Abstract:
Background Most studies of the causes of diarrhoea in low-income and middle-income countries have looked at
severe disease in people presenting for care, and there are few estimates of pathogen-specifi c diarrhoea burdens in
the community.
Methods We undertook a birth cohort study with not only intensive community surveillance for diarrhoea but also
routine collection of non-diarrhoeal stools from eight sites in South America, Africa, and Asia. We enrolled children
within 17 days of birth, and diarrhoeal episodes (defi ned as maternal report of three or more loose stools in 24 h, or
one loose stool with visible blood) were identifi ed through twice-weekly home visits by fi eldworkers over a follow-up
period of 24 months. Non-diarrhoeal stool specimens were also collected for surveillance for months 1–12, 15, 18, 21,
and 24. Stools were analysed for a broad range of enteropathogens using culture, enzyme immunoassay, and PCR.
We used the adjusted attributable fraction (AF) to estimate pathogen-specifi c burdens of diarrhoea.
Findings Between November 26, 2009, and February 25, 2014, we tested 7318 diarrhoeal and 24 310 non-diarrhoeal
stools collected from 2145 children aged 0–24 months. Pathogen detection was common in non-diarrhoeal stools but
was higher with diarrhoea. Norovirus GII (AF 5·2%, 95% CI 3·0–7·1), rotavirus (4·8%, 4·5–5·0), Campylobacter spp
(3·5%, 0·4–6·3), astrovirus (2·7%, 2·2–3·1), and Cryptosporidium spp (2·0%, 1·3–2·6) exhibited the highest
attributable burdens of diarrhoea in the fi rst year of life. The major pathogens associated with diarrhoea in the second
year of life were Campylobacter spp (7·9%, 3·1–12·1), norovirus GII (5·4%, 2·1–7·8), rotavirus (4·9%, 4·4–5·2),
astrovirus (4·2%, 3·5–4·7), and Shigella spp (4·0%, 3·6–4·3). Rotavirus had the highest AF for sites without rotavirus
vaccination and the fi fth highest AF for sites with the vaccination. There was substantial variation in pathogens
according to geography, diarrhoea severity, and season. Bloody diarrhoea was primarily associated with
Campylobacter spp and Shigella spp, fever and vomiting with rotavirus, and vomiting with norovirus GII.
Interpretation There was substantial heterogeneity in pathogen-specifi c burdens of diarrhoea, with important
determinants including age, geography, season, rotavirus vaccine usage, and symptoms. These fi ndings suggest that
although single-pathogen strategies have an important role in the reduction of the burden of severe diarrhoeal
disease, the eff ect of such interventions on total diarrhoeal incidence at the community level might be limited.
