Three people in Whatcom County have become sickened by saltwater bacteria after eating undercooked or raw crab and oysters - part of a statewide surge totaling 44 probable or confirmed cases of the intestinal illness.
The number of cases of people sickened by vibrio bacteria is about twice what it was for this time last year; about 40 to 80 cases are reported annually.
"We seem to be in an active season," said Rick Porso of the state Department of Health's Office of Shellfish and Water Protection.
Most cases occur during summer.
The worst outbreak in recent years was in 2006, when Washington had 80 lab-confirmed vibrio cases, with 36 of them in King County, according to the King County Health Department.
Of the 44 confirmed or probable cases so far this year, King County has 21.
To avoid being sickened, health officials recommend cooking all shellfish during the summer to kill the bacteria.
"It is completely preventable with cooking, so that's what we urge people to do this time of year," Porso said.
Vibrio parahaemolyticus, the bacterium that causes the illness, occurs naturally in marine coastal waters.
In low numbers, vibrio doesn't sicken people. But when water temperatures rise, the bacteria multiply rapidly - raising the risk of vibriosis illness among people who eat raw or undercooked shellfish, particularly oysters.
Public health officials believe the warm summer and daytime low tides contributed to the recent illnesses, and expect more to occur in the coming weeks because current conditions are likely to continue.
Vibriosis causes flu-like symptoms that can include diarrhea, nausea and vomiting. Symptoms usually appear 12 to 24 hours after eating infected shellfish.
The illness is usually mild to moderate and lasts two to five days, but it can be life-threatening to people with weak immune systems or chronic liver disease. People who take antacids also can become very sick.
The three cases reported in Whatcom County were from recreational harvesters who fell ill after eating oysters and crab.
Here's what people should do to kill the bacteria and avoid becoming sick:
- Cook shellfish to an internal temperature of 145 degrees for at least 15 seconds.
- Recreational harvesters should take extra precautions when gathering oysters during the summer, including putting them on ice or refrigerating them as soon as possible after collecting them.
- Harvest as soon as the tide recedes, avoiding oysters that may have been exposed for unknown periods of time.
- Don't rinse cooked oysters with seawater.
- Before gathering shellfish, recreational harvesters should check safety information by calling the toll-free hotline at 1-800-562-5632.
The Department of Health has been sending notices to shellfish growers recommending extra precautions during low mid-day tides and warm weather.
Officials close a growing area when vibrio levels are high or when four or more people who eat shellfish from there are sickened within 30 days. As a result, Hammersley Inlet and several parts of Hood Canal, including Dabob Bay and Quilcene Bay, are closed because of high vibrio levels, while Oakland Bay and Totten Inlet growing areas are closed because of recent illnesses.
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