Viral Hemorrhagic Septicemia

Help Prevent the Spread of this Disease in Ontario


What is Viral Hemorrhagic Septicemia (VHS)?  

  • VHS is an infectious disease of fish.
  • VHS disease outbreaks may happen at any time, but are most likely during the spring as temperatures fluctuate and fish are reproducing.
  • The Great Lakes strain of the virus was discovered in 2005 in Lake Ontario and affects or is carried by multiple species of fish, including: Walleye, Yellow Perch, Muskellunge, Smallmouth Bass, Rock Bass, Chinook Salmon, White Bass, Black Crappie, Freshwater Drum, Round Goby, Gizzard Shad, Emerald Shiners, Bluntnose Minnows and Spottail Shiners.
  • MNR has conducted surveillance for VHS in Ontario in partnership with the Canadian Food Inspection Agency since it was first detected in Ontario waters by:
  • sampling high risk lakes,
  • sampling any die-offs of fish, and,
  • conducting random sampling across Ontario
  • Until 2011, the waters of Lakes Ontario, Erie, and Huron and their connecting waterways and adjacent tributaries up to the first impassable barrier for all fish species were considered positive for VHS. In 2011, VHS was additionally detected in Lake Simcoe.
  • To slow the spread of VHS, the Ministry of Natural Resources has established two management areas in Ontario: the VHS Management Zone (established 2007) and the Lake Simcoe Management Zone (established 2011).
Fish with VHS looking healthy
A fish with VHS can look healthy, showing no signs at all.

Can VHS infect people?


  • No, the virus does not affect humans.
  • Fish carrying the VHS virus are safe to eat and handle.

More information is available in these fact sheets:


Fish with VHS looking sick
A fish with VHS can look sick, showing signs of the disease.


Still have questions? For general inquiries, call:

Natural Resources Information Centre


For reporting fish die-offs, call:



John Lumsden