IDNR Report

A July carp kill at Roush Lake in Huntington County resulted from a virus that only affects common carp and koi, according to DNR fisheries biologists.

Fish collected from the lake and sent to Purdue University in July tested positive for koi herpes virus (KHv).

On July 20, DNR officials received reports of dead carp in the lake. Five days later, fisheries biologist Jed Pearson collected dead carp and captured six live carp and transported them to Purdue's Animal Disease Diagnostic Lab (PADDL) in West Lafayette.

PADDL suspected KHv and sent tissue samples to the National Veterinary Services Lab (NVSL) in Ames, Iowa. On Aug. 20, NVSL reported that it recovered KHv from gill and kidney tissue.

KHv only affects common carp and koi, an ornamental carp. It cannot infect humans. Outbreaks can occur from late spring to early fall. Young carp are most susceptible, but a major kill can include up to 90 percent of adults.

Symptoms include mucus, white patches, gill damage, lethargy, loss of equilibrium, and signs of suffocation. Skin hemorrhaging may or may not be present. When terminal, a bacterial infection will have developed.

An additional stress event is necessary to cause a fish kill in infected fish. Stressors include spawning, fluctuating temperatures, low water levels, stagnant water and low oxygen levels.

To prevent spread of KHv, clean, rinse and dry boats, fishing gear, and all equipment that came into contact with water. Don't forget the bilge and live well.