Surveillance of Tick-Borne Pathogens (TBPs) from Wildlife in the Valle d’Aosta Region, Northwestern Italy

Abstract

Tick-borne diseases are emerging worldwide due to the expanding distribution of tick vectors and represent an increasing public health concern. This study investigated the occurrence of major tick-borne pathogens in ticks collected from wild animals in Valle d’Aosta Region (Northwestern Italy) between 2017 and 2022. Tick pools were screened for Anaplasma spp., Borrelia burgdorferi s.l., Coxiella burnetii, Rickettsia spp., and Tick-Borne Encephalitis virus (TBEV). Most collected ticks were morphologically identified as Ixodes ricinus. Overall, 15.2% of the 158 analyzed pools tested positive for at least one pathogen. Rickettsia spp. was the most frequently detected pathogen (10.7%), with multiple species identified, including R. helvetica, R. monacensis, R. slovaca, and R. raoultii. Anaplasma phagocytophilum was detected in ticks collected from wild ungulates, whereas Borrelia burgdorferi s.l. was only occasionally identified. No samples tested positive for TBEV or C. burnetii. Rickettsia spp. positivity was higher in ticks collected from ungulates and in I. ricinus, although these differences were not statistically significant. These findings provide new insights into tick ecology in Alpine ecosystems, highlighting the circulation of potentially zoonotic pathogens and the altitudinal presence of ticks in the Alps up to 1800–2300 m a.s.l. The study contributes valuable epidemiological data and supports the need for continued surveillance within a One Health framework.