Now, many medical professionals, who have extensively studied the bacterium, are saying that penicillin and tetracycline are effective against anthrax.

CNN: Dr. William Hall: Medical impact of bioterrorism

Intestinal anthrax occurs when people ingest foods contaminated with the bacterium.

CNN: Cutaneous anthrax most common, most survived

Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis.

CNN: Ten things you need to know about anthrax

Anthrax is an infectious, potentially fatal disease caused by a spore-forming bacterium known as Bacillus anthracis.

CNN: Cutaneous anthrax most common, most survived