Early migration pattern of Avibacterium paragallinarum in the nasal passage of experimentally infected chicken and Japanese quail by immunohistochemistry.

Infectious coryza (IC) is often a curse for poultry farmers when it occurs concurrently with several pathogens causing swollen head syndrome. The disease is caused by Avibacterium paragallinarum, which inflicts initial damage to the nasal and respiratory epithelium. This facilitates the progression of disease pathology across the nasal cavity, thereby providing a platform for multiplication of opportunistic microbes.