First report of a CMTV-like ranavirus in farmed Percocypris pingi in China

Abstract

Ranaviruses were recognized as important pathogens from the late 1990s, which are global pathogens that have continued to severely threaten aquaculture and wildlife worldwide. In this study, we report an infection with a CMTV-like ranavirus in cultured Percocypris pingi (P. pingi), a rare fish species that originated in upper Yangtze River system of China. Naturally and experimentally infected fish exhibited body surface ulcers and enlarged spleen and kidney. Histological examination revealed intracytoplasmic inclusions in the liver, spleen and kidney. Meanwhile, hexagonal viral arrays were observed in cytoplasm of infected Epithelioma papulosum cyprini (EPC) cells. Animal experimental trials confirmed that this hexagonal virus, named P. pingi ranavirus (PPRV), was the causative agent. PPRV (Accession no. ON080858) contains a 106.7 kbp genome, with a GC content of 55.03% and 97 ORFs. The results of phylogenetic analysis of the complete genome and dot plot comparisons both confirmed that the virus was classified into the CMTV-like group. Phylogenetic analyses based on MCP, mMMP, DNA polymerase and ribonuclease III genes indicated that PPRV shared the nearest relationship to Triplophysa siluorides ranavirus (Accession no. FYL140220), Chinese giant salamander iridovirus (Accession no. KF512820) and Andrias davidianus ranavirus (Accession no. KF033124), which were from China. Amidst the expanding fish host range of CMTV-like ranaviruses, this is the first report of ranavirus infection in P. pingi.