Convalescent Carriers of Vibrio cholerae

Eighty-one convalescent cholera patients were examined by magnesium sulfate purging and duodenal intubation to detect prolonged Vibrio cholerae infection. Three carriers were identified. The carrier state lasted 50 to 331 days. Carriers were more frequently persons over age 50 and persons not receiving effective antibacterial treatment. Cholera vibrios were frequently isolated from duodenal fluid of carriers and consistently increased in numbers after gall bladder evacuation, indicating vibrios were harbored in the gall bladder. After early convalescence stool from carriers rarely yielded cholera vibrios, but purged stool induced by magnesium sulfate was frequently positive. Rough forms of V. cholerae became the predominate type isolated from carriers after 15 to 29 days of convalescence. In carriers the titers of agglutinating, vibriocidal, and exotoxin neutralizing antibodies rose and fell in a pattern similar to convalescent, non-carrier patients. Convalescent carriers may be an interepidemic reservoir of V. cholerae.