Tularemia is an epizootic infection caused by Francisella tularensis (F. tularensis). Tularemia is mainly a disease of wild animals that is transmitted to humans by contaminated environment or ectoparasites. Any age, sex, or race is universally susceptible to infection. Infection is incidental and is usually a result of interaction with biting or blood-sucking insects, wild animals, or their environment. F. tularensis is an etiologic agent of tularemia and, with rare exception, the only disease produced by this genus. The organism is a small, Gram-negative, pleomorphic, nonmotile, nonspore-forming coccobacillus. It is a strict aerobe that infects the host as a facultative, intracellular bacterium. The two main biovars, F. tularensis biovar tularensis (Type A) and F. tularensis biovar holarctica (Type B) exist. Type A produces the more serious disease in humans with an untreated fatality rate of approximately 5% and is found in the North American...