In November 2003, an outbreak (41 cases; attack rate–4.3%; no deaths) of severe diarrhoea was reported
from a village in Orissa, eastern India. Thirteen of these cases were hospitalized. A matched case-control
study was conducted to identify the possible exposure variables. Since all wells were heavily chlorinated
immediately after the outbreak, water samples were not tested. The cases were managed symptomatically.
Descriptive epidemiology suggested clustering of cases around one public well. Vibrio cholerae
El Tor O1,
serotype Ogawa was isolated from four of six rectal swabs. The water from the public well was associated
with the outbreak (matched odds ratio: 12; 95% confidence interval 1.2-44.1). On the basis of these conclusions,
access to the well was barred immediately, and it was protected. This investigation highlighted the
broader use of field epidemiology methods to implement public-health actions guided by epidemiologic
data to control a cholera epidemic.