COLUMBUS — The Ohio Department of Natural Resources has confirmed that viral hemorrhagic septicemia (VHSv), a virus that causes disease in fish, but does not pose any threat to public health, was confirmed present in muskellunge sampled during routine egg collection in Clear Fork Reservoir in late April.
The reservoir is located in Richland and Morrow counties.
No fish kill yet
The virus was found in ovarian fluid samples collected from the muskellunge as part of routine ODNR testing for VHSv, but has not resulted in a fish kill.
The samples were sent to the U.S. Fish and Wildlife Service (USFWS) Fish Health Center in LaCrosse, Wis., where the VHSv virus was initially isolated. It was later confirmed at the National Veterinary Services Laboratory, USDA Animal Plant Health Inspection Service in Ames, Iowa. These results mark the first isolation of VHSv outside the Great Lakes Basin.
Fisheries officials believe VHSv has been a factor in recent fish kills of several species of fish in the Great Lakes that correspond with the end of spring spawning.
Background
VHSv was first isolated as a virus in 1963, and is presumed responsible for European fish kills as far back as 1938. In 1988, the virus was first detected in marine fishes in the Pacific Northwest.
VHSv is a pathogen of international concern and is reportable to the World Organization for Animal Health.
In 2005, VHSv was first reported in the Great Lakes, but may have been responsible for fish kills since 2003. VHSv has been responsible for numerous fish kills in lakes Erie, Huron, Michigan and Ontario.
The virus has also been the cause of fish mortality in several inland lakes in the states of Michigan, New York and Wisconsin — all within the Great Lakes Basin. As a result, APHIS issued an emergency order in 2006 restricting the interstate movement of live fish of susceptible species from the states and provinces of the Great Lakes.
Emergency orders
Many states around the Great Lakes, including Ohio, developed their own emergency orders restricting intrastate movement to protect other watersheds within their states. For a list of susceptible species, visit www.aphis.usda.gov/.
“One likely possibility is that VHS will act like many other viruses in the environment. Typically, viruses or bacteria infect fish, which may lead to disease in the fish if they are susceptible. Once the disease is expressed in these fish, some percentage of the population will die,” said Ray Petering, chief of the DNR Fisheries Division.
What might happen
“Those remaining will survive and will develop immunity to the viruses or bacteria that cause a disease. Since there are no large-scale treatments for VHS that can be applied to fish in the wild, the presence of this new virus may result in spring fish mortalities that are abnormally high for a few years, as more fish encounter the virus. These mortalities may abate as fish begin to build immunity to the virus.”
Citizens are encouraged to report sick fish or fish kills by calling 1-800-WILDLIFE or use the ODNR Web site at www.dnr.state.oh.us then from the topic list select: Wildlife – Fishing & Hunting.
How you can help
Anglers should contact the ODNR if they observe large numbers of fish exhibiting any of the following: hemorrhaging in the skin, including large red patches particularly on the sides and on the head; multiple hemorrhages on the liver, spleen, or intestines; or hemorrhages on the swim bladder that give the otherwise transparent organ a mottled appearance.
This information will help ODNR track VHS and take appropriate actions to slow the spread of this virus.
Anglers and boaters can help prevent the spread of VHS and other viruses or bacteria that cause disease in fish by not transferring fish between water bodies, and thoroughly cleaning boats, trailers, nets and other equipment when traveling between different lakes and streams.
The use of a contact disinfectant such as a solution of 200 ppm chlorine bleach (5.1 ounces per 10 gallons of water) to clean vessels and live wells is very effective against VHS and other viruses and bacteria that cause disease in fish.
Soaking exposed items such as live wells, nets, anchors and bait buckets in a light disinfectant of 20 ppm chlorine solution (5.1 ounces of liquid household bleach per 100 gallons of water) for 30 minutes is also an effective method to prevent the spread of a wide range of aquatic nuisance species.
ODNR taking action
Routine surveillance, disinfection of eggs used in fish production, public education and additional VHS research will continue by the ODNR, Ohio Department of Agriculture and the U.S. Fish & Wildlife Service in an effort to minimize the spread of VHS and protect fish hatcheries.
