Three San Francisco men and one from Sonoma County, aged 29 to 60, have been stricken since May. They had eaten raw oysters at restaurants and from one retail store in Marin County. The oysters were contaminated with Vibrio parahaemolyticus , a naturally occurring marine bacteria. Symptoms of the bacterial infection include diarrhea, abdominal cramps, nausea, vomiting, headache, fever, and chills. They typically occur 12 to 24 hours after eating.
Problems are more common during warm spells when the bacteria count increases.
People with weakened immune systems, liver diseases, diabetes, hepatitis, or other chronic illnesses are particularly susceptible to becoming ill. Pregnant women also are advised to avoid raw seafood and meat. Brooks tells WebMD that at least three of the four men were in high-risk groups. Two suffered from alcoholism, which can weaken the liver, and a third had cirrhosis. One man had diabetes and previous gastric surgery.