A review on infectious coryza disease in chicken

Abstract

Infectious Coryza (IC) is a serious respiratory tract disease of chickens caused by Avibacterium paragallinarum, formerly known as Haemophilus paragallinarum. The disease has complicated economic impact in poultry industry due to growth retardation and decreased egg production in layer flocks. Chicken (Gallus gallus) is the natural host for A.paragallinarum which are susceptible at all ages. The most prominent clinical sign of IC is edematous swelling of face and distension of infraorbital sinus due to highly accumulation of cheesy like exudates in conjunctival sac. A. paragallinarum is a slow-growing and fastidious bacterium. Most of its strains require V (NAD) factor for their growth in vitro. Three serotypes of A. paragallinarum (A, B and C) have been identified that are distributed throughout the world. Vaccination is the soundest method of preventive practice against infectious coryza. An indigenous coryza vaccine is the best preventive measure against both homologous and heterologous challenges because of those commercial vaccines are not protective against the local variants of A.paragallinarum.

Key words: A.paragallinarum, chicken, infectious coryza, NAD, serotype, serovar, vaccine