Person-to-person transmission of cholera in a psychiatric hospital.

An outbreak of cholera caused by Vibrio cholerae O1, biotype el tor, serotype Ogawa, phage type 4, was reported in a psychiatric hospital in Singapore. A total of 74 inmates (18 symptomatic and 56 asymptomatic) were infected; two of them died. Extensive epidemiological investigations showed that the organism was not transmitted by contaminated food or water but through close person-to-person contact. Early recognition of the outbreak and prompt implementation of epidemic control measures comprising surveillance of diarrhoea, rectal swabbing of all asymptomatic inmates, isolation of those found to be infected, maintenance of a high standard of environmental sanitation and mass chemoprophylaxis with doxycycline, rapidly brought the outbreak under control.