Assessment of the potential and actual risk of lyme disease agent transmission in the territory of Belgrade

Abstract

In the territory of Belgrade, at 16 sites (15 of test and one control), which belong to different enviromental categories such as: parks (Topcider, Hajd park, park Banovo brdo, Sumice, Usce), park-forests (Kosutnjak, Zvezdara, SP Jajinci, Banjica, Ada Ciganlija) and forests (Avala, Lipovica, Bojcinska forest, Manastirska forest, Makis), there were investigated potential and actual risk of transmission of Borrelia burgdorferi sensu lato. Suplja Stena was taken as a control site, where no chemical treatment was performed. Once of month, from March to October 2012, ticks were collected by flag-hours (drag-and-drop) method. Ticks were determined by the species and all Ixodes ricinus were observed by a dark-field microscope. A total of 3,158 individual ticks were collected, out of which 2,797 (88,6%) were Ixodes ricinus, 175 (5,5%) Dermacentor reticulatus and 186 (5,9%) Rhipicephalus sanguineus. At forest sites there were collected 1,102 Ixodes ricinus, in park-forest regions 730 and in the parks 569. Infection rate of ticks by B. burgdorferi sensu lato at the forest sites ranged between 23,8 and 36,3%, in the park-forests region 23,2-32,6% and 23,8 to 40% in the parks. Twelve of the sites met the criteria for high potential risk and three of them for moderate risk. Except for Makis, at all the forest sites, the actual risk from March to April was certain, and in other months the risk varied. In the park-forest regions, the actual risk was registered 16 times, the possible risk 23 times, and the limited riosk once. At the sites belonging to the park areas, cetrain actual risk was established 3 times, possible risk 30 times and the limited 7 times At the control site Suplja Stena, the actual risk of transmission of B. burgdorferi sensu lato was registered during all the months of the reaserch. At the teritory of Belgrade there are favorable conditions for maintaining vector Lyme disease and the potential and actual risk of transmission of Borrelia burgdorferi sensu lato.