Skip to content

Questions and Answers

Q: How do people get anthrax? Back
A: People can catch anthrax from infected animals or contaminated animal products. Most natural infection comes from skin contact. In the past, industrial wool sorters were at high risk of infection. You can also get anthrax infection from eating raw or too-rare meat - but this is uncommon. Even more uncommon - but by far most deadly - is anthrax caught by inhaling spores. This is because a person has to inhale several thousand spores before infection can take hold. Until the events of September, 2001, there hadn't been a case of inhalation anthrax in the U.S. since 1978.

Q: What is anthrax? Back Top
A: Anthrax is an animal disease that has been around for tens of thousands of years. Rarely, anthrax causes serious disease in humans. The germ is a bacterium called Bacillus anthracis that "seeds" itself by forming long-lasting spores. These spores can survive in the environment for a long time. Grass-eating animals, such as cattle, are most often infected because they can eat spores living in the soil. Animal vaccination - and destruction of infected herds - has drastically reduced the number of infected animals. Even so, anthrax spores continue to be found in soil samples from all over the world.

When anthrax spores get inside the body, they grow rapidly. The germs themselves can cause dangerous infections. Far more dangerous is a substance they produce in the body - anthrax toxin - which helps the bug survive by killing off cells of the immune system. This toxin is so deadly that it can kill even after infection is brought under control.

Q: What symptoms should I watch for? Back Top
A: The symptoms of anthrax infection depend on how a person catches the disease. All forms of anthrax if caught early enough can be cured by prompt antibiotic treatment. However, some anthrax strains developed as biological weapons are resistant to many drugs.

Skin infection starts with an itchy bump like a mosquito bite. After a day or two, it forms a small liquid-filled sac. This sac then becomes a painless ulcer with an area of black, dead tissue in the middle. Antibiotic treatment cures this infection. Untreated, it kills about one in five people.

The signs of intestinal infection are nausea, loss of appetite, and vomiting. This is followed by severe abdominal pain, vomiting of blood, and severe diarrhea. Untreated intestinal anthrax is deadly 25% to 60% of the time.

Inhalation anthrax, the most deadly form of the disease, begins with the same symptoms as the flu, including fever, muscle aches, and fatigue. As early as one day after these symptoms appear - but up to weeks later - the symptoms suddenly become much more severe, usually with breathing problems and shock. This form of the disease is often fatal.

Q: How is anthrax treated? Back Top
A: First, anthrax infection has to be identified. This is now much more likely since the CDC began a program to help public-health laboratories rapidly identify germs that might be used in biological warfare or terrorism.

Early treatment is essential. Natural strains of anthrax may be resistant to many antibiotics, but most are sensitive to penicillin. Either of two antibiotics is recommended: doxycycline and Cipro (ciprofloxacin). Because anthrax spores can stay hidden in the lungs for a long time, antibiotic treatment should continue for 60 days. There are reports that some forms of anthrax created as biological weapons are resistant to these drugs, but there is no hard evidence that this is true. In fact, the strain of anthrax in this outbreak appear to be fully sensitive to the antibiotics used to treat this bacteria.

People should NOT stockpile antibiotics. Antibiotic treatment should not be started unless public health authorities have warned of an anthrax outbreak, and even then these drugs can have serious side effects for some people.

More help is on the way. Researchers at Harvard University have invented molecules that work as an antidote for anthrax toxin. One of these molecules also vaccinates against future infection at the same time.

Q: Should I stock up on antibiotics to protect my family and me? Back Top
A: Definitely not. Why? Unless you've been exposed to anthrax, there's no reason to suspect that those cold symptoms you are having are anything but that -- a common cold. Antibiotics won't help if you have a cold or the flu. So if you start taking antibiotics -- and then stop when the threat has passed -- you are letting other germs in your body develop resistance to these important drugs. Then the medicine might not work when you really need it. And here's another reason: antibiotics can be dangerous to some people, and must be used as directed. These important medicines should only be used with medical supervision. The odds of a bad reaction are small -- but they are much greater than the odds of an anthrax attack.

