Jokerball101
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Joined: 6/25/2008
From: Lake City
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Here is some information i dug up on VHS hope it helps
VHS in Great Lakes Fish
Important Questions and Answers on Viral Hemorrhagic Septicemia (VHS) in Great LakesFish.
During the past two years, the fish kills on Great Lakes have involved thousands of fish infected by the Viral Hemorrhagic Septicemia Virus (VHSV); this virus was not previously known to exist in the freshwater environment of North America.Here is some information on VHS compiled by NY Sea Grant.
What is VHS? What is the significance of the recent discovery of VHS in the Great Lakes?
Viral Hemorrhagic Septicemia is an infectious viral disease of fish that has been found in fish from the AtlanticCoast of Europe and Atlantic and PacificCoasts of North America. Historically, VHS was known as a very serious disease of freshwater-reared rainbow trout in Europe. At least four different genetic strains or forms of the virus are known to exist. The North American marine strain has a relatively low infection rate compared to that of the European freshwater strain.Until 2005, VHS was only found in the marine environment in North America. Several fish kills in the Lower Great Lakes since 2005 have been associated with VHS. To date, VHS has been confirmed from wild fish in the Bay of Quinte Lake Ontario, Lake St. Clair, Lake Erie and the St. Lawrence River. Scientists believe that this appearance may represent an invasion of the freshwater strain in North America.
What North American freshwater fish species are affected?
In the Great Lakes, VHS has been found in smallmouth bass, yellow perch, crappie, muskellunge, northern pike, bluegill, walleye, round gobies, sheepshead, and some sucker species. Scientists are concerned; however, that VHS could also strike native salmonids such as trout, salmon and whitefish in the wild, and salmonids in hatcheries and net pen operations.
What does it do to fish? What are the symptoms of a fish with VHSV infection?
Like many fish diseases, the type of symptoms present in a fish change with the severity of the infection.At low infection intensity fish may display few to no symptoms as is the case in most wild disease outbreaks.Hatchery or pen-reared fish are much more susceptible because of the confined conditions. As the infection severity increases, fish become darker and the eyes bulge with some bleeding around the eye and base of the fins. The gills are usually quite pale with some pin point bleeding.Mortalities appear at this point because hemorrhaging reduces the oxygen carrying ability of the blood. Dark red patches may appear on the front and sides of the head.
If the fish is opened up, bleeding on the surfaces of the intestine, liver, swim bladder can be seen. Fluid also builds up in the body cavity giving the fish a swollen belly. Later, if infection increases, the body continues to darken and the eyes really stick out of the head. At this point, the gills look gray or even white and the fish may swim in a corkscrew pattern. Most fish kills from VHS occur in water temperatures from 40 to 60 F (3-12 C) and few occur at temperatures above 62 F (15 C).NOTE:The detection of a VHS infection can only be made from sophisticated laboratory testing.A diagnosis cannot be made based solely on the observation of visible signs because many different diseases of fish have very similar signs of disease.
Is it a health risk to people?
There is no apparent health risk for people contracting VHS.Because it takes a long time to identify the causes of fish kills in lab studies, people should be cautioned against handling or eating any fish that does not act or appear to be healthy because of the risk of contracting avian botulism a bacterial disease that does pose a human health threat.
What should I do if I see a fish kill?
If you observe a fish kill on the Great Lakes, please contact the Wisconsin Department of Natural Resources at (608) 266-8782 or your local DNR office. If you see fish with any of the outward signs of VHS as described above please mention this as well.This will help biologists keep track of where the disease may be appearing.
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