Detection and genotyping of Borrelia burgdorferi in the trans-border area between Italy and Slovenia and evaluation of co-infection with Anaplasma phagocytophilum in ticks

The present monitoring project aimed at detecting the prevalence of Borrelia burgdorferi in ticks in the Friuli Venezia Giulia (FVG) Region (north-eastern Italy) and along the western border of Slovenia and to determine the Borrelia circulating genospecies. Since Anaplasma phagocytophilum had been found in the study area, we also evaluated the co-infection of the two pathogens in tick (Ixodes ricinus) populations. The ticks collected during 2005 in 15 sites located in the study area were analyzed to detect the presence of B. burgdorferi by amplifying the intergenic spacer 5S–23S. Genotyping was performed using a new nested-PCR–RFLP method, targeting the ospA gene. A. phagocytophilum was searched for by amplifying the epank1 gene. The average infection rate of ticks with B. burgdorferi varied from 11.8% to 45.5% in the different study sites. A. phagocytophilum was present in the 1.6% of the investigated ticks and apparently homogeneously distributed. The percentage of co-infection with B. burgdorferi sensu lato was 3.4%. At least four different Borrelia species were found: B. afzelii (54.9%), B. garinii (31.7%), B. burgdorferi sensu stricto (6.1%), and 4.9% of a species unidentified whose phylogenetic analysis showed no similarity with any of the known Borrelia genospecies.