Q: What can I do? Back Top
A: Most people in the U.S. will never be exposed to anthrax. Recent exposures to anthrax appear to have come from letters containing powdered anthrax spores, but there's no cause for panic. Here's what to do if you receive a letter or package that you suspect of containing anthrax or any other dangerous germs:

  • Do not shake or empty the envelope or package. Do not try to clean up any spilled powder or fluid.
  • Put the envelope or package into a plastic bag or other container to prevent the contents from leaking out. If you can't find a container, cover the envelope or package with clothing, paper, or a trash can -- and DON'T remove this cover.
  • Leave the room and close the door. Keep other people from entering the room.
  • Wash your hands with soap and water.
  • Call the local police and report the incident. If you are at work, call your building security officer and/or your supervisor.
  • Make a list of all the people who were in the room when you opened the letter or package. Give this list to the police -- and to local public-health authorities.
  • Remove contaminated clothing and put it into a plastic bag that can be sealed. Give the bag of contaminated clothing to the police.
  • Shower with soap and water as soon as you can. Do not use bleach or disinfectant on your skin.
  • Do not start taking antibiotics until told to do so by your doctor or by health authorities.
Gas masks or respirators won't do much good once an exposure has taken place -- and it's much more likely that you or your children would be injured by improper use of gas masks than by a terrorist attack.

Only preventive treatment with antibiotics can keep an exposed person from developing anthrax. Anthrax vaccine -- a series of six shots over the course of a year with yearly booster shots -- is not recommended for or available to the public. New treatments and vaccines are under development.

Q: Have Americans been infected with anthrax before? Back Top
A: Human anthrax is a rare disease. There were only 18 cases of inhalation anthrax in the U.S. from 1900 through 1978. There were 224 U.S. cases of skin infection between 1944 and 1994. However, the African nation of Zimbabwe experienced a terrible epidemic of skin anthrax with more than 10,000 cases between 1979 and 1985. Gastrointestinal anthrax is very rarely reported.

Q: How is anthrax turned into a weapon for bioterrorism? Back Top
A: Anthrax has been called the perfect germ for bioterrorism. This is because it isn't contagious - only those exposed to a release of spores get sick - so there's no chance that a release of the germs will boomerang and kill unintended victims. The spores last for a long time. During World War II, the British army experimented with an explosive shell filled with anthrax spores. These experiments took place on an island off the coast of Scotland. Spores persisted in the environment for 36 years. A massive decontamination effort finally cleared the region in 1987.

Even so, it's not easy to grow deadly anthrax and it's even harder to make it into a weapon. The spores have to be turned into a microscopically fine powder - no simple trick. Then the powder must be sprayed over a large area with a specially adapted device. Even then, the temperature and the wind must be exactly right to contaminate populated areas. One expert told WebMD that a terrorist would have to be very lucky to successfully deploy anthrax as a weapon of mass destruction.

Q: Where is this anthrax coming from? Back Top
A: An intensive federal investigation is underway, but few details have been released. There is no doubt that these anthrax exposures are the result of a criminal act. So far, all of the anthrax discovered remains fully sensitive to antibiotic treatments. Sophisticated bioweapons programs generally use anthrax that can resist most antibiotics. However, there are signs that the anthrax has been "weaponized" to a degree. Some of the samples from contaminated mail appear to have been treated in order to make them disperse in the air, making them easier to inhale. Other samples appear to contain a skin irritant that makes it easier for the anthrax to attack the skin.

Researchers are looking at the problem in two ways. First, they will grow the anthrax to see how it behaves. Next, they will examine its DNA for unique patterns. Using this data, the various anthrax strains will be compared to similar information from anthrax strains studied in laboratories around the world. Of course, there's no guarantee that this will lead investigators to the bugs' ultimate source.

Q: How can I tell the difference between an anthrax infection and the flu? Back Top
A: The early symptoms of inhalation anthrax are the same as those of a mild case of flu. Treatment to prevent anthrax begins only after a person has had a suspected exposure. There is a new quick test that can show whether a person has been exposed to anthrax, but it is not yet widely available. Your doctor, however, should have access to rapid tests that can identify the flu. Here are some differences in symptoms as the illnesses progress:

  • Shortness of breath is common with anthrax, but unusual with the flu
  • Vomiting is common with anthrax, but unusual with the flu
  • Sore throats are uncommon with anthrax, but typical with the flu
  • Stuffy noses are uncommon with anthrax, but typical with the flu
If you think you have a cold or flu and your symptoms suddenly get much worse -- especially with a severe headache -- seek immediate medical attention.

Q: Can I catch anthrax from someone else? Back Top
A: No. Anthrax can't be spread from person to person.

Q: Who should I contact in my local area if I'm worried? Back Top
A: Contact your local police department, or call 911, and contact your local health department or your doctor for more information if you think you've been exposed to anthrax. Don't start taking antibiotics unless advised to do so by your doctor or by health authorities.

WebMD has a lot more information - check out the links below. On the Internet, the Center for Civilian Biodefense at Johns Hopkins University has a wide range of information at http://www.hopkins-biodefense.org. Also see the latest bulletins from the CDC at http://www.cdc.gov.

Medically reviewed by Michael Smith, MD, Senior Medical Editor, WebMD, March 2005.