title: [Variability of influenza A2 viruses in nature].
abstract: A comparative study of variability of the properties of influenza A2 viruses isolated in different epidemic years (1964-1965, 1968-1969, 1972-1973) showed that in the course of influenza virus evolution changes occurred not only in the antigenic properties of surface proteins (hemagglutinins and neuraminidase) but in a number of other properties as well. In contrast to previously circulating strains, influenza A2 virus strains isolated in the epidemic of 1971-1972 were found to have higher reproducing and neuraminidase activities, greatly increased thermostability and the capacity to induce viremia regularly in white mice.
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D005075:Biological Evolution; D014644:Genetic Variation; D006389:Hemagglutinins, Viral / Q000032:analysis*; D006801:Humans; D009980:Influenza A virus / Q000254:growth & development* / Q000276:immunology / Q000472:pathogenicity; D007251:Influenza, Human / Q000382:microbiology*; D051379:Mice; D009439:Neuraminidase / Q000276:immunology; D009975:Orthomyxoviridae / Q000254:growth & development*; D014170:Transformation, Genetic; D014779:Virus Replication
chemical_list: D000956:Antigens, Viral; D006389:Hemagglutinins, Viral; D009439:Neuraminidase
vernacular_title: Izmenchivost' virusov grippa A2 v estestrennykh usloviiakh