Genetic diversity of bacteria Borrelia burgdorferi sensu lato in Slovenia

Lyme borreliosis is zoonosis that is endemic in Slovenia. Lyme borreliosis is caused by different species of B. burgdorferi sensu lato complex: B. afzelii, B. garinii, and B. burgdorferi sensu stricto. The main hosts of Borreliae are small mammals. Tick Ixodes ricinus is the main vector of the agent. In Slovenia about 40% of I. ricinus ticks have been infected with Borreliae. There are differences in the prevalence of tick infection regarding different parts of Slovenia, and B. afzelii has been isolated frequently from reservoir hosts, and B. garinii from ticks. Regarding human materials B. afzelii has been isolated quite frequently, B. garinii rarely and B. burgdorferi sensu stricto by exception. B. burgdorferi sensu lato strains also differ regarding their virulence and pathogenicity for humans, different strains are associated with different clinical manifestations. Borrelial heterogeneity found in Europe as well as in Slovenia has great impact on vaccine development, while in North America only one species (B. burgdorferi sensu stricto) causes Lyme borreliosis and vaccine development reached clinical studies. Borrelial heterogeneity also has great impact on serological test standardization, and strains that are more frequently isolated in particular geographic regions usually are used as antigen. Our hypothesis is that there are genotypic differences of B. burgdorferi sensu lato present in Slovenia that different borrelial strains show different virulence and are differently pathogenic for humans. We also expect heterogeneity not only among strains isolated from humans, ticks and mammals, but also among strains isolated from different clinical materials. We shall try to elucidate enzootic relationships between Borrelia strains and their vector and host reservoirs that influence on Lyme borreliosis appearance in Slovenia.