THE ETIOLOGIC AGENT OF LYME-DISEASE, BORRELIA-BURGDORFERI, IN TICKS (ACARI, IXODIDAE) FROM EASTERN POLAND

In 1994, 4204 out of 4656 Ixodes ricinus collected both from vegetatio n in three different areas and from hunter-killed deer and wild boar i n the Bialystok province (eastern Poland) were examined individually f or the presence of Borrelia burgdorferi s. 1. Detection of spirochetes was carried out by the routine indirect immunofluorescence assay (IFA ) using polyclonal antibody (anti-B, burgdorferi, strain 1B 29). B. bu rgdorferi spirochetes were evident in 349 (8.8%) nymphal and adult I. ricinus collected from vegetation (n = 3958) and in 8 (3.2%) of those removed from hosts (n = 246). Among the ticks collected from vegetatio n, infection rates in nymphs (5.8-6.4%) in particular areas were about 2-4 times lower than in adults (8.1-24.6%). The calculated minimal an d maximal infection rates of ticks collected from different sites were 1.6% and 15.4%, respectively. Prevalence of B. burgdorferi in I. rici nus was determined with respect to the abundance and seasonal activity of the ticks.