(CNN)Here's what you need to know about anthrax, an acute infectious disease caused by bacterium Bacillus anthracis.
There are three types of anthrax infection: cutaneous (through the skin), inhalation (through the lungs; the most deadly) and gastrointestinal (through digestion). There has been a fourth type of anthrax identified as injection anthrax. This is common in heroin-injecting users in northern Europe. This has never been reported in the United States.
Five people died and 17 people sickened during anthrax attacks in the fall of 2001; outbreak referred to as Amerithrax.
Lundgren, Ottilie - Connecticut woman, dies of inhalation anthrax, November 22, 2001
October 5, 2001 - Sun photo editor Bob Stevens dies of inhalation anthrax.