RESUMEN
Virological and molecular genetic studies of the field material collected in the epicenter of epizooty with high mortality rates among the wild birds on the coast of the Ubsu-Nur lake (Republic of Tyva, 51 degrees NL, 93 degrees EL, June 2006) revealed the etiological role of highly pathogenic avian influenza (HPAI) H5N1. Seven HPAI/H5N1 strains were isolated from the tracheal/cloacal swabs of clinically healthy, ill and recently dead great-crested grebes (Podiceps cristatus), cormorants (Phalacrocorax carbo), balt-coots (Fulica atra), and common terns (Sterna hirundo) collected on June 24, 2006, and incorporated to the RF State Collection of Viruses (with the July 3, 2006 priority). Full-length genome nucleotide sequences were incorporated to the GenBank (with the July 23, 2006 priority) (DQ852600-DQ852607). Comparative analysis of molecular genetic characteristics showed their belonging to the Qinghai-Siberian genotype. The strains were sensitive to rimantadine.