Infection with Perkinsus olseni

What is Perkinsus olseni?

Perkinsus olseni is a protozoan that infects molluscs. Perkinsus olseni belongs to the phylum Apicomplexa.

What species of molluscs can be infected by Perkinsus olseni?

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

Species susceptible to Perkinsus olseni that exist in the natural environment in Canada include:

• Crassostrea gigas (Pacific cupped oyster)
• Crassostrea virginica (American oyster)
• Venerupis philippinarum (Manila clam)

Species susceptible to Perkinsus olseni that do not exist in the natural environment in Canada include:

• Anadara trapezia (Sydney cockle)
• Austrovenus stutchburyi (New Zealand cockle)
• Barbatia novaezealandiae (New Zealand ark clam)
• Chama pacifica (reflexed jewelbox)
• Crassostrea ariakensis (Suminoe oyster)
• Crassostrea hongkongensis (Hong Kong cultured oyster)
• Haliotis cyclobates (whirling abalone)
• Haliotis laevigata (greenlip abalone)
• Haliotis rubra (blacklip abalone)
• Haliotis scalaris (staircase abalone)
• Katelysia rhytiphora (ridged venus clam)
• Paphia undulata (undulated surf clam)
• Pitar rostratus (Uruguayan clam)
• Protothaca jedoensis (Jedo venus clam)
• Tridacna crocea (saffron-coloured clam)
• Tridacna maxima (small giant clams)
• Venerupis aurea (golden carpet shell)
• Venerupis decussata (grooved carpet shell clam)
• Venerupis pullastra (pullet carpet shell)

Does Perkinsus olseni affect human health?

No. The causal agent of Perkinsus olseni is not a risk to human health.

What are the signs of Perkinsus olseni?

Perkinsus olseni causes death in juvenile and adult molluscs. Overall mortality is 30-40% in molluscs that are 3-4 cm long.

Infected molluscs may exhibit any of the following signs:

• behaviour
  • gaping
• appearance
  • decreased rate of growth
  • brown, pus-filled spots in the foot, gills and mantle
  • retracted mantle
  • very thin body
  • pale digestive gland.

Is Perkinsus olseni found in Canada?

No. Perkinsus olseni is not currently found in Canada.

How is Perkinsus olseni spread?

Perkinsus olseni is spread between molluscs by

• contaminated water, and
• contaminated equipment.

People can spread Perkinsus olseni by moving any of the following

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

How is Perkinsus olseni diagnosed?

Diagnosing Perkinsus olseni requires laboratory testing. Not all infected molluscs show signs of disease.

How is Perkinsus olseni treated?

There are no treatment options currently available for Perkinsus olseni.

What measures can be taken to prevent the introduction and spread of Perkinsus olseni?

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

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 in 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 Perkinsus olseni 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 Perkinsus olseni?

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

If Perkinsus olseni 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 Perkinsus olseni?

If you suspect that molluscs you are raising or keeping have Perkinsus olseni, 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