Anthrax from animals: Humans can become infected with anthrax by handling products from infected animals or by breathing in anthrax spores from infected animal products (like wool, for example). People also can become infected with gastrointestinal anthrax by eating undercooked meat from infected animals.
Anthrax from contaminated mail, equipment or clothing:
In the mail handling processing sites, B. anthracis spores may be aerosolized during the operation and maintenance of high-speed, mail sorting machines potentially exposing workers. In addition, these spores could get into heating, ventilating, or air conditioning systems.
Anthrax as a weapon: Anthrax also can be used as a weapon. This happened in the United States in 2001. Anthrax was deliberately spread through the postal system by sending letters with powder containing anthrax. This caused 22 cases of anthrax infection.