Studies made in west Siberia established the existence of at least 4 hantavirus types: Puumala, Tula, Topografov, and Dobrava/Belgrade. The authors detected Puumala virus genovariants in voles, Tula virus in sagebrush and narrow-skulled voles, and Topografov virus in Siberian lemmings. The etiological role of the hantavirus Dobrada/Belgrade was defined in the structure of morbidity of hemorrhagic fever with the renal syndrome. In Russia, hantaviruses were first detected in mites: a hantavirus antigen was found in one of the enzyme immunoassayed pools of the mole mites (Haemogamasus ambulans) collected from the Siberian lemming brooding burrow in the near-floodplain habitats of the transitional Yenisei tundras in southwest Taimyr.