Author : Camer, Gerry A.

Summary : Clinical and gross pathological observations, bacterial isolation, light and electron microscopic examination were conducted in five chickens showing symptoms of infectious coryza. Present findings on natural infectious coryza showed sub-acute to chronic histopathological lesions that were largely confined to the nasal sinuses. Mild to moderate changes were noted in the lower respiratory organs. The light and electron microscopic observations of the nasal mucosa of natural infectious coryza were similar to those described by Sawata et al. (1985)* with exception to previous findings of infiltrating mast cells in the lamina propria of the nasal mucosa after 24 hours challenge infection. Mast cells detected in the lamina propria of the nasal mucosa of both the naturally and artificially infected chickens were too scanty and their presence was negligible. The numerous bacterial organisms in the cilia and microvilli that was described by Sawata et al (1985) were not observed in the present study. Sub-acute and chronic infectious coryza infections detected microorganisms in the subepithelial areas of the nasal mucosa. The results of the above observations and examination were attributed to Haemophilus paragallinarum infection.