Abstract
The indirect hemagglutination (IHA) test was used as a diagnostic method for infectious bovine rhinotracheitis:(IBR) virus infection in the field. Formalized sheep red blood cells were treated with tannic acid, sensitized with IBR virus, and used for the test as antigen. The antigen could be stored at -80°C for at least 3 months. Bovine sera were collected from herds where IBR infection was observed. Serum antibody against IBR virus could be detected specifically in sera collected in herds in the early and late stages of infection. The antibody titers determined by this test were almost equal to those by the serum neutralization test with complement. The IHA test was so sensitive that it could detect antibody early. It was also reproducible. It was considered to be a valuable means for the diagnosis and epizootiological studies of IBR virus infection.
