A well-traveled shellfish bug that has sickened thousands from Europe to Japan and South America over the past half century has finally found its way into Washington state’s prized mussel and clambeds.
The Washington Department of Health this week closed Sequim Bay, near the entrance to Puget Sound, to shellfish harvests after three people fell ill with Diarrhetic Shellfish Poisoning (DSP.)
The same biotoxin had appeared earlier this month in mussels from two shellfish farms in British Columbia, sickening about 50 people. Canadian authorities warned consumers not to eat mussels sold by Island Sea Farms Inc. in late July.
DSP is an intestinal illness caused by a naturally occurring biotoxin that can be carried by certain marine dinoflagellates. Dinoflagellates are microscopic marine organisms that are an important part of the food supply for shellfish around the world.
Dinoflagellates also carry the far more dangerous Paralytic Shellfish Poisoning (PSP), which includes a highly toxic neurotoxin for which there is no cure. DSP, however, causes diarrhea and other symptoms that are not life-threatening and rarely require hospitalization.
DSP outbreaks had been reported in the Netherlands in the 1960s, followed by outbreaks in Japan, France, Scandanavia and South America. Like other shellfish-related illnesses, DSP outbreaks occur in the summer months, when tidal shellfish beds are exposed to warming air temperatures.
But Northwest waters had been spared – until the last few weeks.
The Canadian Food Inspection Agency issued warnings for mussels sold across much of Canada with several brand names, including Saltspring Island, Albion Fisheries and Pacific Rim Shellfish and B&C Food. To date, the outbreak has been limited to shellfish from the two Island Sea Farms operations.
Washington’s outbreak affects a rural bay just outside Puget Sound. Health officials recalled all shellfish sold from the bay since August 1. And officials believe that all of the recalled product has been removed from the market.