Distribution, Abundance, and Epidemiological Significance of Ixodes ricinus Ticks in the Territory of the Tula Region

Based on the analysis of the information concerning distribution and abundance of Ixodidae ticks in the territory of the Tula Region (1998-2012), obtained have been the new data on the expansion of I. ricinus habitat. Results of phyto-geographical zoning of the region have served as a landscape base for investigation of regularities as regards spatial distribution of the species. Specified have been the territories with low, medium, and high population density rate. Biotopes with the most favorable environmental conditions for the species are situated in the mixed woods of the Prioksky region and broad-leaved forests - of the Zasechny one. As for the forest-steppe areas, optimum biotopes are localized in the highland and steppificated oakwoods in the south of South-Eastern Region. Thus it has been established that in the recent decade I. ricinus ticks can be found not only in the forest areas, but in the forest-steppe ones too. This may be related to the increase in their numbers under favorable environmental conditions, reduction of farming lands, and shrub invasion. Average value for I. ricinus numbers in the forest area reaches 39.4 specimen/flag-kilometer; in the forest-steppe zone - 23.7 specimen/flag-kilometer. Identified have been potentially hazardous territories as regards natural-focal tick-borne infections, the agent circulation and transmission of which is sustained by I. ricinus. The finding in its turn sets the grounds for carrying out specific epizootiological surveillance and regulation of preventive measures.