Two sequential outbreaks in two villages illustrate the various modes of transmission of cholera

We investigated two sequential outbreaks of severe diarrhoea in two neighbouring villages of Orissa, in 2005. We conducted descriptive and matched case-control studies. The attack rates were 5.6% (n=62) and 5.2% (n=51), respectively, in the first and second villages. One death was reported in the second village (case fatality 2%). We identified that consumption of milk products prepared in the household of the index case [matched odds ratio (mOR) 5.7, 95% confidence interval (CI) 1.7-30] in the first village, and drinking well water in the second village were associated with the illness (mOR 4.7, 95% CI 1.6-19). We isolated Vibrio cholerae El Tor O1 Ogawa from stool samples from both the villages. Mishandling of milk products led to a cholera outbreak in the first village, which led to sewerage contamination of a well and another outbreak in the second village. Environmental contamination should be expected and prevented during cholera outbreaks.