Experimental infection of Japanese quail (coturnix coturnix japonica) with low- pathogen avian influenza virus H9N2

In order to evaluate clinical sings, mortality rate, serologic responses and virus shedding in quail infected with Low pathogenic avian influenza (LPAI) viruses H9N2, 100 Japanese quail were divided randomly into four equal groups. Group 1 and 3 chicks were vaccinated by avian influenza H9N2 killed vaccine. Group 1 and 2 chicks were infected by 0.1 ml allantoic fluid containing 5×10 5.5 ELD50 Low pathogenic avian influenza (LPAI) viruses H9N2 isolated from chicken, A/Chicken/Iran/772/99(H9N2). Group 4 quails were kept as unvaccinated uninfected control group. Four quails from each group were randomly collected at 1, 2, 3 and 10 days after infection and trachea, lungs, caecal tonsil and pancreas were collected in sterile microtube. RNA from tissue samples were extracted and subjected to reverse transcription-polymerase chain reaction (RT-PCR) using specific primers. The PCR products were sequenced and analyzed. Blood samples collected at 8, 31 and 48 days and antibody titer against influenza disease was measured by Hemagglutination inhibition (HI) test with 4 HA unit influenza antigen. The data were analyzed with SPSS software version 16. The results of the present study showed that quail have a key role in evolution of AIV as intermediate host and influenza virus in quails can be amplified and transmitted avian influenza virus to other animal species and Killed vaccine could not protect quail against influenza infection and propagation of Low pathogenic avian influenza (LPAI) viruses H9N2.