A common source foodborne outbreak of cholera in Singapore

An epidemiological investigation of an outbreak of Vibrio cholerae 01, biotype El Tor, serotype Ogawa, phage type 1, confined to a group of foreign construction workers in Singapore is described. A total of 22 workers were confirmed to have cholera and another 15 had asymptomatic Vibrio cholerae 01 infection between 3 November and 11 November 1982. The source of infection was traced to contaminated seafood prepared at the construction site canteen where two food handlers were found to be infected with V. cholerae 01 (one symptomatic and the other asymptomatic). The incubation period of cholera in this outbreak ranged from 4 to 203 hours with a median of 38 hours. Only two workers had moderate to severe dehydration and required intravenous therapy. Early recognition of the outbreak and prompt implementation of control measures prevented the outbreak from spreading to other parts of Singapore.