Detection of Yezo virus (Nairoviridae, Orthonairovirus, Orthonairovirus yezoense) circulation in Ixodes persulcatus ticks in the Amur Region, Russia

Introduction. The unfavorable epidemiological situation with viral tick-borne infections can be characterized not only by an increase in the incidence of «classical», well-known diseases, but also by the discovery of new pathogens, the role of which remains poorly understood. Yezo virus (YEZV) belongs to the group of recently discovered tick-borne nairoviruses. YEZV circulation is characteristic of Japan, China, and a number of regions in Russia (Primorsky, Khabarovsk, and Zabaykalsky Krais; Tomsk Oblast). The aim of the study was to screen and characterize the molecular genetics of YEZV isolated from ticks in the Amur region. Materials and methods. In the study, 704 individual tick samples (463 I. persulcatus ticks and 241 H. concinna ticks) collected from vegetation in 15 locations in 5 districts of the Amur Region were analyzed for the presence of YEZV RNA. Full-length genomic sequencing of the identified YEZV genetic variant was performed by preliminary enrichment of YEZV cDNA using multiplex PCR with a primer panel developed by us. Results. The YEZV infection rate in the studied sample of I. persulcatus ticks was 0.2% (1/463; 95% CI: 0.1–1.2). Conclusion. The results of this study expand our understanding of the spread of YEZV in Russia. Up-to-date information on the circulation and genetic diversity of nairoviruses that pose a potential threat to humans and animals contributes to the regulation and adjustment of preventive and anti-epidemic measures, as well as the implementation of adequate region-oriented laboratory diagnostics of IPK in the Far East, and especially in areas bordering China.