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Anthrax is a serious disease caused by Bacillus anthracis, a bacterium that forms spores. A bacterium is a very small organism made up of one cell. Many bacteria can cause a disease. A spore is a cell that is dormant (asleep) but may come to life with the right conditions.

There are three types of anthrax:

  • Cutaneous (skin)
  • Inhalation (lungs)
  • Digestive (gastrointestinal)


Anthrax disease develops after exposure to spores produced by the Bacillus anthracis bacteria. Anthrax exposure can come as result of contact with animals or because of use as a biological weapon.

Animals – Humans can become infected with anthrax by handling products from infected animals or by breathing in anthrax spores from infected animal products. People can become infected with gastrointestinal anthrax by eating undercooked meat from infected animals.

Used as a Weapon

The anthrax spores can be manipulated so that they can:

  • Float through the air and disperse as widely as possible
  • Be released into a building’s heating and ventilation system
  • Be distributed through envelopes in the mail

Anthrax is not known to spread from person to person.


The symptoms of anthrax vary depending on the type of anthrax disease.

  • Cutaneous: The first symptom is a small sore that develops into a blister. The blister then develops into a skin ulcer with a black area in the center. The sore, blister and ulcer do not hurt. Symptoms appear within 1-7 days after exposure.
  • Gastrointestinal: The first symptoms are nausea, loss of appetite, bloody diarrhea, and fever, followed by bad stomach pain. Symptoms may appear within 2-5 days of exposure.
  • Inhalation: The first symptoms of inhalation anthrax are like cold or flu symptoms and can include a sore throat, mild fever and muscle aches. Later symptoms include cough, chest discomfort, shortness of breath, tiredness and muscle aches. Symptoms can occur within seven days of infection and can take up to 42 days to appear.


All three types of anthrax can be treated with a 60-day course of antibiotics. Doxycycline is the preferred antibiotic for anthrax infection. Treatment should begin as soon as possible after exposure.

There is a vaccine to prevent anthrax, but it is only available to those in high-risk populations such as laboratory workers and those in the armed forces deployed to countries suspected of having a biological weapons program. Although the current vaccine is not available to the general public, it would be used if an anthrax attack occurred.

For more extensive information about these agents, please visit Centers for Disease Control and Prevention.

Page last updated: May 13, 2021