1. Department of Integrative Biology, Oregon State University, 3029 Cordley Hall, Corvallis, Oregon 97331, USA
2. Directorate of Animal Health, PO Box 12, Skukuza, 1350 South Africa
3. Odum School of Ecology and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D. W. Brooks Drive, Athens, Georgia 30602, USA
4. Department of Biomedical Sciences and Department of Integrative Biology, Oregon State University, 3029 Cordley Hall, Corvallis, Oregon 97331, USA