Prevalence of Rickettsia spp. in Dermacentor reticulatus ticks in Lithuania and in Central Europe

Abstract

Dermacentor reticulatus (also known as meadow tick) is one of the Ixodidae family ticks, which expanded its distribution range in Europe recently. Such migration of ticks partly related to the changing climate conditions. D. reticulatus is also considered as an important vector of different viruses, bacteria, protozoa, which causes a variety of diseases in animals and humans. One of those examples is obligate intracellular bacteria belonging to Rickettsia spp. genus. In D. reticulatus ticks most prevalent rickettsias species are R. slovaca, R. helvetica, and R. raoultii, among which R. slovaca and R. helvetica are considered as pathogenic species for humans. However, data about the current Rickettsia spp. pathogens spread in Lithuania and Europe is still missing. The aim of this research was to determine the prevalence of Rickettsia spp. in D. reticulatus ticks in Lithuania and Europe. In the present study were collected and tested by molecular methods 1402 ticks in Lithuania (1077 ticks) and other European countries (325 ticks). In Lithuania ticks were collected from 21 different locations: Jonava (10) Užunvėžiai (1), Viešvilė (1), Raudonė (3), Kintai (2), Kalnėnai (17), Jurbarkas (1), Vėžininkai (1), Seredžius (0), Prienai (1), Baištrakis (2), Karmėlava (8), Ukmergė (37), Degučiai (32), Marimontas (33), Ivoniškės (45), Ventė (40), Klaipėda (88), Rusnė (46), Vorusnė (188), and Šakiai district (137). Ticks also were collected from different areas in Slovakia (52), Poland (189), Latvia (14), Ukraine (11), and Croatia (59). All samples were gathered from grass (flag method) and identified using standard morphological identification keys, determining the tick species, sex and development stage. DNA extraction from ticks was performed using 2.5% ammonia solution and infection with pathogens determined by using standard polymerase chain reaction (PCR) and horizontal electrophoresis in agarose gel. [...]