A COMMUNITY STUDY OF INAPPARENT CHOLERA INFECTIONS

A village with a population of 1,609 in the endemic cholera area of rural East Pakistan was studied for 10 weeks during the 1966-1967 cholera season to estimate the relative frequency of inapparent and mild cholera infections. Paired serum specimens were obtained from all available village residents before and after the usual cholera season. Active diarrhea surveillance between serologic collections disclosed 5 mild diarrheal illnesses associated with the isolation of Vibrio cholerae. None of these patients was ill enough to require specific treatment or hospitalization. There was evidence from the vibriocidal antibody titrations of 948 serum pairs for at least an additional 22 inapparent infections with V. cholerae. The overall V. cholerae infection rate was estimated to be at least 27.4 per 1,000 for this community although there was not a single clinically recognizable case of cholera. It is suggested that cholera has a high infection to case ratio and that there are many mild and inapparent infections for every clinically-recognizable case. © 1969 by The Johns Hopkins University.