Inhaled anthrax is by far the most dangerous form of this infection, but also the rarest. It causes symptoms that start out like the flu. These symptoms include fever, chest discomfort, malaise, tiredness, and dry cough. The signs of illness appear as early as 48 hours after the spores of the bacteria have been inhaled.
If the symptoms are not treated quickly, the infection can rapidly turn into a severe infection similar to pneumonia (inflammation of the lungs). Shortness of breath, high fever, fast heart rate, and heavy sweating then develop. Meningitis (swelling of the brain) and pain in the abdomen follow. Few survive more than a few days beyond the development of these types of symptoms. Fortunately, early treatment decreases the risk of death.
Cutaneous anthrax is much less dangerous than the inhaled form of anthrax. When infection occurs in this manner, the skin develops a raised, sometimes itchy bump that looks and feels like an insect or spider bite. Within a day or two, sores develop that usually turn black in the centre. Usually, people with cutaneous anthrax feel only mildly ill. Early antibiotic treatment is almost always successful in curing this type of anthrax.
If cutaneous anthrax is not treated, the bacteria may get into the bloodstream and cause more serious symptoms. Signs of spreading infection include fever, chills, and swollen lymph glands close to the area of the sore.
Intestinal anthrax symptoms include severe abdominal pain, nausea, vomiting, severe diarrhea, fever, and bleeding from the gastrointestinal tract (stomach and intestines).
It is important to remember that anthrax is not passed from person to person. It is very rare for a person to develop anthrax unless the spores get below the surface of the skin or the lining of the stomach or intestines. The inhaled form of anthrax develops only after thousands of spores are inhaled all the way down to the lungs.