Viral Hemorrhagic Septicemia (VHS) - Fact Sheet

What is viral hemorrhagic septicemia (VHS)?

VHS is an infectious disease of finfish. It is caused by the viral hemorrhagic septicemia virus, which belongs to the family Rhabdoviridae.

Is VHS a public health risk?

No, VHS does not pose a human health risk.

What are the clinical signs of VHS?

Diseased freshwater fish may exhibit any or all of the following signs of VHS:

  • bulging eyes
  • pale gills
  • signs of bleeding around the eyes, bases of the fins, sides and head
  • dark colouration
  • distended (fluid-filled) belly
  • gasping at the surface
  • corkscrew swimming behaviour
  • high death rate

Where is VHS found?

There are several known strains of VHS virus that affect many freshwater and marine fish species in the northern hemisphere of the world. In Canada, VHS virus infects certain species of finfish in the Pacific and Atlantic oceans and the Pacific Ocean watershed of British Columbia and the Atlantic Ocean watersheds in New Brunswick and Nova Scotia.

The first occurrence of VHS in the Canadian Great Lakes was detected in Lake Ontario in 2005.

VHS virus has been found in finfish from Lake Erie, Lake Huron, Lake Simcoe, Lake Superior, Lower Thames River, and the St. Lawrence River west of the Moses-Saunders dam in Cornwall, Ontario.

How is VHS transmitted and spread?

VHS infection is known to spread from fish to fish in one of two ways: by feeding upon diseased fish or by living in contaminated water. Water becomes contaminated when infected fish shed the virus through their urine or when infected fish die and decompose releasing the virus. People can spread the virus by moving contaminated fish, water, boats and other equipment between bodies of water. Fish-eating birds, such as herons, may also transmit the virus.

Fish do not have to be sick to transmit the virus. Healthy fish can also carry and shed the virus.

How is VHS diagnosed?

VHS may be suspected based on the clinical signs. Diagnosis must be confirmed by laboratory tests.

How is VHS treated?

There is no specific treatment for VHS.

What measures can be taken to prevent the introduction and spread of viral hemorrhagic septicemia?

If you frequently handle or work with finfish, be aware of the clinical signs of viral hemorrhagic septicemia.

Do not introduce live finfish from another country or another province 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.

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 waste in your municipal garbage.

The Canadian Food Inspection Agency (CFIA) recommends that you do not visit Canadian aquaculture farms, zoos or aquariums for 14 days if you have travelled to another country and

  • visited an aquaculture farm, or
  • had contact with wild finfish.

Once in Canada, wash and disinfect the footwear you wore to the farm or when you had contact with wild finfish. Also wash your clothing thoroughly and dry it at a high temperature.

Do not import live infected finfish into Canada.

  • An import permit will be required from the 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.

What is done to protect Canadian aquatic animals from viral hemorrhagic septicemia?

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

If viral hemorrhagic septicemia 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.

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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