%0 Journal Article %T An experimental study on broiler chicken co-infected with the specimens containing avian influenza (H9 subtype) and infectious bronchitis (4/91 strain) viruses %J Iranian Journal of Veterinary Research %I Shiraz University %Z 1728-1997 %A Seifi, S. %A Asasi, K. %A Mohammadi, A. %D 2012 %\ 06/01/2012 %V 13 %N 2 %P 138-142 %! An experimental study on broiler chicken co-infected with the specimens containing avian influenza (H9 subtype) and infectious bronchitis (4/91 strain) viruses %K Avian influenza virus %K Infectious bronchitis virus %K Co-infection %R 10.22099/ijvr.2012.114 %X This experimental study was carried out to induce a co-infection of H9 AIV and IBV with inoculumsprepared from tracheal scrubbed epithelium tissues in natural co-infected birds to rule out the effect of fieldundesired environmental conditions and also other infectious causative agents. Eighty 1-day-old broilerswere randomly divided into four equal groups. At 21 days of age, three test groups were inoculatedintranasally with prepared inoculums containing IBV and H9 AIV alone and a co-infected group. The fourthgroup remained uninfected as a control group. The results showed that experimental co-infection of AIV andIBV increased the severity of clinical signs, mortality rate and gross lesions. The HI titer against AIVinfection in the co-infected group was significantly higher than the HI titer of other groups, which mayindicate that IBV could promote the propagation of H9N2 AIV or stimulate the immune response. %U https://ijvr.shirazu.ac.ir/article_114_644d9318082618ac91713832886305e5.pdf