Which bacterium causes anthrax, a serious disease affecting humans and animals?

Bacillus anthracis causes anthrax, a serious disease affecting humans and animals.

This Gram-positive, rod-shaped bacterium forms highly resistant endospores that can survive in soil for many years. Grazing animals may ingest spores, while people can be exposed through infected animals, animal products, inhalation, or contaminated wounds.

B. anthracis produces three major toxin components: protective antigen, edema factor, and lethal factor. Its capsule helps it resist immune defenses. The disease has cutaneous, inhalational, and gastrointestinal forms; cutaneous anthrax is the most common naturally acquired form.

Anthrax is often confused with infections caused by other Bacillus species, especially Bacillus cereus, but B. anthracis is the species classically responsible for anthrax. Louis Pasteur developed an early anthrax vaccine in the nineteenth century, building on earlier work by Robert Koch.