A multiplex RT-PCR assay for the detection of fish picornaviruses.

With the emergence of high profile fish diseases in the Great Lakes region, surveillance and regulatory inspections of fish populations have increased. This has resulted in a better understanding of known pathogens and isolation of many new pathogens of fish. In this study, a multiplex RT-PCR assay was developed for the detection of three newly discovered fish picornaviruses: bluegill picornavirus-1 (BGPV-1), fathead minnow picornavirus (FHMPV), and eel picornavirus-1 (EPV-1). This assay was found to be very sensitive with a detection limit of 81.9pg/μl of extracted RNA from a pool of FHMPV and BGPV-1 and was able to detect 501 and 224 gene copies/μl of BGPV-1 and FHMPV, respectively. The assay was highly reproducible and did not cross react with other closely related pathogens. We believe that this new assay provides a rapid and cost effective tool for confirming cell culture isolates and conducting prevalence studies of these newly detected fish picornaviruses.