First report of a new strain of the emerging pollinator disease, Deformed Wing Virus, which exists as a diverse complex of variants. DWV type C

Abstract Treatment and control of both established and emerging infectious (RNA) viruses is hampered due to high mutation and replication rates enabling these viruses to operate as swarms of variants. Declining honeybee populations have been attributed to the ectoparasitic mite Varroa destructor and its affiliation with Deformed Wing Virus which contains several variants including, Deformed Wing Virus (DWV) kakugo virus (KV) and Varroa destructor virus-1 (VDV-1). In the current study we use next generation sequencing to investigate the DWV quasispecies, for which we have sequenced and assembled the DWV variant as well as a novel master variant. Using phylogenetics we show that the DWV species complex is made up of three master variants, and suggest these master sequence genotypes are named DWV type A (DWV/ KV), type B (VDV-1) and type C. To investigate the phylogenetic relationship of the new variant with known genotypes, analysis of a conserved region of the RdRp amino acid sequence as well as the whole polyprotien encoding nucleotide sequence (including a molecvular clock model) was carried out. The results suggest that type C viral strain is distinct from type A and B, but together they form a distinct clade to other members of the iflaviridae. The molecular clock estimation predicts that type C diverged from type A and B DWV variants roughly 320 years ago. The discovery of a novel variant of DWV and it’s further study has important implications for the management of global honeybee populations.