Avian Flu in Ferrets A recent outbreak of avian H7N9 influenza in humans in eastern China has been closely monitored for any evidence of human-to-human transmission and its potential for sparking a pandemic. Zhu et al. (p. 183 , published online 23 May) examined the behavior of the avian virus in the ferret, a mammalian model for human influenza. The virus was excreted by the ferrets and could be transmitted readily by contact but displayed limited capacity for airborne infectivity. The pathology of H7N9 is similar to H1N1, and it seems that factors other than the intrinsic pathogenicity of the virus contribute to the reported high fatality rate.