# Presentation: 572526

## 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**

## A BRIEF HISTORY OF VHS

- First reported in rainbow trout in Germany in 1938
- Called Egtved disease in cultured rainbow trout in Denmark (1949-50)
- 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 (2003-2006)  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

## 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

**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

- <date/time>

**VHS viral particles on fish epithelium.  Scanning electron microscope at 48,000 X magnification.**
**From Kunkel, Dennis.  2005.  Microscopy Science and Photography through a Microscope. **
**http://www.denniskunkel.com/.**

## HOW IS THE VHS VIRUS SPREAD?

- <date/time>

- Ballast water

- Effluent (virus can last several weeks)

- Wildlife

- Fomites

- Live fish

- Fish offal

##   OTHER POTENTIAL VECTORS

- <date/time>

-   OTHER POTENTIAL VECTORS

- Has been found in Zebra Mussels, an invasive aquatic species
- Has been found in the regurgitated contents from birds
- Other invertebrates could potentially carry the virus
- Unknown if they can spread infective forms of the disease (may be dose- dependent)
- ??? 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
- 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

- <date/time>

**TRANSMISSION OF VHS**

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

## OTHER INFORMATION

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

## CLINICAL SIGNS OF VHS

- <date/time>

##                 SKIN HEMORRHAGES         

- <date/time>

-                 **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

- <date/time>

*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

*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           

- <date/time>

- 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

- <date/time>

** ****FISH KILLS**

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

##  DIAGNOSING VHS IN THE LAB

- <date/time>

-  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

- 	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