Prevalence of Borrelia burgdorferi in Ixodes ricinus Ticks in Belgrade Area

Objective: Lyme borreliosis is vector-borne zoonosis. The causative agent of Lyme borreliosis is a spirochete of Borrelia burgdorferi (Bb) sensu lato complex, which is transmitted by ticks of the Ixodes ricinus complex. The aim of our paper is to estimate the prevalence of I. ricinus ticks, the level of their infectivity by Bb, and the prevalence of certain genospecies of Bb sensu lato in ixodide ticks inhabiting Belgrade. Materials and Methods: An estimate of the tick population density was expressed by the value of flag/hour. For isolation and cultivation of Borrelia, selective Barbour-Stonner-Kelly II media was used. Typization of Borrelia was made by applying the species-specific polymerase chain reaction (PCR) and polymerase chain reaction-restriction fragment length polymorphism analysis. In statistical analysis, X-2 test was used. Results: Values of flag/hour have varied in relation to year observed and type of habitat: The lowest values were recorded in the city parks (17.9). The values were higher in parks-woods (19.7 and 33.4, respectively). The highest values were detected in localities similar to wooded areas (48.0). The estimated average infestation of ticks with Bb was 21.9%, excluding statistically significant differences by years of investigation. We found the dominance of Borrelia afzelii (75%). Bb sensu stricto (22.2%) as well as Borrelia garinii (2.8%) was much less present. Statistically significant difference was established in the prevalence of the above-mentioned genospecies in relation to the examined localities. Conclusions: We have established the prevalence of all three genospecies in the city of Belgrade. Bb sensu lato was found, with the dominance of B. afzelii.