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.
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.
Anthrax in humans is rare unless the spores are spread on purpose. It is known as a biological agent that has been used in bioterrorism attacks.
What causes it?
Anthrax is caused by Bacillus anthracis bacteria. There are three types of infection:
- Cutaneous (skin) anthrax. This is the most common type and can occur when spores enter your body through a break in the skin.
- Inhalation (lung) anthrax. This can occur when you breathe in spores. It is the most serious type of infection.
- Gastrointestinal (digestive) anthrax. This can occur when you eat food contaminated with anthrax spores.
The infection does not seem to spread from person to person. People who come in contact with someone who has anthrax don't need to get a vaccine or be 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 anthrax infection you have.
With cutaneous anthrax, symptoms usually appear within a week 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 with a black center.
- Swollen lymph nodes, headache, and fever also may occur.
With inhalation anthrax, symptoms usually appear 1 to 7 days after exposure, though it may take up to 2 months.
- 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.
- Within a few days, the infection spreads throughout the body and severe trouble breathing, high fever, and shock may develop.
- The infection is difficult to treat after it has spread.
With gastrointestinal anthrax, symptoms usually occur within a week after exposure.
- At first you may have mouth ulcers, a sore throat, trouble swallowing, loss of appetite, vomiting, or a fever.
- As the infection gets worse, you may have trouble breathing (because of swelling in the throat), bloody diarrhea or vomit, or belly pain caused by fluid buildup.
- The infection can spread throughout the body and is difficult to treat after it has spread.
How is it diagnosed?
Your doctor will ask you questions about your symptoms and about any work, recent travel to other countries, or other activities that may have put you at risk for exposure. If the doctor suspects you may have been exposed to anthrax, testing will be done to confirm exposure or infection. Public health officials also will be notified about a possible anthrax infection.
Anthrax is confirmed when the bacteria are identified from a culture of your blood, spinal fluid, skin sores, or mucus from your nose, airways, or lungs. You may also have other blood tests or a polymerase chain reaction (PCR) test. A skin ulcer may be biopsied.
If your doctor thinks that you have inhalation anthrax, you may have a chest X-ray or a CT scan.
How is anthrax treated?
Antibiotics and antitoxins are used to treat all types of anthrax.
Anyone who is infected needs to be treated right away. Starting treatment before symptoms begin may make the infection less severe and prevent death. Treatment may include supportive care in the hospital.
Anyone who has been exposed to anthrax spores but is not yet sick should be treated with antibiotics and a few doses of the vaccine to prevent infection. Not everyone who has been exposed to anthrax will get sick. But because there's no way to know who will get sick and who won't, anyone who is directly exposed will get treatment. If you think that you have been exposed, call your doctor right away. Public health officials also will be notified about a possible anthrax infection.
How can you prevent it?
In the U.S., the anthrax vaccine is used to protect people who are at higher risk for exposure or who have been exposed. These include:
- Some military personnel.
- Some lab workers.
- Some people who come in contact with animals from other countries.
The vaccine is not available to the general public at this time since the risk of exposure to anthrax is extremely low.
Anthrax is known as a biological agent that has been used in bioterrorism attacks. If you have concerns about anthrax, go to the website of the U.S. Centers for Disease Control and Prevention (CDC) at www.cdc.gov/anthrax for the most current information.
