to their proximity to children and pathogen carriage.
- Mixed-methods approaches revealed that poor feces management and free-roaming animals increase child exposure risks.

## Abstract

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.

In low-resource settings, such as northwestern coastal Ecuador, young children live in close contact with animals and often have limited access to clean water, toilets and safe play spaces. This raises concerns that microbial pathogens from animal feces may be an important, but often overlooked, source of illness. To understand how children may be exposed to these pathogens, we collected feces from common domestic animals around households. Using molecular methods, we found that more than 80% of samples contained microbes that can cause diarrhea in children, often at high levels and sometimes in combination. We also conducted qualitative interviews and walked through households with mothers, observing where animals spent time, where children played, and how animal feces were handled. By combining these two types of information, we identified chickens and dogs as key potential sources of exposure because they roam freely, defecate near living and play areas, carry multiple microbial pathogens, and often interact closely with children and mothers. Our findings suggest practical ways to reduce risk, such as limiting animal roaming near child play spaces and improving everyday feces cleanup in and around the home.