1. The Marine Mammal Center, 2000 Bunker Road, Fort Cronkhite, Sausalito, California 94965, USA
2. Armed Forces Institute of Pathology, Department of Veterinary Pathology, 6825 Sixteenth Street Northwest, Washington, DC 20306, USA (the opinions or assertions herein are those of the authors and do not necessarily reflect the view of the Department of the Army or the Department of Defense)
3. Zoological Pathology Program, College of Veterinary Medicine, University of Illinois, 2160 South First Avenue, Maywood, Illinois 60153, USA
4. Environmental Conservation Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, Washington 98112, USA