Differences in total Vibrio spp., V. vulnificus, and V. parahaemolyticus abundance between clams and oysters in North Carolina

21 Filter feeding shellfish can concentrate pathogenic bacteria, including Vibrio vulnificus and 22 V. parahaemolyticus, as much as 1000 fold from the overlying water. These shellfish, especially 23 clams and oysters, are often consumed raw, providing a route of entry for a concentrated dose of 24 pathogenic bacteria into the human body. Food-borne infections from these microbes are on the 25 rise, and a better understanding of the conditions that might trigger elevated seafood 26 concentrations of these bacteria are needed. Relatedly, if the bacterial concentrations in water 27 are correlated to those in shellfish, this would simplify sampling regimes, as water samples are 28 more rapidly and easily obtained. After sampling oysters and clams, either simultaneously or 29 separately, for over two years, it was concluded that while Vibrio concentrations in oysters and 30 water are related, this is not the case with clams and water. When clams and oysters were 31 collected simultaneously from the same site, the clams were found to have fewer Vibrio than 32 oysters. Further, the environmental parameters that correlated with Vibrio spp. in oysters and 33 water were found to be quite different than those that correlated with Vibrio spp. in clams. 34