title: Cocirculation of two distinct evolutionary lineages of influenza type B virus since 1983.
abstract: During 1988-1989 two highly distinct antigenic variants of influenza type B were recognized in hemagglutination-inhibition tests with postinfection ferret serum. These viruses were antigenically related to either B/Victoria/2/87, the most recent reference strain, or B/Yamagata/16/88, a variant that was isolated in Japan in May 1988. All influenza B viruses isolated in the United States during an epidemic in the winter of 1988-1989 were antigenically related to B/Victoria/2/87. However, in several countries in Asia, both B/Victoria/2/87-like viruses and B/Yamagata/16/88-like viruses were isolated. Sequence analysis of the hemagglutinin (HA) genes of several influenza B isolates from 1987 to 1988 indicated that the HA1 domains of the B/Yamagata/16/88-like viruses and B/VI/87-like viruses isolated in 1988 differed by 27 amino acids. Evolutionary relationships based on this sequence data indicated that the B/Yamagata/16/88-like viruses were more closely related to epidemic viruses from 1983 (B/USSR/100/83-like viruses) than to more recent reference strains such as B/Victoria/2/87. All other Asian strains, as well as selected isolates from the United States in 1988, were confirmed by sequence analysis as being genetically related to B/Victoria/2/87. These data provide clear evidence that two parallel evolutionary pathways of influenza type B have existed since at least 1983 and that viruses from each of the separate lineages were isolated from cases of influenza B in 1988. This finding is similar to earlier observations for type A H1N1 and H3N2 influenza viruses.
authors.affiliation: Division of Viral and Rickettsial Diseases, Centers for Disease Control, Atlanta, GA 30333.
authors.forename: P A
authors.initials: PA
authors.lastname: Rota
authors.forename: T R
authors.initials: TR
authors.lastname: Wallis
authors.forename: M W
authors.initials: MW
authors.lastname: Harmon
authors.forename: J S
authors.initials: JS
authors.lastname: Rota
authors.forename: A P
authors.initials: AP
authors.lastname: Kendal
authors.forename: K
authors.initials: K
authors.lastname: Nerome
mesh_terms: D000595:Amino Acid Sequence; D000956:Antigens, Viral / Q000235:genetics; D001483:Base Sequence; D005075:Biological Evolution; D005814:Genes, Viral; D009981:Influenza B virus / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes
chemical_list: D000956:Antigens, Viral; D015345:Oligonucleotide Probes