Seasonal Activity of Adult Ticks Ixodes persulcatus (Acari, Ixodidae) in the North-West of the Distribution Area.

Simple Summary: The taiga tick is a common tick species in northern Europe. These blood-sucking parasites transmit dangerous human pathogens, including the causal agents of tick-borne encephalitis and Lyme borreliosis. Knowledge of their ecology is essential for the development of scientifically robust recommendations about the best ways of protecting humans from tick attacks. In our work, we described the seasonal course of activity of the adult taiga ticks. We found that potential risks to humans in the study area were greatest in the second half of May and early June, when the ticks were particularly numerous and active. By mid-summer, the activity of the ticks had decreased to a minimum. Our results, derived from thirty years of monitoring studies, show that the taiga ticks have become much more numerous in the north of their range and that they now become active earlier. These changes in the activity of the ticks may be associated with climate warming. The taiga tick Ixodes persulcatus (Schulze, 1930) (Acari, Ixodidae) is the main vector of the tick-borne encephalitis virus and one of the most widespread species of ixodid ticks in the Palaearctic. In this paper, we present long-term data on the seasonal activity of adult ticks in the north-west of their distribution. The seasonal activity of Ixodes persulcatus was studied from 1982 to 1990 and from 2012 to 2023 in the middle taiga subzone of Karelia (N62.0697, E33.961). In the study area, adult ticks I. persulcatus demonstrate a pronounced spring–summer activity with a unimodal curve of abundance change. A comparison of the monitoring data from the 1980s and the 2010s showed a significant increase in the abundance of I. persulcatus in the study area. A tendency towards an earlier start of the tick activity, as compared to the 1980s, is now being observed. [ABSTRACT FROM AUTHOR]