Epizootic Haematopoietic Necrosis

What is epizootic haematopoietic necrosis?

Epizootic haematopoietic necrosis is an infectious disease of finfish. It is caused by the epizootic haematopoietic necrosis virus, which belongs to the family Iridovirdae.

What species of finfish can be infected by epizootic haematopoietic necrosis?

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

Species susceptible to epizootic haematopoietic necrosis virus that occur in the natural environment in Canada:

  • Esox lucius* (northern pike*)
  • Oncorhynchus mykiss (rainbow trout)

Species susceptible to epizootic haematopoietic necrosis that do not exist in the natural environment in Canada include:

  • Bidyanus bidyanus (silver perch)
  • Galaxias olidus (mountain galaxias)
  • Gambusia affinis (Mosquito fish)
  • Maccullochella peelii (Murray cod)
  • Macquaria australasica (Macquarie perch)
  • Perca fluviatilis (European perch)

Note: Species identified with an asterisk have not been confirmed as susceptible to epizootic haematopoietic necrosis.

Is epizootic haematopoietic necrosis a risk to human health?

No. The causal agent of epizootic haematopoietic necrosis is not a risk to human health.

What are the signs of epizootic haematopoietic necrosis?

Epizootic haematopoietic necrosis is a cause of death in

  • hatched life stages of rainbow trout
  • juvenile and adult European perch

Affected finfish may exhibit any of the following signs:

  • behaviour
    • loss of appetite
    • abnormal swimming patterns (slow swimming at surface, swimming in a spiral pattern)
    • assuming a "head stand" position
  • appearance
    • enlarged belly that is filled with fluid
    • dark skin colouration
    • frayed and clubbed fins
    • pinpoint areas of bleeding at the base of fins
    • areas of bleeding in the gills
    • many white or yellow spots in the liver
    • areas of paleness in the muscles

Is epizootic haematopoietic necrosis found in Canada?

No. The causal agent of epizootic haematopoietic necrosis is not currently found in Canada.

How is epizootic haematopoietic necrosis virus spread?

Epizootic haematopoietic necrosis virus is spread between finfish by

  • contaminated equipment, or
  • contaminated water.

People can spread epizootic haematopoietic necrosis virus by moving any of the following:

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

How is epizootic haematopoietic necrosis diagnosed?

Diagnosing epizootic haematopoietic necrosis requires laboratory testing. Not all infected finfish show signs of disease.

How is epizootic haematopoietic necrosis treated?

There are no treatments currently available for epizootic haematopoietic necrosis.

What measures can be taken to prevent the introduction and spread of epizootic haematopoietic necrosis?

If you frequently handle or work with finfish, be aware of the clinical signs of epizootic haematopoietc necrosis.

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 into rearing facilities within Canada should check if federal or provincial and/or territorial permits are required.

Do not use finfish that were 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 epizootic haematopoietic necrosis?

Epizootic haematopoietic necrosis is a reportable disease in Canada. This means that anyone who owns or works with aquatic animals, and knows of or suspects epizootic haematopoietic necrosis in their fish, is required by law to notify the CFIA.

If epizootic haematopoietic necrosis 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 finfish that I am raising or keeping have epizootic haematopoietic necrosis?

If you suspect a finfish that you are raising or keeping may have epizootic haematopoietic necrosis, 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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