MADISON, Wis. (AP) -- A deadly fish virus has been found in the Lake Winnebago chain of lakes -- the first such infection confirmed in inland Wisconsin waters, the state Department of Natural Resources said Saturday.
Two freshwater drum fish, or sheepshead, from Little Lake Butte des Morts preliminarily tested positive for viral hemorrhagic septicemia, or VHS, which causes anemia and hemorrhaging in fish, the DNR said in a news release.
The disease is a "major fish health crisis," the agency said.
"We're concerned. We don't really know what it means in the long term," said George Boronow, a regional fisheries coordinator with the DNR. "We expect it could be devastating on our fish populations."
Other freshwater drum samples taken from Lake Winnebago, home to a large population of sturgeon, also appear to have the virus, the DNR said.
The DNR said it has received reports of hundreds of freshwater drum dying in Lake Winnebago. The disease has so far not shown up in sturgeon, but that doesn't mean it won't, Boronow said.
State fish experts suspect the disease is also in Lake Michigan, Lake Superior and the Mississippi River.
There were major fish die-offs in 2005 and 2006 on the shorelines of Lake St. Clair, Lake Erie, Lake Ontario and on the St. Lawrence River, Boronow said.
VHS is not a threat to humans who eat or handle the infected fish, but it can infect more than 25 game fish, panfish and bait fish species.
Boronow urged anglers and others to take caution so they don't further spread the disease.
Last month the state enacted emergency rules to prevent the spread of VHS to inland waters. The rules prohibit anglers and boaters from moving live fish, and requires them to drain their boats and live wells before leaving Wisconsin's Great Lakes waters, the Mississippi River and those waters' tributaries up to the first dam.
Walleye, spotted musky, yellow perch, bluegill and northern pike are susceptible to VHS. Others include smallmouth bass, crappie, muskellunge, round gobies and some sucker species, the DNR said.
The DNR said it's unclear exactly how the disease is spread but it appears it could be shed by infected fish into the water through waste material, particularly by fish that survive the disease and become carriers. It appears that carrier fish become more resistant to the disease but their offspring do not, Boronow said.