In 2012-2018, 243 samples of blood, serum, urine and saliva of patients with acute febrile diseases hospitalized in medical institutions of Astrakhan, Astrakhan Region and Infectious Diseases Hospital №1 of Moscow were examined in experiments on intracerebral inoculation of newborn white mice. As a result, 8 strains of dengue 1 virus were isolated from patients infected in Thailand (7 strains) and Vietnam (1 strain); eight strains of dengue 2 virus from patients infected in Thailand (5 strains), Indonesia (2 strains) and the Maldives (1 strain); one strain of dengue 3 and one strain of Chikungunya virus (Asian genotype) from patients hospitalized after returning to Moscow from trips to the Philippines; 2 strains of Zika virus (Asian genotype) from patients visiting the Dominican Republic; 6 strains of Crimean-Congo hemorrhagic fever virus genotype Europe 1 and one West Nile virus strain of genotype 1a from patients of the Astrakhan region.

Chenuda virus (CNUV) (Orbivirus, Reoviridae) is the only known orbivirus associated with argas (Argasidae) ticks. Scientific study of this group is necessary for understanding of Orbivirus genus evolution patterns. We conducted a comparative analysis of full genomes of five different viruses of Chenuda virus species, including Baku virus strains (BAKV) circulating in a rather limited area in the Central Asia and Transcaucasia. It was shown that VP4(OC1) and VP6(Hel) proteins variability greatly exceeds the variability of other proteins. The divergence between CNUV and BAKV in this proteins is about 50%. Even in closely related strains isolated from the same geographical region, the conservative genes of which are 90-95% identical, the VP4(OC1) and VP6(Hel) divergence reaches values that would usually be indicative of different serotypes (74.1-82.2%).

Chenuda virus (CNUV) (Orbivirus, Reoviridae) is the only known orbivirus associated with argas (Argasidae) ticks. Scientific study of this group is necessary for understanding of Orbivirus genus evolution patterns. We conducted a comparative analysis of full genomes of five different viruses of Chenuda virus species, including Baku virus strains (BAKV) circulating in a rather limited area in the Central Asia and Transcaucasia. It was shown that VP4(OC1) and VP6(Hel) proteins variability greatly exceeds the variability of other proteins. The divergence between CNUV and BAKV in this proteins is about 50%. Even in closely related strains isolated from the same geographical region, the conservative genes of which are 90-95% identical, the VP4(OC1) and VP6(Hel) divergence reaches values that would usually be indicative of different serotypes (74.1-82.2%).

Genetic research into the Tyuleniy virus (TYUV) (ID GenBank KF815939) isolated in high latitudes from the Ixodes uriae White, 1852, ticks collected in the nesting colonies of the Alcidae (Leach, 1820) birds and Kama virus (KAMV) (ID GenBank KF815940) isolated from the I. lividus ticks collected in the nesting bird colonies in the middle part of the Russian Plane was carried out. Full-genome comparative analysis revealed 70% homology between KAMV and TYUV on the nucleotide level and 74% on the amino acid level. Thus, KAMV is a new member of the TYUV complex belonging to the seabird tick-borne virus group (STBVG) of Flavivirus (Flaviviridae). KAMV is a separate virus and forms separate phylogenetic line together with the TYUV, Meaban virus (MEAV), and Saumarez Reef virus (SREV).

The Artashat virus (ARTSV) was originally isolated fom the Ornithodoros alactagalis Issaakjan, 1936 (Argasidae Koch, 1844), which were collected in the burrow of small five-toed jerboa (Allactaga elater Lichtenstein, 1825) in Armenia in 1972. Later, the ARTSV was isolated from the O. verrucosus Olenev, Sassuchin et Fenuk, 1934 collected in the burrows of Persian gerbil (Meriones persicus Blanford, 1875) in Azerbaijan. Based on the virion morphology, the ARTSV was assigned to the Bunyaviridae viruses. In this work, the ARTSV genome was partially sequenced (GenBank ID: KF801650) and it was shown that the ARTSV is a new member of the Nairovirus genus. ARTSV has from 42% (Issyk-Kul virus) to 58% (Raza virus, Hughes group) similarity with the nairoviruses for nucleotide sequence of part of RNA-dependent RNA-polymerase (RdRp). The similarity on the amino acid level is 65-70%. Low level of homology and the equidistant position of the ARTSV on phylogenetic tree indicate that the ARTSV is a new prototype species of the Nairovirus genus (Bunyaviridae) forming a separate phylogenetic branch.

