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Grass carp reovirus strain 109 (GCReV-109) was previously isolated from a grass carp ( Ctenopharyngodon idellus) with hemorrhagic disease, and its complete genome has been sequenced. However, the infectivity of GCReV-109 has not been studied, and the viral protein VP33, encoded on genome segment S11, had no detectable sequence homology to other known reovirus proteins. In this study, we characterized GCReV-109 infections in vivo and in vitro, as well as the VP33 protein. Infectivity analysis showed that GCReV-109 caused severe hemorrhagic disease and 100 % mortality at dilutions up to 10 in rare minnows ( Gobiocypris rarus) by 8 days postinfection, but no visible cytopathic effect was observed in GCReV-109-infected subcultured grass carp muscle (GCM) cells. To confirm that GCReV-109 could be propagated in GCM cells, three virus genome segments were detected by RT-PCR, and large numbers of virus particles were observed by transmission electron microscopy in samples from the infected GCM cells. The suspension of GCReV-109-infected GCM cells was pathogenic to rare minnows. VP33 protein was expressed and purified for generation of an anti-VP33 antiserum. In western blot analysis of purified GCReV-109 particles, the antiserum specifically recognized a protein band (approximately 33 kDa). This revealed that VP33 is a major structural protein of GCReV-109 that might have immunogenic properties. The protective efficacy of the anti-VP33 antiserum against GCReV-109 infection was tested. The death of infected fish was delayed and the mortality fell to 10 % when fish were treated with the anti-VP33 antiserum, suggesting that it might be useful for the prevention and control of fish reoviral disease. [ABSTRACT FROM AUTHOR]

Paralichthys olivaceus rhabdovirus (PORV), which is associated with high mortality rates in flounder, was isolated in China in 2005. Here, we provide an annotated sequence record of PORV, the genome of which comprises 11,182 nucleotides and contains six genes in the order 3′-N-P-M-G-NV-L-5′. Phylogenetic analysis based on glycoprotein sequences of PORV and other rhabdoviruses showed that PORV clusters with viral haemorrhagic septicemia virus (VHSV), genus Novirhabdovirus, family Rhabdoviridae. Further phylogenetic analysis of the combined amino acid sequences of six proteins of PORV and VHSV strains showed that PORV clusters with Korean strains and is closely related to Asian strains, all of which were isolated from flounder. In a comparison in which the sequences of the six proteins were combined, PORV shared the highest identity (98.3 %) with VHSV strain KJ2008 from Korea. [ABSTRACT FROM AUTHOR]