[Arboviruses and arbovirus infections in the forest steppe zone of Ukraine].
New active natural foci of the tick-borne encephalitis, West Nile, California serologic group (CSG) and Batai viruses have been identified as a result of comprehensive virologic and serologic investigations in the forest-steppe zone of Ukraine. These observations were confirmed by the results of these pathogens study and identification of the corresponding antigens in natural biological substrates and in the blood of ill people. Several human pathogenetic viruses, including Inko, Snow hoc hare with CSG and Crimean hemorrhagic fever were found for the first time in the forest-steppe zone. Viruses populations circulating there are heterogeneous according to their genetic properties. New data concerning their ecology were obtained. A close etiological relation between the acute seasonal febrile diseases and the above mentioned arboviruses was found. Arboviral infections from 23.6% of the total amount of spring-summer-autumn febrile diseases. The West Nile fever (53.1%) is the leading arboviral infection in the forest-steppe zone. A quarter of all arboviral infections is represented by tick-borne encephalitis. Diagnostic preparations have been made and the available methods of laboratory diagnostics of the arboviral infections have been improved.