1. Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06520, USA.
2. Yale School of Public Health, New Haven, CT 06420, USA.
3. American Lyme Disease Foundation, Inc., New Haven, CT 06510, USA.
4. Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
5. Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA.