Identification of Borrelia burgdorferi, Anaplasma phagocytophilum, Francisella tularensis and Coxiella burnetii in ticks from selected regions of north-eastern Poland

Tick-borne diseases (TBD) are an increasing health problem for humans, pets, and livestock. It is closely related to the increasing frequency of ticks. The aim of the study was to identify Borrelia burgdorferi, Anaplasma phagocytophilum, Francisella tularensis, and Coxiella burnetii in ticks from selected regions of north-eastern Poland. The material for molecular tests were ticks belonging to two species: Dermacentor reticulatus (meadow tick) and Ixodes ricinus (common tick), collected in the period from July 2020 to June 2021. The studies were performed on arachnids collected mostly from the ground (90.4%), as well as removed from dogs (8.4%) and humans (1.2%). The genetic material was amplified by PCR in the multiplex PCR variant (B. burgdorferi and A. phagocytophilum) and single PCR (F. tularensis, C. burnetii). Only 9 out of 500 ticks tested showed genetic material indicating infection with the above-mentioned microorganisms (1.8%). D. reticulatus ticks dominated in this group. The highest number of ticks, that is seven D. reticulatus and one I. ricinus, were infected with B. burgdorferi. Only one I. ricinus tick (0.3%) and one D. reticulatus tick (0.2%) carried genetic material of A. phagocytophilum. In the latter case, it was a co-infection with B. burgdorferi. Tests on ticks showed a low degree of infection with B. burgdorferi and A. phagocytophilum bacteria (1.8%) and no genetic material of F. tularensis or C. burnetii. On the other hand, one D. reticulatus tick was coinfected with B. burgdorferi and A. phagocytophilum (0.2%). The low percentage of infected I. ricinus ticks may have been due to the small number of specimens examined, which in turn resulted from the fact that D. reticulatus was the dominant tick species in the research area.