Norovirus outbreak connected to Yaquina Bay oysters Health officials investigating amid recall by company

State and local public health officials are investigating an outbreak of norovirus that sickened 17 people who ate oysters from Yaquina Bay earlier this month.

All 17 people, who were among three separate groups totaling 32 people who ate at restaurants throughout Lincoln County, have recovered. One person had been hospitalized. Those who fell ill reported having eaten the oysters between Feb. 12 and Feb. 14.

The Oregon Health Authority Public Health Division, Lincoln County Health & Human Services and the Oregon Department of Agriculture, teamed up on the investigation.

Oregon Oyster Farms Inc., of Newport says it sold the oysters to restaurants and retail stores in Oregon, to wholesalers in New York and Massachusetts, and at its on-site store. The company has issued a voluntary recall of raw, ready-to-eat shucked oysters sold in half-gallons, one-pint plastic tubs and 10-ounce plastic jars, with sell-by dates of Feb. 19 through March 8. It also is recalling product sold in mesh bags containing five dozen in-shell oysters with harvest dates of Feb. 5 through Feb. 15.

Consumers who have purchased those products from Oregon Oyster Farms Inc., are urged to discard them or return them to the place of purchase for a full refund. Consumers with questions may contact the company at 541-265-5078.

Public health officials are working with the Oregon Department of Agriculture to determine the exact source of the contamination, including investigating whether the contamination was more likely to have occurred in the oyster beds or at some point after harvesting, said Emilio DeBess, DVM, state public health veterinarian with the Public Health Division’s Acute and Communicable Disease Prevention Section.

One unopened jug of oysters collected from a restaurant tested positive for the same strain of norovirus found in stool samples from three ill persons.

DeBess said that although consuming raw oysters is popular, there is a risk involved. “You’re really taking your chances when you don’t cook oysters before you eat them.

“There’s risk of not only contracting norovirus, but also more serious infections such as Vibrio, which causes vibriosis,” DeBess said. “Our recommendation is that people avoid eating oysters or any shellfish unless they’re cooked thoroughly, especially individuals who are immune compromised, elderly, or children.”

Norovirus is the most common cause of outbreaks of foodborne disease in Oregon and the United States. In 24-48 hours after exposure, infected persons typically develop vomiting and diarrhea that last a day or two. Norovirus is present in the feces of infected persons for a couple of days after symptoms resolve. For this reason, public health officials recommend that during an outbreak, affected persons remain home from school or work for 48 hours after symptoms resolve.

Norovirus is highly contagious, and infected persons have enormous numbers of the virus in their feces. It is spread readily from person to person, and alcohol hand gels do not kill the disease, so hand-washing with soap and water is extremely important.

The Food and Drug Administration has the following tips for avoiding infection from raw or undercooked foods:

• High-risk populations including children, the elderly and persons with weakened immunity should avoid eating undercooked food such as shellfish and particularly raw oysters;
• Be a discerning consumer in choosing cold dishes, including sashimi, sushi and raw oysters, at a buffet;
• Ensure food is thoroughly cooked before eating during a hot pot or barbecue meal;
• Handle raw and cooked foods carefully and separate them completely during the cooking process;
• Do not try to use salt, vinegar, wine and wasabi to kill bacteria, because they are not effective; and
• Always wash hands before eating and after going to the toilet.

For more information:

• FDA “Raw Oyster Myths”: http://www.fda.gov/food/foodborneillnesscontaminants/buystoreservesafefood/ucm085385.htm
• FDA “Fresh and Frozen Seafood: Selecting and Serving It Safely”: http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm077331.htm
• CDC Norovirus website: http://www.cdc.gov/norovirus/
• OHA “Risks of Eating Contaminated Raw Oysters”: http://public.health.oregon.gov/DiseasesConditions/DiseasesAZ/Documents/factsheet-vibrio-raw-oysters.pdf
• OHA “Safe Eating of Shellfish”: http://public.health.oregon.gov/HealthyEnvironments/Recreation/Documents/Shellfish-safety.pdf
• OHA Calicivirus (Norovirus) page; includes data: http://public.health.oregon.gov/DiseasesConditions/DiseasesAZ/Pages/disease.aspx?did=110