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Aquaculture VHS Certification


[Bureau of Animal Health & Diagnostic Services]

VHS, Viral Hemorragic Septicemia is a highly contagious pathogen of fresh and saltwater fish. It causes clinical signs including internal hemorrhaging and death in susceptible species. The disease does not pose a risk to people, but the VHS virus has been found to infect at least 28 fish species.  Some fish will show no external signs while others show signs including bulging eyes, bloated abdomens, inactive or overactive behavior, and hemorrhaging in the eyes, skin, gills and at the base of the fins. Infected fish may also have lesions that look like those caused by other fish diseases. Therefore, testing is necessary to determine whether fish are infected. VHS has been reported in several of the Great Lakes and related tributaries where a number of large-scale die-offs of wild fish have occurred. VHS is classified as a reportable disease by the World Organization for Animal Health (OIE).

In the past, VHS was thought to be a concern only for trout and a few other freshwater fish raised for commercial aquaculture in Europe. However, the recent outbreak in the Great Lakes region appears to be a new strain of the virus. This new strain is responsible for die-offs in many freshwater species. A list of species susceptible to VHS is listed below.

It is not known how VHS was transferred to the Great Lakes or how long it has been in the waterways. The disease transmits easily between fish of all ages. Mortality is highest at water temperatures between 37 and 54 degrees Fahrenheit. Testing is necessary to determine whether a fish is infected. The Animal Diagnostic Laboratory at Penn State University has some capacity for fish necropsy and testing.

Sport fishermen and recreational boaters are asked to adhere to good bio-security practices while fishing or boating in waters where VHS has been found. Thoroughly clean fishing equipment, boats, and trailers before using them in a new body of water and do not transfer fish from one body of water to another.

Although VHS has yet to be detected in aquaculture facilities, individuals responsible for the movement of VHS-susceptible species, regardless of origin, should take these steps to protect their facilities:  

  • 1. Request a health certificate stating that those fish have been tested and are free of VHS prior to movement.
  • 2. Enact appropriate bio-security measures within your facility to prevent the spread of this, and other, infectious pathogens. Some elements of a bios-security plan include:
    • Cleaning and disinfection
    • Controlling the movements of people, animals, vehicles, and equipment
    • Isolating new and returning (e.g., brood stock) fish
    • Controlling effluent discharges
    • Conducting audits to evaluate implementation and effectiveness of the bio-security plan.

Species considered VHS susceptible by the Pennsylvania Department of Agriculture:

VHS-susceptible species. For purposes of this order, the term ''VHS-susceptible species'' shall include live animals of the following fish species, as well as any other species designated ''VHS-susceptible species'' by order of the Pennsylvania Fish and Boat Commission or USDA-APHIS after the effective date of this order: 

  • Bluegill (Lepomis macrochirus)
  • Bluntnose Minnow (Pimephales notatus)
  • Bullhead Catfish (Ictalurus spp.)
  • Brown Trout (Salmo trutta)
  • Burbot (Lota lota)
  • Channel Catfish (Ictalurus punctatus)
  • Chinook Salmon (Oncorhynchus tshawytscha)
  • Common Carp (Cyprinus carpio)
  • Crappies (Pomoxis  spp.)
  • Emerald Shiner (Notropis atherinoides)
  • Freshwater Drum (Aplodinotus grunniens)
  • Gizzard Shad (Dorosoma cepedianum)
  • Largemouth Bass (Micropterus salmoides)
  • Lake Trout  (Salvelinus namaycush)
  • Whitefish (Coregonus spp.)
  • Muskellunge (Esox masquinongy)
  • Northern Pike (Esox lucius)
  • Pumpkinseed (Lepomis gibbosus)
  • Rainbow Trout/Steelhead (Oncorhynchus mykiss)
  • Rock Bass (Ambloplites rupestris)
  • Round Goby (Appolonia melanostomus)
  • Redhorse Suckers (Moxostoma spp.)
  • Smallmouth Bass (Micropterus dolomieu)
  • Spottail Shiner (Notropis hudsonius)
  • Trout-perch (Percopsis omiscomaycus)
  • Walleye (Sander vitreus)
  • White Bass (Morone chrysops)
  • White Perch (Morone Americana)
  • White Sucker (Catostomus commersonii)
  • Yellow Perch (Perca flavescens)

The term ''VHS-susceptible species'' does not include dead animals, dead animal parts or the eggs of these species. The term ''VHS-susceptible species'' does not include any of the previously-listed species if it is no longer designated a ''VHS-susceptible species'' by USDA-APHIS after the date of this order.

VHS has not been found in commercially raised fish in the United States. Detections of VHS have been limited in North America to the wild ocean-going and freshwater fish. The goal of the Quarantine Order is to prevent the spread of the disease to aquaculture facilities. The following States are included in the Federal Order: Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin. New York, Pennsylvania, Michigan and Ohio have experienced fish die-offs due to VHS. While such die-offs have not been observed in Illinois, Indiana, Minnesota and Wisconsin, these states are considered to be at-risk of having the disease because they are part of the Great Lakes watershed and unimpeded natural fish movements between these bodies of water can spread the disease. Entire states rather than watersheds are included in the Federal Order because of the unrestricted intrastate movement of fish through human activity, because the federal government can more readily control movement between states and because watershed boundaries are not clearly defined or agreed upon. Future surveillance may be able to more closely delineate the presence of VHS in specific areas.

The amended Federal Order states that no VHS susceptible fish species from any of the eight Great Lakes states may move between states without documentation that the fish have tested negative for the VHS virus. Many states have added additional testing requirements that must be met for movement of fish into the respective state. Consult the state of destination for a complete list of importation requirements.

The portions of Erie, Crawford, and Potter counties that drain into Lake Erie and Lake Ontario are affected by the Pennsylvania Quarantine Order. Commercial fish dealers and propagators in the quarantined areas must do a representative testing of the fish population annually for VHS, for movement of fish outside of the quarantined area into other areas in Pennsylvania. Also, a completed aquaculture inspection certificate is needed for movement of fish out of the quarantine areas.  

If you suspect VHS, you should immediately report all findings


Mary Bates
Clerk Typist 3
(717) 783-9550