What is anthrax?

Anthrax is a spore-forming bacteria, Bacillus anthracis, that is naturally occurring in soil and in hoofed farm animals and has been exploited for biological warfare and terrorism. In the natural world, the bacterium is extremely common, but infections are rare.

Who is at risk of infection?

People who are normally at risk are people who come in contact with farm animals or products from farm animals such as veterinarians, animal handlers or people who work in livestock laboratories. Infection is rare in animals, but even that is much more common than human infection. It's very uncommon for humans to get infected. In the 20th century there were 18 cases of human infection in the United States. It takes a lot of anthrax to infect a human, and it's very difficult to get infected.

How does someone become infected with anthrax?

You can be exposed to either the actual bacterium or the spores it produces. The most common way to get infected is if it touches the skin (cutaneous infection), or if you inhale it or ingest it in food.

What kinds of illness does anthrax cause?

If you inhale it, you eventually may develop an infection that resembles pneumonia, causing fluid to build up in your lungs. Once you develop symptoms, this form of anthrax becomes untreatable. In the cutaneous form, you develop a sore or a blister on your skin, and that is the least deadly.

What is the death rate?

All types of anthrax can lead to death, but cutaneous anthrax is usually curable, and early treatment is important for all forms. The death rate for gastrointestinal anthrax is 25 percent to 75 percent, and for inhalational anthrax it's 90 to 100 percent.

How long does it take for symptoms to appear after exposure?

It takes as little as two to six days, but it can be six weeks or even longer.

What are the early and late symptoms?

It depends on what type you get. If it's cutaneous anthrax, usually it's a sore or blister. If it's gastrointestinal or inhaled anthrax, the early symptoms are flulike — fever, cough, diarrhea. Later on, the inhaled anthrax develops into pneumonia, which progresses rapidly and usually fills the lungs with fluid. At that point it's almost universally fatal.

Is there a vaccine against anthrax?

There is a vaccine. It is currently unavailable to the general public. The military has it, and it is reserved for people who are at high risk, such as military who will be involved in areas where bioterrorism may be used, or laboratory workers who work in areas where they might be exposed to it. It involves multiple shots, and the side effects are usually significant compared to other vaccinations. It takes 18 months before you are protected, and then you need yearly boosters.

How is anthrax treated?

If you are exposed, you will be given antibiotics. Prevention after you have been exposed, but are not yet infected, is effective. Once you have the disease, you still take antibiotics, but there is no really good treatment. Treatment with antibiotics at this point is generally not effective.

How easy is it to spread anthrax?

It is extremely difficult. The dust, powder or spore form that was developed by the Russians for bioterrorism is extremely difficult to get and extremely difficult to spread to large populations. If you spray it on people, you have to get a certain volume of inhaled spores before you can infect someone; you'd have to put them in an enclosed environment. Outside, it's very susceptible to rain, it would disperse from the wind, sunlight can weaken it, and the concentration is lowered. The more common form is a wet form of anthrax, which occurs naturally in soil or farm animals. You could spread it, but it would be difficult to deliver to large populations. There's a lot of talk about putting it in water supplies, but most anthrax would be destroyed by the acidity of the water.

If anthrax is so hard to spread, why is it considered a weapon of biological terror?

Because of all the biological agents that are potential weapons of biological terrorism, it's still the most likely. Other agents are also difficult to spread, and probably more difficult than anthrax.

Is there anything people can do if they are concerned about anthrax?

They should address their concerns with their physician and seek sources of real information, not rely on the lay press. I would strongly discourage people from stocking up on antibiotics or purchasing a gas mask. The hoarding or storing of antibiotics will deplete the stores of antibiotics for people who really need them for actual infections. The likelihood that you will have an untoward reaction from taking the antibiotics is much higher than the likelihood of actually being exposed to anthrax. And what would you do with a gas mask? You'd have to wear it 24 hours a day. Then there's also the worry of developing resistant organisms if everybody's taking antibiotics for no reason at all.

What is our government doing to prepare?

The government is following the plans it's always had for disaster, chemical warfare and bioterrorism. Hospitals, local municipalities, and state and federal governments are all reviewing their plans, but the plans have always been there. The government has supplies of antibiotics and antidotes for biological and chemical warfare, and they are centrally located and able to be delivered within hours of identification of a possible exposure. The government is prepared.

Harvard Medical School Commentary: Putting The Risk Of Bioterrorism Into Perspective

Oct. 10, 2001

By Anthony L. Komaroff, M.D.
Professor, Harvard Medical School

Even after Sept. 11, our world is a very much safer place than it was for our grandparents. People are much less likely to die of the major infectious and non-infectious diseases. The simplest evidence of this is that we live much longer today. One hundred years ago, most Americans died before they were 50. Today we live until we are nearly 80.

However, the events of Sept. 11, and the threats of further terrorist attacks, have made the world feel less safe. As I write this, it appears likely that one man in Florida has died from an act of bioterrorism -- most likely, I would think, the act of a single deranged person, like the Unabomber. Bioterrorism is a real threat, and a lot of my patients are asking about it, and about what they should do to protect themselves.

For the reasons outlined by Dr. Zane:

• It is extremely unlikely that a person walking through a particular enclosed space, such as a mall, would ever be exposed to anthrax.
• Immunization is not currently an option, except for the most vulnerable people (members of the armed forces sent into battle). Moreover, the evidence that immunization protects against anthrax in the lungs, which is what the man in Florida died from, is not solid.
• It makes no sense for people to hoard supplies of antibiotics at home. Government agencies are stockpiling antibiotics for rapid distribution to people who might be afflicted by an attack.
• It especially makes no sense to wear gas masks — for complete safety, you'd have to wear it 24 hours a day. Is that a life?

In my opinion, the threat to Americans from natural infections is much greater than the threat of bioterrorism. For example, tens of thousands of people die each year from influenza, and many of them have not had their flu shots. I ask my patients who are agonizing over the possibility of bioterrorism whether they know if their parents have gotten their flu shots, or if their children's immunizations are up to date. The risk to their family from influenza, alone (not to mention other preventable infectious diseases) is very much greater than the risk of bioterrorism, yet many people ignore immunizations.

I'm not saying that bioterrorism is nothing to be concerned about — just that it be put into perspective. We live in a safer world than did any of our ancestors. Let's try to make it safer yet, by taking action to protect ourselves against the very real threat of natural infections.

Anthony L. Komaroff, M.D., is professor of medicine and editor-in-chief of Harvard Health Publications at Harvard Medical School. Dr. Komaroff also is senior physician and was formerly director of the Division of General Medicine at Brigham and Women's Hospital. Dr. Komaroff is well known for his research on chronic fatigue syndrome, and serves as a member of the U.S. Surgeon General's Chronic Fatigue Syndrome Coordinating Committee.