A population-based study of paralytic shell fish poisoning in Alaska.

During May and June 1994, the authors interviewed and requested a shellfish sample from a population-based sample of 170 residents from Kodiak and Old Harbor, Alaska. Of 51 Old Harbor and 68 Kodiak residents who had eaten shellfish gathered from Kodiak Island, 18 and 6 percent, respectively, had a history of PSP. We calculated the incidence of paralytic shellfish poisoning in Old Harbor and Kodiak as 15 and 1.5 per 1000 persons per year, respectively. Of 12 butter clam batches collected from residents, 6 had a paralytic shellfish poison toxin level greater than the regulatory limit of 80 micrograms saxitoxin equivalent per 100 g of tissue; one of the 29 people who ate these shellfish developed illness. People who eat shellfish collected from non-commercial beaches have a high rate of paralytic shellfish poisoning. It may be possible to raise the regulatory level for paralytic shellfish poison toxin without affecting the public health.