Raw Oysters Linked To Uptick In King County Norovirus Reports

SEATTLE — King County health officials are asking residents to be cautious about eating raw oysters at restaurants after receiving more than a dozen reports of norovirus illnesses linked to them just this month. While Norovirus is typically not serious, it is highly contagious, and Public Health - Seattle & King County said another 14 people became ill after contact with the 13 people infected by the contaminated oysters.

"Norovirus is a very common, highly contagious virus that causes diarrhea, vomiting, nausea, stomach pain and can also cause body aches, fever, and headache," said Elysia Gonzales, a medical epidemiologist at Public Health. "Norovirus spreads very easily when you have close contact with an infected person, such as sharing utensils or taking care of someone who is sick with norovirus, touching surfaces and objects that have been contaminated with norovirus, or, as in the case of this oyster related outbreak, eating foods that have been contaminated with the virus."

Public health officials said some of the oysters connected to the outbreak likely came from a batch harvested in British Columbia, which have now been recalled. The origin of the other oysters is not confirmed, and Gonzales cautioned that eating any uncooked oysters carries an elevated risk.

"Oysters have long been recognized as a source of norovirus," Gonzales said. "Raw or undercooked oysters are a particular problem. Protect your risk by choosing fully cooked oysters that have been thoroughly fried, baked, or made into a stew that has reached 145°F."

Oysters and other shellfish often are contaminated with the virus before harvesting but can also become contaminated later from improper handling, officials said. Inspectors visit restaurants after each outbreak to determine if other risk factors may have contributed to the spread, including workers who are sick, insufficient handwashing practices and other safety lapses.

Learn more on the Public Health Insider blog.