[The use of smells of plant origin as indicators of the extensiveness and intensity of ixodid tick infection with the tick-borne encephalitis virus].

It has been shown that, using a simple olfactometer, through which moist air and smell of vegetative origin penetrate into the centre via different ends of the tube, ticks can be divided into two groups, those infected and not infected with tick-borne encephalitis virus. The method yielding a 100% division, is based on opposite changes in the behaviour of virus infected ticks: the attracting smells become repellent and vice versa. Normal reaction to smell measured by the length of the distance covered by an individual tick towards or from the smell source in the olfactometer tube varies in various groups of control and experimental ticks, but correlates with virus titre of ticks. It is greater in ticks with a higher level of virus reproducibility. The reaction to smell in infected ticks makes it possible to predict the intensity of their infestation.