B.C.'s heat wave may be to blame for several cases of shellfish poisoning

Several people have fallen ill with food poisoning after eating shellfish in B.C. in the last 10 days, and health officials are warning that warm ocean waters might be to blame.

Lorraine McIntyre, a food safety specialist at the B.C. Centre for Disease Control (BCCDC), said there have been 10 confirmed outbreaks of Vibrio illness resulting from a naturally occurring bacterium that is known to proliferate when water temperatures rise in the summer.

Most people who've gotten sick had eaten shellfish they'd harvested themselves, while some fell ill after swimming or other recreational activities, McIntyre said.

"It's nasty," she said of Vibrio illness. "You'll get diarrhea, abdominal cramps, you may have some vomiting. You're just not going to feel well for one to three days."

Fortunately, the Vibrio bacteria isn't a concern for commercial harvesters. McIntyre says commercial operations have to follow strict health and temperature guidelines. As well, commercial oyster harvesters test their shellfish for Vibrio.

McIntyre said the extreme heat wave in June allowed microorganisms to "multiply like crazy" in B.C. waters, which may explain why there have been more Vibrio cases than in previous years at this time.

Satellite temperatures taken at 10 metres below the surface of the ocean during the scorching heat last month measured at 20 C or higher, she added.

"That's deep, so it's warm down there," McIntyre said.

Researchers have previously reported that more than a billion seashore animals like clams and mussels may have died during the heat wave.

The BCCDC says anyone who harvests their own shellfish should check first to see if there are closures in the area because of toxins or bacteria. Clam digging and other similar activities should only happen when the tide is going out.

Seafood should also be cooked before it is eaten to destroy viruses and bacteria, and guts should be removed from crabs before they are cooked.