Anthrax is an infectious disease caused by bacteria called Bacillus anthracis. Infection in humans most often involves the skin, the gastrointestinal tract, or the lungs.

See also:

• Cutaneous anthrax
• Inhalation anthrax

Anthrax commonly affects hoofed animals such as sheep and goats, but humans who come into contact with the infected animals can get sick from anthrax, too. In the past, the people who were most at risk for anthrax included farm workers, veterinarians, and tannery and wool workers.

There are three main routes of anthrax infection:

• Cutaneous anthrax occurs when anthrax touches a cut or scrape on the skin.
• Inhalation anthrax develops when anthrax spores enter the lungs.
• Gastrointestinal anthrax occurs when someone eats anthrax-tainted meat. The disease usually develops within one week, and can affect the mouth, esophagus, intestines, and colon. The infection can spread to the bloodstream, and may result in death.

Anthrax may be used as a biological weapon or for bio-terrorism. In 2001, anthrax sent through the U.S. Postal Service infected 22 people; 7 survivors had confirmed cutaneous anthrax disease.

While at least 17 nations are believed to have a biological weapons program, it is unknown how many nations or groups are working with anthrax. Most bio-terrorism experts have concluded that it is difficult to use anthrax effectively as a weapon on a large scale.

The tests to diagnose anthrax depend on the type of disease suspected.

• If cutaneous anthrax is suspected, you may have a culture of the skin sore to test for the bacteria that causes anthrax.
• If inhalational anthrax is suspected, you may need a chest x-ray, blood cultures, sputum cultures, spinal tap for CSF culture, or gram stain. Samples may be sent to a special lab for more testing, including PCR, immunofluorescence, and immunohistochemistry.

Most people with anthrax are treated with antibiotic therapy. Several antibiotics are effective, including penicillin, doxycycline, and ciprofloxacin (Cipro).

When treating inhalation anthrax, a combination of antibiotics should be used. Doctors often start treatment with an intravenous form of Cipro plus another drug.

Cutaneous anthrax is treated with pill (oral) antibiotics.

The length of treatment is currently about 60 days, since it may take anthrax spores that long to grow.

In the event of a bioterrorist attack, the National Pharmaceutical Stockpile is available to help provide antibiotics should a shortage occur.