Distribution of Dermacentor reticulatus ticks in Lithuania

Abstract

Ornate meadow tick, Dermacentor reticulatus (Fabricius, 1794) is important tick-borne disease vector in Europe. According to some recent observations, in Europe, increasing range of geographical distribution of D. reticulatus is observed. Lithuania is the northern boundary of the distribution of D. reticulatus in central Europe. However, limited information is available on the change of geographical distribution and habitat of D. reticulatus in Lithuania. Ticks were collected by flagging in spring and autumn in 77 locations in Lithuania in 2013-2014 year. Tick sampling was conducted on meadows, in river valleys, in mixed and deciduous forest, and ecotones between forested and grassy areas. Ticks were collected in daytime between 8.00 and 19.00 h by one - three persons at each site. A total of 2571 adult unfed D. reticulatus ticks have been collected in 63 sites located in twenty two districts. According to our observations D. reticulatus ticks were found sporadically in all part of country, except of locations in Samogitian uplands situated in north-western part of Lithuania. Relative tick abundance was estimated by determining the average number of ticks of each stage per person per 30 min. Ticks were found most regularly and in greatest numbers in open areas close to water basin and mixed forest. In the present investigation new areas of D. reticulatus occurrence in Latvia, by 30 km further north from northern Lithuanian border, were detected. This study providing evidence that D. reticulatus has extended its range in the surroundings of its former habitats in Lithuania. The study was partially supported by the Research Council of Lithuania (grant no. MIP-053/2013).