Infection with Mikrocytos mackini

What is Mikrocytos mackini?

Mikrocytos mackini is a protozoan that infects molluscs. Mikrocytos mackini belongs to the phylum Haplosporidia.

What species of molluscs can be infected by Mikrocytos mackini?

Each species of molluscs may have several common names, but only one common name is listed.

Species susceptible to Mikrocytos mackini that exist in the natural environment in Canada include:

  • Crassostrea gigas (Pacific cupped oyster)
  • Crassostrea virginica (American oyster)
  • Ostrea edulis (European flat oyster)

Species susceptible to Mikrocytos mackini that do not exist in the natural environment in Canada include:

  • Ostrea conchaphila (Olympia oyster)

Is Mikrocytos mackini a riks to human health?

No. The causal agent of Mikrocytos mackini is not a risk to human health.

How do I know if a mollusc is infected with Mikrocytos mackini?

Mikrocytos mackini causes disease in oysters. It is a cause of mortality in most life stages of oysters.

  • Signs of disease are most noticeable in oysters ≥2 years old
  • Overall mortality varies between 30-40%

Affected molluscs may exhibit any of the following signs:

  • appearance
    • Spots on the body wall, adductor muscle or surface of labial palps or mantle
    • Spots may include pustules filled with green, yellow-brown or colourless fluid;
    • Brown scars on the shell associated with the spots on the mantle.

Is Mikrocytos mackini found in Canada?

Yes. Mikrocytos mackini has been found in British Columbia.

How is Mikrocytos mackini spread?

Mikrocytos mackini is spread between molluscs by

  • contaminated water, and
  • contaminated equipment.

People can spread Mikrocytos mackini by moving any of the following

  • infected live or dead molluscs,
  • contaminated water, and
  • contaminated equipment.

How is Mikrocytos mackini diagnosed?

Diagnosis of an infection with Mikrocytos mackini requires identification of the parasite through laboratory tests. Not all infected molluscs show signs of disease.

How is Mikrocytos mackini treated?

There are no treatment options currently available for Mikrocytos mackini.

What measures can be taken to prevent the introduction and spread of Mikrocytos mackini?

If you frequently handle or work with molluscs, be aware of the clinical signs of Mikrocytos mackini.

Do not import live infected molluscs into Canada.

  • An import permit is required from the Canadian Food Inspection Agency (CFIA) for certain species of molluscs as of December 2011.
  • People bringing molluscs into Canada should check other federal, provincial, and/or territorial requirements before entering the country.

Do not introduce live molluscs from another country into the natural waters of Canada.

  • People releasing molluscs into the natural waters or rearing facilities within Canada should check if federal or provincial and/or territorial permits are required.

If you frequently handle or work with molluscs, be aware of where Mikrocytos mackini occurs in your area.

  • A federal, provincial and/or territorial permit or licence may be required to relocate molluscs within Canada.

Do not use molluscs that were bought in a grocery store as bait for catching fish or other aquatic animals.

Shells that are removed from molluscs or unwanted molluscs that you harvested or bought for your consumption should be disposed of in your municipal garbage.

The CFIA recommends that you do not visit Canadian aquaculture sites, zoos or aquariums for 14 days if you have travelled to another country and

  • visited an aquaculture site, or
  • had contact with wild molluscs.

Wash and disinfect the footwear you wore to the site or when you had contact with wild molluscs. Also wash your clothing thoroughly and dry it at a high temperature.

What is done to protect Canadian aquatic animals from Mikrocytos mackini?

Mikrocytos mackini is a reportable disease in Canada. This means that anyone who owns or works with aquatic animals, who knows of or suspects Mikrocytos mackini in their molluscs, is required by law to notify the CFIA.

If Mikrocytos mackini is found in Canada, the CFIA would control its spread by implementing disease response activities. These may include

  • controlling the movements of infected animals that people own or work with
  • humanely destroying infected animals
  • cleaning and disinfecting

The control measures chosen would depend on the situation.

What do I do if I think molluscs that I am raising or keeping have Mikrocytos mackini?

If you suspect that molluscs you are raising or keeping have Mikrocytos mackini, you are required under the Health of Animals Act to immediately notify the CFIA of your suspicion.

How do I get more information

For more information about reportable diseases, visit the Aquatic Animal Health page, contact your local CFIA Animal Health Office, or your CFIA Area office:

  • Atlantic: 506-777-3939
  • Quebec: 514-283-8888
  • Ontario: 226-217-8555
  • West: 587-230-2200