Abundance of questing ticks and molecular evidence for pathogens in ticks in three parks of Emilia-Romagna region of Northern Italy

ntroduction and objective. Infectious and parasitic diseases transmitted by ticks, such as Lyme diseases, granulocytic anaplasmosis and piroplasmosis, have been frequently reported in Europe, with increasing attention to them as an emerging zoonotic problem. The presented study was performed to assess the distribution and the density of questing ticks in three regional parks of Emilia-Romagna region of Northern Italy, and to seek molecular evidence of potential human pathogens in tick populations. Materials and Methods. In the period April-October 2010, 8,139 questing ticks were collected: 6,734 larvae, 1,344 nymphs and only a few adults – 28 females and 33 males. The abundance of Ixodes ricinus questing ticks was compared among different sampling sites and related to microclimate parameters. 1,544 out of 8,139 ticks were examined for the presence of pathogens: PCR was used to detect piroplasms DNA and Real time Taqman PCR for Anaplasma phagocytophilum and Borrelia burgdorferi s.l. Results. The predominant species was I. ricinus (overall abundance 1,075.9/100 m2 ); more rarely, Dermacentor marginatus (n = 37 – 0.45%), Scaphixodes frontalis (n = 13 – 0.16%), Hyalomma spp. (n = 6 – 0.07%) and Ixodes acuminatus (n = 3 – 0.04%) were also found. 28 out of 324 (8.6%) samples of ticks were PCR-positive for piroplasm DNA. 11 amplicons of 18S rRNA gene were identical to each other and had 100% identity with Babesia EU1 (Babesia venatorum) using BLAST analysis. Real time Taqman PCR gave positive results for A. phagocytophilum in 23 out of 292 samples (7.9%), and for B. burgdorferi s.l. in 78 out of 292 samples (26.7%). I. ricinus was the only species found positive for pathogens by molecular analysis; 16 tick samples were co-infected with at least 2 pathogens. Discussion. The peak of nymph presence was in May, and the higher prevalence of pathogens occurred in April-June, most often in nymphs; therefore, spring season could represent the higher risk period for the transmission of pathogens. These data could provide guidelines for the preventions of tick-trasmitted diseases in this region.