1. Center for Vectorborne Diseases, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California.
2. Vector-borne Disease Section, Division of Communicable Disease Control, California Department of Public Health, Richmond, Califormia.
3. California Animal Health and Food Safety Laboratory, School of Veterinary Medicine, University of California, Davis, California.
4. Vector-borne Disease Section, Division of Communicable Disease Control, California Department of Public Health, Sacramento, California.