Anthrax is a serious illness caused by a spore-forming bacterium, Bacillus anthracis. Although anthrax affects mainly livestock and wild game, humans can become infected through direct or indirect contact with sick animals. Normally, anthrax isn't transmitted from person to person, but in rare cases, anthrax skin lesions may be contagious.
Most often, anthrax bacteria enter your body through a wound in your skin. You can also become infected by eating contaminated meat or inhaling the spores. Signs and symptoms, which depend on the way you're infected, can range from skin sores to nausea and vomiting or shock.
Prompt treatment with antibiotics can cure most anthrax infections contracted through the skin or contaminated meat. Inhaled anthrax is more difficult to treat and can be fatal.
There are three types of anthrax, each with different signs and symptoms. In most cases, symptoms develop within seven days of exposure to the bacteria.
Inhalation (pulmonary) anthrax
As the disease progresses, you may experience:
When to see a doctor
If you think you may have been exposed — for example, if you work in an environment where anthrax is likely to occur — see a doctor immediately for evaluation and care. If you develop signs and symptoms of the disorder after exposure to animals or animal products in parts of the world where anthrax is common, seek prompt medical attention. Early diagnosis and treatment are crucial.
You can contract anthrax when spores enter an open wound in your skin. The infection begins as a raised, sometimes itchy, bump resembling an insect bite. But within a day or two, the bump develops ...
This illustration shows how the spores that cause inhalation anthrax — the most deadly form of anthrax infection — enter and affect the body. ...
Anthrax spores are formed by anthrax bacteria that occur naturally in soil in most parts of the world. The spores can remain dormant for years until they find their way into a host — usually wild or domestic livestock, such as sheep, cattle, horses, goats and camels. Although rare in the United States, anthrax is still common throughout the developing world, such as in Iran, Iraq, Turkey, Pakistan and sub-Saharan Africa.
Most human cases of anthrax occur as a result of exposure to infected animals or their meat or hides. In the United States, a few people have developed anthrax while making traditional African drums from the skins of infected animals.
One of the few known instances of non-animal transmission occurred in the United States in 2001 when 22 people developed anthrax after being exposed to spores sent through the mail. Five of those who were infected died.
To contract anthrax, you must come in direct contact with anthrax spores. This is more likely if you:
The most serious complication of anthrax is a fatal inflammation of the membranes and fluid covering the brain and spinal cord, leading to massive bleeding (hemorrhagic meningitis).
Preparing for your appointment
Symptoms of anthrax often come on suddenly and can be very serious. If you've been exposed to anthrax or develop symptoms after a possible exposure, go immediately to the emergency room. If your situation is less urgent, set up an appointment with your doctor as soon as possible.
If you have time before you go:
Tests and diagnosis
Your doctor will first want to rule out other, more common conditions that may be causing your signs and symptoms, such as flu (influenza) or pneumonia. You may have a rapid flu test to quickly diagnose a case of influenza. If other tests are negative, you may have further tests to look specifically for anthrax, such as:
Treatments and drugs
The standard treatment for anthrax is a 60-day course of an antibiotic, such as ciprofloxacin or doxycycline. Which single antibiotic or combination of antibiotics will be most effective for you depends on the type of anthrax you have, your age, overall health and other factors. Treatment is most effective when started as soon as possible.
Although some cases of anthrax respond to antibiotics, advanced inhalation anthrax may not. By the later stages of the disease, the bacteria have often produced more toxins than drugs can eliminate.
Antibiotics are recommended to prevent infection in anyone exposed to the spores. Ciprofloxacin, doxycycline and levofloxacin (Levaquin) are approved by the Food and Drug Administration for post-exposure prevention of anthrax in adults and children.
The vaccine isn't intended for the general public. Instead, it's reserved for military personnel, scientists working with anthrax and people in other high-risk professions.
Avoiding infected animals
Even in developed countries, it's important to handle any dead animal with care and to take precautions when working with or processing imported hides, fur or wool.
Last Updated: 2011-06-09
© 1998-2014 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "Mayo Clinic Health Information," "Reliable information for a healthier life" and the triple-shield Mayo logo are trademarks of Mayo Foundation for Medical Education and Research.
Terms and conditions of use