Biological invasion of a fish pathogen, cyprinid herpesvirus 3, into Japanese freshwater ecosystems

Abstract

Cyprinid herpesvirus 3 was first isolated from cultured koi and common carp that were undergoing mass mortality in the USA and Israel in 1998. The first outbreak of this virus in Japan occurred in 2003, and had spread to various lakes and rivers by 2004. In the same year, the virus killed more than 100,000 wild common carp in Lake Biwa, while those that survived infection would become carriers of the virus, possibly serving as a source of the virus in Lake Biwa after the initial outbreak. Transmission of the virus might well occur during the group spawning of common carp.