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Rise in cases of Vibrio parahaemolyticus prompts warning

FOR IMMEDIATE RELEASE                                  Connecticut Department of Public Health

August 16, 2013                                                             Contact: Diana Lejardi

                                                                                      (860) 509-7270



Hartford – The Connecticut Department of Public Health (DPH) is warning residents of the dangers of eating raw or undercooked shellfish after an increase in cases of Vibrio parahaemolyticus infection.

Since June 2013, Connecticut has reported 19 confirmed cases of Vibrio parahaemolyticus infection, compared to an average of seven cases reported during the same time period in the past two years.

 "The unusual number of cases of Vibrio infection is cause for concern," said Dr. Matthew Cartter, State Epidemiologist for DPH. “It tells us that Vibrio bacteria are present in the area and people should use caution when eating or harvesting shellfish.”

People typically get infected with Vibrio from eating raw or undercooked shellfish, particularly oysters, that have Vibrio bacteria in them or from ingesting contaminated seawater. Those with pre-existing medical conditions or who take antacids regularly are at higher risk for illness from Vibrio infection. Cooking shellfish until the shells just open is not sufficient to kill Vibrio bacteria. To prevent Vibrio infections, shellfish need to be cooked to an internal temperature of 145°F for at least 15 seconds. Clams, mussels and oysters will open when cooked. The Food and Drug Administration suggests steaming oysters for 4 to 9 minutes or boiling them for 3 to 5 minutes after they open.

The symptoms of foodborne Vibrio parahaemolyticus infection include watery diarrhea, often with abdominal cramping, nausea, vomiting, and fever. Symptoms typically occur within 24 hours after consumption of contaminated shellfish and can last up to 7 days. Immune compromised people and those with certain medical conditions, including liver disease, are at greatest risk for foodborne disease. Vibrio bacteria can also cause a skin infection when open wounds are exposed to contaminated seawater.

Vibrio bacteria occur naturally in marine waters and grow more rapidly during the warm months. Vibrio levels in shellfish increase during the summer, and infections in humans normally peak in late summer. Once water temperatures begin to cool in October, the bacteria levels decline.