1. Blood Systems Research Institute, 270 Masonic Ave., San Francisco, California 94118, USA;
2. Department of Laboratory Medicine, University of California, San Francisco, California 94118, USA;
3. California Animal Health and Food Safety Lab, School of Veterinary Medicine, PO Box 1770, Davis, California 95617-1770, USA;
4. California Department of Fish and Wildlife, 1701 Nimbus Rd., Suite D, Rancho Cordova, California 95670, USA;