Equine influenza virus from the 1991 Swedish epizootic shows major genetic and antigenic divergence from the prototype virus

• Published in: Virus research Vol. 28; no. 3; p. 263
• Main Authors: Oxburgh, L. (Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Veterinary Microbiology), Berg, M, Klingeborn, B, Emmoth, E, Linne, T
• Format: Journal Article
• Language: English
• Published: Netherlands 01.06.1993
• Subjects: Amino Acid Sequence; Animals; Antigens, Viral - genetics; Antigens, Viral - immunology; Base Sequence; Chick Embryo; Disease Outbreaks; DNA, Viral; Epitopes; EPREUVE D'HEMAGGLUTINATION; EQUINE INFLUENZAVIRUS; Genes, Viral; Genetic Variation; HAEMAGGLUTINATION TESTS; Hemagglutinin Glycoproteins, Influenza Virus; Hemagglutinins, Viral - genetics; Hemagglutinins, Viral - immunology; Horse Diseases - epidemiology; Horses; Influenza A virus - genetics; Influenza A virus - immunology; INFLUENZAVIRUS EQUIN; Molecular Sequence Data; NUCLEOTIDE SEQUENCE; Orthomyxoviridae Infections - epidemiology; Orthomyxoviridae Infections - veterinary; PRUEBAS DE HEMAGLUTINACION; SECUENCIA NUCLEICA; Sequence Homology, Amino Acid; SEQUENCE NUCLEIQUE; SUECIA; SUEDE; SWEDEN; Sweden - epidemiology; VACCIN; VACCINES; VACUNA; VIRUS DE LA INFLUENZA EQUINA; Sweden
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/0168-1702(93)90026-J

The antigenic properties of H3N8 equine influenza virus from the Swedish epizootic of 1991 differ from those of A/eq 2/Fontainebleau/79 (representative of the Swedish vaccine strain) in hemagglutination inhibition tests. The amino acid sequence of the hemagglutinin (HA) of an isolate from the 1991 outbreak was deduced from the nucleotide sequence and comparison was made to the A/eq 2/Fontainebleau/79 strain. Twenty-three amino acid substitutions were found, 10 mapping onto areas of the HA known to bind antibodies in human H3 influenza viruses. The amino acid changes together with the serological data suggest that a major antigenic drift has taken place in equine H3N8 viruses in Sweden and we conclude that recent strains of the virus must be incorporated into vaccines on a regular basis if epizootics of equine influenza are to be controlled in the future.