Implications for shellfish growers of climate change impacts on Vibrio bacteria

Illnesses resulting from various species of naturally occurring Vibrio bacteria are a major problem for shellfish growers throughout the United States and world. In the U.S. Vibrio vulnificus and Vibrio parahaemolyticus are the two species which result in the greatest number of illnesses and deaths. V. vulnificus largely effects people who are immunocompromised but with an extraordinarily high mortality rate. V. parahaemolyticus is ordinarily injurious often resulting in severe gastroenteritis. Both species and their associated illnesses are more prevalent during the warm summer months. Public health approaches to addressing illnesses attributed to these bacteria are developed through the Interstate Shellfish Sanitation Conference which is overseen by the USFDA. Controls for V. vulnificus which only effects a subset of the population have largely focused to-date on education of at-risk consumers. This has had limited success after a decade or more of intensive effort and is transitioning to harvest controls and post harvest processing. Controls for V. parahaemolyticus which potentially impacts all consumers has focused on harvest controls such as time post harvest to refrigeration and harvest methodology. A warming climate has implications for the months of the year post harvest controls and/or processing may be required by shellfish producers. It may also result in V. vulnificus becoming more of a problem for the east and west coasts where to date it has been largely an issue for the Gulf of Mexico.