The anthrax experience of October 2001 set off a public health scare unlike any this country has ever seen. A series of government buildings in Washington DC, from the Senate to the US Supreme Court, were shut down when traces of anthrax were uncovered inside; government agencies issued advisories on how to handle suspicious-looking packages; news and mailroom employees across the country began donning latex gloves to sort mail; Americans rushed to stockpile antibiotics (against public health officials' advice); and panicked citizens flooded hospitals with their common cold symptoms or called law enforcement to report sightings of suspicious white powder (usually flour).

Understandably, public health departments were flooded with calls from a frightened public, everyone asking similar questions: How real is the threat? What are the symptoms? How can I protect myself?

"It's important to remember that very few people have been affected by anthrax," says Jason Pate, a senior research associate and bioterrorism expert at the Monterey Institute of International Studies in California. "The fact that you can't see it makes it more terrifying, but the critical thing is that anthrax is not contagious and not going to cause an epidemic."

Here are some of the most commonly asked questions about anthrax, with responses drawn from interviews with experts on bioterrorism and information put out by the federal government's Centers for Disease Control and Prevention (CDC) and the Department of Health and Human Services.

Q: What is anthrax?

A: Anthrax is an animal disease that has been around for thousands of years. It's caused by a spore-forming bacteria, Bacillus anthracis, which live in the soil and on infected animals, such as cattle, sheep, goats, camels, antelope, and other hoofed animals. Spores can be found in pastures in most parts of the world. Like all other bacteria, you can't sense anthrax -- it's invisible to the naked eye, odorless, and tasteless.

Anthrax is an infectious disease, but the good news is that it's not contagious. In this case, "infectious" means that anthrax bacteria causes an infection, but one that's not generally passed from person to person.

Q: How are people exposed to anthrax?

A: About 95 percent of the world's human anthrax cases are skin infections, usually the result of handling infected animal products, according to the CDC. Eleven of the 22 cases of anthrax reported in 2001 by people who handled contaminated mail were cutaneous anthrax and non-lethal. The bacteria enter the skin through a cut or abrasion. Many people who come down with cutaneous anthrax (the skin infection) are exposed to the bacteria from handling products made from infected animals, such as wool, hides, leather, or animal-hair items.

In rare instances, people handling contaminated animal products develop inhalation anthrax. As occurred in the five lethal cases of anthrax in the fall of 2001, people may breathe in anthrax spores, which can release a toxin that can do fatal damage to the respiratory system and brain. Finally, if people eat raw or undercooked meat from animals infected with anthrax, the bacteria can invade the intestines.

Experts stress that anthrax in any form is rare in the US From 1900 to 1978 there were only 18 documented cases of inhalation anthrax in the country. From 1944 to 1994 there were slightly more than 200 cases of cutaneous anthrax; the most recent pre-9/11 case was reported in North Dakota in August 2000: A man contracted the disease when he helped dispose of five cows that died of anthrax. To date, there have been no reports of the intestinal form ever occurring in the United States.

Q: How dangerous is anthrax?

A: The degree of danger depends largely on how anthrax gets into your system. The cutaneous (skin) form responds well to antibiotics, and people usually recover if treated. Even among untreated people, survival rates are about 80 percent.

A lung infection caused by inhaling anthrax spores is far more dangerous, but rare because it's difficult to disperse anthrax in the air effectively and it takes several thousand spores to cause a dangerous infection. Once established, inhalation anthrax is often fatal, according to the CDC. Nearly half of all deaths occur within 24 to 48 hours of serious respiratory symptoms. Without treatment, the ingested form is fatal in 25 to 60 percent of cases.

Fortunately, the type of anthrax being mailed was susceptible to antibiotics. An antibiotic-resistant strain of bacteria would have been far harder to treat, as would a virus.

Q: How do you know if you have anthrax?

A: The symptoms of anthrax vary depending on which kind you have and usually appear within seven days of exposure.

The symptoms of inhalation anthrax resemble that of a common cold, marked by fever, coughing, and overall fatigue. After a few days, you may develop severe difficulty breathing and shock. Without antibiotic treatment, this form of anthrax is often fatal.

Symptoms of skin infection from anthrax include a rash with small fluid-filled bumps that look like spider or mosquito bites, swelling of the skin, swollen lymph glands, and fever. The red, raised bumps may form ulcers that develop a black area in the center as the skin dies (which is why anthrax gets its name from the same Greek root for anthracite, which is coal). Later, the ulcers may develop scabs that eventually fall off.

Finally, if you have intestinal anthrax, your symptoms may include nausea, loss of appetite, vomiting (possibly bringing up blood), fever, abdominal pain, and severe diarrhea.

The CDC says symptoms are usually noticeable within seven days of exposure, but they can take up to 60 days to appear. That's why people who are exposed to anthrax have to take antibiotics for at least two months.

Q: Can anthrax be prevented?

A: An animal vaccine is available and widely used in countries where anthrax is common. This vaccine has been licensed for use in humans, and the CDC reports it to be 93 percent effective. At this time, however, the vaccine is in short supply and it has been set aside for use by people who handle animals, work in laboratories where anthrax is studied, or are in the military.

