Pathogenic microorganisms in ticks removed from Slovakian residents over the years 2008–2018

Abstract A total of 750 ticks feeding on humans were collected from various localities during the years 2008–2018. The majority of ticks (94.8%) came from Slovakia, with 3.5% from the Czech Republic, 0.9% from Austria, and 0.3% from Hungary. Travellers from Ukraine, Croatia, France, and Cuba also brought one tick from each of these countries. The majority of the analysed ticks were identified as Ixodes ricinus (94.3%). Dermacentor reticulatus (0.93%), Haemaphysalis concinna (0.1%), Haemaphysalis sp. (0.1%), Ixodes arboricola (0.1%), and Rhipicephalus sp. (0.1%) were also encountered. The most frequently acquired stage of I. ricinus was the nymph (69.9%) followed by adult females (20.4%) and larvae (8.3%). Ticks were predominantly found on children younger than 10 years (46.3%) and adults between 30–39 years (21.4%). In children younger than 10 years, the ticks were usually found on the head, while in other age categories, the ticks were predominantly attached to legs. Ticks were further individually analysed for the presence of Rickettsia spp., Coxiella burnetii, Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Neoehrlichia mikurensis, Bartonella spp. and Babesia spp. The overall prevalences of tick-borne bacteria assessed in I. ricinus ticks acquired in Slovakia were: rickettsiae 25.0% (95% CI: 21.7–28.2), B. burgdorferi s.l. 20.5% (95% CI: 17.4–23.5), A. phagocytophilum 13.5% (95% CI: 10.9–16.0), Babesia spp. 5.2% (95% CI: 3.5–6.9), C. burnetii 3.0% (95% CI: 1.5–4.6), and N. mikurensis 4.4% (95% CI: 2.0–6.8). Pathogenic species Rickettsia raoultii, Rickettsia helvetica, Rickettsia monacensis, A. phagocytophilum, Borrelia garinii, Borrelia afzelii, Borrelia valaisiana, Babesia microti, and Babesia divergens were identified in D. reticulatus and I. ricinus ticks.