Tick Dispersal and Borrelia Species in Ticks from Migratory Birds: Insights from the Asinara National Park, Sardinia, Italy

Rapid environmental changes driven by human activities are contributing to a significant decline in global biodiversity, with avian species being particularly affected due to their migratory behavior. As highly mobile hosts, birds facilitate the geographic dispersal of ectoparasites, including ticks, which serve as vectors for numerous zoonotic pathogens. This study, conducted in collaboration with the Faunistic Observatory of the Asinara National Park between 2021 and 2023, aimed to investigate the potential role of migratory birds in tick dispersal and the presence of Borrelia spp. DNA. Birds were captured using mist nets during pre-breeding (April–May) and post-breeding (October–November) migration periods. Ticks were systematically collected and identified at the species level, and molecular analyses were performed using real-time and conventional PCR to detect the presence of Borrelia spp. DNA. Results showed a distinct seasonal variation in tick species composition. In autumn, Ixodes ricinus was predominant (99%), whereas Hyalomma species were more frequently observed in spring (78%). Molecular screening revealed Borrelia spp. DNA in 26.1% of the collected ticks, with Borrelia garinii being the most prevalent species. These findings underscore the ecological significance of migratory birds in the dissemination of ticks and tick-borne pathogens, highlighting their potential role in shaping disease transmission dynamics across different geographic regions. This study provides valuable insights into the seasonal fluctuations in tick populations associated with migratory avifauna and the epidemiological risks posed by these interactions. Continued surveillance of migratory birds as vectors of zoonotic pathogens is essential for informing public health strategies and mitigating the risks of emerging infectious diseases, but further investigation is needed to clarify the actual role of migratory birds in the transmission of Borrelia spp.