The Current Problem : Koi Herpesvirus (khv)

Koi herpesvirus (KHV) is a pathogen agent that predominantly affects common and koi carp (Cyprinus carpio and Cyprinus carpio koi, respectively) causing disease and mass mortality in farmed and wild populations of these breeds. Following the first reports of KHV in Israel and Germany in 1998, the geographical range of this disease has become extensive. The disease has been spread to many countries worldwide, predominantly through the trade in koi carp and it is now known to occur at least 28 countries. Most recently KHV outbreaks have been reported to the World Organization for Animal Health from Romania, Slovenia, Spain and Sweden. Morbidity of affected populations can be 100% and mortality 70–80%, but the latter can be as high as 90 or 100% . Disease patterns are influenced by virulence of the virus, age and condition of the fish, population density and stress factors. The disease is temperature dependent, too, occurring between 16 and 25°C. Symptoms include mottled gills, bleeding gills, blisters or pale patches on the skin, sunken eyes, constant, lethargic and uncoordinated swimming.