Clams added to Pacific Northwest shellfish warning

WASHINGTON (Reuters) - U.S. health officials added a warning about clams on Friday to their caution against eating raw oysters from the Pacific Northwest following more reports of stomach sickness caused by bacteria from the shellfish.

Seventy-two illnesses linked to contaminated oysters and clams were reported from May 20 through July 31, the Food and Drug Administration said. Another 105 probable cases were recorded during the same time period.

The illnesses were reported in Washington state, Oregon and New York, FDA officials said.

Either shellfish should be thoroughly cooked before eating, FDA officials advised.

Cooking can kill the Vibrio parahaemolyticus (Vp) bacterium linked to the sickness. Vp can cause mild stomach illness in healthy people and serious illness in the elderly or others with weak immune systems.

Symptoms, including diarrhea, abdominal cramps, nausea, vomiting, fever and chills, usually start within 24 hours and last no more than three days.

People who have those symptoms after eating clams or oysters should contact a doctor and their local health department, the FDA said.

Vp occurs naturally in oysters and clams, but levels rise when water temperatures are warmer, officials said.

The FDA advisory follows a July 31 warning against eating raw oysters from the Pacific Northwest.