1. Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, New York, USA
2. Program in Emerging Infectious Diseases, Duke-National University of Singapore, Singapore
3. Department of Pathology, Duke University Medical Center, Durham, North Carolina, USA
4. Department of Microbiology, University of Washington, Seattle, Washington, USA
5. Department of Microbiology and Immunology, Young Loo Lin School of Medicine, National University of Singapore, Singapore