Aim: To evaluate risk from Lyme disease regarding way of removing ticks and time of ticks attachment on the skin. Evaluate clinical manifestations among patients with Lyme disease registered in Belgrade. Calculate values of ecologic and entomologic risk index in selected sites and existence of correlation with number of Lyme disease cases.
Methods and subjects: The study covered a ten-year period from 2000 through 2009 year. The study included 5366 persons with the tick bite in the Institute of Epidemiology MMA and 1178 patients with Lyme disease registered on the territory of Belgrade. Epidemiological questionnaire was used to collect information about time and place of a tick bite, the method of removing the tick, the time spent in the skin, the remnants of the tick in the skin and the appearance of clinical manifestations of LB. On 5 sites in the territory of the five municipalities of Belgrade, selected on the basis of epidemiological ecological indications, 9648 ticks were collect...ed and determined. Ticks were determined by the type by key of Pomerancev and developmental stage and gender according to the methodology of Furman and Katts. The presence of B. burgdorferi in ticks was determined by microscopy of native preparations in moist dark field microscopy by Kovalevsky's method. Entomological risk index is determined by the methodology Mather et al, and ecological index is determined by the methodology of Schulz et al.
Results: Clinical manifestations of Lyme disease manifested in the form of EM were recorded in 29/5366 (0.5%) persons with a tick bite. The risk of developing Lyme disease was significantly higher in patients who had tick attached on skin from 48-72 hours (RR 28.67, 95% CI, 3.21 to 255.83, p = 0.001) and in patients with tick attached longer than 72 hours (RR, 37.64; 95% CI, 4.22 to 335.7, p = 0.0004). People who were removing ticks by themselves were at greater risk of developing LB (RR = 7.01, 95% CI, 3.11 to 15.79; χ2 = 30.01, p <0.0001) as well as those in whom the tick was not completely removed (RR = 10.78, 95% CI, 4.93 to 23.60, p <0.0001, Fisher's exact probability test).
In patients with Lyme disease are the most common skin manifestations were 1098/1178 (93.21%), while the other clinical manifestations were present in much vii
smaller numbers: neurological in 33/1178 (2.80%) cases, rheumatic in 29/1178 (2.46%) cases and cardiology in 13/1178 (1.10%).
Entomological risk index showed a significant correlation with the number of patients observed by age (ρ = 0.628, p = 0.026) and months (ρ = 0.900, p <0.0001), but showed no significant correlation regarding the areas (ρ = 0.553, p = 0.167). Ecological index showed a significant correlation with the disease regarding areas (ρ = 0.918, p = 0.014).
Conclusion: Based on the results of the study it can be concluded that an early and proper removal of ticks are an important measure for the prevention of Lyme disease.
Entomological and ecological risk index can be a useful tool for assessing the risk of transmission of LB in certain areas indicating the necessity of taking appropriate preventive measures at both the individual level and at the level of the wider community.
