HARTFORD, Conn. (AP) Warm water in Long Island Sound is being blamed for a naturally occurring bacteria that sickened at least five people who ate oysters, clams and other shellfish from shallow areas near Norwalk and Westport.

The state has recalled shellfish before due to pollution from storm water runoff or similar reasons. But the Department of Agriculture says a recall announced Monday due to naturally occurring bacteria is a first.

David Carey, director of the agency's Bureau of Aquaculture, says the extreme heat in mid-July is partly to blame for the warm water in shallow areas of the Sound. The state has shut shellfish harvesting areas until September when the water is expected to cool down.

If ingested, the bacteria that's known as Vibrio parahaemolyticus can cause acute stomach illness.