An outbreak of vibriosis – a bacterial infection that primarily affects the digestive tract – has sickened 25 people who ate raw oysters in the Seattle area last month.
Vibriosis causes watery diarrhea, fever, headache, severe abdominal cramping, and vomiting, and can be a very serious condition for those who have compromised immune systems. Symptoms generally last for around a week and, in most cases, medical treatment is not required.
“The Vibrio bacterium is naturally found in salty, brackish waters where oysters are grown,” the Washington State Public Health Department said.
The illness is most common in the summer months because the bacteria multiplies in oysters as the water where they live in warms up.
“It’s important to keep shellfish as cold as possible to minimize the bacteria increasing in number,” said Jeremy Lloyd, an epidemiologist who works for the Public Health Department.
Seattle experiences an average of 30 cases yearly, according to the Public Health Department of Seattle-King County, and the majority of them occur during the hotter summer months. The Public Health Department also stressed that it was not the restaurants’ handling of the oysters that made the diners ill, but rather the shellfish themselves, and that cooking the shellfish reduces the risk of food-borne illnesses many times over. The department also recommends washing your hands after eating or handling any type of raw shellfish.
The oysters that contained the bacteria were sold by seven separate restaurants and grocery stores in the greater Seattle area, including Salted Sea, Elliott’s Oyster House and Chinook’s Oyster House.
The origin of the oysters that contained the vibriosis bacteria has not been released by authorities, although generally the illness is more prevalent warm-water oyster beds such as those in the Chesapeake Bay and in the Gulf of Mexico.