[Parasitic systems under the conditions of human pressures (the problems of parasitic contamination)]

Foundations of the Parasitic Contamination (PC) conception being considered as an element of biological contamination and manifested itself in urbanized ecosystems under an influence of diversiform ecological (amenable to anthropopressure) and socio-economical factors are presented. PC is regarded as the "superthreshold" contamination exceeding the "natural background" (i.e. the parasitological situation outside urbanized ecosystems). As a rule, PC is accompanied with events as follow: an increase (often explosive in character) of hosts' number of all ranks, of vectors numbers and finally of parasites' numbers (parasitic expression); a partial replacement of parasite faunas (parasitic succession); a capture of new territories and hosts (parasitic expansion). As a rule, all processes run synchronously. They lead to disturbances of evolutionary generated relations (quantitative and qualitative ones) in parasitic systems and thereafter to changes in a tension of epidemic, epizootic and epiphytotic processes. It is assumed, that rates of evolutionary processes going in parasitic systems is increased at the recent historical stage. Their entropy character is being changed: they often transform from more of less regulated (balanced) processes, which were achieved in a long course of component coevolution, into chaotic (unbalanced) ones. It is stimulated with a powerful and at the same time differently vectored anthropogenic pressure onto parasitic system components. It promotes inhibition processes involved in generating of a natural parasite-host mutual adaptation.