Oregon Authorities Close Coast to Shellfish Harvesting

State health officials closed the Oregon coast to shellfish harvesting Friday after tests confirmed that clams collected at one beach contained a potentially deadly toxin.

The state Health Division also told businesses to stop selling clams, oysters and mussels, said spokeswoman Debbie Cannon.

Test results showed razor clams from Clatsop Beach in northern Oregon contained a rare toxin called domoic acid, Cannon said.

The tests were ordered after the neurotoxin was discovered in clams harvested off Long Beach Peninsula in Washington state, about 10 miles north of Clatsop Beach across the Columbia River estuary.

Six people, five from Washington state and one from Oregon, reported nausea, vomiting and diarrhea after eating shellfish harvested from the Long Beach Peninsula, said Dr. Bill Keene, Health Division epidemiologist.

“There’s no indication at this time that we have a medical problem,” Keene said. “What we have is the potential for problems.”

The neurotoxin, secreted by a microscopic marine organism, has no visible effect on the shellfish, but in humans it causes a potentially deadly illness known as amnesiac shellfish poisoning.

In mild cases, amnesiac shellfish poisoning causes nausea, vomiting and diarrhea. Symptoms show up between 30 minutes to 24 hours after eating tainted shellfish, Cannon said.

Symptoms of severe cases usually show up within 48 hours, and include headache, dizziness, facial grimacing, disorientation, short-term memory loss and coma, Cannon said.

In November, 1987, however, four deaths and several severe illnesses in Montreal were linked to mussels contaminated with the neurotoxin.