A haemagglutination and haemagglutination inhibition test for bluetongue virus.

Haemagglutination of bluetongue virus (BTV) was demonstrated for the first time by making use of a purified preparation of the virus. The reaction was found to be independent of variations in the pH, temperature, buffer system and origin of the erythrocytes used in the test. A haemagglutination inhibition test, subsequently developed, was demonstrated to be serotype specific. The storage of the virus for indefinite periods was facilitated by lyophilization of BTV in the presence of a low concentration of sucrose.