Genetic and antigenic analysis of the influenza virus responsible for the 1992 Hong Kong equine influenza epizootic.
An outbreak of influenza occurred among thoroughbred racehorses in Hong Kong in November-December 1992, with morbidity of 37%. All horses involved had been vaccinated against equine-1 and equine-2 influenza viruses but not against the virus responsible for the 1989 equine influenza outbreak in northern China (influenza A/equine/Jilin/89, subtype H3N8). Therefore the source and nature of the virus causing the Hong Kong outbreak was investigated. Virus isolated from a horse infected during the outbreak was used for genetic analysis. All the viral gene segments were similar to those of equine-2 (H3N8) influenza viruses and unrelated to those of equine/Jilin/89 virus. The nucleotide sequence of the viral hemagglutinin gene showed high homology (99.4%) to that of influenza A/equine/Suffolk/89 (H3N8) virus which has circulated extensively in Europe. However, these viruses differed in their antigenic reactivity to a panel of monoclonal antibodies. Preliminary epizootiological information plus the concordance of amino acid sequence between hemagglutinins of the Hong Kong isolate and a contemporaneous equine-2 influenza virus isolate from the United Kingdom indicated that the probable source of the Hong Kong outbreak was horses recently imported from England or Ireland.
Lai
A C
AC
Department of Veterinary Science, University of Kentucky, Lexington 40546-0099.
Lin
Y P
YP
Powell
D G
DG
Shortridge
K F
KF
Webster
R G
RG
Daly
J
J
Chambers
T M
TM
D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000032:analysis*; D004196:Disease Outbreaks; D005838:Genotype; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral / Q000737:chemistry / Q000235:genetics; D006723:Hong Kong / Q000453:epidemiology; D006734:Horse Diseases / Q000453:epidemiology* / Q000821:virology; D006736:Horses; D006801:Humans; D009980:Influenza A virus / Q000235:genetics* / Q000276:immunology; D007251:Influenza, Human / Q000662:veterinary* / Q000821:virology; D008969:Molecular Sequence Data; D013997:Time Factors
D000956:Antigens, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral