[Parasitological factors impeding the transmission of the agent of babesiosis (Babesia microti) to man from the tick Ixodes persulcatus].

Based on the analysis of own and literature data, it is concluded that the following ma- in permanent system of ecologicalarasitological factors prevents the effective vector functions of the tick I. persulcatus in transmission of B. microti: lack of distinct nymphs' anthropophily; small spontaneous invasion of hungry adults; a duration of the parasitic phase in humans is insufficient to complete the sporogonic development, because victims interrupt the phase. Therefore, not excluding the possibility of sporadic babesiosis disea- ses, it can be stated that within the boundaries of a vast territory, where the taiga tick is the only potential source of infection for humans, the B. microti infection has not, and will not reach significant values in infectious pathology.