Complete genome sequencing of three Tamdy (TAMV) virus strains was carried out. The prototype strain TAMV/LEIV-1308Uz was isolated for the very first time from the Hyalomma asiaticum asiaticum Schülce et Schlottke, 1929 (Ixodidae, Hyalomminae) collected in the August 1971 from sheep in the arid area near Namdybulak town (41 degrees 36' N, 64 degrees 39' E) in the Tamdinsky district of the Bukhara region (Uzbekistan). TAMV was revealed to be a prototype member of the new phylogenetic group within the limits of the Nairovirus. The TAMV homology for RdRp (L-segment) amino acid sequence is not less than 40% with Crimea-Congo hemorrhagic fever virus (CCHFV), Hazara virus (HAZV), and Dugbe virus (DUGV), which are also linked with Ixodidae ticks. The TAMV homologies with the Issyk-Kul virus (ISKV) and Caspiy virus (CASV) for RdRp are 37.6% and 37.7%, respectively. These data conformed to the low values of GnGc (M-segment) and nucleocapsid protein N (S-segment) homology. The TAMV homologies with the nairoviruses for GnGc is in average 25%; with the nairoviruses linked with Ixodidae ticks (CCHFV, DUGV, HAZV) - 33%; with Argasidae ticks (ISKV, CASV) - 28%. The TAMV/LEIV-1308Uz, LEIV-6158Ar, and LEIV-10226Az have high level of identity. The TAMV/LEIV-10226Az from Azerbaijan has 99% homology for both nucleotide and amino acid sequences of the prototype TAMV/LEIV-1308Uz RdRp. The TAMV/LEIV-6158Ar from Armenia is more divergent and has 94.2% and 96.3% homologies with the TAMV/LEIV-1308Uz, respectively. The homology between the TAMV/LEIV-1308Uz and TAMV/LEIV-10226Az for GnGc is 93%. The TAMV/LEIV-6158Ar has 90% homology for this protein with the TAMV/LEIV-1308Uz and 93% with the TAMV/LEIV-10226Az, respectively. Differences in nucleocapsid protein between three TAMV strains are 5-7%.

The Gissar virus (GSRV) was originally isolated from the ticks Argas reflexus, Fabricius, 1794 collected in a dovecote of Gissar village in Tajikistan (38 degrees 40' N, 68 degrees 40' E). Using electron microscopy, GSRV was classified to Bunyaviridae without referring to genus due to the absence of the antigenic relation with known bunyaviruses. In the present paper genome of GSRV was sequenced (MiSeq, Illumina). Molecular genetics and phylogenetic analysis showed. GSRV has a high level of homology with the Grand Arbaud Virus (GAV) (94% for nucleocapsid protein, 87.5% for RdRp, and 82% for the envelope proteins GnGc) isolated from the ticks A. Reflexus in a dovecote in France. GSRV and GAV have a narrow ecological niche associated with the icks A. Reflexus and birds (predominantly Columbidae). According to the conducted study, GSRV is classified as the topotypic for Central Asia variant of GAV, Uukuniemi group, genuses of the Phlebovirus (Bunyaviridae) (ID GenBank KJ425423, KJ425424, KJ425425).

