Cold, Flu, & Cough Health Center

What is anthrax?

Anthrax is a serious, sometimes deadly disease caused by infection with anthrax bacteria. These bacteria produce spores that can spread the infection.

Anthrax in humans is rare unless the spores are spread on purpose. It became a concern in the United States in 2001, when 22 cases occurred as a result of bioterrorism. Most of those cases affected postal workers and media employees who were exposed to spores when handling mail.

Most cases of anthrax occur in livestock, such as cattle, horses, sheep, and goats. Anthrax spores in the soil can infect animals who eat plants growing in the soil. People can be exposed to spores in infected animal products or meat. This is not much of a concern in North America, because livestock are vaccinated against anthrax. But people can get anthrax from handling animal skins or products made out of animal skins from parts of the world where anthrax is more common.

What causes anthrax?

Anthrax is caused by Bacillus anthracis bacteria. There are three types of infection:

• Cutaneous (skin) anthrax . This can occur when spores enter your body through a break in the skin. Half of the cases in the 2001 U.S. terrorist attacks were this type.¹
• Inhalation (lung) anthrax . This can occur when you breathe in spores. It is the most serious type of infection. Half of the cases in the 2001 attacks were this type.²
• Gastrointestinal (digestive) anthrax. This can occur when you eat food contaminated with anthrax spores. This has occurred in developing regions of Asia, the Middle East, and Africa, but not in North America.

The illness does not seem to spread from person to person. People who come in contact with someone who has anthrax don't need to be immunized or treated unless they were exposed to the same source of infection.

What are the symptoms?

The symptoms and the incubation period-the time from exposure to anthrax until symptoms start-depend on the type of infection you have.

With cutaneous anthrax, symptoms usually appear 5 to 7 days after exposure to spores, though it may take longer.

• The first symptom may be a small, raised bump that might itch.
• The bump becomes a painless, fluid-filled blister and later forms a black center of dying tissue.
• Swollen lymph nodes, headache, and fever also may occur.

With inhalation anthrax, symptoms usually appear 1 to 7 days after exposure. (But it can take as long as 60 days).

• At first you may feel like you have the flu, with a sore throat, a mild fever, and muscle aches. But you may also have shortness of breath, which is not common with the flu.³
• Severe trouble breathing, high fever, and shock may occur 1 to 5 days later.
• Death usually follows within a day or two.