Abstract: On October 26, 2007, Employee #1, a Wildlife Biologist conducted a necropsy on a mountain lion in the garage of his government provided housing on the Grand Canyon National Park. Employee #1 was responsible for the wildlife-human interaction program. Employee #1 would capture and track mountain lions. On October 26, 2007, Employee #1 discovered a dead female mountain lion. Employee #1 assumed the mountain lion died during a fight with a male mountain lion. Employee #1 transported the mountain lion to his residential home where the necropsy was performed. On October 30, 2007, Employee #1 was not feeling well and went to the medical clinic. On November 2, 2007, Employee #1 was found dead on the living room couch in his resident. An investigation was initiated by the employer and it was discovered that Employee #1 conducted a necropsy on a mountain lion. A United States Public Health Officer (PHS) Medical Epidemiologist reviewed the photos Employee #1 took of the necropsy and recommended both Employee #1 and the mountain lion be tested for plague. Tests confirmed the presence of Yersinia pestis in both Employee #1 and the mountain lion.