Anthrax is a rare disease caused by bacillus anthracis, a bacterium that is found naturally in soils in the Southwestern United States and other countries. It is an animal disease and is virtually never spread from human to human. It is not found in Florida soil, livestock or wildlife. When the bacteria are in the dormant spore stage, anthrax turns into a white or beige powder. HOW IS IT TRANSMITTED?

In its dormant or spore state, anthrax can enter the body in three ways:

Most people who contract anthrax come down with the cutaneous form, in which spores enter the skin, usually through a cut or a scratch. This is the type the NBC News employee in New York has contracted. Most of the time, these cases occur in people who handle animal hides or wool that contained anthrax spores. In the United States, 224 human cases of cutaneous anthrax were reported from 1944 to 1994.

People who eat undercooked meat from animals that were infected with anthrax can contract gastrointestinal anthrax, in which spores germinate into bacteria in the intestines, causing nausea, vomiting, fever and abdominal pain. Untreated, about 25 percent to 60 percent of people with ingestional anthrax die. Worldwide, relatively few anthrax cases have been gastrointestinal.

Inhalation anthrax is the form that affected the man who died in Florida. Tests showed that two other South Florida residents had the anthrax bacteria in their nasal passages. It is extremely rare and by far the most deadly form of the disease. Only 18 cases were reported in the United States in the 20th century. WHEN DID WE FIRST LEARN ABOUT IT?

Anthrax has been known since biblical times. The fifth plague described in the Book of Genesis as killing the Egyptians' cattle resembles anthrax and the disease is described in the early writings of Hindus, Greeks and Romans. An epidemic swept through European countries in the 17th century.

Anthrax bacteria are named for the Greek word for coal, anthrakis, because they cause coal-black lesions when they infect the skin. The bacterium's life history -- and the etiology of the disease it causes -- were discovered in the mid 19th century by Robert Koch, a German bacteriologist who was a developer of the germ theory of disease. CLEANING IT UP

HOW IS ANTHRAX CLEANED UP?

Solutions of one part bleach to 10 parts water are effective in routine decontamination of surfaces that are contaminated with active, germinated bacteria. Spore destruction is much tougher -- formaldehyde is needed -- but a mild detergent solution will wash spores away. When investigators leave a site that might be contaminated they are sprayed down with Tide solution, which goes into 55-gallon drums. The drums are taken to a special site for disposal. Since inhalation anthrax is not a water-borne disease, that's overkill. And a piece of good news in all of this: Active, germinated colonies of anthrax need nutrition from a human or animal host to keep multiplying. Once immersed in water, the colonies disappear quickly. Spores -- the dormant state of the anthrax bacterium -- can live for years. But again, spores in water will not cause inhalation anthrax. HOW DO EXPERTS DECONTAMINATE AN OFFICE BUILDING?

Experts say the chances of contracting anthrax from spores on surfaces, in rugs, on fan blades, from any source of secondary aerosolization is virtually nil. As hard as it is to imagine, spores all over your house or workplace will not make you sick. To make you sick, the spores must be concentrated in huge numbers, aerosoled and sprayed. After they fall down onto the floor, they're not going to give you inhalation anthrax. That being said, we all want to know our workplaces and homes are as spore-free as possible. In a known contamination such as at American Media in Boca Raton, environmental cleaners will scrub all surfaces with a detergent solution and vacuum and revacuum rugs. Then they'll burn the vacuum bags and the rubbish and dispose of the dirty wash water. Anthrax is hard to kill, but an errant spore here or there is not going to hurt anyone. WHAT CAN I DO AT HOME?

"Homeowners should carry on normal hygienic precautions," says Dr. Istvan Krisko, an infectious disease specialist in Palm Beach County. "Wash surfaces, clean the house, wash hands." CUTANEOUS ANTHRAX

HOW DOES CUTANEOUS ANTHRAX WORK?

The anthrax spores enter through a cut or scratch. infect the skin, the infection starts out like a small itchy insect bite. Within 1-2 days, the lesion develops into a pus-filled blister that is red around the edges. A day or two later, this becomes an open sore that is especially recognizable because it is black. Eventually, this dries up and leaves a black scab, which falls off after a week or two. ARE THERE OTHER SYMPTOMS?

Yes. They include fever, malaise and headache. Lymph glands in the area near the lesion may swell. Untreated, about a quarter of those affected die because the anthrax bacteria migrate into the bloodstream, causing an overwhelming infection and releasing toxins. Treatment with antibiotics reduces the death rate to about 1 percent. INHALATION ANTHRAX

HOW DOES INHALATION ANTHRAX WORK?

The disease starts when a person inhales spores into the lung, where they can penetrate tiny sacks called alveoli.

Once there, the spores travel to lymph nodes in the mediastinum, in the middle of the chest, which can take just a few hours.

In the lymph nodes, in a process that can take anywhere from days to weeks, the spores turn into anthrax bacteria, which begin producing deadly toxins that attack body tissues. Because this germination process can vary widely, it is hard to know, until about 60 days have passed, if a person who inhales the spores has contracted the disease. WHAT ARE THE SYMPTOMS OF INHALATION ANTHRAX?

