Identification and genetic analysis of Kadipiro virus isolated in Shandong province, China.

BACKGROUND: Kadipiro virus (KDV) belongs to the Reoviridae family, which consists of segmented, non-enveloped, double-stranded RNA viruses. It has previously been isolated from Culex, Anopheles, Armigeres and Aedes mosquitoes in Indonesia and China. Here, we describe the isolation and characterization of SDKL1625 from Anopheles sinensis mosquitoes in Shandong province, China. METHODS: In this study, we isolated Kadipiro virus in Aedes albopictus C6/36 cell culture and the complete genome sequencing was made by next generation sequencing. RESULTS: We isolated and characterized a Kadipiro virus from Anopheles sinensis mosquitoes in 2016 in Shandong province, China. Nucleotide and amino acid homology analysis of SDKL1625 showed higher levels of sequence identity with QTM27331 (Odonata, China, 2016) than with JKT-7075 (Culex fuscocephalus, Indonesia, 1981). The SDKL1625 has 86-97% amino acid identity with the JKT-7075, 88-99% amino acid identity with the QTM27331. Among the 12 fragments, VP1, VP2, VP4, VP6, VP7, VP9 and VP12 showed high amino acid identity (> 90%) and VP5 showed the lowest identity (86% and 88%). CONCLUSIONS: This is the first identification of KDV from mosquito in China. Virus morphology and genome organization were also determined, which will further enrich our understanding of the molecular biological characteristics of KDV and seadornaviruses.

A novel Coltivirus-related virus isolated from free-tailed bats from Côte d'Ivoire is able to infect human cells in vitro.

BACKGROUND: Zoonotic transmission events play a major role in the emergence of novel diseases. While such events are virtually impossible to predict, wildlife screening for potential emerging pathogens can be a first step. Driven by recent disease epidemics like severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and Ebola, bats have gained special interest as reservoirs of emerging viruses. METHODS: As part of a bigger study investigating pathogens in African bats we screened animals for the presence of known and unknown viruses. RESULTS: We isolated and characterised a novel reovirus from blood of free-tailed bats (Chaereophon aloysiisabaudiae) captured in 2006 in Côte d'Ivoire. The virus showed closest relationship with two human pathogenic viruses, Colorado tick fever virus and Eyach virus, and was able to infect various human cell lines in vitro. CONCLUSION: The study shows the presence of a coltivirus-related virus in bats from Sub-Sahara Africa. Serological studies could help to assess its impact on humans or wildlife health.

Structural organization of an encephalitic human isolate of Banna virus (genus Seadornavirus, family Reoviridae).

Banna virus (BAV) is the type species of the genus Seadornavirus within the family Reoviridae. The Chinese BAV isolate (BAV-Ch), which causes encephalitis in humans, was shown to have a structural organization and particle morphology reminiscent of that of rotaviruses, with fibre proteins projecting from the surface of the particle. Intact BAV-Ch virus particles contain seven structural proteins, two of which (VP4 and VP9) form the outer coat. The inner (core) particles contain five additional proteins (VP1, VP2, VP3, VP8 and VP10) and are 'non-turreted', with a relatively smooth surface appearance. VP2 is the 'T = 2' protein that forms the innermost 'subcore' layer, whilst VP8 is the 'T = 13' protein forming the core-surface layer. Sequence comparisons indicate that BAV VP9 and VP10 are equivalent to the VP8* and VP5* domains, respectively, of rotavirus outer-coat protein VP4 (GenBank accession no. P12976). VP9 has also been shown to be responsible for virus attachment to the host-cell surface and may be involved in internalization. These similarities reveal a previously unreported genetic link between the genera Rotavirus and Seadornavirus, although the expression of BAV VP9 and VP10 from two separate genome segments, rather than by the proteolytic cleavage of a single gene product (as seen in rotavirus VP4), suggests a significant evolutionary jump between the members of these two genera.

Genus Coltivirus (family Reoviridae): genomic and morphologic characterization of Old World and New World viruses.

We report a genomic and morphologic study of the European Eyach (EYA) virus (genus Coltivirus, family Reoviridae) and a comparative analysis with the American Colorado tick fever (CTF) virus (the type species of the genus). The previously established, but distant, antigenic relationship between these viruses was strengthened by genetic findings (presence of cognate genes, amino acid identity between 55 and 88%, similar conserved terminal motifs, suspected read-through phenomenon in segment 9 of both viruses) and by indistinguishable ultramicroscopic morphologies. Moreover, putative constitutive modifying enzyme activities were suspected to be carried out by homologous viral proteins (RNA-dependent RNA polymerase, methyl/guanylyl transferase, NTPase). These findings, together with the comparative analysis to genomes of southeast Asian isolates, support the recent classification of arboviruses with 12 segments of dsRNA within two distinct genera (genus Coltivirus and genus Seadornavirus) and raise interesting questions about the evolutionary origins of coltiviruses. The previously proposed hypothesis that EYA virus was derived from an ancestral virus introduced in Europe with the migration of lagomorphs from North-America, would imply a divergence date between American and European isolates of over 50 million years ago (MYA). This analysis allows for the first time to propose an evolutionary rate for virus dsRNA genomes which was found to be in the order of 10(-8) to 10(-9) mutations/nt/year, a rate similar to that of dsDNA genomes.