Geographical Distribution of Tick Species and Tick-Borne Pathogens in Italy (2000-2022): A Systematic Review

Italy hosts a wide diversity of tick species and tick-borne pathogens (TBPs), with documented expansions in their distribution driven by environmental, ecological, and climatic changes. Although numerous studies have investigated their presence, available data remain fragmented and heterogeneous, limiting a comprehensive national overview.

This systematic review searched for studies published between January 2000 and December 2022 reporting the presence, prevalence, or geographical distribution of ticks and/or TBPs in Italy. A two-level screening process was conducted by 24 reviewers working in pairs, with conflicts resolved by a third reviewer. Eligible studies included primary field investigations on wild or domestic animals, humans, or the environment, with morphological or molecular identification of tick species and laboratory-confirmed detection of TBPs. Data were extracted into a structured database, analyzed using R software, and synthesized descriptively with spatial mapping of tick and pathogen distribution.

Of 12,017 records identified, 356 studies met the inclusion criteria, reporting 43 tick species, with Ixodes ricinus, Rhipicephalus sanguineus s.l., Hyalomma marginatum, and Dermacentor marginatus being the most widely distributed. The most frequently reported pathogens were Anaplasma phagocytophilum, Rickettsia spp., and Borrelia burgdorferi s.l. Substantial heterogeneity in study design and geographic coverage limited quantitative comparisons, although the dataset covered 78.5% of Italian provinces. This review provides a comprehensive overview of ticks and TBPs in Italy and identifies priority areas for future surveillance and research within a One Health framework.