A novel nyavirus lacking matrix and glycoprotein genes from Argas japonicus ticks.

Viruses are highly diverse and are the sole agents that can infect organisms in all domains of life. Viruses are defined as capsid-encoding organisms as opposed to ribosome-encoding cellular organisms. However, recent advances in virology indicate the existence of unique viruses that do not meet this basic definition, such as capsidless viruses. During virome analysis of the soft tick Argas japonicus, we identified virus-like sequences closely related to the members of genus Nyavirus (family Nyamiviridae). Further analysis revealed sequences derived from a novel nyavirus that lacks two structural protein genes, matrix (M) and glycoprotein (G). This unique nyavirus is tentatively named Sekira virus (SEKRV). To our knowledge, this is the first study to report a nyavirus deficient in M and G genes in nature. The mechanism of infection, replication, and persistence of SEKRV remain unknown, yet this finding provides new insight into virus evolution and the diverse way of viral life in nature.

A novel Bunyavirus from the soft tick, Argas vespertilionis, in Japan.

Soft ticks, Argas vespertilionis, were collected from feces of bats in Japan. Cytopathic effect (CPE) was observed after inoculating the homogenates of ticks to Vero cells. Sequencing of RNA extracted from the cell supernatant was performed by next generation sequencer. The contigs had identity to segments of Bunyaviruses, Issyk-Kul virus. The identities of segment L, M and S were only 77, 76 and 79% to Issyk-Kul virus, respectively. Therefore, we named this novel virus Soft tick bunyavirus (STBV). In the phylogenetic tree, segment L of STBV was closely related to a cluster consisting of the genus Nairovirus of the family Bunyaviridae.

Crimean-Congo Hemorrhagic Fever Virus Clade IV (Asia 1) in Ticks of Western Iran.

Crimean-Congo Hemorrhagic Fever virus (CCHFV) is transmitted through the bite of an infected tick, or by direct contact with CCHFV-infected patients' blood or the products of infected livestock. In 2012, ticks were collected in eight regions of Lorestan Province, Iran. In total, 434 ticks were collected. Reverse transcriptase polymerase chain reaction was used for the detection of CCHFV RNA. Of 434 ticks, 419 (96.6%) ticks were from the family Ixodidae (hard ticks) and 15 (3.5%) ticks were from the family Argasidae (soft ticks). The presence of CCHFV RNA was detected in 29 (6.7%) of 434 ticks. The infected tick species include Hyalomma asiaticum (n = 7, 7.4%), Hyalomma anatolicum (n = 12, 13.2%), Hyalomma marginatum (n = 1, 16.7%), and Rhipicephalus sanguineus (n = 9, 4.3%). These empirical data demonstrated that the majority of CCHFV-positive ticks belonged to the Ixodidae. None of the Argasidae and Haemaphysalis sulcata species was infected with CCHFV. The phylogenetic analyses of the tick-derived CCHFV strains revealed that all 29 viral strains fell in clade IV (Asia 1). The most abundant species of tick collected in this study was R. sanguineus followed by different species of Hyalomma. Given the infection rate among collected ticks, H. marginatum was the most abundant infected tick species (16.7%) followed by H. anatolicum (13.2%), H. asiaticum (7.4%), and R. sanguineus (4.3%).

[The taxonomy of the Issyk-Kul virus (ISKV, Bunyaviridae, Nairovirus), the etiologic agent of the Issyk-Kul fever isolated from bats (Vespertilionidae) and ticks Argas (Carios) vespertilionis (Latreille, 1796)].

The Issyk-Kul virus (etiological agent of the Issyk-Kul fever) was originally isolated from bats (Nyctalus noctula Schreber, 1774 (Chiroptera: Vespertilionidae)) and their parasites ticks (Argas (Carios) vespertilionis Latreille, 1796 (Parasitiformes: Argasidae)) in Kirghizia. Sporadic cases and epidemics of the Issyk-Kul fever are observed in Central Asia since 1979. The ISKV genome was de novo sequenced using the next-generation sequencing technology. According to the molecular-genetic and phylogenetic analysis, the ISKV is a member of a novel group in the genus Nairovirus (Bunyaviridae). Based on the data obtained, molecular-genetic methods can be used for ISKV detection (PCR) for the Issyk-Kul fever monitoring and diagnosis in the endemic areas.