Woolsorter's disease; Ragpicker's disease; Cutaneous anthrax; Gastrointestinal anthrax
Last reviewed: June 9, 2011.
Anthrax is an infectious disease due to a type of bacteria called Bacillus anthracis. Infection in humans most often involves the skin, gastrointestinal tract, or lungs.
Causes, incidence, and risk factors
Anthrax commonly affects hoofed animals such as sheep, cattle, and goats, but humans who come into contact with infected animals can get sick from anthrax, too. In the past, the people who were most at risk for anthrax included farm workers, veterinarians, and tannery and wool workers.
There are three main routes of anthrax infection:
Cutaneous anthrax occurs when anthrax spores touch a cut or scrape on the skin.
• It is the most common type of anthrax infection.
• The main risk is contact with animal hides or hair, bone products, and wool, or with infected animals. People most at risk for cutaneous anthrax include farm workers, veterinarians, and tannery and wool workers.
Inhalation anthrax develops when anthrax spores enter the lungs through the respiratory tract. It is most commonly contracted when workers breathe in airborne anthrax spores during processes such as tanning hides and processing wool.
Breathing in spores means a person has been exposed to anthrax, but it does not mean the person will have symptoms.
• The bacteria spores must "germinate" or sprout (the same way a seed might sprout before a plant grows) before the actual disease occurs. The process usually takes 1 to 6 days. Forty-three days is the longest known incubation period.
• Once the spores germinate, they release several toxic substances. These substances cause internal bleeding, swelling, and tissue death.
Gastrointestinal anthrax occurs when someone eats anthrax-tainted meat.
Anthrax may be used as a biological weapon or for bioterrorism. In 2001, anthrax sent through the U.S. Postal Service infected 22 people; 7 survivors had confirmed cutaneous anthrax disease.
Symptoms
Symptoms of anthrax differ depending on the type of anthrax.
Symptoms of cutaneous anthrax start 1 to 7 days after exposure:
• An itchy sore develops that is similar to an insect bite. This sore may blister and form a black ulcer (sore).
• The sore is usually painless, but it is often surrounded by swelling.
• A scab often forms, and then dries and falls off within 2 weeks. Complete healing can take longer.
Symptoms of inhalation anthrax:
• Begins with fever, malaise, headache, cough, shortness of breath, and chest pain
• Fever and shock may occur later
Symptoms of gastrointestinal anthrax usually occur within 1 week and may include:
• Abdominal pain
• Bloody diarrhea
• Diarrhea
• Fever
• Mouth sores
• Nausea and vomiting (the vomit may contain blood)
Signs and tests
The tests to diagnose anthrax depend on the type of disease that is suspected.
A culture of the skin, and maybe a biopsy, are done on the skin sores. The sample is looked at under a microscope to identify the anthrax germ.
Tests may include:
• Blood culture
• Chest CT scan or chest x-ray
• Spinal tap to check for infection around the spinal column (See:CSF culture)
• Sputum culture
Fluid or blood samples may be sent to a special laboratory for more testing, including PCR, immunofluorescence, and immunohistochemistry.
Treatment
Most people with anthrax are treated with antibiotics. Several antibiotics are effective, including penicillin, doxycycline, and ciprofloxacin.
When treating inhalational anthrax, a combination of antibiotics should be used. Doctors often start treatment with ciprofloxacin plus another drug, given through a vein (intravenously). The length of treatment is about 60 days for people who have been exposed to anthrax, because it may take spores that long to germinate.
Cutaneous (skin) anthrax is treated with antibiotics taken by mouth, usually for 7 to 10 days. Doxycycline and ciproflaxin are most often used.