Washington: Scientists have completed the genome sequencing and analysis of the duck, which was one principal natural host of influenza A viruses that killed 36 people and caused a loss of 6.5-billion-dollars to China's economy.

As a natural host of influenza A viruses (including H5N1), the duck is known to often remain asymptomatic under influenza infection.

To uncover the interactive mechanisms between the host and influenza viruses, researchers sequenced the genome of a 10-week-old female Beijing duck, and conducted transcriptomic studies on two virus-infected ducks.

This work yielded the draft sequence of a waterfowl-duck for the first time, and the data indicated that the duck, like the chicken and zebra finch, possessed a contractive immune gene repertoire comparing to those in mammals, and it also comprises novel genes that are not present in the other three birds (chicken, zebra finch and turkey).

By comparing gene expression in the lungs of ducks infected with either highly or weakly pathogenic avian influenza H5N1 viruses, the team identified genes whose expression patterns were altered in response to avian influenza viruses.

They also identified factors that may be involved in duck host immune response to avian virus infection, including the avian and mammalian -defensin gene families.

"This study provides very important data to better understand the interaction between the host and the avian influenza," Jianwen Li, project manager from BGI, said.
He said that scientists will be able to explore more deeply the mechanisms on the spread and infection of avian influenza.