DEFINITION

Tularemia is a zoonosis caused by Francisella tularensis. Humans of any age, sex, or race are universally susceptible to this systemic infection. Tularemia is primarily a disease of wild animals and persists in contaminated environments, ectoparasites, and animal carriers. Human infection is incidental and usually results from interaction with biting or blood-sucking insects, contact with wild or domestic animals, ingestion of contaminated water or food, or inhalation of infective aerosols.

Tularemia is common in Arkansas, Oklahoma, and Missouri, where >50% of the cases in the United States occur. Increasing numbers of cases have been reported from the Scandinavian countries, eastern Europe, and Siberia. The illness is characterized by various clinical syndromes, the most common of which consists of an ulcerative lesion at the site of inoculation, with regional lymphadenopathy and lymphadenitis. Systemic manifestations, including pneumonia, typhoidal tularemia, and fever without localizing findings, pose a greater diagnostic challenge.