Abstract
A second type of freshwater crab reovirus has been isolated from Chinese mitten crab, Eriocheir sinensis H. Milne Edwards, in China; we named it E. sinensis reovirus ( Es RV816). The negatively stained virion is a non‐enveloped icosahedral particle, 60 ± 5 nm in diameter. Its genome is composed of 10 dsRNA linear pieces exhibiting an electrophoretic pattern of 5/3/2. The largest segment (RNA‐1) was cloned and sequenced. The deduced amino acid sequence, corresponding to the RdRp of the virus, showed 26% identity with the RdRp of Operophtera brumata (L.) cypovirus 19 in the genus Cypovirus and 24% identity with RdRp of Nilaparvata lugens (Stal) reovirus in the genus Fijivirus . On the basis of its ultrastructure and physicochemical properties, this virus is quite different from other crab reoviruses, and particularly with another freshwater crab reovirus Es RV905, recently classified in a new genus Cardoreovirus . This virus ( Es RV816) possesses all the characters of the members of the reoviridae family and could represent a new genus.