Natural foci diseases as a stable biological threat.

The key aspects of the natural foci of especially dangerous diseases as a type of biological threats are presented. Approaches to epidemiological surveillance and control to the spread of the agents of especially dangerous diseases on endemic areas are described for zoonosis that has a medical value. The knowledge of specific design of tools for the implementation of epidemiological surveillance, monitoring and evaluation of natural foci diseases in developing countries is low; accordingly, little is known on the ecology and transmission dynamics for the agents of especially dangerous diseases. Important is to know the effectiveness of serological monitoring of the indigenous population to determine the activity of natural foci of hemorrhagic fever with renal syndrome, tick-borne encephalitis, tularemia, Q-fever, Lyme disease and West Nile disease. The main species of reservoirs and vectors for these agents have been determined in different regions of Ukraine. New tick-borne agents that were unknown for certain regions have been detected. These data indicate the spreading of different pathogens in combination with natural foci.