Each year, unfed adult ticks were collected from vegetation in several areas where people are exposed to ticks. We studied 66,289 adult I. persulcatus ticks, including 3,473 collected from vegetation and 62,816 removed from humans. Only living ticks were studied for Borrelia infection by dark-field microscopic analysis of tick gut contents in standard vital preparations at a magnification of X600. Two hundred fifty microscopic fields per preparation were studied, in 1,797 unfed ticks collected from vegetation and 7,442 ticks removed from patients. Both TBE and ITBB are reportable diseases for official statistics throughout Russia.
Diagnosis is established on the basis of clinical signs and serologic evidence.
The correlation coefficient r was determined by Kendall rank correlation analysis. The degree of independence of TBE virus and Borrelia prevalence in concurrently studied ticks removed from humans was estimated by 2x2 contingency analysis. The resulting chi-square values, ranging from 0.22 to 1.01, provided evidence for lack of any dependence between the prevalence of TBE virus and Borrelia in ticks. Figure Click to view enlarged image Figure. Conclusions Our data provide evidence for a distinct correlation between prevalence of TBE virus and Borrelia in I. persulcatus ticks collected from vegetation in natural foci and removed from humans.