Epidemiology of Cholera in Delhi—1992

Vibrio cholerae O1 biotype E1 Tor was first identified in India in 1965 after which cholera became endemic in the country. In early 1993 however V. cholerae Non O1 became a major cause of epidemic in Delhi and other parts of India. The authors describe the epidemiology of cholera in Delhi during 1992 when it was highly epidemic. 1075 of 2783 stool samples from patients admitted to the Infectious Diseases Hospital Delhi during 1992 were positive for V. cholerae O1 biotype E1 Tor. The first isolation was made on April 3 and the last on December 14 although 87% of isolations occurred during May-September summer and monsoon months. Detailed epidemiological information was collected for 198 cases of diarrhea of which 103 were confirmed cases of cholera. Half of these cases occurred in children younger than age 10 years. Adult females especially housewives comprised the other major group of individuals affected by cholera. Most cholera cases occurred in those who were illiterate or educated up to primary level. Important risk factors were contact with a person having similar illness storage of water in wide-mouthed containers use of glass or mug to draw water from containers absence of sanitary latrines and the habit of washing hands with water alone after defecation and before cooking and eating food. Approximately 30% of cases had access to a piped water supply which was found safe in Delhi during 1992. These findings suggest that hygienic practices were more important than contaminated water sources for the transmission of cholera in Delhi during 1992.