Once the spores germinate, the symptoms appear quickly. The symptoms are caused by the toxins, which kill cells and cause fluids to accumulate in tissues. The first ones are nonspecific -- like fever, cough, headache, vomiting and chills. But within hours to a few days, the disease enters a second phase. Patients have trouble breathing because their lungs are compressed by fluid in the mediastinum. They sweat profusely and go into shock because their blood vessels leak and their blood pressure drops. About half the patients have bloodfilled fluid in the tissue covering their brains, which compresses the brain, causing coma and delirium. Once the second phase of the disease begins, death can occur within hours. CURRENT CASES

IS THE FLORIDA CASE A MILITARY-TYPE ANTHRAX WEAPON?

Scientists familiar with the federal investigation said no exact match had been made between samples of the Florida germ and other known strains, or subspecies, of anthrax. But they added that preliminary tests pointed away from its being one of the well-known strains used over the decades to make anthrax weapons, and away from prevalent strains found in germ banks, which distribute microbes to hospitals, businesses and universities for diagnostic purposes as well as scientific research on new medical treatments. So far, weapons experts say, the Florida case appears to be crude bioterrorism. WHAT ABOUT THE NEW YORK CASE?

The FBI has begun a criminal investigation to find the source of the anthrax in the New York case. Attorney General John Ashcroft said a letter to NBC postmarked Sept. 25 "may have transmitted the anthrax," but authorities stopped short of saying the mail was the source. The envelope "may have contained material contaminated with the spore-form of anthrax," according to a statement from the federal Centers for Disease Control and Prevention. DIAGNOSIS AND TREATMENT

HOW IS ANTHRAX DIAGNOSED?

1. Anthrax is diagnosed by isolating Bacillus anthracis from the blood, skin lesions or respiratory secretions or by measuring specific antibodies in the blood of persons with suspected cases.

2. The specimens are put into a cell culture.

3. The bacteria will grow in the culture.

4. They can readily identified under a microscope. The state's regional labs are staffed and equipped to test for anthrax and other agents around the clock, every day of the year. HOW IS ANTHRAX TREATED?

Because there are so few cases of human anthrax, and because it would be unethical to deliberately expose people to the bacteria in tests, little is known for certain about treating people exposed to it. But experiments with animals have provided some clues.

A wide variety of antibiotics -- including penicillin and doxycycline as well as ciprofloxacin and other antibiotics in its class, the fluoroquinolones -- can kill anthrax bacteria, but only if they are given before symptoms appear. By then, the bacteria have already released large quantities of their deadly toxins into the body. Experts have recommended treating asymptomatic people who may have been exposed to anthrax for 60 days. Ciprofloxacin is the only drug formally identified by the Food and Drug Administration as an anthrax treatment. IS AN ANTHRAX INFECTION CONTAGIOUS?

No. Anthrax does not spread from person to person. It can spread only when it is in its spore form. The bacteria do not produce spores while they are actively growing in an infected person. WHAT HAPPENS IF ANTHRAX IS DIAGNOSED?

State and county health workers, along with epidemiologists with the U.S. Centers for Disease Control and Prevention, launch a "contact investigation," similar to epidemiological surveys used to trace the source and breadth of common outbreaks, such as meningitis, food poisoning and shigella, which can cause dysentery.

Health workers would identify, then examine, anyone who has had contact with the victim, and those people may be given antibiotics as a precaution to ward against the disease. The victim's home and workplace would be examined as well as investigators try to determine where the disease came from.

Federal officials say they can fly supplies of antibiotics and other drugs within 12 hours to any location in the United States where they may be needed for an outbreak of anthrax or other bioterrorism emergency. The government has arrangements with drug manufacturers to have fresh supplies available on an emergency basis.

The government's emergency program includes the National Pharmaceutical Stockpile, which was mobilized for the first time in response to the World Trade Center disaster on Sept. 11. IS THERE A VACCINE TO PREVENT INFECTION?

The nation's current supply of anthrax vaccine was licensed in 1970 by the FDA to prevent the form of anthrax that afflicts the skin. In 1985, the Army solicited proposals from pharmaceutical manufacturers for an improved vaccine. This vaccine is now given to military personnel, but its effectiveness against inhaled anthrax has been questioned. Its manufacturer, Bioport of Lansing, Mich., is not now making the vaccine because its factory does not meet FDA requirements.

Avant Immunotherapeutics, a biotechnology company in Needham, Mass., announced Wednesday that it had licensed some of its vaccine technology to a government contractor that is working on vaccines against biowarfare agents. But the company said it could not comment on what technology was licensed nor what pathogens the vaccines would be directed against. On its Web site, Avant says it has done preclinical work on a vaccine for anthrax. ANTHRAX AS A WEAPON

CAN ANTHRAX BE USED AS A WEAPON?

The hurdles to making anthrax weapons include getting the right strain, or subspecies, of the germ. Experts say there are scores of strains of Bacillus anthracis, only some known to be exceptionally deadly. Then a would-be biowarrior would have to brew up swarms of lethal microbes and coax the fragile rod-shaped bacteria into forming spores, the hardy, hardened, dormant state. Then clumps of spores must be refined to precise specifications if they are to find their way into the human lung. Weapons experts say the particles must be 1 to 5 microns wide; 20 of them would line up across the stalk of a human hair. Dr. Martin E. Hugh-Jones, an anthrax expert at Louisiana State University, said terrorists could not simply open a jar of anthrax spores on a subway or sprinkle some spores around and infect thousands of people. A person must inhale about 8,000 to 10,000 spores to be infected, he said. Or the spores must somehow reach a cut or scratch in the skin to infect the body.

-- SOURCES: New York Times, Palm Beach Post, AP, CDC; Research by Cathy Wos and Ron Brackett

From Sptimes.com