Anthrax is an acute disease in humans and animals caused by the bacterium Bacillus anthracis which is highly lethal in some forms. There are effective vaccines against anthrax, and some forms of the disease respond well to antibiotic treatment.
The anthrax bacillus is one of only a few that can form long-lived spores: in a hostile environment, caused perhaps by the death of an infected host or extremes of temperature, the bacteria become inactive dormant spores which can remain viable for many decades and perhaps centuries. Spores are found on all continents except Antarctica. When spores are inhaled, ingested, or come into contact with a skin lesion on a host they reactivate and multiply rapidly.
Anthrax most commonly infects wild and domesticated herbivorous mammals which ingest or inhale the spores while eating grass or browsing. Ingestion is assumed to be the most common route by which herbivores contract anthrax, but this is as yet unproven. Carnivores living in the same environment may ingest infected animals and become infected themselves. Anthrax can also infect humans when they are exposed to blood and other tissues from infected animals (via inhalation or direct inoculation through broken skin), eat tissue from infected animals, or are exposed to a high density of anthrax spores from an animal's fur, hide, or wool.
