Francisella is a genus of gram-negative bacteria that was named after the American bacteriologist, Dr. Francis P. Tularensis. The bacteria is typically found in areas with water and soil, and can cause severe illness in humans and animals. Some common synonyms for Francisella include Tularemia, Rabbit fever, Deerfly fever, and Francisella tularensis. Tularemia is the most common synonym and is derived from the bacteria's original name, Pasteurella tularensis. Rabbit fever is based on the fact that the bacteria is commonly found in rabbits and can be spread to humans through ticks, mosquitoes, and other insects. Deerfly fever is another synonym that is used because the bacteria can also be found in deerflies.