About the Authors
Division of Vector-Borne Infectious Diseases, Arbovirus Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: RJK BRM. Performed the experiments: RJK. Analyzed the data: RJK. Contributed reagents/materials/analysis tools: RJK MBC BRM. Wrote the paper: RJK. Critically reviewed paper: MBC. Assisted with figure preparation: MBC.