Gastroenteritis illnesses among customers of a Seattle seafood restaurant who ate raw oysters there in June have caught the attention of public health officials, who posted a public notice Wednesday.

One person has tested positive for vibriosis infection caused by the Vibrio parahaemolyticus bacteria and two others have symptoms consistent with vibriosis, according to the notice from the Seattle-King County Public Health Department.

All three ate raw oysters at the Salted Sea restaurant on Rainier Avenue South in Seattle, two on June 9 and the third on June 17, before becoming ill. The health department has been investigating the situation since June 22.

“An on-site investigation was conducted at Salted Sea by environmental health inspectors. No factors were identified that contribute to the spread of Vibrio, such as insufficient refrigeration temperatures or evidence of cross-contamination,” according to the notice posted by the health department.

“Without further information from the ill persons on the variety of oysters consumed, we were unable to pinpoint the particular growing area the oysters came from and no closures or recalls were issued.”

As of mid-day Wednesday, the Salted Sea was open for business. The restaurant manager was not immediately available for comment. The Salted Sea opened in the spring of 2015, according to the restaurant’s website.

The Seattle-King County health officials notified the Washington State Department of Health about the illnesses. The state is responsible for tracking such reports and the harvest locations of implicated oysters.

Although the specific variety of oysters consumed by the sick people is not yet known, the city-county health department reported the oysters served in the victims’ meals were harvested in multiple growing areas and bays in Washington.

Anyone who has eaten raw seafood at the restaurant recently and developed symptoms of vibriosis should seek medical attention and tell their doctors of the possible exposure to the bacteria so the proper diagnostic tests can be performed.

Symptoms include watery diarrhea, bloody diarrhea, abdominal cramping, nausea, vomiting, headache and fever. People are usually sick for one to seven days, according to the U.S. Centers for Disease Control and Prevention. People usually become sick within 24 hours of eating contaminated seafood.

Annually, vibriosis causes an estimated 80,000 illnesses and 100 deaths in the United States, CDC reports. Most cases occur between May and October when coastal water temperatures are warmest. Several varieties of Vibrio bacteria can cause illnesses in humans. The bacteria are naturally occurring in marine waters.

Seattle-King County reports between 20 and 90 confirmed cases of vibriosis have been reported annually for the past 10 years. The five-year average is 30 cases per year, but higher numbers in recent years spurred action by health officials.

“One major preventative measure taken this year toward improved shellfish safety was the implementation of an updated Washington State Vibrio parahaemolyticus (Vp) Control Plan,” according to the Wednesday notice.

“Led by the Washington State Office of Shellfish and Water Protection, this proposal revised the existing WAC to place more preemptive controls on shellfish harvesting during periods of warm water temperatures.”

In 2015 there were 32 laboratory-confirmed cases of vibriosis in the state, with 34 cases and 46 cases confirmed in 2014 and 2013, respectively.

Advice to consumers
To prevent infection by Vibrio bacteria, the Seattle-King County Public Health Department offered these tips:

• Always cook shellfish and other seafood thoroughly before eating;
• Wash cutting boards and counters used for shellfish preparation immediately after use to avoid cross contaminating other foods;
• Wash hands thoroughly with soap after handling raw shellfish;
• Stay out of brackish or salt water if you have any wounds — including minor scrapes and cuts — or cover wounds with waterproof bandages to prevent a skin infection; and

• Wash wounds and cuts with soap and water if they have been exposed to seawater, raw seafood or raw seafood juices, to prevent skin infections from Vibrio bacteria.

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