Coxiella burnetii (C. burnetii), the bacterium that causes Q fever, gets transmitted by inhalation and remains extremely stable in the environment. It has a very low infectious dose (very few bacteria can cause illness), making it a potential agent for bioterrorism. These factors have led to inclusion of C. burnetii on the Health and Human Services list of Select Agents. Cattle, sheep, and goats commonly get infected with C. burnetii. People, especially those who handle farm animals, can become exposed to C. burnetii by breathing in dust contaminated from infected animal body fluids.