1. College of Veterinary Medicine, Oklahoma State University, Stillwater, OK, USA
2. Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
3. Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Norris Cotton Cancer Center at Dartmouth and Dartmouth Hitchcock, Lebanon, NH, USA