[An evaluation of different methods for making vital preparations for the detection of Borrelia in ixodid ticks].

Comparative assessment of suitability of darkfield microscopy of the preparation from the ticks dissected by needles in a drop of saline for evaluation of spontaneous infection rate of unfed imago ticks--vectors of Lyme disease--has been made, by using Ix. persulcatus and Ix. ricinus collected in Leningrad Province as models. Examination of 100 individuals by parallel exploration of the glass-covered drops and the preparations from the middle intestine of the ticks demonstrated the presence of Borrelia in equal (28) cases. The material from 150 other dissected ticks has been examined concurrently in glass-covered and uncovered preparations. 44 infected vectors have been revealed in the first case and 35 in the second. The difference is due to incomplete detection of slightly infected individuals.