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

Mirosław M Michalski,Katarzyna Kubiak,Magdalena Szczotko,Małgorzata Dmitryjuk

doi:10.3390/pathogens10050587

Mirosław M Michalski, Katarzyna Kubiak + Show 2 more

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https://doi.org/10.3390/pathogens10050587

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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.

Highlights

Understanding the interrelationship between wildlife, livestock and public health presents a great challenge
Among the 484 ticks collected from cervids and wild boars (Sus scrofa) from three subregions of northeastern Poland between 2018–2020, I. ricinus (n = 242, 50%) and D. reticulatus (n = 242, 50%) were identified (Table 1)
All 16 cases of Borrelia spp. were detected in I. ricinus and D. reticulatus collected from cervids (16/439, 3.6%, 95% confidence intervals (95% CI): 2.1–5.8%)

Summary

Introduction

Understanding the interrelationship between wildlife, livestock and public health presents a great challenge. Man-made landscapes, a mix of natural habitats and farmland, modify the abundance, composition and cohesion of populations and allow for contact between wildlife, livestock and humans. Bacteria and protozoa in ticks may be pathogenic to both humans and domesticated animals [3,4]. The screening of wild animals, such as cervids and wild boars, is essential for revealing the relationship between sylvatic and domestic pathogen cycles. It provides basic information for a risk assessment of animal and human health in a given region [5]. Human interference in the natural ecosystems changes the populations of wild animals, as well as of ticks and the pathogens they transmit. The risk of tick-borne pathogen (TBP) transmission is increasing all over the world [6,7]

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