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Anthrax Facts and Powder Exposure

Anthrax is an infectious disease caused by the Bacillus anthracis bacteria. The bacteria are spread as spores. A spore is a protective covering on the bacteria, like the shell of a seed. The spore keeps the bacteria alive for long periods of time, waiting for the right condition to grow. People get infected with anthrax when the spores get into the body and begin to multiply. They spread through the body and produce toxins that cause severe illness. The natural form of anthrax infects cows and other animals with hooves. Anthrax rarely infects humans. Cases of human anthrax are rare in the U.S. but occur more commonly in developing countries. In very rare cases, anthrax spores have been released intentionally, in the form of a fine powder, to cause harm (bioterrorism).

People can become infected with anthrax by getting the spores in their bodies. This usually happens by handling infected animals or animal products. There are 4 main types of anthrax:

  • Cutaneous (skin). Spores enter the body through a cut or scrape. It's the most common type of anthrax and usually the mildest form.

  • Gastrointestinal (GI, digestive tract). Bacteria enter the body in infected food or water that contains spores. GI anthrax usually happens from eating raw or undercooked meat from an infected animal.

  • Inhalation (breathed). Spores enter the body by being breathed into the lungs usually by people working with infected animals or animal products. This is the most serious form of anthrax and needs treatment.

  • Injection. This is a more recently discovered form of anthrax that has been reported in Europe among people who injected themselves with heroin. People working with anthrax in a lab with the bacteria can also get accidentally infected this way.

Here are some important things to know about anthrax:

  • Not everyone exposed to anthrax becomes infected.

  • Anthrax is not contagious. But the skin form may spread in rare cases. GI and inhalation anthrax don't spread from person to person.

  • The different types of anthrax have different symptoms.

  • For all forms of anthrax, symptoms are mild at first. The symptoms can be similar to those of other illnesses.

  • If anthrax is not recognized and treated, the first, mild phase is followed by severe illness that can get worse very quickly.

  • Anthrax infection is treated mainly with antibiotics.

Cutaneous anthrax

Cutaneous anthrax occurs after spores touch an opening in the skin (a crack, cut, or scrape). Here are some important things to know about the cutaneous form of anthrax:

  • Most anthrax cases are of the cutaneous type.

  • Not everyone exposed will get sick.

  • If the infection occurs after exposure, symptoms usually start within 1 to 7 days.

  • The disease starts as a small red bump (like an insect bite) that turns into a blister.

  • The blister breaks in 1 to 2 days. Then a painless black sore forms. This sore dries up in 1 to 2 weeks.

  • Cutaneous anthrax can be spread to others, but this is very rare.

Inhalation anthrax

Inhalation anthrax occurs after breathing in anthrax spores that are in the air. Usually, the spores come from an infected animal product (such as an animal hide). Very rarely, anthrax spores have been released intentionally to cause harm (bioterrorism). Here are some important things to know about the inhalation form of anthrax:

  • This is the most serious form of anthrax.

  • Not everyone exposed will get sick.

  • You can't get inhalation anthrax from another person.

  • If infection occurs, symptoms often start in 1 to 7 days. But they may appear 6 to 8 weeks after exposure.

  • At first, an infection feels like the flu, with a sore throat, fever, dry cough, muscle aches, and chest discomfort.

  • There may be 1 to 3 days of improvement. After this, there may be sudden, severe shortness of breath, as well as other symptoms.

GI anthrax

GI anthrax occurs after eating or drinking food or water containing anthrax spores. Here are some important things to know about the GI form of anthrax:

  • Not everyone exposed will get sick.

  • If infection occurs after exposure, symptoms start in 1 to 7 days.

  • When the stomach and intestines are affected, there is fever, abdominal (belly) pain, vomiting blood, and bloody diarrhea.

  • If the mouth and throat are affected there will be fever, and sores on tongue and throat. Swallowing may be painful.

Injection anthrax

Here are some important things to know about the injection form of anthrax:

  • A group of small blisters or bumps appears where the drug was injected. These may itch.

  • A painless sore with a black center appears after the blisters or bumps.

  • The tissues around the sore swell.

  • Pus collects deep under the skin or in the muscle in the infected area.

  • Symptoms can include fever and chills.

  • Injection anthrax has symptoms like those of cutaneous anthrax. But injection anthrax can get worse faster. It may also be harder to recognize and treat.

  • Skin infections commonly happen with injection drug use. These usually are not anthrax.

A form of injection anthrax has occurred in northern Europe among some people who inject themselves with the street drug heroin. This type of injection anthrax has never been reported in the U.S.

Responding to a suspected anthrax exposure

Follow these guidelines when you come in contact with a substance that may be anthrax. But please keep in mind that this is very rare:

Suspicious unopened letter or package

A letter or package may be suspicious if it has:

  • Excessive postage

  • Handwritten or poorly typed address

  • Incorrect titles or titles with no name

  • Misspellings of common words

  • No return address

  • A city or state in the postmark that does not match the return address

Isolate the suspicious substance by placing it in a sealed plastic bag. Or cover the substance. You might cover it with something like clothing, paper, a plate, or a trashcan. Leave the room and close the door. Wash your hands with soap and water. This will remove all spores from the skin surface.

Unidentified powder found in letter or on surface

Don't try to clean up the powder. Cover the powder or letter with something like clothing, paper, a plate, a sealed plastic bag, or a trashcan. Don't remove this cover. Leave the room and close the door. Wash your hands with soap and water. This will remove all spores from the skin surface. If your face or clothing was contaminated, remove clothing and place it in a plastic bag or other sealed container. Shower with soap and water as soon as possible.

In either type of exposure, contact your local police department to learn what to do next. If you are at work, contact your supervisor or your security office. If the exposure is verified, preventive treatment with antibiotics will be advised until testing of the substance is complete.

If you have symptoms of an illness that you suspect may be anthrax, contact your healthcare provider, public health clinic, or local emergency department right away for further advice. If you think you were exposed but are having no symptoms of illness, contact your healthcare provider or the emergency department once cleanup and reporting has been completed. You may need to take antibiotics for prevention.

For the latest information, see the CDC website at www.cdc.gov/anthrax. Or contact your state public health department.

Online Medical Reviewer: Barry Zingman MD
Online Medical Reviewer: L Renee Watson MSN RN
Online Medical Reviewer: Rita Sather RN
Date Last Reviewed: 10/1/2022
© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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