First detection of koi herpesvirus and carp oedema virus in Iraq associated with a mass mortality in common carp ( Cyprinus carpio )

At the end of October 2018, a mass fish mortality occurred in Iraq, involving thousands of tons of cultured and wild common carp (Cyprinus carpio) along Euphrates and Tigris rivers. Fish were found dead or moribund along rivers coasts, showing lethargy, dyspnoea and flared gills. At necropsy, discoloration patches were noticed on the gills. Wet preparations showed rare metacercariae and Dactylogyrus spp. Samples were subjected to bacteriological tests and virological investigation through real-time PCR and nested PCR. Both were positive for koi herpesvirus (KHV) and carp oedema virus. Results obtained were confirmed by the OIE reference laboratory of KHV disease (KHVD) at Cefas (UK) and by sequence analysis. This is the first report on the detection of both viruses in Iraq.