About the Authors
Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
Institut für Virologie, Freie Universität Berlin, Berlin, Germany
The authors have declared that no competing interests exist.
Conceived and designed the experiments: BBK ST NO. Performed the experiments: BK KWJ. Analyzed the data: BBK KWJ NO. Wrote the paper: BBK NO.