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What Is Anthrax?

There's been a lot of discussion about anthrax on the news lately. What exactly is anthrax, and should you be concerned about it?

Anthrax is an infection caused by the bacteria Bacillus anthracis. Although it's most commonly found in grazing animals like sheep, pigs, cattle, horses, and goats, anthrax can sometimes infect humans.

In the environment, anthrax can form spores (a version of the germ in a hard shell) that can live in the soil for years. People can become infected by coming in contact with these spores through a break in their skin (such as a cut, scratch, or rash), by eating contaminated food (usually meat), or by inhaling the spores. But anthrax is not contagious; it can't be spread from person to person.

Some people are concerned that anthrax is linked to the terrorist attacks of September 11 and that terrorists may be trying to spread the bacteria, particularly through the U.S. mail system. Be assured that federal and local officials, as well as the U.S. Centers for Disease Control, are investigating all anthrax cases and are taking measures to ensure public safety.

It's extremely unlikely that you or someone you know could get anthrax. In fact, until recently, there had only been one reported case of pulmonary (inhaled) anthrax in the United States in the past 25 years.

What Are the Types of Anthrax?
There are three main types of anthrax:

  • cutaneous (skin) anthrax, which can occur if someone handles contaminated animals or animal products (especially animal hides) while they have a cut, abrasion, or rash on the skin
  • intestinal anthrax, which can occur if someone eats contaminated meat
  • pulmonary (inhaled) anthrax, which is extremely rare but can occur if someone breathes anthrax spores - usually found in the dust kicked up by animals - all the way down into the lungs

More than 95% of anthrax cases in the world are from cutaneous anthrax. This is the least dangerous form. Intestinal anthrax is much less common, but it can make a person much sicker.

Symptoms vary depending on the type of anthrax:

  • Cutaneous anthrax usually involves skin sores that may turn black after a few days. (The name "anthrax" comes from the Greek word for coal and refers to these sores.)
  • Intestinal anthrax symptoms include severe abdominal pain, nausea, vomiting, severe diarrhea, and bleeding from the gastrointestinal tract.
  • Pulmonary anthrax usually begins with flu-like symptoms but, if untreated, can rapidly turn into severe pneumonia (an inflammation of the lungs).

It usually takes less than 7 days for symptoms of skin and intestinal anthrax to appear, but symptoms can appear as early as 48 hours after the lungs have been exposed to anthrax spores.

How Difficult Is It to Get Anthrax?
It's very difficult to get anthrax. Simply being exposed to the spores (meaning, being in an environment where the spores are) or coming in contact with an infected animal doesn't guarantee that a person will develop the disease. The spores must penetrate the skin or the lining of the gastrointestinal tract, or get all the way down the airway into the lungs, in order for a person to develop anthrax. In the case of pulmonary anthrax, thousands of spores have to be inhaled to get the disease, and that is extremely difficult to do. In fact, several people who were tested for recent anthrax exposure were found to have spores in their nasal passages only, and were not found to have developed the disease.

How Is Anthrax Diagnosed and Treated?
Anthrax exposure or infection can be determined by:

  • using special "field tests" developed by the United States military that look for chemical evidence of anthrax spores (This is used as a preliminary test, and the results are known in minutes.)
  • performing cultures for anthrax bacteria using swabs from the nasal passages (or from any skin sores) taken from people believed to have been exposed to anthrax (Cultures are the most accurate way to look for evidence of anthrax infection, and the results are known in a couple of days.)
  • performing blood tests to determine if a person has formed antibodies (proteins that fight off foreign substances in the body) against anthrax (A positive test for the antibody means that anthrax spores have found their way into a person's body - even if he is not showing any symptoms of the disease.)

These tests are done at possible sites of exposure to anthrax, and are not routinely done at hospitals or in doctors' offices.

Doctors can treat anthrax with antibiotics - mostly ciprofloxacin, tetracycline, and penicillin. Anthrax is almost always successfully treated with antibiotics if the disease is caught in the early stages, and doctors around the country are on increased alert for suspected anthrax symptoms.

People with sores from cutaneous anthrax may feel only mildly ill. But if they are not treated with antibiotics, the bacteria can enter the bloodstream, causing the disease to progress and become more serious.

Is Anthrax a Threat?
The anthrax bacteria can be easily manufactured in a laboratory - perhaps in a more potent form that is more resistant to treatment - and the current concern is that man-made anthrax can be used as a biological weapon. Others have tried to weaponize anthrax in the past, without much success. That's because it's extremely difficult to produce anthrax in a form that will deliver enough spores into people's lungs to make them sick.

Some people are concerned about "outbreaks" of anthrax. The word "outbreak" usually refers to contagious diseases (like the flu) that spread quickly among people of a certain community or city. Anthrax is not a contagious disease, so an outbreak of this type wouldn't occur in the same way that contagious diseases spread. Rather, an outbreak of anthrax could occur when a cluster of people are exposed to spores from the same source.

Fast Facts on Anthrax

  • Anthrax is not contagious.
  • Anthrax is very rare. Until very recently, anthrax wasn't even talked about because it was so rare - and it still is. Even with some of the possible exposures to anthrax right now in the United States (and many of these will turn out to not be anthrax), a person's chances of getting anthrax are about exactly the same as they were before you heard about anthrax on the news -  very, very low.
  • Anthrax is almost always successfully treated with antibiotics if the disease is caught in the early stages. This is especially true of the cutaneous version.
  • There is a vaccine for anthrax, but it is only available to people in the military because they are much more likely to come into contact with anthrax in other parts of the world. The vaccine is not given routinely to people in the United States - except for veterinarians, who might come into contact with the disease when treating animals.
  • There is no reason for people who haven't come into contact with a possible source of anthrax to start stockpiling or taking antibiotics such as ciprofloxacin. Not only will stockpiling antibiotics make it harder for people who truly need them to get them, but taking antibiotics when you are not sick can cause adverse reactions (such as stomach irritation). Also, there is no reason to take such drugs to "prevent" anthrax, except in cases where exposure has been confirmed. Taking antibiotics before exposure won't help and may actually have the harmful effect of making other common bacteria antibiotic-resistant.

What Should You Do?
First and foremost, don't panic. The threat of being exposed to anthrax is minuscule, even in light of recent events.

If your child is fearful about anthrax, remind her that anthrax is extremely rare and that it's unlikely she will ever be exposed to anthrax spores. Talk to your child about her fears and reassure her that she is protected and loved.

If you feel worried yourself, consider this: more than 208 billion pieces of mail go through the U.S. Postal Service each year, making the probability that you or someone you know will be affected by anthrax almost nonexistent. However, it may make you feel better to keep in mind the following characteristics of suspicious letters or parcels, released by the U.S. Postal Service:

  • no return address
  • a lopsided or uneven appearance
  • the words "personal" or "confidential" marked on the outside
  • misspellings of common words
  • excessive postage or tape
  • strange odors or stains

If in the unlikely event that you do receive a suspicious envelope at home or at work, notify your local police or other authorities.

Reviewed by: Frederick Meier, MD
Date reviewed: October 2001

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