Long-Term Study of Borrelia and Babesia Species Distribution in Ixodes Ricinus and Dermacentor Recticulatus Ticks Removed From Humans in Poland, 2016-2019

Abstract

Monitoring changes in the prevalence of different Borrelia genospecies/ species in ticks might be an important indicator of risk assessment and of differences in pathogenicity in humans. Furthermore, the evaluation of pathogens in feeding ticks represents the risk of human exposure better than studies on questing ticks. The objective of our study was to assess the prevalence and distribution of Borrelia and Babesia species in ticks removed from humans, in a larger sample collected for several months during four years of studies. We confirmed high Borrelia prevalence, including B. miyamotoi, in ticks removed from humans as well as the shift in Borrelia genospecies/ species frequency of occurrence during the four-year study. Despite the fact that Babesia prevalence was relatively low, the majority of tested isolates are considered to be pathogenic for humans. The results of our study have also shown that Borrelia and Babesia coinfections in ticks are more common in Borrelia-infected ticks. Even if the overall risk of developing Lyme borreliosis after a tick bite in Europe is rather low, the knowledge of prevalence and distribution of Borrelia and Babesia species in ticks might be an important indicator of both tick-borne disease risk and pathogenicity assessment.