Newly emerging tick-borne infections, their prevalence and genetic variability in northern Italy

A number of recently identified Ixodes ricinus transmitted pathogens have been studied and their potential for future further emergence evaluated in northern Italy. Our study was carried out in the Valle dei Laghi (northeastern Italian Alps) where a total of 2033 questing I. ricinus ticks (1706 nymphs and 327 adults) were collected by dragging from 2011 to 2013. In addition, feeding ticks were collected from humans and from hunted or live-trapped wildlife animals. Of the ticks collected from hosts, 617 were larvae collected from wild ungulates, birds and rodents. Ticks were than screened for the detection of the following pathogens: Anaplasma phagocytophilum, Babesia spp., Borrelia spp., Rickettsia spp and Neoehrlichia mikurensis. Moreover, we studied genetic variability of A. phagocytophilum, B. burgdorferi s.l. and its ecological associations with hosts and vectors in the area. In ticks collected by dragging we found an high prevalence of Borrelia sp (22,18%) while Rickettsia sp and Anaplasma phagocytophilum were detected with a prevalence of 9,19 % and 1,86 % respectively. A high degree of variability was observed among the pathogens detected in the larval ticks. Larvae from wild ungulates were infected with A. phagocytophilum (5.3%), B. venatorum (0.5%), R. helvetica (7.9%) and R. monacesis (2.6%). Larvae from rodents were infected with B. venatorum (2.3%), B. afzelii (7.9%), R. helvetica (2.6%), R. slovacca (0.3%), R. monacensis (2.3%), N. mikurensis (5.8%) and larvae from birds were infected with B. capreoli (1%), B. garinii (18.7%), B. afzelii (1.1%), B. valaisiana (14.3%), B. turdi (6.6%) and R. helvetica (5.5%). Additionally, we compared genetic variability of different A. phagocytophilum strains identified in feeding ticks collected from roe deer, rodents, birds, sheep's, dogs and humans. Our results showed two distinguished enzootic cycles and provide new insights into the ecology of this pathogen in Europe compared to what observed in USA.