Learn About Anthrax Infection

What is the definition of Anthrax Infection?

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

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What are the alternative names for Anthrax Infection?

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

What are the causes of Anthrax Infection?

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 three main routes of anthrax infection: skin (cutaneous), lung (inhalation), and mouth (gastrointestinal).

Cutaneous anthrax occurs when anthrax spores enter the body through 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.

Injection anthrax can occur in someone who self-injects drugs (heroin).

Anthrax may be used as a biological weapon or for bioterrorism.

What are the symptoms of Anthrax Infection?

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)

Symptoms of injection anthrax are similar to those of cutaneous anthrax. In addition, the skin or muscle beneath the injection site may get infected.

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What are the current treatments for Anthrax Infection?

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.

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What is the outlook (prognosis) for Anthrax Infection?

When treated with antibiotics, cutaneous anthrax is likely to get better. But some 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. Many cases in the second stage are fatal.

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

When should I contact a medical professional for Anthrax Infection?

Contact your provider if you think you have been exposed to anthrax or if you develop symptoms of any type of anthrax.

How do I prevent Anthrax Infection?

There are two main ways to prevent anthrax.

For people who have been exposed to anthrax (but have no symptoms of the disease), providers 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.

Cutaneous anthrax
Cutaneous Anthrax
Inhalation Anthrax
Bacillus anthracis
What are the latest Anthrax Infection Clinical Trials?
Natural History of Anthrax: A Study of Primary Infected, Recovered, and Exposed (SPoRE) Individuals and Evaluation of AVA Vaccinated Recipients

Summary: This study will examine pathophysiology and immune response of anthrax in infected or exposed individuals to learn more about the disease symptoms, prevention and response to treatment. In addition, it will evaluate immune response to the anthrax vaccine AVA (Anthrax Vaccine Adsorbed) in healthy, non-infected individuals. The following individuals may be eligible for this study: People with confir...

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A Phase 1, Randomized, Parallel-Group, Double-Blind Trial of AV7909 (Liquid) and Thermostable AV7909 (Lyophilized) in Healthy Adult Volunteers

Summary: This is a randomized, parallel-group, double-blind, Phase 1 study designed to assess safety, tolerability and immunogenicity 2 formulations of adjuvanted anthrax vaccine (AV7909), lyophilized and liquid. Forty healthy young adults, 18 to 45 years old, inclusive, who meet all eligibility criteria, will be randomly allocated to one of two study groups in a 1:1 ratio: 20 will receive AV7909 as the th...

What are the Latest Advances for Anthrax Infection?
Survival of Patient With Hemorrhagic Meningitis Associated With Inhalation Anthrax.
Systematic Review of Hospital Treatment Outcomes for Naturally Acquired and Bioterrorism-Related Anthrax, 1880-2018.
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Antitoxin Use in the Prevention and Treatment of Anthrax Disease: A Systematic Review.
Who are the sources who wrote this article ?

Published Date: June 20, 2021
Published By: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

What are the references for this article ?

Centers for Disease Control and Prevention website. What is anthrax? www.cdc.gov/anthrax/basics/index.html. Updated November 20, 2020. Accessed August 6, 2021.

Lucey DR, Grinberg LM. Anthrax. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 278.

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. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 207.