Anthrax occurs worldwide but is most common in developing countries. In humans, anthrax occurs in three forms, depending on the mode of transmission: cutaneous, inhalational, and GI.
Anthrax is caused by the bacteria Bacillus anthracis, which exists in the soil as spores that can live for years. Transmission to humans usually occurs through exposure to or handling of infected animals or animal products. Anthrax spores can enter the body through abraded or broken skin (cutaneous anthrax), by inhalation (inhalational anthrax), or through ingestion of undercooked meat from an infected animal (GI anthrax). Anthrax isn’t known to spread from person-to-person.
Signs and symptoms
From the time of exposure, signs and symptoms of infection usually occur within 1 to 7 days but may take as long as 60 days to appear. The signs and symptoms of anthrax depend on the form acquired:
Cutaneous anthrax: This is the most common form of anthrax. Skin infection may begin as a small, elevated, itchy lesion that resembles an insect bite, develops into a vesicle in 1 to 2 days, and finally becomes a small, painless ulcer with a necrotic (black) center. Enlarged lymph glands in the surrounding area are common. Without treatment, the mortality rate from cutaneous anthrax is 20%; the mortality rate is less than 1% with treatment.
Inhalational anthrax: The patient may initially report flulike signs and symptoms, such as malaise, fever, headache, myalgia, and chills. Such milder signs and symptoms may progress to severe respiratory difficulties, such as dyspnea, stridor, chest pain, and cyanosis, followed by the onset of shock. Even with treatment, inhalational anthrax is usually fatal.
GI anthrax: Ingestion of anthrax spores can cause acute inflammation of the intestinal tract. The patient may present with nausea, vomiting, decreased appetite, and fever, which then progress to abdominal pain, vomiting blood, and severe diarrhea. With treatment, death occurs in 25% to 60% of cases.
Anthrax can be diagnosed through cultures of the blood, skin lesions, or sputum of an exposed patient. If B. anthracis is isolated, the diagnosis is confirmed. Additionally, specific antibodies may be detected in the blood.
Treatment that’s initiated as soon as exposure to anthrax is suspected is essential to preventing anthrax infection; early treatment may also help prevent fatality. Many antibiotics are effective against anthrax. The most widely used are penicillin, ciprofloxacin, and doxycycline.
Points To Remember
- Any case of anthrax in either livestock or a person must be reported to the appropriate public health office.
- Supportive measures are geared toward the type of anthrax exposure.
- An anthrax vaccine is available but, due to limited supplies, it’s now administered only to U.S. military personnel and isn’t for routine civilian use.