1. Department of Veterinary Pathology, Armed Forces Institute of Pathology, Washington, DC 20306, USA
2. PathoGenesis Corporation, Seattle, Washington 98119, USA
3. NOAA, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, Charleston, South Carolina 29412, USA
4. Department of Natural Resources, Cooperative Oxford Laboratory, Oxford, Maryland 21654, USA