Bacillus anthracis is the causative agent of anthrax, a rare and potentially fatal disease to both animals and humans. It is naturally occurring in soil and can infect animals or people when the spores are inhaled, come in contact with open wounds or consumed through contaminated food or water. B. anthracis produces a binary toxin composed of protective antigen (PA) and one of two subunits, lethal factor (LF) or edema factor (EF). Symptoms depend on the route of infection and range from a skin ulcer with a dark scab to difficulty breathing. To confirm an anthrax diagnosis, samples of blood, skin lesions, spinal fluid, or respiratory secretions must be tested by ELISA or PCR. ELISA assays typically detect anti-lethal factor IgG or anti-protective agent IgG.