(HealthDay News) — (Tasrir) — In an advisory, the FDA told consumers to avoid oysters and bay clams harvested from Netarts and Tillamook bays in northern Oregon since May 28, as well as shellfish harvested from areas around Willapa Bay in southern Washington since May 26.
Shellfish harvested from those areas during that period were also distributed to Arizona, California, Colorado, Hawaii, Nevada and New York, so the FDA has warned restaurants and retailers in those states not to serve the shellfish because of the potential for paralytic shellfish poisoning (PSP).
“Food containing PSPs may look, smell, and taste normal. These toxins cannot be removed by cooking or freezing,” the agency stressed. “Consumers of these products who are experiencing symptoms of illness should contact their healthcare provider and report their symptoms to their local Health Department.”
High levels of toxins were first found in shellfish on the Oregon coast in mid-May, state health officials said in a public advisory.
Since then, the outbreak has sickened at least 20 people in Oregon, the advisory noted. In response, Oregon health authorities have closed the state’s entire coastline to the harvesting of mussels, razor clams and bay clams. Agriculture officials have also closed three bays to commercial oyster harvesting.
Officials in neighboring Washington state have also closed the state’s Pacific coastline to the harvesting of shellfish, including mussels, clams, scallops and oysters.
PSP is caused by saxitoxin, a naturally occurring toxin that’s produced by algae. Saxitoxin is a neurotoxin, meaning it can damage nerve tissue, according to the U.S. Centers for Disease Control and Prevention.
People who eat contaminated shellfish typically fall ill within 30 minutes, the FDA warned. Symptoms include numbness of the mouth and lips, vomiting, diarrhea, shortness of breath and irregular heartbeat in severe cases. Treatment for severe cases may require mechanical ventilators to help with breathing, and asphyxiation is usually the cause of death.
But for “patients surviving 24 hours, with or without respiratory support, the prognosis is considered good, with no lasting side effects,” the FDA added.
What caused the rise in PSP levels in these shellfish? A “very large” algae bloom along Oregon’s coast has meant that shellfish are eating contaminated algae, Matthew Hunter, shellfish program manager for the Oregon Department of Fish and Wildlife, explained during a media briefing, CBS News reported.
Oregon officials said it may take weeks, months or even up to a year for toxin levels to subside, depending on the type of shellfish, the FDA said.
Such high levels of PSP haven’t been detected in Oregon in decades, according to Hunter, who cited a shellfish harvesting closure in the state in 1992.
