Tick-Borne Pathogens in Ticks Collected from Wild Ungulates in North-Eastern Poland

Abstract

This study was carried out in north-eastern Poland during two hunting seasons between 2018 and 2020. Ticks (Ixodes ricinus and Dermacentor reticulatus) were removed from wild cervids and boars and examined for the presence of Borrelia spirochetes and Rickettsiales members: Rickettsia spp. and Anaplasma phagocytophilum. The present study contributes to the knowledge of even-toed ungulates, which are an important reservoir of the above-mentioned pathogens and a potential source of infections for humans through ticks as vectors. Almost 40% of the collected ticks (191 out of 484) were infected with the following pathogens: 3.3% with Borrelia spp., 19.2% with A. phagocytophilum and 26.9% with Rickettsia spp. Only the ticks collected from cervids carried Borrelia. Typing of the species DNA confirmed the presence of B. afzelii, B. garinii, B. lusitaniae and B. miyamotoi. An analysis of Rickettsia spp. sequences using the GenBank data revealed the presence of R. helvetica, R. raoultii and R. monacensis. Monoinfections (79.1%) dominated over co-infections (20.9%). Among co-infections, the most frequent was A. phagocytophilum/Rickettsia spp. (70%), however co-infections, including B. afzelii/A. phagocytophilum, B. afzelii/Rickettsia spp., B. miyamotoi/A. phagocytophilum and B. afzelii/B. garinii/B. lusitaniae, were also noted. Significant differences were observed in the affinity of some pathogens to their vectors. Thus, Borrelia spp. and A. phagocytophilum were more frequently detected in I. ricinus (5.3% and 23.1%) than in D. reticulatus (1.2% and 15.3%). Infection frequency with Rickettsia spp. was similar (approximately 25–29%) in both tick species. The prevalence of A. phagocytophilum and Rickettsia spp. in ticks removed from cervids was 19.8% and 27.1%, and in ticks from wild boars it was 13.3% and 24.4%, respectively.

The Risk of Exposure to Ticks and Tick-Borne Pathogens in a Spa Town in Northern Poland

“…The results of the DNA sequencing of the gltA gene suggested that D. reticulatus was infected mainly with R. raoultii and I. ricinus with R. helvetica . The rate of infection in D. reticulatus was slightly lower than that revealed in ticks feeding on wild ungulates (49%) in north-eastern Poland [ 28 ] and also in the population of questing D. reticulatus of other regions of Poland (40.7–44%) [ 10 , 30 , 37 , 38 , 39 ]. In European countries, the percentage of infected D. reticulatus with Rickettsia spp.…”

“…In our study, spirochaetes from the B. burgdorferi complex were detected only in I. ricinus . Although the specific DNA of that bacteria has been detected in D. reticulatus in other regions of Poland [ 10 , 28 , 29 , 30 ] their role as a vector was not confirmed. Among the examined I. ricinus ticks, 20% of them were infected with Borrelia , with the predominance of pathogenic B. afzelii (52.4%) and B. garinii (42.1%).…”

“…Rickettsia spp. DNA was detected by PCR under the thermal conditions described by Michalski et al [ 28 ] using the CS409 and Rp1258 primers [ 69 ] ( Table 4 ) amplifying a fragment of the gltA gene.…”

Detection of Tick-Borne Pathogens of the Genera Rickettsia, Anaplasma and Francisella in Ixodes ricinus Ticks in Pomerania (Poland)

“…However, nucleotide sequence analysis revealed that only R. helvetica was present in the examined tick populations from four sites in Western Pomerania. The latest research by Kowalec et al [ 29 ] and Michalski et al [ 30 ] conducted in I. ricinus ticks collected from central and northeastern Poland showed the presence of the species R. raoulti and the novel “ Candidatus Rickettsia mendelii ” in these ticks, apart from R. helvetica and R. monacensis . The authors’ current research, unpublished (material harvested in 2019–2020), in ticks collected from urbanized areas of Western Pomerania has not yet revealed the presence of species other than R. helvetica and R. monacensis.…”

Abundance of Ixodes ricinus Ticks (Acari: Ixodidae) and the Diversity of Borrelia Species in Northeastern Poland

“…This is probably due to the relative homogeneity of the area in terms of the shape of the surface and natural features and the mosaic structure with complexes of forests, lakes, peat bogs, used meadows, pastures, agricultural land, and relatively low human interference [ 62 ]. This ensures the optimal structure of vegetation and microclimate for ticks at the studied sites and access to mammalian hosts (rodents, deer) [ 63 , 64 ], which affects the reproduction of ticks and the maintenance of their population.…”