Anthrax is caused by the bacteria Bacillus anthracis. While anthrax commonly affects hoofed animals such as sheep and goats, humans may get sick from anthrax, too. The most common type of anthrax infection is cutaneous anthrax, an infection of the skin and also Anthrax of the inhalation type.
Breathing in spores means a person has been exposed to the disease, but it doesn't mean they'll get symptoms. The bacteria spores must "germinate," or sprout (the same way a seed might before a flower grows) before the actual disease occurs. The process can take up to 60 days.
Once the spores germinate, they release of several toxic substances, which cause internal bleeding, swelling and tissue death. The main form of inhalational anthrax is a bloody infection of the lymph nodes in the chest, a condition called hemorrhagic mediastinitis. Up to half of affected individuals may also have hemorrhagic meningitis.
Stage one can last from a few hours to a few days. Symptoms may resemble a cold or the flu, and can include fever, chills, sweating, fatigue, malaise, headache, cough, shortness of breath and chest pain. Stage two often develops suddenly. Symptoms include fever, severe shortness of breath, and shock.