Study on the transmission of E1 Tor cholera during an outbreak in Can-Itom community in the Philippines.

During surveillance for cholera in the community of Can-Itom (Negros Occidental, Philippines) in which the disease is endemic, a limited outbreak of cholera occurred. Although it was not possible to determine how the infection arose, the index case was detected and the spread of infection traced. The infection was found to be transmitted initially from person to person until the water of a dug well became contaminated, as a result of which a water-borne outbreak of a rather explosive nature occurred. Although 25 out of 288 individuals living in the community were infected with the El Tor biotype of Vibrio cholerae, there was no manifest case of cholera; 13 persons had mild diarrhoea and 12 were asymptomatic. The outbreak subsided without any control measures having been adopted.