November 9, 2007


USDA Amends VHS-Susceptible Species List

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) has amended its Federal Order on viral hemorrhagic septicemia (VHS) by revising the list of VHS-susceptible species. Since the VHS strain of concern is only known to occur in the Great Lakes region, the updated list includes only those species found in freshwater environments in the United States and Canada. The updated list only includes those species that have been infected with VHS under natural or non-experimental conditions and in which the virus has been isolated in a cell culture with the strain identified through molecular detection.

VHS is a destructive pathogen that, while not harmful to people, causes internal hemorrhaging and death in a wide range of fish species. APHIS issued the original October 2006 Federal Order in response to the rapid spread of VHS in the Great Lakes and related tributaries. That order prohibited the importation of 37 species of live fish from two Canadian provinces into the United States and the interstate movement of the same species from the eight states bordering the Great Lakes.

When APHIS originally issued the order, the agency took a conservative approach and restricted the movement of all species listed by the World Organization for Animal Health (OIE) as susceptible to all known strains of VHS. The species no longer affected by the Federal Order include:
Atlantic Cod (Gadus morhua)
Coho salmon (Oncorhynchus kisutch)
Chum salmon (Oncorhynchus keta)
Grayling (Thymallus thymallus)
Haddock (Gadus aeglefinus)
Herring (Clupea spp)
Japanese flounder (Paralichthys olivaceus)
Pacific cod (Gadus macrocephalus)
Pink salmon (Onchorhynchus gorbuscha)
Rockling (Onos mustelus)
Sprat (Sprattus spp)
Turbot (Scophthalmus maximus)
Whitefish (Coregonus spp).

APHIS also recently determined that several additional freshwater fish species not included in the original order are susceptible to VHS. These species originate in freshwater locations in the United States and/or Canada and have been infected by the VHS virus under natural (i.e. non-experimental) conditions of exposure. Scientists have been able to isolate the VHS virus in these species through laboratory testing. As a result, three new species are now listed in the Federal Order:
Lake whitefish (Coregonus clupeaformis)
Spottail shiner (Notropis hudsonius)
Trout-perch (Percopsis omiscomaycus).

Two species that remain on the Federal Order's VHS-susceptible list have had their scientific names clarified:
Shorthead redhorse (Moxostoma macrolepidotum)
Silver redhorse (Moxostoma anisurum).

APHIS issued the original Federal Order in response to the rapid spread of VHS in the Great Lakes region and the potential impact of the disease on a growing number of fish species, including species of fish raised commercially in the United States. Dead and diseased wild fish have been reported in the St. Lawrence River and in Lake Erie, Lake Huron, Lake Michigan, Lake Ontario and Lake St. Clair. Outbreaks of VHS have also been reported in inland lakes of Michigan, New York and Wisconsin.

The intent of the Federal Order is to prevent the introduction of VHS into aquaculture facilities by controlling the movement of live fish species from the Great Lakes region at risk of harboring the VHS virus. The order allows APHIS to gather more information on the disease and puts a federal regulatory program in place that allows for the interstate movement of fish susceptible to VHS via testing and certification.

This revised Federal Order will remain in effect until the interim rule is published. Both the modified and the original emergency order [and additional information] can be found on our Web site at http://www.aphis.usda.gov/animal_health/animal_dis_spec/aquaculture .

For additional information, please contact P. Gary Egrie by telephone at (301) 734-0695 or by e-mail at Paul.G.Egrie@aphis.usda.gov .