title: Type A influenza (H2N2) viruses isolated in Leningrad in 1980.
abstract: In April-May 1980, two independent outbreaks of influenza-like illness occurred in Leningrad among children's-home children aged from 3 months to 2 years (of 68 children under observation, 50 became ill) and among boarding-school pupils aged 15-17 years (of 50 pupils under observation, 13 became ill). A total of five influenza A virus strains were derived from one clinically healthy and three affected children of the children's home. Similar viruses were obtained from one affected boarding-school pupil and from an infected woman aged 24 years (a sporadic case within a household). On the basis of laboratory findings, all these seven strains were identified as influenza A H2N2 subtype strains. Six of the affected children showed significant seroconversion only to H2 haemagglutinin from February to May 1980. Type A influenza H2N2 virus was isolated from three persons, including the sporadic case, who also showed significant seroconversion to H2 haemagglutinin. H2N2 influenza A virus was isolated on two occasions, at a 7-day interval, from the girl N. Ju. Laboratory findings obtained from the study of the viruses isolated using up-to-date immunological and molecular-biochemical techniques enable us to conclude the following. The A/Leningrad/80 isolates belong to H2N2 sero-subtype. The viruses isolated are similar but not identical to the A/Singapore/I/57 reference strain in details of polypeptide and gene composition.
mesh_terms: D000956:Antigens, Viral / Q000032:analysis; D004196:Disease Outbreaks / Q000382:microbiology*; D006385:Hemagglutination Inhibition Tests; D006389:Hemagglutinins, Viral / Q000276:immunology; D006801:Humans; D053121:Influenza A Virus, H2N2 Subtype; D009980:Influenza A virus / Q000145:classification / Q000276:immunology / Q000302:isolation & purification*; D007251:Influenza, Human / Q000382:microbiology*; D009439:Neuraminidase / Q000276:immunology; D012367:RNA, Viral / Q000032:analysis; D012703:Serotyping; D014586:USSR
chemical_list: D000956:Antigens, Viral; D006389:Hemagglutinins, Viral; D012367:RNA, Viral; D009439:Neuraminidase