Clinical and immunologic characteristics of Vibrio cholerae O139 Bengal infection in North American volunteers.

Vibrio cholerae O139 Bengal has recently emerged as a cause of epidemic cholera in Asia. To evaluate clinical and immunologic responses to infection, V. cholerae O139 Bengal AI1837 was administered to healthy adult North American volunteers. Two of 4 persons ingesting 10(4) cfu became ill (incubation period, 48 h; mean diarrheal stool, 1873 g), as did 7 of 9 persons receiving 10(6) cfu (incubation period, 28 h; mean diarrheal stool, 4548 g). Ill volunteers did not demonstrate a vibriocidal antibody response to the challenge strain or other V. cholerae. Three months later, volunteers were rechallenged with the homologous O139 Bengal strain. Only 1 of 6 persons who had been ill on initial challenge had diarrhea, compared with 11 of 13 controls (P = .01; protective efficacy = 80%). V. cholerae O139 Bengal can cause severe diarrhea typical of cholera, with clinical characteristics and a dose-response similar to those seen with V. cholerae O1 El Tor. A moderately high level of protection against subsequent disease is provided by initial clinical infection.