Koi Herpes Virus Kills 16,000 Carp in Missouri Lake

Biologists speculate an infected koi or goldfish may have been dumped into the lake.

June 21, 2012

KVH caused a common carp die off in a Missouri lake.

According to the Missouri Department of Conservation, a die-off of common carp in a Missouri lake was caused by the koi herpes virus (KHV) . Approximately 16,000 common carp died at Blue Springs Lake the week just before Memorial Day. It is speculated that someone introduced the virus in the lake by dumping a piece of infected bait, or an infected koi or goldfish into the lake.

The koi herpes virus, first documented in England in 1996, is most associated with the common carp as well as koi. The virus is common with ornamental koi, although goldfish can carry the virus without showing any symptoms. Fish other than carp are not affected by the virus.

According to an information sheet published by the University of Florida, KHV has an 80 to 100 percent mortality rate, and there is no cure for the disease. Symptoms include mottled gills with red and white patches, bleeding gills, blisters or pale patches on the skin, sunken eyes, constant and lethargic surface swimming, respiratory distress and uncoordinated swimming. Fish infected with the virus tend to die when water temperatures reach 72 to 78 degrees Fahrenheit, while fish infected with the virus living in waters with lower temperatures tend to survive. There is no documented occurrence of the virus at or higher than 86 degrees Fahrenheit.