The H7N9 avian flu virus that infected more than 130 people in China this spring, primarily from close contact with poultry, hasn’t yet become highly contagious among people. But given that humans lack the antibodies to combat the virus, its high lethality rate (44 of the infected died), and the possibility that it could resurface this fall or winter, scientists and public health officials are racing to unravel its mysteries.

 

Recent studies of H7N9 show that it can pass among ferrets, which are often used to model human flu transmission. If the virus gains the ability to spread easily among people, it has the potential to be deadlier than the 2009 H1N1 swine flu pandemic, which may have been responsible for more than 200,000 deaths worldwide.