Anthrax as a biological weapon

Anthrax makes an effective biological weapon because Bacillus anthracis forms spores that can survive for decades and which are highly resistant to antibiotics, certain forms of radiation, and extremes of temperature. These spores can be delivered in an aerosol and thus lodge in the alveoli of the lungs.
Inhalational anthrax begins with flu-like symptoms one to six days after exposure, with apparent remission after a few days, but with subsequent shortness of breath, high fevers, pleural effusions, and shock. Five out of eleven patients who developed inhalational anthrax following the attacks of 2001 in the United States succumbed to the disease.
The antibiotics of choice are ciprofloxacin and doxycycline. In cases of bioterrorism, this treatment should be continued for sixty days.