1. Department of Microbiology, University of Washington, Seattle, Washington, USA
2. Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin—Madison, Madison, Wisconsin, USA
3. Howard Hughes Medical Institute, Institute for Stem Cell and Regenerative Medicine, and Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington, USA
4. Laboratory of Virology, National Influenza Centre (South of France), Hospices Civils de Lyon, Bron, France, and Laboratorie Virpath EA4610, Université Claude Bernard Lyon 1, Lyon, France
5. Washington National Primate Research Center, University of Washington, Seattle, Washington, USA