Tularemia Study Guide

Overview and Clinical Importance

Tularemia (also known as rabbit fever) is a highly infectious zoonotic disease caused by the gram-negative bacterium Francisella tularensis. This disease primarily affects lagomorphs (rabbits and hares) and rodents, often resulting in high mortality rates during outbreaks. Tularemia is considered a Category A bioterrorism agent and is a reportable disease in the United States due to its high infectivity, potential for airborne transmission, and significant public health implications.

Etiology and Microbiology

Causative Organism

Francisella tularensis is a small (0.2 x 0.2 μm), gram-negative coccobacillus that is nonmotile, nonspore-forming, and facultatively intracellular. The organism requires cysteine-enriched media for growth and is considered highly fastidious.

Subspecies Classification

Epidemiology

Geographic Distribution

Tularemia has been found in every U.S. state except Hawaii. The highest incidence occurs in Arkansas, Missouri, Oklahoma, and Kansas, which together account for more than half of reported cases. The disease is most commonly reported during late spring, summer, and early autumn when tick and deer fly vectors are most active.