Tularemia

Tularemia is a potentially fatal multi-systemic disease of humans and other animals caused by the bacterial pathogen Francisella tularensis. The disease can be transmitted by ticks, biting flies, water exposure, food, and aerosols and occurs around the northern hemisphere including North America, Europe, and Asia. There are several defined species and subspecies, including F. tularensis subsp. tularensis (Jellison Type A) which is pathogenic for rabbits and occurs in North America, F. tularensis subsp. holarctica (Type B) and mediaasiatica which are less pathogenic for rabbits, and F. tularensis subsp. novicida which has been regarded sometimes as the separate species F. novicida. Because it can have a high aerosol-related infection rate, low infectious dose, and ability to induce fatal disease, F. tularensis is considered a potential agent of biological warfare and is classified by the US Department of Health and Human Services as a List A select agent. We discuss microbiological, clinicopathological, epidemiological, and ecological aspects of tularemia.