Characterization of Two Strains of Tribeč Virus Isolated in Ukraine

Isolation and characterization of two novel serotypes of Tibet orbivirus from Culicoides and sentinel cattle in Yunnan Province of China

Tibet orbivirus (TIBOV), a new candidate of Orbivirus genus, was initially isolated from mosquitoes in Tibet in 2009 and subsequently from both Culicoides and mosquitoes in several provinces of China and Japan. Little is known about the origin, genetic diversity, dissemination and pathogenicity of TIBOV, although its potential threat to animal health has been acknowledged. In this study, two viruses, V290/YNSZ and V298/YNJH, were isolated from the Culicoides and sentinel cattle in Yunnan Province. Their genome sequences, cell tropism in mammalian and insect cell lines along with pathogenicity in suckling mice were determined. Genome phylogenetic analyses confirmed their classification as TIBOV species; however, OC1 proteins of the V290/YNSZ and V298/YNJH shared maximum sequence identities of 31.5% and 33.9% with other recognized TIBOV serotypes (TIBOV-1 to TIBOV-4) and formed two monophyletic branches in phylogenetic tree, indicating they represented two novel TIBOV serotypes which were tentatively designated as TIBOV-5 and TIBOV-6. The viruses replicated robustly in BHK, Vero and C6/36 cells and triggered overt clinical symptoms in suckling mice after intracerebral inoculation, causing mortality of 100% and 25%. Cross-sectional epidemiology analysis revealed silent circulation of TIBOV in Yunnan Province with overall prevalence of 16.4% (18/110) in cattle, 10.8% (13/120) in goats and 5.5% (6/110) in swine. The prevalence patterns of four investigated TIBOV serotypes (TIBOV-1, -2, -5 and 6) differed from each one another, with their positive rates ranging from 8.2% (9/110) for TIBOV-2 in cattle to 0.9% (1/110) for TIBOV-1 and TIBOV-5 in cattle and swine. Our findings provided new insights for diversity, pathogenicity and epidemiology of TIBOV and formed a basis for future studies addressing the geographical distribution and the zoonotic potential of TIBOV.

Isolation and characterization of Wad Medani virus obtained in the tuva Republic of Russia

Wad Medani virus (WMV) belongs to the genus Orbivirus and is a poorly studied arbovirus with unclear medical significance. Presently, a limited number of WMV strains are characterized and available in NCBI GenBank, some isolated many years ago. A new WMV strain was isolated in 2012 from Dermacentor nuttalli ticks collected from sheep in the Tuva Republic, Russia, and sequenced using high-throughput methods. Complete coding sequences were obtained revealing signs of multiple intersegment reassortments. These point to a high variability potential in WMV that may lead to the formation of strains with novel properties. These new data on WMV can promote better understanding of: ecological features of its circulation; relationships within the genus Orbivirus; and the medical significance of the virus.

Genetic diversity of Kemerovo virus and phylogenetic relationships within the Great Island virus genetic group

Kemerovo virus (KEMV) is a member of the Great Island virus genetic group, belonging to the tick-borne arboviruses of the genus Orbivirus within the family Reoviridae. Nine strains of KEMV, which were isolated from various locations in Russia, were sequenced by high-throughput sequencing to study their intraspecific diversity and the interspecific relationships of viruses within the Great Island genetic group. For the first time, multiple reassortment within KEMV was reliably demonstrated. Different types of independently emerged alternative reading frames in segment 9 and heterogeneity of the viral population in one of the KEMV strains were found. The hypothesis of the role of an alternative open reading frame (ORF) in segment 9 in KEMV cellular tropism was not confirmed in this study.