Enteric pathogen infections among infants in rural Bangladesh: prevalence, trial impact, and associations with enteric dysfunction and growth

Background

Repeated enteric infections and chronic enteric dysfunction have been associated with undernutrition in children. Interventions that reduce enteric pathogen exposure in young children could thereby improve growth and developmental outcomes. We assessed enteric pathogen prevalence in Bangladeshi infants, the impact of a combined homestead food production and food hygiene intervention on pathogen infections, and associations between pathogen infections, enteric dysfunction markers, and child growth outcomes.

Methods

We analyzed panel data from 231 children born between April and December 2018 within the Food and Agricultural Approaches to Reducing Malnutrition (FAARM) cluster-randomized trial in Sylhet, Bangladesh. Stool samples were collected at 0–3, 6–8, and 10–13 months of age and assessed for enteric dysfunction biomarkers (myeloperoxidase, alpha-1 antitrypsin, and neopterin) by ELISA and 14 enteric pathogens by multiplex RT-PCR. Diarrhea prevalence was recorded using 7-day recall. Child length and weight were measured at birth and trial endline. Multilevel regression assessed the intervention effect and quantified associations between pathogen exposure, enteric dysfunction, and growth outcomes.

Findings

Enteric pathogen prevalence was high (84%) despite low 7-day diarrhea prevalence (5%), and co-infections were common. There was no intervention effect on the prevalence of enteric pathogens. Shigella spp. and Giardia lamblia were associated with higher myeloperoxidase concentrations, while sapovirus was associated with higher alpha-1 antitrypsin concentrations. Repeated protozoan infections (mainly Giardia lamblia ) were associated with lower length-for-age, while repeated viral infections (mainly rotavirus and sapovirus) and Cryptosporidium infections were associated with lower weight-for-height and weight-for-age. There was marginal evidence that bacterial infections were associated with lower length-for-age.

Conclusion

The intervention was insufficient to reduce the high burden of enteric pathogens in infants, and subclinical infections were associated with enteric dysfunction and poorer growth outcomes. Comprehensive strategies addressing all key exposure pathways are needed to limit pathogen infections and their consequences for child development.

Author Summary

Infections of the gut are extremely common in young children in low-income settings and can cause lasting harm even when they do not produce obvious symptoms like diarrhea. In this study, we examined stool samples from infants in rural Bangladesh and found that over 80% carried at least one enteric pathogen at any given time, despite only 5% showing signs of diarrhea. This confirms that the majority of these infections go unnoticed by caregivers and standard health monitoring.

We investigated whether a combined program promoting home gardens, poultry rearing, better child feeding, and improved household food hygiene could reduce these infections, but found no measurable effect on pathogen burden. We found clear links between infection with specific pathogens and both gut inflammation and poorer child growth: protozoan parasites were associated with stunting, while viruses and Cryptosporidium were linked to wasting and underweight.

These findings underscore that visible illness is a poor proxy for pathogen exposure in infants in low-income settings, and that more comprehensive strategies, such as transformative water, sanitation, and hygiene approaches, may be needed to meaningfully reduce the hidden burden of enteric infections and their consequences for child development.