Risk of Lyme disease at various sites and workplaces of forestry workers in eastern Poland.

Knowledge about the seasonal activity of various stages of the Ixodes ricinus tick is of great importance while developing models of the circulation of pathogens transmitted by ticks in a given environment, as well as while evaluating the risk of infection with these pathogens among individuals performing work in this environment. The objectives of the study was determination of the relative activity of Ixodes ricinus ticks occurring at 4 different workplaces of workers employed in one randomly selected forestry inspectorate, and the comparison of this activity to the Borrelia burgdorferi prevalence in ticks collected from the above-mentioned working stands. Ticks were collected by dragging a woollen flag over lower vegetation and litter along the paths and edges of a forest in July and September 2011 at the following sites and workplaces: acquisition of timber, growing of forest, forest cultivation and forest protection. The relative activity (density) of ticks was determined by means of a combined method of single sample and area sampling. A forest area of approximately 100 m(2) was brushed with a flag. The isolates obtained from Ixodes ricinus ticks were examined for the presence of Borrelia burgdorferi sensu lato DNA by polymerase chain reaction, using primers FLA1 and FLA2 specific for the fragment of fla gene sequence. In the statistical analysis, the Mann-Whitney test, χ(2) test and Spearman test were applied. The differences between Ixodes ricinus activity at individual places of work where various biotopes were observed, were not statistically significant. A statistically significant variation in the tick infection rate, depending on work stands, was found for all the tick stages, i.e. for nymphs (χ(2)=76.516, p<0.000001), females (χ(2)=18.832, p<0.000292) and males (χ(2)=69.257, p=0.000001). Nevertheless, the statistical analysis showed the significant difference in total infection rates only between timber acquisition and growing of forest sites (p=0.049), and between growing of forest and forest cultivation sites (p=0.049). The study showed also the lack of relationship between the ticks' activity and Borrelia burgdorferi infection of ticks at individual places and sites of work of forestry workers. In conclusion, forestry workers employed at such stands of work as timber acquisition, growing of forest, forest cultivation and forest protection are nearly at the same risk of Borrelia burgdorferi infection.