IMMUNOLOGIC RESPONSE OF CHICKEN TO NATURAL, EXPERIMENTAL INFECTION AND VACCINATION WITH HAEMOPHILUS PARAGALLINARUM

Abstract

H.paragallinarum is a small delicate bacterium, Gram negative organism that has an in vitro growth requirement for Nicotinamide adenine dinucleotide (NAD-V factor).

Recently, it has been recognized that some strains of H.paragallinarum isolated from poultry in South Africa are apparently V-factor independent. These strains have been shown to be typical H.paragal/inarum in all other properties other than the fact that they do not require V-factor in a complex medium (Horner et al., 1992; Mouahid et al., 1992 and Bragg et al., 1993))

H.paragallinarum has been identified as the causative agent of infectious coryza of poultry (Yamamoto, 1984).

Infectious coryza is an upper respiratory tract infection in chickens. The disease is acute onset and spread rapidly within the flock, may occur in both growing chickens and layers. The major economic effect of the disease is an increased culling rate in meat chicken and a reduction in egg production (10-40%) in laying and breeding fowls, particularly on multi-age farms (Yamamoto, 1991).