Study on clinical signs and gross lesions due to individually and concurrent experimental infection of H9N2 avian influenza and Ornithobacterium rhinotracheale in SPF chickens

In this study, clinical signs and gross lesions of (A/Chicken/Iran/ m.1/2010) H9N2 virus and (ORT -R87-7/1387) Ornithobacterium rhinotracheale bacteria alone and a co-infected group in SPF broiler chickens were investigated. Eighty 1-day-old specific pathogen-free White Leghorn chickens were randomly divided into four equal groups. At the age of three weeks, the chicks in the experimental groups were inoculated by virus and bacteria, individually or concurrent and in control group allantoic fluid was inoculated. We used PCR for detection of the bacteria and virus in various organs of experimentally infected broiler. Chickens of AIV and ORT coinfected group showed clinical signs such as ruffled feathers, depression, reduced appetite, cyanosis of wattles and combs, and respiratory distress. The gross lesions such as congestion in the tracheal, airsaculitis, fibrinous cast formation in tracheal and swollen kidneys were observed in birds of the AIV ORT co-infected group. While ORT and AIV groups alone had minor clinical signs and gross lesions. The results of this study indicated that concurrent infectious with H9N2 virus and ORT bacteria could exacerbates clinical signs and gross lesions in infected chickens.