Sushama SontakkeDepartment of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606. Current address is the Vaccines Division, Bureau of Biologics and Radiopharmaceuticals, Therapeutic Products Programme, LCDC Building, 3rd floor, AL 0603C2, Tunney's Pasture, Ottawa, ON, Canada K1A 0L2.