Single and Co-Infections by Tick-Borne Pathogens in Synanthropic European Hedgehogs (Erinaceus europaeus) in Northwestern Italy

Tick-borne pathogens (TBPs) are increasingly recorded in urban areas, where synanthropic wildlife may sustain pathogen transmission cycles. The European hedgehog (<i>Erinaceus europaeus</i>), frequently infested with ectoparasites, may serve as an urban reservoir of zoonotic TBPs. We investigated TBPs in host tissues and associated ectoparasites (<i>Ixodes</i> spp. and <i>Archaeopsylla erinacei</i>) from 129 hedgehogs in northwestern Italy. <i>Anaplasma phagocytophilum</i>, <i>Borrelia burgdorferi sensu lato</i> and <i>Rickettsia</i> spp. were detected in skin, spleen and ectoparasites (<i>Ixodes</i> spp. and <i>Archaeopsylla erinacei</i>). One spleen sample was positive for <i>B. miyamotoi.</i> Molecular identification revealed <i>A. phagocytophilum</i> ecotype 1, <i>B. afzelii</i> and <i>B. bavariensis</i>. A flea-borne <i>Rickettsia</i> closely related to the zoonotic <i>Rickettsia asembonensis</i> was identified for the first time in European hedgehogs. All pathogens were more prevalent in skin than in spleen. In skin, <i>A. phagocytophilum</i> and <i>B. burgdorferi</i> s.l. showed a positive interaction, whereas both were negatively associated with <i>Rickettsia</i> spp. These findings highlight hedgehogs as potential urban reservoirs of zoonotic TBPs, posing a potential risk for humans and domestic animals. The marked skin tropism of these pathogens supports the use of skin for TBP surveillance and underlines its role as a key interface for vector-borne transmission.