Intra vitam assays for detecting fish infected with cyprinid herpesvirus 3 (CyHV-3)

Koi carp is one of the most sensitive variants of common carp Cyprinus carpio to cyprinid herpesvirus 3, commonly known as koi herpesvirus (KHV). Given that this species is traded at high prices throughout the world, intra vitam assays for detecting KHV in targeted fish with a high detection efficiency are essential. In this study, 4 intra vitam assays were compared with regard to their efficiency of detecting KHV in koi carp on each day after viral exposure via experimental infection. The results indicated that PCR from the gills and scales sampled by biopsy using dissecting scissors and forceps, respectively, can detect KHV for apparently longer periods than the other assays. This study also suggests that a PCR detection assay for environmental samples could be developed as a convenient intra vitam assay to confirm the presence of virus in environments inhabited by virus-shedding fish.