How live animal markets create a perfect storm for bird flu

Katz and Todd Davis, principal investigator on the CDC team that studies flu viruses that infect other mammals and birds, told STAT in a recent interview that this year’s surge in H7N9 case numbers is likely due to the fact that the virus is infecting poultry in more parts of the country. More infected birds equals more exposed people.Swayne’s research, which hasn’t yet been published, points to how that happens. He and colleagues at the Department of Agriculture’s Southeast Poultry Research Laboratory in Athens, Ga., infected chickens, then slaughtered and defeathered them.The study was done in laboratories with a BSL 3 (enhanced) rating, meaning safety mechanisms were in place to ensure viruses from the experiment could not make their way out of the lab and that the researchers were protected.But the researchers proved that the viruses could be transmitted through slaughter by placing healthy chickens, and later ferrets, in cages in the laboratory where the experiments were being conducted. The healthy chickens all became infected and most of the ferrets — which are used as stand-ins for people in influenza research — did too.