Isolation and Genetic Characterization of Mangshi Virus: A Newly Discovered Seadornavirus of the Reoviridae Family Found in Yunnan Province, China

BACKGROUND: Seadornavirus is a genus of viruses in the family Reoviridae, which consists of Banna virus, Kadipiro virus, and Liao ning virus. Banna virus is considered a potential pathogen for zoonotic diseases. Here, we describe a newly discovered Seadornavirus isolated from mosquitos (Culex tritaeniorhynchus) in Yunnan Province, China, which is related to Banna virus, and referred to as Mangshi virus. METHODS AND RESULTS: The Mangshi virus was isolated by cell culture in Aedes albopictus C6/36 cells, in which it replicated and caused cytopathic effects, but not in mammalian BHK-21 or Vero cells. Polyacrylamide gel analysis revealed a genome consisting of 12 segments of double-stranded RNA, with a “6–4–2” pattern in which the migrating bands were different from those of the Banna virus. Complete genome sequencing was performed by full-length amplification of cDNAs. Sequence analysis showed that seven highly conserved nucleotides and three highly conserved nucleotides were present at the ends of the 5′- and 3′-UTRs in each of 12 genome segments. The amino acid identities of Mangshi virus shared with Balaton virus varied from 27.3% (VP11) to 72.3% (VP1) with Banna virus varying from 18.0% (VP11) to 63.9% (VP1). Phylogenetic analysis based on amino acid sequences demonstrated that Mangshi virus is a member of the genus Seadornavirus and is most closely related to, but distinct from, Balaton virus and Banna virus in the genus Seadornavirus of the family Reoviridae. CONCLUSION: Mangshi virus isolated from mosquitoes (C. tritaeniorhynchus) was identified as a newly discovered virus in the genus Seadornavirus and is phylogenetically close to Banna virus, suggesting that there is genetic diversity of seadornaviruses in tropical and subtropical areas of Southeast Asia.