Koi Herpesvirus Disease - Fact Sheet

What is koi herpesvirus disease?

Koi herpesvirus disease is an infectious disease of finfish. It is caused by the koi herpesvirus, which belongs to the family Herpesviridae.

What species of finfish can be infected by koi herpesvirus disease?

Koi herpesvirus disease has been found in common carp (Cyprinus carpio) and koi carp (Cyprinus carpio koi).

Is koi herpesvirus disease a risk to human health?

No. The causal agent of koi herpesvirus is not a risk to human health.

What are the signs of koi herpesvirus disease?

Koi herpesvirus disease is a cause of death in hatched life stages of common and koi carp. Infected animals can die within hours of the appearance of disease.

Affected finfish may exhibit any of the following signs:

  • behaviour
    • abnormal swimming patterns (slow swimming at surface, erratic swimming)
    • gasping
  • appearance
    • pale gills or brown patches in the gills
    • over- or under-production of mucus on the gills and skin
    • areas of bleeding in the gills and skin
    • sunken eyes
    • swollen kidney
    • swollen spleen

Is koi herpesvirus disease found in Canada?

Yes. In Canada, koi herpesvirus disease has been found in Ontario and Manitoba.

How is koi herpesvirus spread?

Koi herpesvirus is spread between finfish by

  • contaminated water, and
  • contaminated equipment.

People can spread koi herpesvirus by moving any of the following:

  • infected live or dead finfish,
  • contaminated equipment, or
  • contaminated water.

How is koi herpesvirus disease diagnosed?

Diagnosing koi herpesvirus disease requires laboratory testing. Not all infected finfish show signs of disease.

How is koi herpesvirus disease treated?

There are no treatment options currently available for koi herpesvirus disease.

What measures can be taken to prevent the introduction and spread of koi herpesvirus disease?

If you frequently handle or work with finfish, be aware of the clinical signs of koi herpesvirus disease.

Do not import live infected finfish into Canada.

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

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

  • People releasing finfish 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 finfish, be aware of where koi herpesvirus occurs in your area.

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

Do not use finfish bought in a grocery store as bait for catching finfish or other aquatic animals.

When cleaning and gutting finfish, dispose of all finfish waste 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 finfish.

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

What is done to protect Canadian aquatic animals from koi herpesvirus disease?

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

If koi herpesvirus disease 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 a finfish that I am raising or keeping have koi herpesvirus disease?

If you suspect a finfish that you are raising or keeping may have koi herpesvirus disease, you are required under the Health of Animals Act to immediately notify the CFIA.

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
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