title: [Antigenic characteristics of different variants of influenza virus A(H3/N2) and their circulation in the USSR and People's Republic of Bulgaria in 1968-1980].
abstract: Influenza A (H3N2) virus strains isolated in 1968-1980 in the USSR (1908 strains), PRB (1413 strains) and in other countries were studied comparatively. Among 15 drift variants described in the literature only 6 were found to have sequential epidemic spread. In all the instances the epidemics occurred after importation of the virus from abroad, the interval between the emergence of a new drift variant and its detection in the study areas ranged from 2 1/2 months to 1 1/2 years and was not synchronous for the USSR and PRB. A progressive decrease of the antigenic determinant typical of the prototype A/Hong Kong/1/68 in hemagglutinin and neuraminidase of the drift variants was observed. The strains isolated in 1979-1980 were not directly related to the A/Hong Kong/1/68 strain but were connected with it through intermediate variants circulating in 1974-1975.
mesh_terms: D000956:Antigens, Viral / Q000032:analysis*; D002031:Bulgaria; D003429:Cross Reactions; D004196:Disease Outbreaks / Q000453:epidemiology; D000939:Epitopes / Q000032:analysis; D006389:Hemagglutinins, Viral / Q000032:analysis; D006801:Humans; D009980:Influenza A virus / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000382:microbiology; D009439:Neuraminidase / Q000276:immunology; D014586:USSR
chemical_list: D000956:Antigens, Viral; D000939:Epitopes; D006389:Hemagglutinins, Viral; D009439:Neuraminidase
vernacular_title: Antigennaia kharakteristika raznykh variantov virusa grippa A(H3/N2) i ikh tsirkuliatsiia v SSSR i NRB v 1968-1980 gg.