1. Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, 1 Garrod Drive, Davis, California 95616, USA
2. Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, 127 Experiment Station Road, Stoneville, Mississippi 38776, USA
3. Department of Ecology and Evolutionary Biology, 4000 Terasaki Life Science Building, University of California, Charles E. Young Drive E, Los Angeles, California 90095, USA
4. The Marine Mammal Center, 2000 Bunker Road, Fort Cronkhite, Sausalito, California 94965, USA
5. National Marine Mammal Laboratory/AFSC/NMFS/NOAA, 7600 Sand Point Way NE, Bin C15700, Seattle, Washington 98115, USA
6. Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, 1 Garrod Drive, Davis, California 95616, USA
7. Department of Bacteria, Parasites & Fungi, Statens Serum Institut, 5 Artillerivej, Copenhagen 2300S, Denmark