The discovery of viral hemorrhagic septicemia, which makes fish bleed to death, in Ohio's Clear Fork Reservoir has prompted investigators to catch and examine hundreds of fish in a effort to track down the source of the outbreak, the Columbus (Ohio) Dispatch reported Monday.

"The bug is out," Ken Phillips, a U.S. Fish and Wildlife Service microbiologist based in La Crosse, Wis., told the newspaper. "In theory, it could make it all the way to the Mississippi River."

They say the disease can kill trout, perch, walleye and other game fish by the thousands, adding that there is no known way to stop its spread or kill the virus.

"It could be devastating," said Larry Mitchell Sr., president of the League of Ohio Sportsmen and the Ohio Wildlife Federation.

Officials say the virus could also pose a threat to Ohio's fish hatcheries, which are now under quarantine. The Dispatch reported that in 2006, the virus killed tens of thousands of freshwater drum and yellow perch in Lake Erie.