1. Public Health Aerobiology and Biomarker Laboratory, Institute for Applied Environmental Health, University of Maryland School of Public Health, College Park, Maryland, USA
2. Department of Epidemiology and Biostatistics, University of Maryland School of Public Health, College Park, Maryland, USA
3. Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
4. Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
5. Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
6. Department of Computer Science, Rice University, Houston, Texas, USA
7. Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA