Associations of poor water, sanitation, and hygiene and parasite burden with markers of environmental enteric dysfunction in preschool-age children infected with Schistosoma mansoni in Uganda.

Background: Environmental enteric dysfunction (EED) is an acquired subclinical condition of the small intestine with lasting health implications for nutritional status, linear growth and development among children. EED is characterised by structural and functional changes to the gut barrier. There are no standardised diagnostic criteria, however, a number of biomarkers have been evaluated to capture EED domains. While the causes of EED are not fully understood, risk factors include poor water, sanitation and hygiene conditions and exposure to enteric pathogens. Very few studies have evaluated the impact of schistosomiasis on EED despite repeated intestinal damage from parasite eggs passing across the gut barrier.

Methods: In a cohort of 354 preschool-aged children aged 12-47 months with Schistosoma mansoni infection recruited from the Lake Albert region of Uganda, we assessed exposure to water, sanitation and hygiene conditions and measured markers from each EED domain: intestinal inflammation (faecal calprotectin), epithelial damage (serum intestinal fatty-acid binding-protein), increased permeability (urine lactulose to mannitol ratio and faecal alpha-1 antitrypsin) and microbial translocation (serum endotoxin core antibody).

Results: In multivariable linear regression models, we found that children whose drinking water was sourced from Lake Albert had higher concentrations of intestinal fatty-acid binding-protein (β = 0.48, 95% CI 0.20-0.76, p < 0.001), and lack of toilet/latrine access was associated with higher concentrations of calprotectin (β = 0.48, 95% CI 0.18-0.78, p < 0.01). Higher schistosomiasis intensity (eggs per gram of stool) was associated with higher calprotectin (β = 0.10, 95% CI 0.02-0.17, p = 0.01), but not with other EED markers.

Conclusions: Few studies have investigated schistosomiasis-related morbidities in very young children infected with schistosomiasis. Our findings from Uganda show that poor water, sanitation and hygiene conditions and heavier schistosomiasis burden are associated with intestinal inflammation and damage, contributing to EED. Improved treatment coverage for preschool-aged children infected with schistosomiasis may reduce the burden from EED and associated long-term morbidities.