Detection and Isolation of H9N2 Subtype of Avian Influenza Virus in House Sparrows (Passer domesticus) of Ahvaz, Iran

Avian influenza (AI) is an acute infectious disease with worldwide significance causing extensive economic losses in the poultry industry. Avian influenza viruses (AIVs) belong to the family Orthomyxoviridae and categorized in the genus influenza virus A. These viruses have been isolated from more than 100 species of free-living birds. Migratory birds are considered as reservoirs for AIVs and are the major agents responsible for global outbreaks. The Passeriformes are found in most parts of the world and cover a variety of habitats from rural to urban areas. House sparrows are members of the family Passeridae and due to their free flying, are strongly associated with seabirds, indigenous, and industrial poultry. The aim of this study was to determine the role of house sparrows in AIV (H9N2) circulation in the Ahvaz region. The intestinal and tracheal samples were taken from 200 sparrows around Ahvaz during 2017. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed using specific primers in order to detect M and H9 genes of AIVs. The positive specimens in the PCR for the M gene were inoculated into 9-11-day-old embryonated chicken eggs via the allantoic fluid. The results showed that 11 out of 200 samples were positive for the two genes of M and H9. According to the findings of the present study, house sparrows are infected with H9N2 and pose a threat to commercial poultry. These birds may play a significant role in the transmission of AIV between wildlife and domestic animals. Therefore, this issue is important to be considered in preventive measurements.