Vibrio bacteria naturally live in certain coastal waters and are present in higher concentration between May and October when water temperatures are warmer. About a dozen Vibrio species can cause an infection known as vibriosis. Vibriosis is typically characterized by watery diarrhea, usually with abdominal cramping, nausea, vomiting, and fever. It can also cause wound or soft tissue infections. In people with underlying medical conditions, especially liver disease, Vibrio bacteria can cause bloodstream infections characterized by fever, chills, dangerously low blood pressure, blistering skin lesions, and sometimes death. Treatment is not necessary in mild cases, but patients should drink plenty of liquids to replace fluids lost through diarrhea. Antibiotics can be lifesaving in severe illnesses. Most people with mild illness will recover within 3 days and suffer no long-term consequences. However, people who are seriously ill with V. vulnificus infection sometimes need intensive care or limb amputation.

Most people with vibriosis develop it after eating raw or undercooked shellfish, particularly oysters. Others develop it after a wound or soft tissue is exposed to salt water, brackish water, raw seafood, or juice or drippings from raw seafood. About 80% of infections occur from May through October when water temperatures are warmer.

Increased Vibriosis Activity in Washington

With the warmer weather, the Washington State Department of Health has seen a significant increase in lab-confirmed cases of Vibrio parahaemolyticus infections. The DOH Communicable Disease team provided a recent history of vibriosis cases reported in Washington year-to-date. While the chart includes ALL vibriosis cases (not only those caused by V. parahaemolyticus) and include foodborne, wound and ear infections, the vast majority are caused by Vp.

Vibriosis Reported by Month Through July 16th, 2016-2021

Month of Report


DOH issued a press release announcing an increase in vibriosis and reminding consumers about safer consumption of shellfish during this time of year. You can find the press release here.

You must report vibriosis cases within 24 hours.

To report, call the reporting line at (360) 728-2235 or fax the reportable disease fax form to (360) 813-1168.