The Massachusetts Department of Health has ordered a precautionary closure of oyster beds in Edgartown in Katama Bay effective August 26, 2015. There are three confirmed cases of Vibrio food poisoning linked to consumption of raw oysters harvested in that area. Environmental conditions are conducive to the growth of the Vibrio parahaemolyticus bacteria there.
Harvesting and processing of shellfish from these areas for commercial use is prohibited for the next seven days. If more cases are confirmed, an extended FDA-enforced closure could be issued. This is the first time a harvest area in Massachusetts has been closed because of Vibrio contamination this year.
Vibrio bacteria grow in warmer waters, multiply as the temperature increases. The current water temperatures in Katama Bay are consistent with environmental conditions that were associated with Vibrio outbreaks in 2013 and 2014. The Vibrio season runs from May to October every year.
Any person at high risk for food poisoning should not eat any raw shellfish at any time. That includes the elderly, pregnant women, young children, and those who have compromised immune systems and chronic illnesses.
The symptoms of a Vibrio infection are watery diarrhea, abdominal cramps, nausea, vomiting, fever, and chills. The illness usually occurs with 24 hours of exposure to the pathogenic bacteria and usually lasts three days. About 10% of those stricken with this infection develop a blood infection and may require hospitalization.
The Massachusetts Department of Public Health expanded their Vibrio control system to all oyster harvest areas in 2013 after continued reports of the illness. Consumers reported consumption of raw oysters in waters beyond Eastern Cape Cod Bay at that time.
If you have eaten raw oysters and have experienced these symptoms, see your doctor. Treatment isn’t necessary in most cases, but in severe cases, antibiotics such as tetracycline or ciprofloxicin are used. The most important thing is to replace fluids lost to diarrhea by drinking plenty of water.
About 80,000 people contract Vibrio infections every year. And about 100 of those people die. There has been a 75% increase in the number of Vibrio infections since 2008 in the U.S.