Full-length genomes of the Sakhalin virus (SAKH) and Paramushir virus (PRMV) (Sakhalin group, Nairovirus, Bunyaviridae) isolated from the ticks Ixodes uriae White 1852 were sequenced using the next-generation sequencing (Genbank ID: KF801659, KF801656). SAKV and PRMV have 81% identity for the part of RNA-dependent RNA-polymerase (RdRp) on the nucleotide level and 98.5% on the amino acid level. Full-length genome comparison shows that SAKV have, in average, from 25% (N-protein, S-segment) to 50% (RdRp, L-segment) similarity with the nairoviruses. The maximum value of the amino acid similarity (50.3% for RdRp) SAKV have with the Crimean-Congo hemorrhagic fever virus (CCHFV) and Dugbe virus (DUGV), which are also associated with the Ixodidae ticks. Another virus studied is Rukutama virus (RUKV) (isolated from ticks I. signatus Birulya, 1895) that recently was classified (based on morphology and antigenic reaction) to the Nairovirus genus, presumably to the Sakhalin group. In this work the genome of the RUKV was sequenced (KF892052-KF892054) and RUKV was classified as a member of the Uukuniemi group (Phlebovirus, Bunyaviridae). RUKV is closely related (93.0-95.5% similarity) with our previously described Komandory virus (KOMV). RUKV and KOMV form separate phylogenetic line neighbor of Manawa virus (MWAV) isolated from the ticks Argas abdussalami Hoogstraal et McCarthy, 1965 in Pakistan. The value of the similarity between RUCV and MWAV is 65-74% on the amino acid level.

Full-genome sequencing of the Caspiy virus (CASV - Caspiy virus) (ID GenBank KF801658) revealed its attribution to the Nairovirus genus of the Bunyaviridae family as a separate species. CASV forms separate line, which is the most close to the Hughes virus (HUGV) and Sakhalin virus (SAKV) groups containing viruses linked with seabirds and ticks parasitizing on them and distributed over the shelf and island ecosystems in the Northern Eurasia, as well as the North and South America.

Complete genome sequencing of the Sokuluk virus (SOKV) isolated in Kyrgyzstan from bats Vespertilio pipistrellus and their obligatory parasites--Argasidae Koch, 1844, ticks was carried out. SOKV was classified as attributed to the Flaviviridae family, Flavivirus genus. The maximum homology (71% for nucleotide and 79% for amino acid sequences) was detected with respect to the Entebbe bat virus (ENTV). ENTV and SOKV form a group joining to the yellow fever virus (YFV) within the limits of the mosquito flavivirus branch. Close relation of SOKV with bat covers and human housings permits to assume SOKV potentially patogenic to human health.

Full-length genome of the Chim virus (CHIMV) (strain LEIV-858Uz) was sequenced using the next-generation sequencing approach (ID GenBank: KF801656). The CHIMV/LEIV-858Uz was isolated from the Ornithodoros tartakovskyi Olenev, 1931 ticks collected in the great gerbil (Rhombomys opimus Lichtenstein, 1823) burrow in Uzbekistan near Chim town (Kashkadarinsky region) in July of 1971. Later, four more CHIMV strains were isolated from the O. tartakovskyi, O. papillipes Birula, 1895, Rhipicephalus turanicus Pomerantsev, 1936 collected in the great gerbil burrows in Kashkadarinsky, Bukhara, and Syrdarya regions of Uzbekistan, and three strains--from the Hyalomma asiaticum Schulze et Schlottke, 1930 from the great gerbil burrows in Dzheskazgan region of Kazakhstan. The virus is a potential pathogen of humans and camels. The phylogenetic analysis revealed that the CHIMV is a novel member of the Nairovirus genus (Bunyaviridae) and closely related to the Qalyub virus (QYBV), which is prototype for the group of the same name. The amino acid homology between the CHIMV and QYBV is 87% for the RdRp catalytic center (L-segment) that is coincident with both QYBV and CHIMV associated with the Ornithodoros ticks and burrow of rodents as well. The CHIMV homologies with other nairoviruses are 30-40% for the amino acid sequences of precursor polyprotein GnGc (M-segment), whereas 50%--for the nucleocapsid N (S-segment). The data obtained permit to classify the CHIMV as a member of the QYBV group in the genus of Nairovirus (Bunyaviridae).

