Bugmyrin et al.
Pathogens in Ixodes persulcatus and Ixodes ricinus ticks (Acari, Ixodidae) in Karelia (Russia)
Ticks Tick Borne Dis. 2022;13(6):102045. doi:10.1016/j.ttbdis.2022.102045.

A long-term study from 2007 until 2018 has been conducted to evaluate the pathogenic potential of ticks in Karelia, Russia.

I. persulcatus and I. ricinus ticks were analyzed for a variety of pathogens, including new viruses with unclear pathogenicity: TBE virus, Borrelia burgdorferi sensu lato, Ehrlichia spp., Alongshan virus, Ixovirus, Phlebovirus and unknown phenuivirus.

I. persulcatus is the most abundant and widespread tick species in Karelia, while I. ricinus is less abundant in this region and only present in southwestern Karelia.

In Karelia, systematic registration of TBE incidence has been carried out since 1957. Since then, an increase has been reported from 0.1–2.0 cases per 100,000 inhabitants to more than 7 per 100,000 in the period from 1998–2013. TBE virus could not be detected in southwestern Karelia where I. ricinus dominates.

The average infection rate of I. persulcatus ticks with B. burgdorferi was 23.4% and 11.9% in I. ricinus. The average infection rate for TBE virus was 4.4% in I. persulcatus and 1.1% in I. ricinus. Two new TBE virus strains were isolated, and the phylogenetic analyses revealed that these two strains belong to the Baltic group of the Siberian subtype (as ten strains described earlier from this region).

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