Molecular imaging can potentially play a strong role in basic infectious disease research and clinical response by providing a noninvasive, spatiotemporal measurement of viral infection and host inflammation [17, 18] . To explore the potential utility of molecular imaging in influenza infection, we chose the ferret (Mustela putorius furo) model. Ferrets have been used as an animal model of influenza infection and pathogenesis since 1934, when they were reported to develop an acute respiratory tract illness when exposed to influenza viruses from humans and swine [19] . In contrast to mice, the ferret can be infected by human isolates without adaptation and display signs and symptoms of infection such as sneezing and nasal secretions that are similar to what is seen in humans [20] [21] [22] [23] . The ferret is an attractive model for imaging influenza pulmonary infections given the ferret's long trachea, large lung capacity, and bronchiolar branching. These anatomical features can potentially bridge imaging with histopathologic evaluation. Finally, the ferret more closely mimics humans in distribution of sialic acid (SA) receptors in the respiratory tract with higher a-2-6 SA in the upper respiratory tract and SA with a-2-3in the lower [24] .