Research Article: A Longitudinal Study of Household Water, Sanitation, and Hygiene Characteristics and Environmental Enteropathy Markers in Children Less than 24 Months in Iquitos, Peru

Date Published: April 12, 2018

Publisher: The American Society of Tropical Medicine and Hygiene

Author(s): Natalie G. Exum, Gwenyth O. Lee, Maribel Paredes Olórtegui, Pablo Peñataro Yori, Mery Siguas Salas, Dixner Rengifo Trigoso, Josh M. Colston, Kellogg J. Schwab, Benjamin J. J. McCormick, Margaret N. Kosek.


Poor child gut health, resulting from a lack of access to an improved toilet or clean water, has been proposed as a biological mechanism underlying child stunting and oral vaccine failure. Characteristics related to household sanitation, water use, and hygiene were measured among a birth cohort of 270 children from peri-urban Iquitos Peru. These children had monthly stool samples and urine samples at four time points and serum samples at (2–4) time points analyzed for biomarkers related to intestinal inflammation and permeability. We found that less storage of fecal matter near the household along with a reliable water connection were associated with reduced inflammation, most prominently the fecal biomarker myeloperoxidase (MPO) (no sanitation facility compared with those with an onsite toilet had −0.43 log MPO, 95% confidence interval [CI]: −0.74, −0.13; and households with an intermittent connection versus those with a continuous supply had +0.36 log MPO, 95% CI: 0.08, 0.63). These results provide preliminary evidence for the hypothesis that children less than 24 months of age living in unsanitary conditions will have elevated gut inflammation.

Partial Text

Environments with high fecal contamination put children at risk for chronic exposure to enteric pathogens, especially in the developing world where an estimated 4.5 billion people lack access to safely managed sanitation.1 Frequent episodes of acute gastroenteritis and subclinical enteropathogen infections may lead to persistent inflammation and structural changes in the small bowel, a condition known as environmental enteropathy (EE).2 The development of EE during the critical growth period of < 2 years of age may lead to irreversible linear growth deficits, oral vaccine failure, and a loss of human capital from reduced cognitive achievement.3–5 A total of 303 children were enrolled from the catchment area and 270 children remained in the study for the 6-month baseline survey with WASH household characteristics. Between each 6-month sampling period, until the children were 24 months of age, the lost to follow up ranged between 7.0% and 11.6% (Table 1). After merging the water storage variables, a total of 258 children in the cohort were included for the analysis. Table 1 describes the WASH variables from each 6-month survey. The WASH variables that were the most time-varying in the population with at least one change reported by a household over the 24-month study included the following: 1) type of sanitation facility used by the household (63.9% of population); 2) household hygiene score (60.5% of the population); and 3) drinking water source option used by the household (55.5% of the population). We present an in-depth analysis of WASH conditions in a prospective longitudinal study to show associations between water reliability and toilet type with EE biomarkers in a birth cohort for the first 24 months of life. After adjusting for potentially confounding covariates, the hypothesized water pathway showed higher EE for less protected drinking water sources (+0.32 log MPO and +0.28 log NEO for water piped to a yard or plot, and +0.20 log NEO for water from a tube well compared with a household piped water connection), lower EE as the water quantity stored per capita increased (−0.33 log MPO for third quartile, −0.26 log MPO for fourth quartile, −0.21 log NEO for second quartile, and −0.26 log NEO compared with the first quartile of amount of water stored), and higher EE for households that had a water supply that experienced interruptions (+0.36 log MPO). The hypothesized sanitation pathway also showed lower EE for households that did not have access to a toilet facility, and therefore, defecated in places thought to be a greater distance from their household living environments (−0.43 log MPO). Higher KT ratios were also found for households with unimproved pit latrines when compared with homes with improved flush toilets.   Source:


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