The U.S. Food and Drug Administration is warning restaurants, food retailers and consumers to avoid certain shellfish from Washington and Oregon over concerns they've been contaminated with toxins that cause paralytic shellfish poisoning, which has sickened around two dozen people so far.
The affected shellfish include oysters and bay clams harvested from growing areas in Netarts and Tillamook Bays in Oregon since May 28, as well as all shellfish from Willapa Bay, Washington. Additional areas of concern in Washington from the end of May include Stony Point, Bay Center and Bruceport, according to the FDA.
Shellfish from those areas were then distributed throughout those states and in Arizona, California, Colorado, Hawaii, Nevada and New York.
PSP is the most common and severe form of shellfish poisoning and is caused by neurotoxins, called saxitoxins or paralytic shellfish toxins, that are naturally produced by marine algae, called phytoplankton. Molluscan shellfish consume this algae and can then retain the toxin for different lengths of time, with some rapidly cleansing themselves of them while others take longer to remove them. The FDA says this lengthens the period of time in which they pose a consumption risk to humans.
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Once harvested, the toxins can't be removed from the shellfish by cooking or freezing. They may also look, smell and taste normal, so the FDA warns customers to watch for PSP symptoms, which develop in most people within 30 minutes of consuming contained seafood.
PSP intoxication symptoms can include tingling of the mouth, respiratory paralysis, limb numbness, "pins and needles" sensation, floating feeling, vomiting and more, per the FDA. There is no antidote, but treatment includes respiratory support and fluid therapy.
Those who survive 24 hours after consumption are considered to have a good prognosis with no lasting side effects. However, those who die from high levels of PSP usually do so from asphyxiation, as the respiratory system becomes paralyzed.
The Oregon Health Authority says at least 20 people have fallen ill with PSP in the state amid the outbreak and some were hospitalized, though some reports say the number is more likely around 31. The confirmed illnesses were in people who reported recreationally harvesting mussels in Oregon, OHA said, and an official from the state's Fish and Wildlife Department cited a "very large" algal bloom as cause for the "unprecedented levels" of PSP toxins.
Oregon officials have since closed the entire coastline to recreational shellfish harvesting, and Washington, which has yet to see any reported illnesses linked to the outbreak, closed Grays Harbor and Willapa Bay to harvesting, due to the high levels of toxins.
Many factors are known to contribute to harmful algal blooms, but how those factors come together to create the bloo" isn't well understood, according to the National Oceanic and Atmospheric Administration.
However, the agency says they're occurring more often and in locations not previously affected due to climate change and increasing nutrient pollution, noting human activities disturbing ecosystems as one contributor.
