Canadian Food Inspection Agency (CFIA) laboratory tests have validated the presence of the harmful mollusc disease dermo in oysters harvested from Egmont Bay in Prince Edward Island (P.E.I.). This marks the first confirmed case of dermo in P.E.I., as confirmed by CFIA in a recent news release. While dermo does not pose a threat to human health or food safety, it can lead to increased oyster mortality and reduced growth rates.
In a separate communication, CFIA disclosed that tests have also identified the initial instances of both dermo and MSX in oyster samples collected from Chaleur Bay in Quebec. This revelation comes after the initial detection of dermo in Canadian waters eight months ago in oysters from Spence Cove, located approximately five kilometers west of the Confederation Bridge in New Brunswick.
Dermo, also known as Perkinsosis, is caused by a parasite called Perkinsus marinus and has been previously observed in Atlantic waters spanning from Mexico to Maine. It impacts both cultured and wild American oysters (Crassostrea virginica).
According to a British government fact sheet on the disease, outbreaks of Perkinsosis typically occur in warm summer water temperatures surpassing 20°C, with clinical signs including pale digestive glands, gaping, mantle shrinkage, and stunted growth. CFIA’s news release clarified that dermo does not affect other bivalves in the area, such as mussels, scallops, or clams.
The recent confirmation of dermo in oysters from Egmont Bay adds to the challenges faced by P.E.I.’s oyster industry, already grappling with the discovery of MSX last July. MSX, short for multinucleate sphere unknown, was initially detected in samples from Bedeque Bay in P.E.I., with subsequent cases identified in various regions of the province. Similar to dermo, MSX solely impacts oysters and not humans consuming oysters from MSX-infected waters.
CFIA highlights that the parasite responsible for dermo is easily transmittable among oysters, particularly when they are between one to three years old, with mortality rates typically ranging from 50% to 75%.
The Canadian Food Inspection Agency has the authority to restrict oyster movement to prevent the spread of dermo or other animal diseases. If a product in a primary control zone is deemed a potential risk, its movement will be controlled, necessitating a permit from CFIA for transportation within, through, or outside the primary control zone.
Any new primary control zones will be promptly posted on CFIA’s website, with notifications sent to provincial partners, stakeholders, Indigenous communities, and industry players through existing communication channels once established.