Seasonal Dynamics and Pathogen Diversity of Tick Species Parasitizing Migratory Birds in Sardinia, Italy: Implications for the Spread of Rickettsia, Babesia, and Theileria Species

Migratory birds play a key role in the ecology of tick-borne pathogens, serving as both hosts for ticks and as potential carriers of a wide range of infectious agents that can affect wildlife, domestic animals, and humans. Their long-distance movements contribute to the dispersal of ticks and the pathogens they harbor, with potential implications for the emergence and spread of zoonotic disease. This study focuses on the prevalence of Rickettsia spp. and Babesia/Theileria spp. in ticks collected from migratory birds in Sardinia, Italy, during two consecutive migration seasons (April–May and October–November 2021), corresponding to the spring and autumn migratory periods. A total of 961 ticks, primarily Ixodes ricinus, was collected from various bird species. Molecular analyses using polymerase chain reaction (PCR) and sequencing enabled the detection and identification of multiple Rickettsia species, with R. helvetica, R. monacensis, and R. aeschlimannii being the most frequently identified. Protozoan pathogens, including B. venatorum and Theileria ovis, were also detected in the tick samples. These findings underscore the diversity of pathogens in bird-associated ticks and the role of migratory birds in the geographical spread of these diseases. These results also provide valuable insights into pathogen transmission dynamics and stress the importance of monitoring migratory birds to assess and mitigate the risks of zoonotic diseases. Further research is needed to clarify the ecological interactions among birds, ticks, and pathogens across different geographic regions.