Koi herpesvirus (KHV) is a disease that affects fish such as common carp, goldfish and koi. The impact of KHV on native minnow species of North America is not fully known.
KHV disease is found worldwide and likely was introduced in North America from the release or escape of infected ornamental fish.
KHV is suspected to be the cause of a June 2011 fish kill which involved an estimated 300 to 500 common carp in Michigan.
"This virus is capable of large-scale common carp die-offs as seen in Ontario in 2007 and 2008," said Gary Whelan, DNR Fish Production Manager. "The virus is an internationally reportable disease, and it is being officially reported at this time."
source: Michigan Department of Natural Resources