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The genus Orbivirus, family Reoviridae, includes 22 species of viruses with genomes composed of ten segments of linear dsRNA that are transmitted between their vertebrate hosts by insects or ticks, or with no identified vectors. Full-genome sequence data are available for representative isolates of the insect borne mammalian orbiviruses (including bluetongue virus), as well as a tick borne avian orbivirus (Great Island virus). However, no sequence data are as yet available for the mosquito borne avian orbiviruses. We report full-length, whole-genome sequence data for Umatilla virus (UMAV), a mosquito borne avian orbivirus from the USA, which belongs to the species Umatilla virus. Comparisons of conserved genome segments 1, 2 and 8 (Seg-1, Seg-2 and Seg-8) - encoding the polymerase-VP1, sub-core 'T2' protein and coresurface 'T13' protein, respectively, show that UMAV groups with the mosquito transmitted mammalian orbiviruses. The highest levels of sequence identity were detected between UMAV and Stretch Lagoon orbivirus (SLOV) from Australia, showing that they belong to the same virus species (with nt/aa identity of 76.04%/88.07% and 77.96%/95.36% in the polymerase and T2 genes and protein, respectively). The data presented here has assisted in identifying the SLOV as a member of the Umatilla serogroup. This sequence data reported here will also facilitate identification of new isolates, and epidemiological studies of viruses belonging to the species Umatilla virus. [ABSTRACT FROM AUTHOR]

Eubenangee virus has previously been identified as the cause of Tammar sudden death syndrome (TSDS). Eubenangee virus (EUBV), Tilligery virus (TILV), Pata virus (PATAV) and Ngoupe virus (NGOV) are currently all classified within the Eubenangee virus species of the genus Orbivirus, family Reoviridae. Full genome sequencing confirmed that EUBV and TILV (both of which are from Australia) show high levels of aa sequence identity (>92%) in the conserved polymerase VP1(Pol), sub-core VP3(T2) and outer core VP7(T13) proteins, and are therefore appropriately classified within the same virus species. However, they show much lower amino acid (aa) identity levels in their larger outer-capsid protein VP2 (<53%), consistent with membership of two different serotypes - EUBV-1 and EUBV-2 (respectively). In contrast PATAV showed significantly lower levels of aa sequence identity with either EUBV or TILV (with <71% in VP1(Pol) and VP3(T2), and <57% aa identity in VP7(T13)) consistent with membership of a distinct virus species. A proposal has therefore been sent to the Reoviridae Study Group of ICTV to recognise 'Pata virus' as a new Orbivirus species, with the PATAV isolate as serotype 1 (PATAV-1). Amongst the other orbiviruses, PATAV shows closest relationships to Epizootic Haemorrhagic Disease virus (EHDV), with 80.7%, 72.4% and 66.9% aa identity in VP3(T2), VP1(Pol), and VP7(T13) respectively. Although Ngoupe virus was not available for these studies, like PATAV it was isolated in Central Africa, and therefore seems likely to also belong to the new species, possibly as a distinct 'type'. The data presented will facilitate diagnostic assay design and the identification of additional isolates of these viruses.