Detection of Moraxella bovis antibodies in infectious bovine keratoconjunctivitis by a passive hemagglutination test.

: A passive hemagglutination test was developed to detect antibody response to Moraxella bovis in tears. Tannic acid-treated sheep erythrocytes were sensitized with sonicated antigen prepared from M bovis cultures. The test was found to be a relatively simple, specific, and reliable procedure for titrating antibodies in lacrimal secretions. The hemagglutination test could be a valuable method for seroepizootiologic investigation of infectious bovine keratoconjunctivitis.