State and county health officials are advising seafood lovers to cook their oysters this summer.
More than 40 people in the state have been sickened this year with vibriosis, including one from Thurston County who ate an oyster thought to have been harvested from the Brinnon area.
Several parts of the Hood Canal are closed to commercial oyster harvesting, affecting 19 Jefferson County businesses, because of the vibriosis bacteria.
No cases have been reported on the North Olympic Peninsula.
As of this week, several parts of the Hood Canal, including Dabob and Quilcene bays in East Jefferson County, and Hammersley Inlet near Shelton are closed to commercial harvesting because of high vibrio levels, the state Health Department announced.
Commercial operations can resume once the vibrio levels go down.
“It’s not a big economic impact on them,” said Dr. Tom Locke, public health officer for Jefferson and Clallam counties.
The Vibrio parahaemolyticus bacteria can grow quickly when warm weather coincides with midday low tides.
The state Health Department recommends cooking all shellfish in the summer months to kill the bacteria.
“We’ve had a warm summer, which increases the risk that eating raw oysters might make people sick,” said Jerrod Davis, director of the Office of Shellfish and Water Protection.
“It’s much safer to eat cooked oysters, especially this time of year.”
Vibriosis can cause watery diarrhea, often accompanied by nausea, stomach cramps, headache, vomiting, fever and chills.
Symptoms generally appear within 12 to 24 hours of consuming raw shellfish and typically last for two to five days.
It can be life-threatening for those with weak immune symptoms or chronic liver disease.
Locke said the Hood Canal is particularly susceptible to vibriosis because of its relatively warm temperatures.
Commercial oyster harvesting is a multimillion-dollar industry along Hood Canal.
“The state has a rigorous testing program to ensure that commercially harvested oysters are safe to eat,” Locke said.
Although commercial harvesters use special control measures in the summer to keep people who eat raw oysters from getting sick, the state Department of Health closes commercial growing areas when vibrio levels become high or when there are four confirmed vibriosis illnesses within a 30-day period.
Rick Porso, manager of the Office of Shellfish and Water Protection, said Quilcene Bay was closed July 19, and Dabob Bay was closed Monday.
The closures affect 19 Jefferson County companies.
“The companies may or may not be operating at this time of year because they know that during this time of year, vibrio seems to be flaring up,” Porso said.
“If they have a high level of bacteria, we require two good samples at least seven days apart.”
Dabob Bay also was closed last August because of the vibrio bacteria, affecting 14 commercial shellfish companies.
“This is sort of that time of year that we see vibriosis,” Locke said.
“The safest thing to do is cook the oysters.”
Elsewhere, commercial operations at Oakland Bay and Totten Inlet in south Puget Sound were closed this summer because they had four confirmed vibriosis illnesses.
“I definitely recommend against people harvesting oysters in the wild at this time of year,” Locke said.
Recreational shellfish harvesting was closed on most North Olympic Peninsula beaches earlier this summer because of elevated levels of marine biotoxins that cause paralytic shellfish poisoning, or PSP, or diarrhetic shellfish poisoning, or DSP.
Unlike vibrio, marine biotoxins are not destroyed by cooking.
For information on recreational shellfish closures, phone 800-562-5632 or visit www.doh.wa.gov.
