Breast-feeding children in the household as a risk factor for cholera in rural Bangladesh: an hypothesis.

Vibrio cholerae 01 produces symptomatic and asymptomatic infections. In this study, we investigated a cholera epidemic in northern Bangladesh to specifically search for risks of developing symptomatic infection. A case-control study in six villages found that cases were more likely than controls to have in their family a child who was still breast-feeding and who had been asymptomatic during the epidemic. Among 24 case-control pairs with cholera-like diarrhea as cases, there were 11 discordant for the presence of such a child in the family, in 9 of them, the child was in the case-family (relative risk = 4.5, p = 0.033). Among 13 case-control pairs with laboratory-confirmed cholera as cases, there were 7 discordant for the presence of a breast-feeding child, and in 6 of them, the child was in the case-family (relative risk = 6, p = 0.06). Breast-feeding children in this area are usually kept naked, and defecate onto a cloth pad held against their buttocks by a family member who may be repeatedly exposed to the soiled cloth. Symptomatic infection with V. cholerae may depend on exposures to situations that augment the ingested dose of V. cholerae, and these findings led us to hypothesize that breast-feeding children, if infected, may play a substantial role (attributable risk = 55%) in facilitating such transmission in rural Bangladesh.