Francisella is a genus of bacteria that includes various species within the family Francisellaceae. These bacteria are small, gram-negative coccobacilli, typically measuring about 0.2-0.5 micrometers in diameter. They are facultative intracellular pathogens that can infect a wide range of animals, including humans.
The genus Francisella is named after the American bacteriologist Edward Francis, who first isolated and characterized the bacterium Francisella tularensis, the best-known species within this genus. F. tularensis is responsible for causing tularemia, also known as rabbit fever, a zoonotic disease that primarily affects wild animals like rabbits, rodents, and hares but can also be transmitted to humans through various routes, such as insect bites, contaminated water, or handling infected animals. This bacterium is highly infectious and has the potential for being used as a biological weapon.
In addition to F. tularensis, other species within the Francisella genus include Francisella philomiragia, which can cause opportunistic infections in humans, particularly those with compromised immune systems, and Francisella novicida, which is often used as a model organism for studying the pathogenesis of tularemia.
Overall, the genus Francisella comprises several important bacterial species with varying pathogenic potentials, and proper identification, surveillance, and control measures are crucial to managing the risks associated with these bacteria.
