Detection and molecular genetic characterization of segmented flavi-like Yanggou virus in Dermacentor nuttalli Ol. (1929) ticks in Buryatia

The unfavorable epidemiological situation with tick-borne vector-borne infections may be characterized not only by an increase in the occurrence of already known diseases, but also by the identification of new infections and pathogens, the role of which remains poorly understood. An example of such pathogens is Yanggou tick virus (YGTV), which belongs to the group of segmented flavi-like viruses. The aim . To detect and molecular genetic characterization of YGTV found in Dermacentor nuttalli Ol. (1929) ticks on the territory of the Republic of Buryatia. Materials and methods . The study analyzed 350 individual samples of adult ticks of D. nuttalli species collected in the spring-summer period of 2023 on the territory of five districts of the Republic of Buryatia. The detection of YGTV RNA was performed by PCR followed by nucleotide sequence determination and phylogenetic analysis for each of the 4 genome segments. Results . In one sample of the tick D. nuttalli , collected in the Ivolginsky district of the Republic of Buryatia, YGTV RNA was detected, which was further confirmed by sequencing of the obtained genome fragment. The incidence of YGTV RNA among the studied D. nuttalli ticks in Buryatia was 0.3 % (95 % CI: 0.1–1.6). Primers were designed to obtain fragments of all four segments of the YGTV genome. The identified genetic variant of YGTV, when analyzed phylogenetically across all four segments, clearly clusters with YGTV sequences found earlier in China and Russia (the Republic of Altai and Tyva). The detected variant shows the highest sequence identity with the prototype strain Erzin14-T20074. Conclusion . The study shows for the first time the presence of YGTV in the territory of the Republic of Buryatia, which actualizes the need to monitor the circulation of this virus in natural foci of tick-borne infections in this territory, as well as to further clarify the boundaries of the spread of flavi-like viruses potentially dangerous for humans.