Ticks and Tick-Borne Pathogens: Occurrence and Host Associations over Four Years of Wildlife Surveillance in the Liguria Region (Northwest Italy)

Tick-borne diseases (TBDs) are a considerable public health problem worldwide. The occurrence of <i>Anaplasma</i> spp., <i>Borrelia burgdorferi</i> s.l., <i>Coxiella burnetii</i>, <i>Rickettsia</i> spp., and tick-borne encephalitis virus (TBEv) was investigated via PCR and sequencing in 683 ticks collected from 105 roe deer, 61 wild boars, 49 fallow deer, and 2 chamois, in the Liguria region, northwest Italy, between 2019 and 2022. The ticks were morphologically identified. Four different tick species were found: <i>Ixodes ricinus</i> (66.8% of the collected ticks), <i>Dermacentor marginatus</i> (15.8%), <i>Rhipicephalus sanguineus</i> s.s. (15.7%), and <i>Haemaphysalis punctata</i> (0.9%). Six ticks (0.9%) were only identified as <i>Rhipicephalus</i> spp. Of the 222 pools analyzed, 27.9% were positive. Most pools (n = 58, 26.1% of pools analyzed) were positive for <i>Rickettsia</i> spp., and several species were found: <i>Rickettsia slovaca</i> was the dominant species (15.3%), followed by <i>R. monacensis</i> (8.1%), while <i>R. helvetica</i> (1.8%), <i>R. massiliae</i> (0.5%), and <i>R. raoultii</i> (0.5%) were found only sporadically. <i>Anaplasma phagocytophilum</i> was identified in three pools and <i>B. burgdorferi</i> s.l. in one pool. All samples were negative for <i>C. burnetii</i> and TBEv. Significant associations were found between <i>I. ricinus</i> and roe deer, <i>D. marginatus</i> and wild boar, and between <i>R. monacensis</i> and <i>I. ricinus</i>. The prevalence of <i>Rickettsia</i> spp. differed significantly between tick and host species. This updated picture of tick species and TBPs in wild ungulates in Liguria, where the population of these animals is increasing, shows a widespread presence of potentially zoonotic <i>Rickettsia</i> spp. Continuous monitoring and public information on preventive measures are needed.