Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis. Anthrax most commonly occurs in hoofed mammals and can also infect humans.
Anthrax is important in the history of medicine. In 1875, the pioneering bacteriologist Robert Koch convincingly proved for the first time that a particular disease, anthrax, was caused by a specific microbe, Bacillus anthracis. Koch's proof involved four steps, which have become known as Koch's postulates:
- The microbe must always be present in animals showing the disease, and never in healthy animals.
- It must be possible to isolate the microbe and grow it in pure culture.
- Inoculating a healthy animal with the cultured microbe must cause the animal to develop the disease.
- It must be to isolate the microbe from the infected animal, culture it, and show that it is the same kind microbe with which it had been inoculated.