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A photomicrograph demonstrating a positive Gram stain with Bacillus anthracis.


Anthrax (Bacillus Anthracis)

What is Anthrax and How Do People Get It?

Anthrax disease is a severe illness caused by bacteria named Bacillus anthracis. Anthrax disease can result in pneumonia, blood infection, and death.


Most of the time anthrax bacteria live in an inactive form called spores. Inactive anthrax spores live naturally in soil and can be carried in the wool or on the skin of animals-usually cows, sheep, or goats. A hard coating helps the spores survive heat, drying, and radiation for long periods of time.


People can touch, eat, or breathe in anthrax spores. When this happens, the anthrax spores enter the human body and can turn into active bacteria. This is called exposure to anthrax. Not everybody who is exposed to anthrax will get sick. But many will, and as anthrax bacteria multiply inside the body, they can cause very serious illness.


For example, 1 person in New York in 2006 and 2 people in Connecticut in 2007 were exposed to anthrax while making drums from imported animal skins. The skins contained anthrax spores. These people became extremely sick with anthrax disease. Getting anthrax this way is very unusual. In California, there has been no anthrax disease in humans since 1983, but there are cases of anthrax in farm animals (usually cattle) every few years.


Terrorists could use anthrax to hurt people on purpose by releasing anthrax spores in public places. In 2001, letters containing powdered anthrax spores were sent through the U.S. mail, causing skin and lung anthrax in 22 people. Five people died, all due to lung anthrax.


What if there is an Anthrax Emergency in San Francisco?

The San Francisco Department of Public Health (SFDPH) has a plan to respond quickly to an anthrax emergency. SFDPH will evaluate the anthrax situation and may recommend ways for people to keep themselves and their family safe. Recommendations may include antibiotics for people who are at risk of illness. SFDPH will also participate in efforts to provide needed medical support and treatment, and to reduce any ongoing sources of anthrax spores.


How can I keep from getting Anthrax?

To lower your risk of getting anthrax from a natural source:

  • Do not eat meat that has not been properly slaughtered and cooked.
  • Do not work with raw animal hides, fur or skin, especially those of goats, sheep, or cows.


To lower your risk of getting anthrax if terrorists release spores on purpose:

  • If you were exposed to a suspicious substance or if you were in an area thought to contain anthrax spores, it may help to wash your skin and hair thoroughly with soap and water. It may also help to change and wash your clothing, or if you cannot wash your clothes immediately, put them in a plastic bag to keep them separate from your other things. In such an emergency, SFDPH will provide specific instructions.


Is there a Medicine to Prevent Anthrax Disease?

Yes. If you have been exposed to anthrax, there are certain antibiotics you can take before you get sick as a way to prevent illness. These antibiotics can prevent anthrax disease, even if the anthrax spores have already gotten into your body. They work best when you start taking them as soon as possible after anthrax exposure. In an emergency involving anthrax, SFDPH will announce which antibiotics to take, who should take them, how and where you can get them, and how to take them after exposure to anthrax.


Is there a Vaccine (shot) to Prevent Anthrax?

Yes there is a vaccine but it is in short supply and is available only for the military.

Can I Catch Anthrax from Someone?

No. Anthrax is spread by contact with spores, not by contact with sick people. No one has ever been known to catch anthrax directly from another person who is sick with anthrax.


What are the Signs of Anthrax Disease?

  • Lung Anthrax or Pneumonia is the most likely form of disease after an intentional release of anthrax and occurs by breathing in anthrax spores. After exposure, it usually takes 2-7 days (but sometimes up to 2 months) until illness starts. First there are a few days of symptoms like headache, cough, and muscle aches. But there is usually no runny nose. Then after a few days, there can be trouble breathing, chest pain, large lymph glands, worse headache, stomach pain, and vomiting or diarrhea. With lung anthrax, bacteria almost always enters the bloodstream, leading to severe illness or death.
  • Skin Anthrax occurs when spores enter the body through a break in the skin. Within 7 days, a painless skin blister appears at the point of entry. This blister becomes a painless open sore and then a black scab.
  • Intestine Anthrax occurs after eating undercooked meat from an animal that has anthrax infection. An upset stomach develops 2-5 days afterward. Later there can be bloody diarrhea, fever, and severe stomach pain.



See a doctor right away if you are having the symptoms listed above AND you think you may have been exposed to anthrax. It is important to start medical treatment as soon as possible.


Is there Treatment for Anthrax Disease?

Yes. All three forms of anthrax disease (lung, skin, and intestine) can be treated with the proper antibiotics. However, the chance of cure depends on how soon treatment gets started and on whether the disease is in lung, skin, or intestine. Nearly everyone who has skin anthrax can be cured with proper antibiotics.

Lung anthrax is the most dangerous. In 2001, only half of those with lung anthrax survived, even with antibiotics and hospital treatment. This is why it is so imporant for people with anthrax exposure to start taking antibiotics before they get sick.


What is being done to check for Anthrax in the Mail?

The U.S. Postal Service now tests for anthrax where mail is sorted, including the San Francisco mail sorting center. Anthrax in mail could be quickly found and steps would be taken to protect postal workers and the public.


How can I find Information during an Anthrax Emergency?

Check the SFDPH website Local media such as newspapers, TV stations and radio will carry emergency instructions. Emergency radio stations inclue: KCBS 740 AM and KGO 810 AM.


What can I do Now if I am Worried about Anthrax?

  • Read about anthrax at and at the CDC page
  • Go to to learn about steps you can take now to prepare for all disasters.
  • Keep a card in you wallet with a list of your health problems, the names and doses of medicines you take, and any medicines you are allergic to.


Additional Information


Frequently asked questions (FAQ) about Anthrax:


Information on Anthrax for Health Care Providers

  • Reporting: A suspected or confirmed case of Anthrax must be reported immediately (within one hour) to SFDPH by calling (415) 554-2830. Click here for more reporting information.
  • Documents:
    • "Infectious Disease Emergencies: A Preparedness and Response Guide for San Francisco Clinicians"  


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