print   Print full article

Signs and Symptoms

Bacillus anthracis infects and produces toxins that can damage cells directly and cause localised oedema. The three kinds of infection vary in their symptoms and prognoses:

  • Cutaneous anthrax is the most common form and is usually caused by the bacterium getting into a cut or abrasion on the skin, as can happen from contact with contaminated meat, wool, hides, or leather. The incubation period is 1 to 12 days. The infection begins as a bump that looks like an insect bite and within days opens into a painless ulcer with a black area in the centre. Nearby lymph glands may swell. About 20 per cent of untreated cases result in death, but death is rare in those who receive antimicrobial therapy.
Cutaneous anthrax lesions

                              Cutaneous anthrax lesions

  • Inhalational anthrax is the most lethal form and is caused by breathing in spores. The incubation period is believed to be 1 to 7 days generally but may range up to 60 days. There are two stages to the infection. Initial symptoms resemble those of a viral respiratory illness, including sore throat, mild fever, muscle aches, a non-productive cough, and malaise. This first stage can last from hours to a few days, and the infected person may temporarily begin to feel somewhat better. The second stage may develop suddenly, with symptoms including shortness of breath, high fever, shock, meningitis, chest pain, and respiratory failure. The fatality rate is high, only about 15 per cent of patients survive overall after symptoms begin. With aggressive treatment, about 55 per cent of patients survive.
  • Gastrointestinal anthrax, caused by the consumption of raw or undercooked contaminated meat, has an incubation period of 1 to 7 days. The symptoms include severe abdominal distress and fever. The symptoms can be concentrated around either the pharynx, with lesions at the base of the tongue, sore throat, fever, and enlarged lymph nodes, or the lower bowels, with nausea, loss of appetite, vomiting, and fever, followed by abdominal pain, vomiting blood, and bloody diarrhoea. The fatality rate is 25% to 60%.

Last Review Date: December 4, 2020