The risk of Vibrio illness in the Florida raw oyster eating population, 1981-1988

In the period 1981-1988, 333 cases of bacteriologically confirmed Vibrio illness were reported in Florida adult residents. A total of 197 patients (59.2%) had consumed raw oysters the week prior to becoming ill, and among those 197, 38 (19.3%) had a liver disease, 13 (6.6%) had past gastric surgery, and 15 (7.6%) were diabetic. To calculate a population-based incidence rate, the authors obtained prevalence estimates of annual raw oyster consumption, liver disease, previous gastric surgery, and diabetes through a random telephone survey of Florida adult residents and applied them to the January 1985 Florida population. The estimated age-standardized annual incidence of Vibrio illness per million was 95.4 for raw oyster eaters with liver disease, 9.2 for raw oyster eaters without liver disease, and 2.2 for non-raw oyster eaters. Those with prior gastric surgery had a moderately increased risk of Vibrio illness. The annual incidence for Vibrio septicemia was 82.8 for raw oyster eaters with liver disease, 2.0 for raw oyster eaters without liver disease, and 0.4 for non-raw oyster eaters. While estimates on which these data are based are subject to a number of potential biases, this is the first study to provide estimates of the risk of Vibrio illness in raw oyster eaters, and it supports the recommendation that raw oyster consumption should be avoided by persons with liver disease.