What Is Anthrax?

Anthrax is one of the oldest recorded diseases, mentioned in the biblical book of Exodus and among classical Greek and Roman authors. Devastating epidemics of the disease were recorded by medieval and modern writers.

It has been called wool sorter's disease because is contracted by humans who handle wool and inhale spores from dried feces. It is normally associated with grass eaters: sheep, goats, cattle and - to a lesser degree - swine.

The disease is uncommon but there have been outbreaks in the past decades in the southwest U.S.

The pulmonary form of anthrax is the most virulent but the hardest to contract as it requires inhalation of a large number of spores some 8 to 20 thousand into the deep regions of the lung. Particles that settle in the nose are not likely to cause disease.

Incubation takes from one to five days, but as much as 60 days. The disease starts with flu-like symptoms, and progresses to an acute respiratory distress syndrome, in which there is breakdown of the blood vessels in the lung. The mortality rate is high whether or not antibiotics are given.

The skin form of anthrax comes from direct contact. It progresses slowly, spreading to the lymph nodes and the rest of the body.

The gastrointestinal form of anthrax is the rarest. It comes from eating infected meat or material contaminated with feces. Treatment is effective if begun early in the disease. Although Cipro is the only FDA approved antibiotic, others, such as doxycycline are effective.

The American Lung Association notes that most suspicious powders turn out to be something else.

One millionth of a gram of anthrax is a lethal dose. A kilogram can eradicate hundreds of thousands of individuals living in a metropolitan area. Another characteristic making anthrax an effective biological agent is that anthrax spores can be stored for decades without losing their viability.

Sources: American Lung Association, Defence Journal, Brown University.