Background of the antigen
Bacillus anthracis is an aerobic spore forming bacterium that causes anthrax, an acute infectious disease of cattle, sheep, goats, camels, antelopes and other herbivores. Infection can occur in humans when they are exposed to infected animals or tissue from infected animals via three routes: cutaneous, inhalation and gastrointestinal. B. anthracis spores persist in the soil for many years as they are resistant to heat, cold, radiation, desiccation, and disinfectants. In vivo, B anthracis produces a polypeptide (polyglutamic acid) capsule that protects it from phagocytosis. The virulence factors of B anthracis are its capsule and three component toxin, both encoded on plasmids.
