About the Authors
Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: JD SN EF. Performed the experiments: JD SN. Analyzed the data: JD SN LZ LL PW. Contributed reagents/materials/analysis tools: LZ LL PW. Wrote the paper: JD SN EF.