KHV disease data from wild Cyprinus carpio from Lake Elysian (Le Seuer, MN) and cohabitation disease trial of Cyprinus carpio, Pimephales promelas and Carassius auratus

Abstract

Koi herpesvirus (KHV) is an important pathogen worldwide and a common cause of mass mortality events of wild common carp (Cyprinus carpio) in North America, however reference strains and genomes obtained from wild carp are not available. Additionally, it is unclear if fishes native to North America are susceptible to KHV infection due to incomplete susceptibility testing. Here we present the first North American type strain and whole genome sequence of KHV isolated from wild carp collected from a lake with history and recent incidence of carp mortality. Additionally, the strain was used in an in-vivo infection model to test the susceptibility of a common native minnow (Pimephales promelas) and goldfish (Carrasius auratus) which is invasive in North America. Detection of KHV DNA was confirmed in the tissues of a single fathead minnow but the same tissues were negative for KHV mRNA and samples from exposed fathead minnows were negative on cell culture. There was no detection of KHV DNA or mRNA in goldfish throughout the experiment. KHV DNA in carp tissues was reproducibly accompanied by detection of KHV mRNA and isolation on cell culture. Additionally, environmental KHV DNA was detected on all tank filters during the study. These findings suggest that fathead minnows and goldfish are not susceptible to KHV infection and that detection of KHV DNA alone in host susceptibility trials should be interpreted with caution