The role of blood-sucking ticks and insects in natural foci of infections

During 60 years passed after the creation of the conception on natural focus of human infections by the academician E. N. Pavlovskiĭ our knowledge on a role of blood-sucking insects and ticks in this phenomenon have been significantly enlarged. It has been recovered, that these arthropods serve not only as vectors of infection agents, but also as natural reservoirs and amplificators of these agents. In the process of the infection agent circulation in the natural focus there are several additional pathways of circulations without a participation of vertebrates. These pathways are as follows: the dispersion of infection agent in cases of simultaneous feeding of infected and "clean" ticks, and also the sexual, transovarial and transphase transmissions of pathogens. These mechanism of circulation are most often occur in the ixodid ticks, which can play the main role in supporting the infection agent in the focus.