Development of New PCR and Quantitative PCR Protocols for the Detection of Plecoglossus altivelis Poxvirus-like Virus in Atypical Cellular Gill Disease of Ayu

Abstract

Plecoglossus altivelis poxvirus-like virus (PaPV) is the presumptive causative agent of atypical cellular gill disease (ACGD), which has caused significant losses in aquaculture of ayu P. altivelis in Japan. ​In this study, we investigated a new PCR protocol and a quantitative PCR (qPCR) protocol with primers designed from the vaccinia virus A16L homologous gene sequence of PaPV. ​The new PCR showed a positive reaction for affected fish in all eight ACGD cases tested and no cross-reaction with carp edema virus, and was more sensitive than a PCR with BOKE30 primers. ​The qPCR quantified around 10⁸–10⁹ virus DNA copies/mg in the diseased fish gills.