A woman holding her throat.
Anthrax can cause enlarged lymph nodes, difficulty swallowing, and a sore throat, among other symptoms.

What is Anthrax?

What is anthrax? Anthrax is a rare but serious infection caused by rod-shaped bacteria, Bacillus anthracis. While anthrax usually affects wild and domestic animals, humans can become infected via contact with an infected animal or through contaminated animal products.

It is extremely rare in developed nations; however, it is still a concern because the bacteria have been used in bioterrorist attacks in the U.S.

Signs and Symptoms of Anthrax

There are four routes of infection with anthrax, and each presents with different signs and symptoms. Typically, symptoms begin within six days of exposure; however, symptoms of inhalation anthrax can take upwards of six weeks to develop.

Cutaneous Anthrax

This infection that develops after spores enter the body through a skin wound. This is the most common, and mildest form of infection. Signs and symptoms may include:

  • Itchy, raised bump that develops rapidly into a painless lesion with a black center.
  • Sore swelling.
  • Swelling of the lymph nodes in the area.
  • Possible flu-like symptoms (i.e. headache, fever, etc.)

Gastrointestinal Anthrax

This infection develops after eating raw or undercooked meat from an infected animal. Infection can affect the gastrointestinal tract from the throat to the colon. Signs and symptoms may include:

  • Nausea and/or vomiting.
  • Abdominal pain
  • Decreased appetite
  • Headache
  • Fever
  • Sore throat
  • Swallowing difficulties
  • Swollen neck
  • Severe, bloody diarrhea (later stages of the illness)

Inhalation Anthrax

This infection develops after breathing in spores. This is the most severe type of infection, and often results in death, despite treatment. Signs and symptoms may include:

  • Flu-like symptoms (i.e. fever, fatigue, muscle aches) for a few hours to days
  • Slight chest discomfort
  • Shortness of breath
  • Nausea
  • Fever
  • Coughing up blood
  • Pain with swallowing
  • Difficulty breathing
  • Meningitis
  • Shock (collapse of the circulatory system)

Injection Anthrax

This infection develops after injecting illegal drugs, including heroin. Signs and symptoms may include:

  • Injection site redness
  • Swelling
  • Meningitis
  • Shock
  • Multiple organ failure
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Causes of Anthrax

People can become infected when the bacteria spores enter the body. This can happen if a person breathes in the spores, eats or drinks food or water that is contaminated with spores, through a cut in the skin, or through injection of illegal drugs. Once inside the body, the spores can be activated, which allows the bacteria to multiply and spread throughout the body, producing toxins, and resulting in severe sickness.

An important point to note is that anthrax is not contagious. However, it may be possible that the discharge from anthrax skin lesions is contagious, and that transmission may occur through direct or indirect contact with the lesion discharge.

Risk Factors for Anthrax

Certain activities have been identified that increase the risk of infection, including:

Working With Infected Animals or Animal Products

Inhalation anthrax may occur when an individual inhales the spores during processing of contaminated animal products including hair, hides, and/or wool.

Cutaneous anthrax may occur when an individual handles contaminated animal products, which increases the risk of the spores entering the body through a wound in the skin.

Eating Undercooked or Raw Meat From Infected Animals

Eating raw or undercooked meat from infected animals increases the risk of gastrointestinal anthrax. This typically occurs in countries that do not vaccinate their livestock against the bacteria and/or when animals are not inspected for disease before being slaughtered.

Working in a Laboratory That Tests for Anthrax

If proper safety precautions are not followed, the risk may be heightened in laboratory workers that handle the bacteria.

Working in Mailing, Military, or Emergency Response

Military and emergency response professionals are at an increased risk if there is a bioterrorist attack. They may be exposed during an attack or when responding to an attack.

Mail workers may be at an increased risk if the spores are sent via mail.


This includes traveling to certain regions of South and Central America, Sub-Saharan Africa, Southwestern and Central Asia, Eastern and Southern Europe, and the Caribbean.

Anthrax is naturally occurring in the soil and commonly affects wild and domestic animals in these countries. Therefore, traveling to these regions increases the risk of contracting this infection.

Travelers should be aware of what they consume, and the types of souvenirs they purchase. Additionally, consuming raw and undercooked meat, as well as contact with animals and animal products should be avoided to reduce the risk of infection.

Injecting Illegal Drugs

Injection anthrax after injecting heroin has been recently reported in northern Europe. As of now, this type of transmission route has not been reported in the U.S.

Treatment Options for Anthrax

Treatment involves antibiotics, including ciprofloxacin, levofloxacin, or doxycycline, among others. Treatment may include a single antibiotic, or combination of antibiotics, as well as other supportive measures including fluids, ventilators, and vasopressors to stabilize blood pressure.

For inhalation, antitoxin therapies, including raxibacumab and obiltoxaximab, are sometimes used to help eliminate the toxins produced by the bacteria. Additionally, anthrax immunoglobulin may also be used in combination with antibiotics to help neutralize the toxins.

For injection, some cases have responded to surgical removal of the infected tissue.

The type and length of treatment depends on various factors including the type of infection, age, and overall health of the patient. Treatment is most effective when it is started as soon as possible.

In Conclusion

While anthrax is not common in developing nations, it remains a threat as it has been used as a biological weapon in the U.S. It is a serious illness that requires prompt treatment for optimal outcomes. While many case can be successfully treated with antibiotics, inhalation anthrax is often fatal, even with treatment.