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Canadian Food Inspection Agency confirms MSX disease in PEI oysters

The Canadian Food Inspection Agency (CFIA) has confirmed the first case of MSX in Prince Edward Island. Haplosporidium nelsoni (also known as multinucleate sphere unknown, MSX) was confirmed in American oysters (Crassostrea virginica) collected in Bedeque Bay, Prince Edward Island on July 11.

MSX causes decreased rates of growth and increased oyster mortality. A Primary Control Zone has been declared for the area the parasite was discovered, where the movement of the bivalve shellfish and things capable of being affected or contaminated by the disease can only be removed, moved in, or taken into that area with a permit issued by the CFIA.

Collection, sampling and testing of oysters from other water bodies in PEI is ongoing. “The federal and provincial governments continue to work together to develop appropriate response plans, as additional information about the disease situation and impacted areas are received,” a press statement from the federal government states.

Although MSX has previously been identified in American oysters in certain areas of Cape Breton Island, N.S. and in Pacific cupped oyster (Crassostrea gigas) in the Pacific Ocean adjacent to British Columbia, the life cycle of the parasite is unknown. The government advices that farmers biosecurity measures and monitoring for signs of disease on farms and lease sites can help limit the impacts of disease-causing agents.