Epidemiologists caution against recreationally harvested shellfish

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ANCHORAGE (KTUU) - We're now in the days of 15 hours of sunlight: The sun is shining. Birds are chirping.

And the algae, including the toxin-producing kind, is thriving.

Researchers with the State of Alaska Section of Epidemiology have said previously that people need to be wary of consuming non-commercially harvested shellfish.

The group tends to put out notices every so often warning people of Paralytic Shellfish Poisoning, also known as PSP. It's a serious illness caused by eating shellfish contaminated with dinoflagellate algae, an aquatic plant that produces harmful toxins.

"PSP is something we see every year in Alaska," said Louisa Castrodale, an epidemiologist with the State of Alaska Dept. of Health and Social Services.

"We track cases of PSP, and there are also things that are sort of precursors to PSP," she said. "But it can be tricky to predict."

PCP is not common, based on the numbers reported to the Section of Epidemiology, but it is dangerous. Some of the toxins, according to the Alaska Div. of Public Health, are 1,000 times more potent than cyanide. Depending on the levels of the toxin in the shellfish, a single one can be fatal to humans.

"There are a lot of factors that go into that," Castrodale said, "but there's a lot of nice work that's been done on monitoring levels of toxins (in Alaskan shellfish)."

Symptoms can include tingling of the lips and tongue, which may begin within minutes or hours of ingesting infected shellfish. Tingling of the fingers and toes, loss of muscle control in arms and legs, and difficulty breathing have also been reported. Some people experience "a sense of floating" or nausea, vomiting, and even muscles of the chest and abdomen becoming paralyzed. With high exposure, death can occur in as little as two hours from paralysis of the breathing muscles.

So how can you avoid it?

According to Castrodale, not eating non-commercially harvested shellfish can help, since commercial farmers have required guidelines for testing that they follow. You can also try to get your shellfish tested before ingesting.

Need more information about testing for PSP in Alaska? Click here.

"Because there isn't routine testing of all the shellfish and all the beaches, at any given time, there is a risk of getting paralytic shellfish poisoning," Castrodale said.

PSP can be found in various types of shellfish. This includes clams, mussels, oysters, geoducks, and scallops. Crab meat hasn't been found to contain PSP toxins, but the guts have, which means the meat needs to be cleaned thoroughly and the guts and butter should be discarded before cooking.

As for the rest, cooking them doesn't make them any safer to eat if you're looking to avoid PSP, because the toxins aren't destroyed by heating or freezing.

Toxin levels can also vary from shellfish to shellfish, even if they are found on the same beach. For this reason, researchers said, you should never assume a beach is totally safe.

For more information on PSP from the State of Alaska Section of Epidemiology, click here.

And, according to multiple state agencies and scientific studies, only laboratories can reliably test shellfish for PSP toxins. They can be present without any visible signs.

The only way to protect yourself and anyone else from PSP is by not eating non-commercial shellfish. Commercial shellfish are tested routinely, and thus are considered safe to eat as the unsafe ones will not be distributed.

If you think you have PSP, you should seek medical care immediately. Call 911 or have someone take you to the emergency room, if possible.

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