Multinucleate sphere unknown (MSX) and perkinsosis (Dermo) in oysters

We are responding to the presence of MSX and Dermo in oysters.

In Canada, multinucleate sphere unknown (MSX) and perkinsosis (also known as Dermo) are federally reportable diseases. All suspected cases must be reported to us.

On September 2, 2025, these waters were declared as areas where the aquatic animal diseases MSX and Dermo are present or very likely to be present:

  • Prince Edward Island
  • New Brunswick
  • Nova Scotia
  • Newfoundland and Labrador
  • Québec

Follow biosecurity guidance to prevent the spread of disease from declared areas to other locations within Canada.

MSX and Dermo are not food safety concerns.

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Latest situation

We are responding to the presence of MSX and/or Dermo in oysters collected in Canada.

Map of the declared areas in eastern Canada

Movement controls for MSX and Dermo in eastern Canada are now made through the aquatic animal Domestic Movement Control Program (DMCP). The previous primary control zones (PCZs) for MSX and Dermo have been revoked.

Last updated: 2025-09-02

Haplosporidium nelsoni (MSX) Regulated Areas

Primary control zones

PCZ orders Status of order declaring PCZ Location Disease Date of declaration
PCZ-16 Active Baie-des-Chaleurs, QC MSX and Dermo 2025-07-16
PCZ-15 Active PEI Dermo 2025-07-16
PCZ-14 Active Island of Newfoundland, NL Dermo 2025-06-05
PCZ-13 Active Eastern Shore, NS Dermo 2025-05-29
PCZ-12 Revoked Green Point Rd. to Pointe-Sapin, NB MSX and Dermo 2024-12-03
PCZ-11 Revoked Pointe-Sapin to Fagan Point, NB MSX and Dermo 2024-11-29
PCZ-10 Active Braeshore to Ponds, NS Dermo 2024-11-27
PCZ-09 Active Tidnish to Green Point Road, NB MSX and Dermo 2024-11-22
PCZ-08 Revoked North Rustico to Stanhope, PEI MSX 2024-09-25
PCZ-07 Revoked Union Corner to Wood Islands, PEI MSX 2024-09-25
PCZ-06 Revoked West Point to Cape Egmont, PEI MSX 2024-08-16
PCZ-05 Revoked Darnley Basin, PEI MSX 2024-08-08
PCZ-04 Revoked Gaspereaux to Cable Head West, PEI MSX 2024-07-23
PCZ-03 Revoked New London Bay / Stanley Bridge, PEI MSX 2024-07-23
PCZ-02 Revoked Montrose to Darnley Basin, PEI MSX 2024-07-23
PCZ-01 Revoked Bedeque Bay, PEI MSX 2024-07-19

CFIA permits under the Domestic Movement Control Program

Moving to the Domestic Movement Control Program (DMCP) for MSX and Dermo simplifies the permitting process for oyster growers, harvesters and processors within a declared area. For declared areas, CFIA permits are not required for movement of oysters or gear within the declared infected area.

You must get a CFIA DMCP permit before moving oysters, spat or gear out of a declared area (that is, Prince Edward Island, New Brunswick, Nova Scotia, Newfoundland and Labrador and Québec) to an area of better health status.

More information is available on the Aquatic animal domestic movements page.

Application forms

Follow these steps to apply for a domestic movement permit:

  1. Before completing the application:
  2. Complete the following application to move molluscs or declared things:
  3. Submit the application
    • send the completed application by email, fax or regular mail to our National Centre of Permissions (contact information is on the application form)

Sign up for email notifications to receive important updates on this program.

Other movement controls/permits for declared areas

Fisheries and Oceans Canada (DFO) continues to manage oyster movements within and between provinces through the Introductions and Transfer (I&T) licensing program, in collaboration with the respective provincial authority and, when appropriate, in consultation with the CFIA.

For questions related to the Introductions and Transfers licensing program, contact the DFO Introductions and Transfers Committee for your province.

Contact us

For more information, contact your local CFIA Animal Health Office.

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