Antibody Response in Chickens to Infection with Haemophilus gallinarum

Abstract

H. gallinarum strains 0083 and 17756 were adapted to grow in broth consisting of brain heart infusion (Difco), DPN.H (Sigma), 25 [mu]g/ml, and horse serum, 1.0%.Yields of 5-6% of whole-cell plate agglutination antigen were obtained routinely in this medium. The antigens were sensitive, specific, and stable. Agglutinins were detected 7 to 14 days after development of coryza as a result of infection by intrasinus inoculation of H. gallinarum or by contact. Birds not showing frank disease after infection had a delayed antibody response. Such birds were as resistant to reinfection as birds which had recovered from the disease. A "healthy" carrier state was demonstrated in chickens which had recovered from H. gallinarum infection.