Bacillus anthracis is a bacterium that causes anthrax, a serious infectious disease. It is a spore-forming organism, meaning it can produce dormant spores that survive in harsh environments for long periods. These spores can be found in soil and can infect animals, particularly herbivores, when ingested or inhaled. Humans can become infected through contact with contaminated animals or animal products, such as wool or hides. There are three main forms of anthrax: cutaneous, inhalational, and gastrointestinal, each varying in severity. Vaccines and antibiotics are available for prevention and treatment of anthrax infections.