Abstract: | Indication of Borrelia (B. burgdorferi sensu lato) in 205 adult unfed I. persulcatus ticks from a natural focus was carried out simultaneously by methods of PCR and dark-field microscopy of vital preparations. PCR method revealed Borrelia prevalence in considerable number of ticks, in which Borrelia were not found by microscopy of 250 microscopic fields in a preparation from each individual tick. At the same time, PCR method didn't give positive results for approximately 8% of ticks, which contained rather high concentration of Borrelia (more than 10 per 100 microscopic fields). In general, PCR method doesn't have advantages in comparison with a microscopy of vital preparations for study the Borrelia prevalence in ticks. |