Anthrax is a disease caused by a bacterium called Bacillus anthracis, that has existed for hundreds of years and which still occurs naturally in both animals and humans in many parts of the world, including Asia, southern Europe, sub-Sahelian Africa and parts of Australia.

Anthrax bacteria can survive in the environment by forming spores. In its most common natural form, it creates dark sores on the skin, from which it derives its name. Anthrax is Greek for coal. Anthrax is primarily a disease of herbivorous mammals, although other mammals and some birds have been known to contract it. Until the introduction and widespread use of effective veterinary vaccines, it was a major cause of fatal disease in cattle, sheep, goats, camels, horses, and pigs throughout the world.

Anthrax continues to be reported from many countries in domesticated and wild herbivores, especially where livestock vaccination programmes are inadequate or have been disrupted. Humans generally acquire the disease directly or indirectly from infected animals, or occupational exposure to infected or contaminated animal products. Control in livestock is therefore the key to reduced incidence. The disease is generally regarded as being non-contagious. Records of person-to-person spread exist, but are rare.