The vaccine is given in an initial course of three injections, two weeks apart, followed by booster shots at 6, 12, and 18 months and an additional booster every year after that.

Q: Is there an approved treatment for anthrax?

A: Yes. Three types of antibiotics are approved for all types of anthrax infections: ciprofloxacin (Cipro), doxycycline, and penicillin. Other antibiotics can be effective as well. Because the disease is so serious, people who have been exposed to anthrax bacteria -- whether or not they have symptoms -- should take antibiotics for 60 days to reduce the risk the disease will develop or to halt its progression. Taking antibiotics will also minimize the chance of developing side effects, such as meningitis.

Q. Should I take antibiotics as a preventive measure?

A: No. Unless you have been exposed to the bacteria, the US Department of Health and Human Services recommends against the preventive use of Cipro or other antibiotics. That's because antibiotics have side effects that may outweigh the actual danger to you, and taking antibiotics routinely causes bacteria to develop a resistance to them.

Q. Should I order antibiotics over the Internet, or ask my doctor for Cipro or another antibiotic to have on hand in the event of an attack?

A: No. Federal health agencies have strongly urged physicians not to prescribe Cipro to patients to stockpile in the event of an attack. Many Web sites that began pushing Cipro and other antibiotics in the wake of the recent anthrax cases are taking advantage of people's fears, and ordering these drugs to stockpile isn't a good idea. To begin with, most common antibiotics won't prevent symptoms caused by biological weapons other than drug-susceptible bacteria. According to the Infectious Disease Society of America, stockpiling antibiotics is also dangerous and unethical on a number of counts. Not only may consumers such as pregnant women and children take drugs that wouldn't ordinarily be prescribed for them, but stockpiling antibiotics could divert the nation's supply away from areas where the drugs may actually be needed. In addition, the practice "destabilizes" the government's capability for rapid response to possible emergencies, according to the IDSA. Urging people not to hoard antibiotics, federal health authorities note that the government is prepared to distribute the appropriate drugs in an emergency. In fact, according to the US Department of Health and Human Services, the government has enough antibiotics on hand to treat more than 40 million Americans.

Q: What should I do if I receive a letter that I suspect contains anthrax?

A: First of all, don't panic. It's likely that you're not dealing with anthrax. Don't shake the suspicious letter or empty its contents, the CDC advises. Instead, put the envelope or package in a plastic container that can't leak. (If you don't have a container, cover the envelope with anything at hand -- including a trash can or clothing -- then leave the room and close the door.) If necessary, have someone cordon off the area to keep other people out. Next, wash your hands thoroughly and call 911 to notify the local police and FBI. If you're at work, notify your building's security official or your supervisor.

If you've spilled some of the powder, DON'T try to clean it up. Cover it with a piece of paper or towel, then leave the room and close it off so other people won't come into contact with it. The CDC advises that you put any clothing that's come into contact with the powder into a leak-proof bag or container, then wash your hands or shower with soap and water before calling 911.

Q. How can I tell if a letter or package might contain anthrax?

A: The US Postal Service says that characteristics of suspicious packages and letters include the following:

-- Excessive postage

-- Handwritten or poorly typed addresses

-- Incorrect titles, titles without names, and misspellings of common words

-- Oily stains, odors, and discolored envelopes

-- No return address

-- Excessive weight or a lopsided envelope

-- Protruding wires or aluminum foil

-- "Excessive security measures" such as string, masking tape, and so on

-- Letters marked "personal" or "confidential"

-- A city or state in the postmark that doesn't match the return address

If you've received a suspicious letter or package, don't try to open it. Instead, the US Post Office advises you to isolate the piece of mail, evacuate the immediate area, and call a Postal Inspector to report that you've gotten a mail parcel that may contain chemicals or biological agents.

Q. How does anthrax compare to other diseases?

A: In terms of comparison, the flu leads to an average of 36,000 deaths and more than 200,000 hospitalizations in the US each year.

Q. How hard is it to use anthrax as a biological weapon?

A: In the absence of an air attack, it's quite difficult. It's tricky to create spores in the lab, keep them from clumping together, and disperse them effectively. In Tokyo in 1993, the Aum Shinrikyo cult attempted to spread anthrax from a rooftop several times within a week without success -- although the cult was well-funded and included experienced biologists.

In the event of an emergency, government health agencies plan to ship antibiotics from their stockpiles to wherever they are needed.

Q. How can I find out more about anthrax and bioterrorism?

A: You can visit the federal government's Centers for Disease Control and Prevention at http://www.cdc.gov, which will give you the latest government advisories as well as updates on reported cases. You may also want to visit Johns Hopkins Bloomberg School of Public Health’s Center for Civilian Biodefense Strategies.

-- Nina Silberstein is a health and medical writer in Portland, Oregon. Deepi Brar, Stephen Levine, Psyche Pascual, and Paige Bierma contributed to this report.

Photo by Sion Touhig/Getty Images

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First published October 17, 2001
Last updated February 26, 2008
Copyright © 2001 Consumer Health Interactive