Oregon officials closed the state鈥檚 entire coast to shellfish harvesting on Friday after an unprecedented outbreak of paralytic shellfish poisoning, which appears to also be affecting parts of Washington and California.
During a press conference Friday morning, officials said Oregon had never experienced such a large outbreak before, in terms of both the toxic levels being detected in shellfish and the number of people becoming ill.
who harvested shellfish have become ill. An Oregon Health Authority spokesperson said most illnesses have been mild, although some people required hospitalization.
鈥淭hese are unprecedented levels that we鈥檙e seeing, and especially in bay clams and oysters,鈥� Matthew Hunter, shellfish program manager with the Oregon Department of Fish and Wildlife, said.
Paralytic shellfish poisoning is the most severe type of shellfish poisoning. It is caused by eating shellfish contaminated with saxitoxins, a naturally occurring toxin. Many kinds of shellfish can be contaminated by this toxin, but it most often affects mussels and clams. Saxitoxins and similar biotoxins affecting shellfish are tied to algal blooms in the ocean. These blooms are colloquially called 鈥渞ed tides鈥� or 鈥渂rown tides,鈥� though they don鈥檛 always color the water.
Symptoms usually appear within an hour after a person eats toxic shellfish. They include numbness and tingling of the face, lips, tongue, arms and legs, as well as digestive issues like diarrhea, vomiting and nausea. Extreme cases could include neurological symptoms, like paralysis, or respiratory failure.
Cooking shellfish will not destroy these poisonous biotoxins, and for biotoxin poisoning. People who become ill need to wait for the toxins to naturally flush from their bodies.
Hunter said officials need to do more testing to see if these toxin levels have hit their peak, or if they are starting to decline.
鈥淚 doubt we鈥檙e at the decline because we鈥檙e seeing ,鈥� Hunter said.
California to razor clam harvesting in early May due to domoic acid, which is tied to a different type of biotoxin. That state has yet to close parts of its coast to shellfish harvesting because of paralytic shellfish poisoning, but Hunter said he 鈥渨ould be very surprised if this isn鈥檛 an event that鈥檚 covering all three states.鈥�
Oregon first detected high levels of toxins among shellfish along the Central Oregon Coast on May 17. Since then, high levels of toxins have been found in several different types of shellfish across the Oregon coast, including bay clams, razor clams, oysters and mussels.
Paralytic shellfish poisoning has a long history of sickening people and animals along the West Coast, but Hunter said it and other shellfish poisons appear to be getting worse along with climate change.
鈥淲e鈥檝e shown that the changing of the oceans has definitely increased the frequency, the duration and the toxicity of all of our biotoxins,鈥� Hunter said. 鈥淭hat鈥檚 definitely something that we鈥檙e going to have to do adaptive management for.鈥�
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