About the Authors

Ravi S. Kasinathan

Affiliation Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America

William M. Morgan

Affiliation Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America

Robert M. Greenberg

rgree@vet.upenn.edu

Affiliation Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: RSK RMG. Performed the experiments: RSK WMM RMG. Analyzed the data: RSK WMM RMG. Wrote the paper: RSK RMG.