The number of people sickened by a bacteria found in some shellfish has more than doubled in the past week.

A state Department of Agriculture official said 32 cases of the illness are either confirmed or under investigation.

Of those, 14 were linked to clams and oysters harvested from beds off Westport and Norwalk, which were shut down earlier this month due to concerns about the bacteria.

"It is an outbreak, at this point," said David Carey, director of the department's Bureau of Aquaculture.

The state shut down the beds last week and issued a voluntary recall of shellfish harvested there over the last month, due to high levels of the naturally occurring bacteria Vibrio parahaemolyticus. The bacteria, which rapidly multiply in higher temperatures -- such as the heat waves that hit the region in July -- can cause acute gastrointestinal illness.

There is a lag time between when the illness strikes and when it is confirmed so more cases are expected to be identified in the coming weeks.Last week, just five cases in the state were linked to the bacteria.

More Information

What is Vibrio?
Vibrio is a type of bacteria that occurs naturally in warm coastal areas, such as the Gulf of Mexico. It is found in higher concentrations in the summer months, when the water is warmer. The bacteria typically cause disease in people who eat seafood contaminated with it. There are two main types of Vibrio.
Vibrio parahaemolyticus is the source of Connecticut's outbreak and usually causes non-bloody diarrhea.
The second type, Vibrio vulnificus, is found along the Gulf Coast and is far more serious. It typically infects the bloodstream and can be life-threatening. About half of its infections are fatal.
Infection from Vibrio bacteria can be prevented by thoroughly cooking all seafood.

Of the 32 cases being looked into by the bureau -- which includes both Connecticut residents and reports from out of state -- 13 are still unconfirmed and five originated in harvest areas in other states.

Vibrio parahaemolyticus is generally found in uncooked fish, including crabs, shrimp and lobsters. It occurs in other kinds of fish as well, and some people have been known to become ill from it after eating sushi, said Dr. Rock Ferrigno, chairman of Bridgeport Hospital's emergency department.

There have been no illnesses from this outbreak treated at Bridgeport hospital, he said. Greenwich Hospital and Danbury Hospital also said they hadn't seen anyone with the infection.

Stamford Hospital, on the other hand, has seen at least four cases, and at least one person was hospitalized, said Dr. Michael Parry, director of infectious diseases at the hospital.

Typically, Parry said, Vibrio-related illness causes diarrhea and other lower intestinal problems, but doesn't usually cause vomiting.

"It's not usually life-threatening, but it can make you pretty sick," he said.

Ferrigno said Vibrio-related illness is most severe in young children, the elderly and those with compromised immune systems, such as people receiving cancer treatment. "The healthier you are, the less effect (the bacteria) will have," Ferrigno said.

It usually takes up to 24 hours to develop symptoms, and it's typically a few days before those afflicted see a doctor, said Kristin DeRosia-Banick, environmental analyst for the Agriculture Bureau. If Vibrio is suspected, a stool sample is tested. DeRosia-Banick said it can take several weeks to see if a stomach illness is related to Vibrio contamination. That's why the state is still in the process of determining the extent of this outbreak, Carey said.

The Fairfield County beds remain closed indefinitely, but DeRosia-Banick said they could be reopened within the next few weeks.

Presence of the bacteria is expected to decline as fall approaches and water cools.

"It depends how quickly the temperatures drop," she said.; 203-330-6290;;