It has also been used for the laboratory diagnosis of Acanthamoeba keratitis, Francisella and Nocardia. For medically important organisms such as "Francisella", clear guidelines exist for differentiation of subspecies. This acquired immune mechanism is found in Prevotella and Francisella bacteria. The Cpf1 nuclease of "Francisella novicida" recognizes the PAM 5'-TTTN-3' or 5'-YTN-3'. They also include certain pathogens, such as "Francisella tularensis" which causes tularemia (rabbit fever). Also, "H. leporispalustris" transmits "Coxiella burnetii" and "Francisella tularensis". The infectious disease Tularemia caused by the bacterium "Francisella tularensis" is named after Tulare County. Later, it became known as "Francisella tularensis", in honor of the discovery by Dr. Francis. Francisella tularensis is a pathogenic species of Gram-negative coccobacillus, an aerobic bacterium. Francisella is a genus of pathogenic, Gram-negative bacteria. Strict aerobes, "Francisella" colonies bear a morphological resemblance to those of the genus "Brucella".