1. The Marine Mammal Center, Golden Gate National Recreation Area, Sausalito, California 94965, USA
2. Department of Pathology, Micrōbiology and Immunology, University of California at Davis, California 95616, USA and Zooloogical Society of San Diego, San Diego, California 92112, USA
3. School of Veterinary Medicine, University of California, Davis, California 95616, USA
4. Wildlife Pathology International, 2905 Stanford, Fort Collins, Colorado 80525, USA