1986 Volume 39 Issue 6 Pages 368-373
An epizootiological survey on hemagglutination inhibiting (HI) antibodies to equine influenza viruses (EIV) was carried out with horse sera collected from several districts in Kumamoto Prefecture over a period from September to October, 1984.
Most of the sera of 600 racehorses with a history of EIV vaccination showed a high HI- antibody titer, a titer of 1: 8 or more being regarded as antibody-positive. Then 63.2 to 71.2% of the sera with a history of the vaccination showed an HI- antibody titer when the N. T. and P strains of EIV were used as antigens. The positive rate decreased to 5.5 to 24.7% when the M. F. S. and K strains of EIV were used. The positive rate among 106 sera with no history of the vaccination was about a half of that in the former group.
HI antibody was not detected from the sers of 123 meat horses, except 3 which showed a titer of 8 to 16 to the N and T strains of EIV. It was presumed that the meat-horse group might have not been exposed to EIV infection.It should be noted that HI antibody to the N strain of EIV (subtype 1) was detected in most of the serasurveyed.
