Abstract
We describe the disease spectrum and socio-demographic and epidemiological features of an epidemic of cholera due to a new pathogen, Vibrio cholerae O139, in patients attending a very large hospital in the metropolitan city of Dhaka, Bangladesh. This hospital treats 70,000-90,000 patients a year with diarrhoeal diseases. A 4% systematic sample of 1854 patients attending from January to April 1993 were studied. Five hundred and two (27%) of the 1854 patients were culture positive for V. cholerae O139 and 63 (3%) were culture positive for V. cholerae O1 biotype El Tor. Patients with V. cholerae O139 were mainly adults with a short history of watery diarrhoea. Eight-three percent of patients had moderate to severe dehydration. All recovered except one 80-year-old man with compromised renal function who died. Seventy-eight percent of patients required initial intravenous rehydration followed by oral rehydration therapy with rice ORS; they also received tetracycline to reduce diarrhoea severity. Most patients were from urban slums with inadequate sanitation facilities and hygiene practices. The newly recognized V. cholerae O139 infection produced an epidemic of severe dehydrating diarrhoea indistinguishable from clinical cholera in a population which experiences two epidemic peaks of cholera in a year due to V. cholerae O1. Infection with the latter does not appear to confer any cross-protection from V. cholerae O139. The new pathogen suppressed, albeit temporarily, V. cholerae O1. Unlike other non-O1 serogroups of V. cholerae this new serogroup appears to have epidemic potential.