TOPEKA, Kan. (AP) — State wildlife and parks staff are collecting and testing samples from fish carcasses to determine whether a koi herpes virus is behind fish kills in at least two Kansas lakes.

According to the Kansas Department of Wildlife, Parks and Tourism, staff have confirmed die-offs at Pomona Reservoir in Osage County and Hillsdale Reservoir in Miami County. Anglers on social media have reported die-offs at other lakes, but they have not been confirmed.

The Topeka Capital-Journal reports that common carp are the only species that appear to be affected, leading staff to belief that the koi herpes virus is the cause. Test results should be back within 3 to 4 weeks, said department Chief of Public Affairs Nadia Reimer.

Brian Larsen, of Vassar, witnessed the fish kill at Pomona.

"It was latter part of May and into early June as we were fishing every day during the crappie spawn here," Larsen said. "Even while out canoeing for the fun of it, we were seeing hundreds of large, dead carp floating all over the lake. The smell was horrible."

Wildlife staff estimates that thousands of carp are affected, but the virus has no effect on other species, including humans.