Isolation And Characteristics Of XJ Orthoreovirus From Bats

The globe spread of SARS has caused devastating loss of human life and economy. The search for the primary reservoir host of SARS-CoV led to the finding of novel coronaviruses among bats in Hong Kong. One of these was detected in Chinese horseshoe bats (Rhinolophus sinicus (R.rouxii)) in Hong Kong which is currently named bat SARS-CoV (bat-SARS-CoV).As a natural reservoir of manifold zoonotic viruses, bats have been involved in several emerging zoonoses in recent years,Such as Hendra virus,Nipah virus which has caused devastating loss of human life and economy。Bats belong to the Order Chiroprera, which is the second large Order in mammalia. At present there are about 1000 recognized species worldwide, making up almost a quarter of all known mammal species. There are 11 species of fruit bats in China, which are Rousettus leschenaulti, Ramplexicaudatus, Pteropus dasymallus, P. lylei, P.vampyrus, P. giganteus, Cynopterus sphinx, C. brachotis,Sphaerias blanfordi, Eonycteris spelaea, E. sobrinus.However, the ecology and behaviour of these bats remain,despite some very patchy preliminary work, largely unknown。It is obvious then that the lives of humans and fruit bats become more and more intertwined, which as a consequence exposes us to manifold zoonotic viruses. The time has come to begin including fruit bats in the surveillance of pathogen-carrying reservoirs.We have isolated 3 strains virus from 150 bats,Which obtained from Guan Dong province,by Vero-E6 cells and BHK-21 cells.A virus from lung of Rousettus leschenaulti ,named XJ Virus (XJV) ,Which is the subject of this study.XJV causing a syncytial cytopathic effect(CPE)in Vero-E6 cells. When examined by negative contrast electron microscopy, XJV in the culture medium of infected cells contained naked isometric particles approximately 75 nm in diameter. The outer capsid displayed ringlike structures, the centres of which were penetrated with stain. Examination of ultrathin sections of syncytia revealed the presence of viral particles within the cytoplasm and associated with cytoplasmic inclusion bodies. XJV replicted and caused syncytial CPE in all type of mammalian cell lines available in laboratory. Two styles of CPE on different cells,Vero-E6 cells and BHK-21 cells represent respectively.The first reovirus of bat origin, NBV, was isolated in 1968 from the heart blood of a flying fox (Pteropus poliocephalus) in New South Wales, Australia. NBV was the first mammalian orthoreovirus to display the fusogenic properties characteristic of avian orthoreoviruses. Pulau virus (PulV), was isolated from Pteropus hypomelanus.Serological and sequence characterization revealed that PulV was closely related to NBV. of Melaka virus (MelV), the third virus in the NBV species group, and its isolation from a human patient with fever and acute respiratory illness. It is not known whether these bat orthoreoviruses are capable of infecting and causing disease in animals or humans. Data indicate that not only was the MelV capable of human-to-human transmission, but also that its origin was probably bats. Furthermore, serological survey data suggest that the related bat-derived PulV is also capable of infecting humans,raising the possibility that PulV might have caused respiratory illness that was undiagnosed or misdiagnosed in the past.The defining characteristics for inclusion within the genus include: (1) a genome comprising 10 segments of dsRNA grouped into large, medium, and small size-classes which encode the correspondingλ,μ, andσ-class viral proteins; (2) a polycistronic S-class genome segment encoding 2–3 distinct gene products; (3) a double-shelled capsid of approximately 85-nm diameter with turret-like structures projecting from the vertices of the core particle; and (4)isolation from vertebrate hosts .XJV isolated from fruit bat, SDS-PAGE show the virus contain 10 segments,When XJV compared to NBV,Pulau Virus,Melaka Virus ,the S segment nucleotide sequences identity S1:60-49.8%;S2:86.1-95.3%;S3:86.3-96.0%;S4:81.3-88.3%f,while the deduced protein sequence encoded by the S2 and S4 gene had sequence identityσA:97.8-99.3%;σB:90.6-95.3%.So we suggest that XJV as the forth virus in the NBV species group.