Pathogen diversity of the neglected winter tick Alloceraea inermis in Hungary

Ticks are important vectors of pathogens affecting human and animal health, making the identification of tick-borne agents essential. This study focused on the understudied winter tick, Alloceraea inermis (syn. Haemaphysalis inermis), which is widely distributed across Eurasia and, in some regions, appears to be increasing in occurrence. This species may play an important role in maintaining and potentially transmitting pathogens among its animal hosts. Although A. inermis rarely feeds on humans, occasional human parasitism does occur. Over two years, a total of 208 A. inermis ticks (123 females and 85 males) were collected from vegetation in a deciduous forest in Hungary during its autumn-winter activity period. Pathogen screening was performed using a reverse line blot hybridization assay targeting members of the genera Anaplasma, Babesia, Borrelia, Ehrlichia, Rickettsia, and Theileria. Species of Rickettsia were the most prevalent pathogens, with Rickettsia helvetica detected in 25.5% (53/208) of the samples, along with evidence for an uncharacterized Rickettsia species. Species of Babesia were the second most common pathogen group, with Babesia microti identified in 19.2% (40/208) of the ticks. Species of Borrelia were detected in 16.3% (34/208) of the samples, and "Candidatus Neoehrlichia mikurensis" was present in 14.9% (32/208) of the samples. The detected pathogens were more diverse and more frequent than expected, in some cases even surpassing prevalences in Ixodes ricinus observed in previous studies. In the future, we aim to clarify the vector role of A. inermis and assess associated health risks.