Vibrio infections associated with raw oyster consumption in Florida, 1981-1994

Abstract

While the problem of raw-oyster-associated Vibrio vulnificus infection is well known, less is known about other Vibrio infections associated with raw oyster consumption. Case reports of 333 patients with raw-oyster-associated infections with V. vulnificus and other Vibrio species reported in Florida from 1981 through 1994 were reviewed to define the epidemiology of these infections. The average annual incidence of raw-oyster-associated Vibrio infection was 10.1 per 1,000,000 raw oyster-consuming adults (95% confidence interval: 8.3 to 11.9). Infection resulted in gastroenteritis for 231 (69%) patients, of whom 97 (42%) were hospitalized for a mean length of stay of 4.9 days, and 2 (1%) died. Vibrio species most often identified in patients with gastroenteritis included V. parahaemolyticus (29%), V. cholerae non-O1 (28%), V. hollisae (15%), and V. mimicus (12%). The remaining 102 (31%) patients with raw-oyster-associated Vibrio infections developed primary septicemia and 50 (49%) died. Primary septicemia resulted from infection with V. vulnificus (80%), V. parahaemolyticus (9%), V. cholerae non-O1 (8%), and V. hollisae (3%). Non-V. vulnificus species accounted for 72% of all raw-oyster-associated Vibrio infections, and differed from infections with V. vulnificus in their lack of a seasonal distribution and the absence of underlying medical conditions in infected patients. These findings emphasize that Vibrio species other than V. vulnificus are more commonly associated with raw oyster consumption, are capable of producing significant morbidity, and may not be controlled by measures such as seasonal marketing restrictions and targeted education of 'high-risk' consumers that have been proposed to prevent infection with V. vulnificus.