Prevalence and monitoring of ixodid ticks in the western region of Ukraine

Abstract

Ixodes ricinus is the most common tick in Europe, distributed almost throughout the continent, except the northern regions. Dermacentor reticulatus is a widespread species of tick in Europe and Western Asia. The study included monitoring the distribution density and seasonal activity of ticks D. reticulatus and I. ricinus in the natural environment during 2018-2019. A total of 1592 D. reticulatus ticks and 712 I. ricinus ticks were collected in Ternopil, Ivano-Frankivsk and Lviv oblasts. There was a tendency to increasing of the number of ticks of both species in 2019 compared to 2018. The largest number of ticks was collected in autumn 2019, during the autumn peak of activity, which amounted to 710 adult ticks. Thus, the average density of ticks of both species collected in the Ternopil region was 40 ticks/1000 m2, in Ivano-Frankivsk – 32 and 45 in Lviv regions in 2018 and 62, 46 and 63 ticks/1000 m2 in 2019, respectively. In the spring of 2018, almost twice as many adult ticks of D. reticulatus were detected as in the fall in all areas. With regard to I. ricinus ticks, we did not observe a statistically significant difference in seasonal activity. In the spring and autumn, two peaks of ticks’ activity were registered in all regions and the average number of ticks in the spring in the meadows was 20 ticks/1000 m2, and on the wooded area – 39 ticks/1000 m2, and in autumn – 17 and 41 ticks/ 1000 m2 respectively. During both years and in all three oblasts, females prevailed over males during all the period. Although the density of ticks of both species in all areas was quite high, but the ticks were unevenly distributed. The largest number of D. reticulatus ticks was found in the Lviv region in 2019, which ranged from 46 to 119 ticks/1000 m2. Low and medium density of adult ticks D. reticulatus and I. ricinus, from 11 to 77 ticks/1000 m2 was observed in Ivano-Frankivsk region in 2018. Throughout the study period, the seasonal activity of D. reticulatus and I. ricinus ticks was significantly affected by air temperature, which fluctuated during collection of ticks.