An Ogawa cholera outbreak 6 months after the Inaba cholera outbreaks in India, 2006.

Background/purpose: Cholera has been reported in the state of Orissa, India during the last decades. An explosive outbreak of diarrhea occurred in Central Cuttack Ward 22 of Orissa (population approximately 10,621), between March 12-23, 2006. This outbreak was investigated by a team from the Regional Medical Research Centre of Bhubaneswar to identify the causative agents and to determine the antimicrobial susceptibility pattern and associated virulent genes.

Methods: Clinical and epidemiological data were collected from 100 hospitalized patients with diarrhea from the Sriram Chandra Bhanja Medical College, Cuttack, Orissa. Rectal swabs and water samples were collected and tested for diarrheagenic enteropathogens. Isolated Vibrio cholerae were subjected to antibiotic susceptibility tests and polymerase chain reaction analysis for the detection of virulent genes.

Results: Of the 23 rectal swabs collected, 19 (82.6%) were positive for V. cholerae serogroup O1, serotype Ogawa. All strains were uniformly susceptible to ampicillin, gentamicin, chloramphenicol, ciprofloxacin, norfloxacin, neomycin, and tetracycline, but resistant to co-trimoxazole, furazolidone, nalidixic acid, and streptomycin. Polymerase chain reaction revealed that all strains had ctxA, tcpA (biotype El Tor), zot, and ace genes, suggesting their possible role in the outbreak.

Conclusion: This is the first localized outbreak of V. cholerae O1, serotype Ogawa, in the state of Orissa in 2006 after a gap of 6 months dominated by Inaba strains.