Molecular characterization of H9N2 avian influenza viruses isolated from vaccinated broiler chickens in northeast Iran.

Avian influenza is a highly contagious respiratory disease of poultry caused by influenza A viruses, family Orthomyxoviridae. H9N2 avian influenza outbreaks are a major problem of the poultry industry in Iran. To determine the genetic differences between field viruses and the vaccine strain, the genomes of four strains isolated in 2011 from vaccinated broiler flocks with a history of respiratory illness were sequenced.

Sequence and phylogenetic analysis of neuraminidase genes of H9N2 avian influenza viruses isolated from commercial broiler chicken in Iran (2008 and 2009).

A total of 512 tissue samples collected from 30 farms located in various states of Iran during 2008-2009 as part of a program to monitor avian influenza viruses (AIVs) infection in Iran's poultry population. To determine the genetic relationship of Iranian viruses, neuraminidase (NA) genes from ten isolates of H9N2 viruses isolated from commercial chickens in Iran during 2008-2009 were amplified and sequenced. The viruses' neuraminidase gene was >90% similar to those of A/Quail/Hong Kong/G1/97 (H9N2) sublineage.