Over the next few days, the central papule ulcerates, ruptures, dries, and darkens to form a depressed black crust. The formation of this black crust indicates tissue death. From the localized lesion infection may spread through the bloodstream and cause sweating, fever, chills, shock, cyanosis, and collapse. The lesion is painless and is surrounded by marked edema that may extend for some distance. Pus and pain occurs only if a pyogenic organism infects the lesion. Similarly, marked lymphangitis and fever usually point to a secondary infection. In most cases the disease remains limited to the initial lesion. The main dangers are that a lesion on the face or the neck may swell and hinder the airway or may give rise to secondary meningitis. If the host defenses fail to contain the infection, septicemia develops. Approximately twenty percent of untreated cases of cutaneous anthrax progress to fatal septicemia. However, B anthracis is susceptible to penicillin and other common antibiotics, so effective treatment is almost always available upon diagnosis.
Gastrointestinal anthrax is uncommon but severe, it is analogous to cutaneous anthrax but occurs on the intestinal mucosa. As in cutaneous anthrax, the spores invade the mucosa through a preexisting lesion. The spores germinate and are taken into the bloodstream from the mucosal site of germination to the lymphatic system eventually producing systemic anthrax, which is usually fatal. The incubation period is one to seven days. The symptoms before the occurrence of systemic anthrax may vary in pain intensity. But the symptoms usually consist of low fever, and gastrointestinal symptoms similar to gastrointestinal disease. During this phase the bacteria is multiplying and producing toxins in the regional lymph nodes and spleen. These toxins eventually cause the breakdown of the organs it encounters, the spleen in particular. As a result the host expierences a sudden onset of illness with dyspnea, cyanosis, high fever, and disorientation, which progress in a few hours to shock, coma, and death.
