Role of household animals in maintenance of cholera infection in a community

Abstract

A total of 1,287 specimens from 195 domestic animals (including poultry birds) in a community in Varanasi, a region not endemic for Vibrio cholerae, were investigated during the period from July 1972 to September 1973 for the presence of V. cholerae in a search for reservoirs of infection during an epidemic and an interepidemic period. Fifty-four strains of V. cholerae, of which eight were of serotype 1 and the remaining 46 of other serotypes (so-called NAG vibrios), were isolated from 2 J animals. The results indicated that nonhuman reservoirs exist for V. cholerae (of serotype 1 and of other serotypes) in household cows, goats, dogs, and chickens, and that these reservoirs in animals may serve as sources of infection in humans in the community. Serotype 1 was found only during the season when cholera was most prevalent, but other serotypes were isolated throughout the year. The evidence suggested the presence of a chronic carrier state in cows and in a chicken leading to intermittent excretion of vibrios. Reinfection with different serotypes was common. The data from this study also indicated that in the absence of detectable human carriers, animals might be instrumental in maintaining the infection in the community.