The species Vibrio cholerae at present contains 60 known serovars, or serogroups, among which V. cholerae 0–1 is the etiologic agent of cholera.1 The so-called NAG (nonagglutinable) vibrios or NCV (noncholera vibrios) have also been included in the species V. cholerae by decision of the International Subcommittee on the Taxonomy of Vibrios in 1971 and are now distinguished only by serovar number.2 While V. cholerae other than serovar 0–1 can sometimes cause cholera-like diarrhea, they do not possess the same epidemic propensity as the true V. cholerae; the two clinical entities will therefore be described separately.