Anthrax can also be spread by eating undercooked meat from infected animals. Symptoms vary depending on how the disease was contracted, but symptoms usually occur within seven days. Skin infection begins as a raised itchy bump that resembles an insect bite but within one to two days develops into a vesicle and then a painless ulcer, usually 1-3 cm in diameter, with a characteristic black area in the center. Lymph glands in the adjacent area may swell. About 20 percent of untreated cases of cutaneous anthrax result in death.
Deaths are rare with appropriate anti-microbial therapy.
After several days, the symptoms may progress to severe breathing problems and shock. Inhalation anthrax is usually fatal. Initial signs include nausea, loss of appetite, vomiting and fever, followed by abdominal pain, vomiting of blood and severe diarrhea. Intestinal anthrax results in death in 25 percent to 60 percent of cases. Anthrax is diagnosed by isolating B. anthracis from the blood, skin lesions or respiratory secretions or by measuring specific antibodies in the blood of persons with suspected cases.