The Syr-Darya valley fever virus (SDVFV) was originally isolated from the blood of the patient with fever in the Kyzylorda province, Kazakhstan, in July 1973 and was classified to the Cardiovirus genus (fam. Picornaviridae). Later, SDVFV was isolated from the ticks Hyalomma as. asiaticum Schulze et Schlottke, 1929 (Hyalomminae) (1 strain) and Dermacentor daghestanicus Olenev, 1929 (Rhipicephalinae) (7 strains), collected in the floodplains of the Syr-Darya river and the Ili river. In this paper, complet genome of the SDVFV (strain LEIV-Tur2833) was sequenced using the next-generation sequencing approach (GenBank ID: KJ191558). It was demonstrated that, phylogenetically, the SDVFV is closely related closest to the Theiler's murine encephalomyelitis virus (TMEV) and Vilyuisk human encephalomyelitis virus (VMEV). The similarity of the SDVFV with VHEV and TMEV based on P1 region of the polyprotein-precursor (structural proteins VP1-VP4), reaches 75% and 91% for nucleotide sequences and 80% and 93% for putative amino acid sequences, respectively. For nonstructural proteins regions P2 (2A-2C) and P3 (3A-3D) similarity of SDVFV with TMEV and VHEV is 96%-98%.

Complete genome sequence of the Burana virus (BURV) was determined using the next-generation sequencing approach (ID GenBank KF801651). The prototype strain of BURV LEIV-Krg760 was originally isolated from the ticks Haemaphysalis punctata Canestrini et Fanzago, 1877 (Ixodidae, Haemaphysalinae), collected from cows in Tokmak wildlife sanctuary, eastern part of the Chu valley (43 degrees 10' N, 74 degrees 40' E) near Burana village, Kirgizia, in April 1971. Molecular genetics and phylogenetic analyses showed that the BURV belonged to the Nairovirus genus, Bunyaviridae and is related to Tamdy virus (TAMV) that is also associated with the ixodidae ticks of pasture biocenosis in Central Asia. Previous studies showed that TAMV is the prototypic virus of new phylogenetic Tamdy group in the Nairovirus genus. Thus, BURV was classified as a new virus of the Tamdy group, Nairovirus, Bunyaviridae.

Complete genome sequences were obtained for the LEIV-13841Ka (ID GenBank KF767463-65) and LEIV-279Az (ID GenBank KF767460-62) virus strains, which were classified as different strains of the Zaliv Terpeniya virus (ZTV). LEIV-13841Ka was isolated from the ticks Ixodes (Ceratixodes) uriae White, 1852 collected on Ariy Kamen (Commander Islands) in 1986. LEIV-279Az was isolated from the mosquitoes Culex modestus Ficalbi, 1889, collected in heron colony (Ardea Linnaeus, 1758) in Azerbaijan (1969) and was initially identified as Uukuniemi virus (UUKV). According to the results obtained LEIV-279Az is ZTV strain as well. LEIV-13841Ka and LEIV-279Az RdRp sequences have high level of homology (99%) with previously sequenced ZTV/LEIV-271Ka. The L-segment nucleotide sequences are homological with ZTV/LEIV-271Ka on the level of 94% and 98% for LEIV-13841Ka and LEIV-279Az, respectively; M-segment--89% and 88%, respectively. Such homologies for the amino acid sequences of Gn/Gc polyprotein are 98.3% and 97.7%. NP proteins of ZTV/LEIV-13841Ka and LEIV-279Az have 88.7% and 84.6% homologies with ZTV/LEIV-271Ka both for amino acid and nucleotide sequences, respectively. Thus, for the very first time we demonstrated ZTV strain isolated from mosquitoes in subtropical Transcaucasia zone. Obtained results permit to expand suggested areal of ZTV and to fill up data upon the ecology of the Uukuniemi virus group.