About the Authors

Michelle L. Castelletto

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

Holman C. Massey Jr.

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

James B. Lok

jlok@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: MLC HCM JBL. Performed the experiments: MLC. Analyzed the data: MLC JBL. Contributed reagents/materials/analysis tools: MLC HCM. Wrote the paper: MLC JBL.