Study suggests genetic changes can help predict flu outbreaks

An international research team has shown how changes in a flu virus that has plagued Chinese poultry farms for decades helped create the novel avian H7N9 influenza A virus, which has sickened more than 375 people since 2013. | Courtesy of St. Jude Children's Research Hospital

A study released Monday by St. Jude Children's Research Hospital suggests that monitoring changes in certain flu viruses could lead to early warning signs of possible global health emergencies.

The study was conducted by the hospital and the China Agricultural University, Beijing, and looked at how changes in flu viruses seen on Chinese poultry farms created the H7N9 influenza A virus.

More than 375 people have been sickened by H7N9 since 2013. The study focused on a different chicken-related flu virus, H9N2, and identified any changes seen in the genetics of the virus over nearly two decades.

H9N2 causes egg production in chickens to drop and could lead to deadly co-infections in the animals. Genome sequencing was used to track the changes in the chicken virus between 1994 and 2013. The “genetic diversity” of the virus fell in 2009. Between 2010 and 2013, the H9N2 virus that emerged flourished on poultry farms despite chickens having received vaccines for the virus.

The research suggests that this change led to the H7N9 avian flu virus, which has caused two outbreaks in humans since 2013, resulting in 115 deaths.

"Sequencing the viral genome allowed us to track how H9N2 evolved across time and geography to contribute to the H7N9 virus that emerged as a threat to human health in 2013," said Robert Webster, a member of the St. Jude Department of Infectious Diseases. "The insights gained from this collaboration suggest that tracking genetic diversity of H9N2 on poultry farms could provide an early warning of emerging viruses with the potential to spark a pandemic.”