1. Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma.
2. Instituto de Investigación en Recursos Cinegéticos IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain.
3. Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Dieseases, Centers for Disease Control and Prevention, Atlanta, Georgia.