Viral Hemorrhagic Septicemia An acute to chronic, highly contagious viral disease of fish which is expanding its range and the species it infects “The Ebola virus of fish” - Anonymous - Anonymous

A BRIEF HISTORY OF VHS  First reported in rainbow trout in Germany in 1938  Called Egtved disease in cultured rainbow trout in Denmark ( )  Primarily an enzootic viral disease in rainbow trout and turbot in Europe, Sweden and Finland (Types I-III)  Virus brought to US for experimental purposes

A BRIEF HISTORY OF VHS (CONTINUED)  Isolated in Pacific herring and pilchard along the Pacific Coast of North America (Type IVa)  Recently appeared in the Great Lakes Basin (Type IVb) – affects many more species than other types of the virus ( ) Found in Lake St. Clair, Lake Ontario, Lake Erie, the St. Lawrence River, and Lake Conesus  Identified near Lake Winnebago, Wisconsin, Lake Michigan, Lake Huron and Budd Lake (2007)  At least 42 species affected

SPECIES AFFECTED TO DATE Atlantic cod Black crappie Bluegill Bluntnose minnow Brown bullhead Brown trout Brook trout Burbot Channel catfish Chinook salmon Coho salmon Chum salmon Emerald shiner Freshwater drum Gizzard shad Grayling Haddock Herring Japanese flounder Largemouth bass Mummichog Muskellunge Pacific cod Pike Pink salmon Pumpkinseed Rainbow trout Redhorse sucker Rock bass Rockling Round goby Silver and shorthead redhorse Smallmouth bass Sprat Stickleback Striped bass Turbot Walleye White bass White perch Whitefish Yellow perch FISHES IN RED OCCUR IN COLORADO

CAUSE OF VIRAL HEMORRHAGIC SEPTICEMIA Rhabdovirus (bullet-shaped) VHS is NOT a human pathogen The VHS virus is a reportable animal disease There is no current treatment for the virus

Viral hemorrhagic septicemia virus VHS viral particles on fish epithelium. Scanning electron microscope at 48,000 X magnification. From Kunkel, Dennis Microscopy Science and Photography through a Microscope.

HOW IS THE VHS VIRUS SPREAD? Ballast water Effluent (virus can last several weeks) Wildlife Fomites Live fish Fish offal

OTHER POTENTIAL VECTORS OTHER POTENTIAL VECTORS Has been found in Zebra Mussels, an invasive aquatic species Has been found in Zebra Mussels, an invasive aquatic species Has been found in the regurgitated contents from birds Has been found in the regurgitated contents from birds Other invertebrates could potentially carry the virus Other invertebrates could potentially carry the virus Unknown if they can spread infective forms of the disease (may be dose- dependent) Unknown if they can spread infective forms of the disease (may be dose- dependent) ??? Frozen baitfish ??? ??? Frozen baitfish ??? Bottom photo courtesy of Pete Walker

HOW LONG DOES THE VIRUS LAST IN WATER? Depends on water temperature and whether it is fresh or sea water Depends on water temperature and whether it is fresh or sea water Type IVb (yellow) lasted up to 49 days in unfiltered freshwater (Kyle Garver) Type IVb (yellow) lasted up to 49 days in unfiltered freshwater (Kyle Garver) Unfiltered fresh water Unfiltered sea water pfu = plaque forming units

TRANSMISSION OF VHS FISH TO FISH FISH TO FISH –Urine, feces, sexual fluids POSSIBLE VERTICAL TRANSMISSION POSSIBLE VERTICAL TRANSMISSION –Appears to be a surface contaminant ENTRY TO FISH ENTRY TO FISH –Thought to gain entry via secondary gill lamellae

OTHER INFORMATION Transmissible to all ages of fish Transmissible to all ages of fish Survivors can become life-long carriers that shed virus Survivors can become life-long carriers that shed virus Mortality occurs at 37-50° F (seen in Spring) Mortality occurs at 37-50° F (seen in Spring) At temperatures >59°F death rarely occurs At temperatures >59°F death rarely occurs

CLINICAL SIGNS OF VHS

SKIN HEMORRHAGES SKIN HEMORRHAGES Photos: Garth Traxler (USGS, Seattle WA), Dr Jim Winton (USGS, Seattle WA), Dr Mohamed Faisal (MSU, Lansing MI) and Dr Paul Bowser (Cornell, Ithaca NY)

HEMORRHAGES OF INTERNAL ORGANS Photos: Garth Traxler (USGS, Seattle WA), Dr Jim Winton (USGS, Seattle WA), Dr Mohamed Faisal (MSU, Lansing MI) and Dr Paul Bowser (Cornell, Ithaca NY)

EXOPHTHALMIA ASCITES EXOPHTHALMIA ASCITES Photos: Garth Traxler (USGS, Seattle WA), Dr Jim Winton (USGS, Seattle WA), Dr Mohamed Faisal (MSU, Lansing MI) and Dr Paul Bowser (Cornell, Ithaca NY)

HEMORRHAGES HEMORRHAGES IN MUSCLE IN SWIM BLADDER Photos: Garth Traxler (USGS, Seattle WA), Dr Jim Winton (USGS, Seattle WA), Dr Mohamed Faisal (MSU, Lansing MI) and Dr Paul Bowser (Cornell, Ithaca NY)

FISH KILLS FISH KILLS Makah Tribal Salmon Hatchery, Washington – 1988 (Coho salmon)

DIAGNOSING VHS IN THE LAB DIAGNOSING VHS IN THE LAB FRESH KIDNEY AND SPLEEN TAKEN FROM FISH GROWN AT SPECIFIC TEMPERATURES ON APPROPRIATE CELL LINES TO LOOK FOR CYTOPATHIC EFFECTS CONFIRMED BY SEROLIGICAL TESTS AND PCR

What is being done nationally to prevent spread of VHS October 24, 2006 – Federal Order issued preventing interstate transport 37 species of LIVE fish from the 8 states and 2 Canadian provinces surrounding Great Lakes November 14, 2007, amended the order allowed importation or interstate travel of VHS-susceptible live fish under certain conditions – relaxed the laws somewhat to decrease hardship on the aquaculture industry of those states and provinces. May 4, 2007 – allowed catch and release activities Only applies to live fish (fertilized eggs, gametes, dead fish, organs, blood, scales not covered) Future issuance of a proposed USDA/APHIS ruling or amendment - currently there is no national fish regulation in place to regulate interstate fish movements

WHAT IS THE FUTURE OF VHS? WHAT IS THE FUTURE OF VHS IN UNITED STATES AND COLORADO? ● OBVIOUSLY A POTENTIALLY DANGEROUS VIRUS ● VIGILANCE IS NECESSARY ● VIRULENT VIRUS CAPABLE OF INFECTING MANY SPECIES UNDER A WIDE RANGE OF CONDITIONS

Slide show developed by: Carolyn Gunn, DVM Aquatic Animal Health Lab Colorado Division of Wildlife Brush, Colorado

What is being done in Colorado? Continued inspections of salmonids Monitoring other fish species Article VII, #014, C1a gives the state authority to stop importation of prohibited disease agents, including VHSv. Review and amendment of current aquatic species importation and transportation rules (Fish Health Board and Wildlife Commission) Looking at importations on a case-by-case basis

What happens if this disease gets into a fish production facility? Report to CDA, USDA-APHIS, OIE and Director Destruction, quarantine, disinfection Complete disinfection of facility