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Anthrax

Woolsorter's disease; Ragpicker's disease; Cutaneous anthrax; Gastrointestinal anthrax

Anthrax is an infectious disease caused due to a bacterium called Bacillus anthracis. Infection in humans most often involves the skin, gastrointestinal tract, or lungs.

Causes

Anthrax commonly affects hoofed animals such as sheep, cattle, and goats. Humans who come into contact with infected animals can get sick with anthrax as well.

There are 3 main routes of anthrax infection: cutaneous, inhalation, and gastrointestinal.

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, tanners, and wool workers.

Inhalation anthrax develops when anthrax spores enter the lungs through the airways. 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 bacterial spores must germinate or sprout (the same way a seed sprouts before a plant grows) before the actual disease occurs. This process usually takes 1 to 6 days.
  • 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.

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 or eschar).
  • 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)

Exams and Tests

The tests to diagnose anthrax depend on the type of disease that is suspected.

A culture of the skin, and sometimes a biopsy, are done on the skin sores. The sample is looked at under a microscope to identify the anthrax bacterium.

Tests may include:

More tests may be done on fluid or blood samples.

Treatment

Antibiotics are usually used to treat anthrax. Antibiotics that may be prescribed include penicillin, doxycycline, and ciprofloxacin.

Inhalation anthrax is treated with a combination of antibiotics such as ciprofloxacin plus another medicine. They are given by IV (intravenously). Antibiotics are usually taken for 60 days because it can take spores that long to germinate.

Cutaneous anthrax is treated with antibiotics taken by mouth, usually for 7 to 10 days. Doxycycline and ciprofloxacin are most often used.

Outlook (Prognosis)

When treated with antibiotics, cutaneous anthrax is likely to get better. But up to 20% of people who do not get treated may die if anthrax spreads to the blood.

People with second-stage inhalation anthrax have a poor outlook, even with antibiotic therapy. Up to 90% of cases in the second stage are fatal.

Gastrointestinal anthrax infection can spread to the bloodstream and may result in death.

When to Contact a Medical Professional

Call your health care provider if you have been exposed to anthrax or if you develop symptoms of any type of anthrax.

Prevention

There are 2 main ways to prevent anthrax.

For people who have been exposed to anthrax (but have no symptoms of the disease), doctors may prescribe preventive antibiotics, such as ciprofloxacin, penicillin, or doxycycline, depending on the strain of anthrax.

An anthrax vaccine is available to military personnel and some members of the general public. It is given in a series of 5 doses over 18 months.

There is no known way to spread cutaneous anthrax from person to person. People who live with someone who has cutaneous anthrax do not need antibiotics unless they have also been exposed to the same source of anthrax.

References

Centers for Disease Control and Prevention. Anthrax. Last updated July 22, 2014. Available at: www.cdc.gov/anthrax/index.html. Accessed September 9, 2015.

Lucey DR, Grinberg LM. Anthrax. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 294.

Martin GJ, Friedlander AM. Bacillus anthracis (anthrax). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 208.

    • Cutaneous anthrax

      Cutaneous anthrax - illustration

      Anthrax is caused by the bacteria Bacillus anthracis. While anthrax commonly affects hoofed animals such as sheep and goats, humans may get sick from anthrax, too. The most common type of anthrax infection is cutaneous anthrax, an infection of the skin. Bacillus anthracis

      Cutaneous anthrax

      illustration

    • Cutaneous Anthrax

      Cutaneous Anthrax - illustration

      Cutaneous anthrax is an infection of the skin caused by the bacterium Bacillus anthracis. The bacteria causes disease when it comes into contact with non-intact skin. During an infection, an initial skin lesion forms then blisters. The blister breaks down into a black ulcer and nearby lymph nodes may become infected and painful. A scar is often formed which then dries and falls off within two weeks. In 20% of untreated individuals, the infection may spread to the bloodstream and become fatal. Although with proper treatment, death is extremely rare.

      Cutaneous Anthrax

      illustration

    • Inhalation Anthrax

      Inhalation Anthrax - illustration

      Inhaled anthrax is particularly deadly. Although the spores are dormant when breathed in, they germinate when exposed to a warm, moist environment, such as the lungs. Not all particles are small enough to pass into the alveoli, or air sacs, but those that do begin to multiply and may spread to the lymphatic system. When the spores germinate in the lymph nodes, several toxins are released. Particles illustrated are not to scale.

      Inhalation Anthrax

      illustration

    • Antibodies

      Antibodies - illustration

      Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.

      Antibodies

      illustration

    • Bacillus anthracis

      Bacillus anthracis - illustration

      Bacillus anthracis is an aerobic spore-forming bacterium that causes disease in humans and animals. The bacteria is found in two forms: cutaneous anthrax and inhalation anthrax. Cutaneous anthrax is an infection of the skin caused by direct contact with the bacterium. Inhalation or respiratory anthrax is an infectious disease caused by inhaling the spores of the bacterium. While anthrax commonly affects hoofed animals such as sheep and goats, humans may acquire this disease as well. Anthrax is a potential agent for use as a biological weapon or bio-terrorism. Bacillus anthracis

      Bacillus anthracis

      illustration

      • Cutaneous anthrax

        Cutaneous anthrax - illustration

        Anthrax is caused by the bacteria Bacillus anthracis. While anthrax commonly affects hoofed animals such as sheep and goats, humans may get sick from anthrax, too. The most common type of anthrax infection is cutaneous anthrax, an infection of the skin. Bacillus anthracis

        Cutaneous anthrax

        illustration

      • Cutaneous Anthrax

        Cutaneous Anthrax - illustration

        Cutaneous anthrax is an infection of the skin caused by the bacterium Bacillus anthracis. The bacteria causes disease when it comes into contact with non-intact skin. During an infection, an initial skin lesion forms then blisters. The blister breaks down into a black ulcer and nearby lymph nodes may become infected and painful. A scar is often formed which then dries and falls off within two weeks. In 20% of untreated individuals, the infection may spread to the bloodstream and become fatal. Although with proper treatment, death is extremely rare.

        Cutaneous Anthrax

        illustration

      • Inhalation Anthrax

        Inhalation Anthrax - illustration

        Inhaled anthrax is particularly deadly. Although the spores are dormant when breathed in, they germinate when exposed to a warm, moist environment, such as the lungs. Not all particles are small enough to pass into the alveoli, or air sacs, but those that do begin to multiply and may spread to the lymphatic system. When the spores germinate in the lymph nodes, several toxins are released. Particles illustrated are not to scale.

        Inhalation Anthrax

        illustration

      • Antibodies

        Antibodies - illustration

        Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.

        Antibodies

        illustration

      • Bacillus anthracis

        Bacillus anthracis - illustration

        Bacillus anthracis is an aerobic spore-forming bacterium that causes disease in humans and animals. The bacteria is found in two forms: cutaneous anthrax and inhalation anthrax. Cutaneous anthrax is an infection of the skin caused by direct contact with the bacterium. Inhalation or respiratory anthrax is an infectious disease caused by inhaling the spores of the bacterium. While anthrax commonly affects hoofed animals such as sheep and goats, humans may acquire this disease as well. Anthrax is a potential agent for use as a biological weapon or bio-terrorism. Bacillus anthracis

        Bacillus anthracis

        illustration

      Tests for Anthrax

       

      Review Date: 5/1/2015

      Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

      The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
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