Beware of eating raw oysters that were harvested in ‘growing area 6’, the southern tip of Hood Canal, Washington state, warns the FDA, as they may be tainted with Vibrio parahaemolyticus bacteria. So far there have been six reports of humans becoming ill after consuming them.

Authorities say that the area in Washington state linked to the contaminated oysters has been closed. Distributors and harvesters in that area have been instructed to recall any oysters collected.

Investigators say these oysters have been transported to California, Florida, Hawaii, Idaho, New York, Oregon, Washington, British Columbia, Hong Kong, Malaysia, and Singapore.

What is Vibrio parahaemolyticus?

It is a bacterium which belongs to the same family as the one that causes cholera. The bacterium exists in brackish saltwater and inhabits the coast of the USA and Canada, during the summer months it is present in much higher concentrations.

How does V. parahaemolyticus cause illness?

If you become infected you will most likely have watery diarrhea, accompanied with abdominal pain, nausea, vomiting, a high temperature and chills.

Symptoms generally appear within 24 hours of ingestion. Most infected people will start getting better after about three days.

In very rare cases, an open wound can become infected if exposed to warm seawater.

It is a rare disease and tends to hit people with weakened immune systems.

Why does the infection happen?

Most commonly, people become infected after eating raw or uncooked shellfish, particularly oysters.

Is V. parahaemolyticus infection common?

It is a common cause of foodborne illness in Asia. It is a less commonly recognized cause of illness in the USA, partly because labs seldom use the selective medium that is needed to identify the bacterium. Many US states do not require that V. parahaemolyticus infections be reported.

How is V. parahaemolyticus treated? In most cases treatment is not needed. It is believed that antibiotics will make no difference to reducing the severity or length of the illness. An infected patient should drink plenty of liquids.

If the illness is prolonged or severe, a doctor may prescribe an antibiotic such as tetracycline, ampicillin or ciprofloxicin.

More information about foodborne infections (FDA)
Seafood Network Information Center
FDA Warning

Written by: Christian Nordqvist