Pattern of tick infestation on roe deer in the province of Trento, Italy

Roe deer (Capreolus capreolus) acts as one of the most important feeding hosts for the tick I. ricinus and significantly contributes in modulating spatial distribution and abundance of this tick species in the Alps. Nevertheless, the role played by this wild ungulate within TBEv foci is still matter of study. We examined the pattern of tick infestation on the forelegs of 171 roe deer shot during September 2004, within 19 game reserves of the province of Trento, Italy. The lower part of the forelegs (distal to tarsal joint) was removed immediately after the roe deer was shot and sealed in a plastic bag. The pairs of forelegs were inspected for number of adult ticks, nymphs and larvae, also considering their aggregation in co-feeding and their location. A total of 4832 larvae, 608 nymphs and 16 adults, along with 143 co-feedings between nymphs and larvae, were collected. All the specimens belonged to the species Ixodes ricinus. The most significant factors which affected tick abundance and the number of ticks in co-feeding groups were altitude, which was negatively correlated to both variables, and the geographical location. Intrinsic factors (i.e. sex, age and weight of roe deer) did not appear to exert a significant effect. The co-feedings were mainly composed by one or two nymphs and two or more larvae and were mainly attached in the interdigital skin (between the third and the fourth toes). The number of co-feeding ticks differed significantly among game reserves, reaching their maximum in those areas where human cases of TBE were recorded