Dangerous levels of domoic acid in mussels have prompted state public health officials to warn consumers not to eat bivalves harvested recreationally in Del Norte County.

The warning applies to recreationally harvested mussels, clams and whole scallops, according to a press release received Friday from the California Department of Public Health. The naturally occurring toxin, also known as Amnesic Shellfish Poisoning, or ASP, can cause illness or death in humans, according to the release.

A CDHP warning against eating sport-harvested razor clams from Del Norte and Humboldt counties due to dangerous domoic acid levels remains in effect as does a statewide annual quarantine on sport-harvested mussels due to the toxin. The annual quarantine applies to all species of mussels harvested in California and will continue through at least Oct. 31, according to the press release.

The warning does not apply to commercially-sold clams, mussels, scallops or oysters from approved sources, according to the press release. Shellfish sold by state-certified harvested and dealers are subject to frequent mandatory testing for toxins.

Symptoms of domoic acid poisoning can occur within 30 minutes to 24 hours after eating toxic seafood. In mild cases, symptoms may include vomiting, diarrhea, abdominal cramps, headache and dizziness. These symptoms disappear within several days, according to the press release.

In severe cases, the victim may experience trouble breathing, confusion, disorientation, cardiovascular instability, seizures, excessive bronchial secretions, permanent loss of short-term memory, coma or death. No cases of human poisoning from domoic acid are known to have occurred in California, according to the press release.

For more information on current shellfish advisories and quarantines, call the Shellfish Information Line at 800-553-4133.