Anthrax is a disease caused by infection with the spore-forming bacterium Bacillus anthracis. While anthrax most commonly occurs in animals, it can also infect humans.

Symptoms of disease vary depending on how the disease was contracted, but usually occur within 7 days after exposure. The serious forms of human anthrax are inhalation anthrax, cutaneous anthrax, and intestinal anthrax.

Inhalational anthrax is caused by breathing in anthrax spores. Initial symptoms of infection may resemble a common cold. After several days, the symptoms may progress to severe breathing problems and shock.

Cutaneous anthrax occurs when the anthrax bacterium or its spores enter a cut on the skin. Initially, an itchy lump (like an insect bite) occurs, this develops (within 1-2 days) into a blister and finally into a painless ulcer which is blackened in the centre. The skin around the ulcer is frequently swollen.

Intestinal anthrax may follow the consumption of contaminated food. Initial symptoms of nausea, loss of appetite, vomiting, and fever are followed by abdominal pain, vomiting of blood, and severe diarrhea.

Direct person-to-person spread of anthrax is extremely unlikely, if it occurs at all. Therefore, there is no need to isolate anthrax patients or to treat their contacts, such as household contacts, friends, or coworkers, unless they also were also exposed to the same source of infection.

In persons exposed to anthrax, infection can be prevented with antibiotic treatment.

Early antibiotic treatment of anthrax is essential–delay lessens chances for survival.