Study on virulence and gene sequencing of the Avibacterium paragallinarum isolated from broiler and layer farms

Isolates of A. paragallinarum from infraorbital sinus samples of birds were identified by conventional method and HP-2 PCR. 0.2 ml(10¹¹ CFU) of culture suspension of each isolate grown on brain heart infusion broth was instilled intranasally of four seven weeks old chickens for pathogencitiy test in day old chicks. The infected chickens showed nasal discharge, conjunctivitis and depression. Sequencing of HA gene was carried out for phylogenetic analysis of A. paragallinarum. The gene sequencing of isolated local strains A. paragallinarum had 98.9–99.6 per cent homology with A. paragallinarum Modesto strain and A. paragallinarum 0083 strain. The PCR test permitted rapid and specific identification of A. paragallinarum and was found suitable for the diagnostic and epidemiological studies.