Viral hemorrhagic septicemia

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Viral hemorrhagic septicemia is a lethal virus infecting freshwater fish in the Great Lakes region of North America. The virus is not dangerous to humans. VHS previously had been found in only two Great Lakes — Ontario and Erie — and in Lake St. Clair, which links Erie and Huron.^[1]

VHS causes massive internal hemorrhaging of the internal organs of a known 37 species of fish in the Great Lakes basin, including muskellunge, freshwater drum, yellow perch, bluegills, crappie, shad, northern pike and suckers. It is not known to cause harm in humans. Emerald shiners, a popular baitfish, are also known to be infected.^[2]

Thoroughly cleaning boats, trailers, nets and other equipment when traveling between different lakes and streams also helps. A solution of one part chlorine bleach to 10 parts water kills the VHS virus and other germs that cause disease in fish. It also kills a wide range of aquatic nuisance species such as zebra mussels.^[3]

Of particular concern is that the disease has infected a broad range of fish species. Unlike the virus' European cousin, VHS has killed trout and perch, gobies, emerald shiners and muskies in Lake St. Clair. Then the DNR added whitefish, salmon and walleye to the list.^[4]

Infected fish basically bleed to death internally. Some fish show no external symptoms, but others show signs of infection that include bulging eyes, bloated abdomens, bruised-looking reddish tints to the eyes, skin, gills and fins. Some infected fish have open sores that may look like the lesions from other diseases or from lamprey attacks.^[5]

On January 25, 2007, the virus was detected for the first time in Lake Huron.^[6] The virus has been linked to several large fish kills in the Great Lakes. ^[7]