Study on Vibrio cholerae infection in a small community in Calcutta. Joint ICMR-GWB-WHO Cholera Study Group, Calcutta, India.

The presence of a high level of latent infection in an affected community was postulated as one of the conclusions of earlier studies undertaken during cholera epidemics. A small community, consisting of 59 persons, was investigated for 100 days to determine the prevalence and persistence of infection after the occurrence of 2 index cases of cholera. In the community 39 excretors (66.1%) were detected, the 2 index cases and 37 carriers. Excretion of Vibrio cholerae was detected as much as 100 days after the occurrence of the index cases. No subsequent case of clinical cholera occurred in the community. These observations show that incidence of infection can be very high and that infection can last for a long period after an index case even in the absence of overt disease.