Auburn, Oct. 8---What is anthrax? How did it get in Florida? Why is anthrax often associated with biological terrorism?

These are questions millions of Americans are asking as more details emerge from what many believe may be a deliberate release of anthrax spores at a media office complex in Boca Raton, Fla.

Anthrax is an infectious disease caused by a spore-forming bacterium known as Bacillus anthracis, according to the United States Center for Disease Control.

When the first employee of American Media in Boca Raton tested positive for the presence of anthrax spores, Florida and federal officials were still not willing to rule out the possibility of natural exposure to the bacteria.

Bob Stevens, the employee who subsequently died as a result of the exposure, was an avid outdoorsman, leading many experts to suspect the anthrax exposure may have stemmed from contact with contaminated soil or animals.

Roughly 95 percent of the anthrax cases in humans stem from exposure to soil or animals, either through ingestion or skin lesions.

"Anthrax is most commonly associated with wild and domestic lower vertebrates, cattle, sheep, goats, and other ruminant animals, though it can also occur in humans when they’re exposed to infected animals or tissue from infected animals," says Dr. Jean Weese, an Alabama Cooperative Extension System food scientist.

Exposure from animals or soil now seems highly unlikely in Stevens’ case, since another American Media employee, Ernesto Blanco, a mailroom worker, also tested positive for the presence of the spores from inhalation. Since anthrax is an extremely rare disease, it is unlikely the exposure of the two American Media employees could have occurred from two entirely different sources.

"It’s so unlikely the spores were picked up from soil that the chances are nil," says Weese.

Stevens fell ill after a recent trip to North Carolina. However a Florida state epidemiologist says it is highly unlikely he was exposed to anthrax during his stay in North Carolina because the incubation period is between six and 45 days, a period which would not have included the trip.

Another factor that rules out the likelihood of natural exposure is the fact that no traces of anthrax bacteria have ever been detected in the soils of Florida and other states in the southernmost latitudes of the United States.

All of these things considered, Weese says, increases the likelihood that the anthrax spores were deliberately introduced, although the FBI, which is investigating the outbreak, contends there currently is no evidence the case is linked with terrorism.

Symptoms associated with exposure to Bacillus anthracis vary depending on how the disease was contracted but usually occur within 7 days.

Initial symptoms typically resemble the common cold. After several days, however, the symptoms progress to severe breathing problems and shock.

Direct person-to-person spread of anthrax is extremely unlikely, Weese says.

Individuals in whom the presence of anthrax spores are detected face good chances for survival so long as they are treated with antibiotics before symptoms occur. However, antibiotics are almost completely ineffective after symptoms occur with the inhaled form of anthrax, Weese says.

There is a vaccine against anthrax that is 93 percent effective in controlling the disease. Because anthrax is considered to be a potential agent for use in biological warfare, the Department of Defense has mandated that all active duty military personnel who may be involved in conflict be vaccinated for the disease.

Currently, the vaccination, which is extremely expensive compared with vaccines for more common diseases, is not widely available for civilian use.