In a press release Friday, The Massachusetts Department of Public Health and the Massachusetts Department of Fish and Game, Division of Marine Fisheries announced the closure of oyster beds in Plymouth Harbor, Kingston Bay, Duxbury Bay, Bluefish River and Back River in the towns of Plymouth, Kingston, Duxbury and Marshfield following an outbreak of Vibrio parahaemolyticus tied to oysters harvested from the area.
Harvesting and possession of oysters from these areas for commercial purposes is strictly prohibited until further notice. DPH has also launched a recall of oysters collected from these areas since July 22, 2013. This is the first time a specific harvest area in Massachusetts has been implicated in a Vibrio outbreak.
DPH has linked three cases of Vibrio illness to oysters consumed from this area, including two cases where the oysters were consumed out of state. In all three cases, the people who consumed the oysters have recovered.
“We understand the impact this may have on many of our local businesses. We are committed to partnering with industry to ensure the public’s health and safety through a successful Vibrio control plan,” said Cheryl Bartlett, R.N., Massachusetts Commissioner of Public Health. “The most important step of this plan is to eliminate possible sources of exposure to prevent future food-borne illness.”
Since May 31, 2013, the DPH Bureau of Environmental Health Food Protection Program has received 50 reports of laboratory-confirmed Vibrio parahaemolyticus in Massachusetts residents, compared to 27 cases during the same time period last year. Nineteen of the 50 cases have been traced to out-of-state harvest areas, or multiple beds and/or mishandling at food retail establishments in Massachusetts.
The majority of the remaining cases have been linked to consumption of raw oysters harvested from Massachusetts growing areas.
When ingested, Vibrio causes watery diarrhea, often with abdominal cramping, nausea, vomiting, fever and chills. Usually these symptoms occur within 24 hours of ingestion and last three days. Severe disease is rare and occurs more commonly in people with weakened immune systems. About ten percent of cases will develop a blood infection that may require hospitalization. Vibrio can also cause an infection of the skin when an open wound is exposed to warm seawater.
Vibrio is an emerging, naturally occurring bacterial pathogen often found in oysters harvested from warmer waters. It has caused illnesses in the Gulf Coast and West Coast of the United States for a number of years. It is not related to pollution of Massachusetts shellfish.
In 2012, the FDA recommended that DPH and DMF – the two state agencies with joint authority over shellfish sanitation and control – implement a Vibrio control plan for shellfish harvest and growing areas in Eastern Cape Cod Bay.
Due to the increase in Vibrio cases in 2012 and continued reports of Vibrio among consumers reporting consumption of raw oysters in waters beyond Eastern Cape Cod Bay, the FDA advised Massachusetts to expand Vibrio controls to all oysters harvested in the Commonwealth in 2013. A statewide Vibrio Control Planhas been in effect since May 2013.
Under federal regulations, state shellfish authorities are required to take action when shellfish are linked to an outbreak of two or more people not from the same household. If a harvest area is responsible for the outbreak, Massachusetts is required to close the area.