Anthrax – Symptoms and Causes

ByJanis Updated

Where Anthrax Exists

Anthrax spores naturally exist in soil worldwide. These spores can stay inactive for years until they find a suitable host, typically wild or domestic animals like sheep, cattle, horses, and goats.

While anthrax is uncommon in the United States, it remains prevalent in many developing regions. These areas include Central and South America, sub-Saharan Africa, Central and southwestern Asia, southern and Eastern Europe, and the Caribbean.

Most human anthrax infections result from contact with infected animals or animal products. In the US, some cases have occurred among people making traditional African drums using contaminated animal skins.

Human infection typically happens through three main routes:

  • Contact with skin (cutaneous anthrax)
  • Consumption of contaminated meat (gastrointestinal anthrax)
  • Inhalation of spores (inhalation anthrax)

The persistence of anthrax spores in soil makes complete eradication difficult, particularly in agricultural regions where livestock exposure continues to occur.

Signs and Symptoms

Anthrax infections can appear in several forms, with symptoms varying based on how the bacteria enters the body. Each type has distinct warning signs that typically develop within 7 days of exposure.

Cutaneous (skin) anthrax is the most common form. Signs include:

  • A small, painless sore that develops into a blister
  • A painless skin ulcer with a black center that appears after the blister
  • Swelling around the sore

Inhalation anthrax begins with flu-like symptoms that can quickly become severe:

  • Fever and chills
  • Chest discomfort
  • Shortness of breath
  • Confusion or dizziness
  • Cough
  • Nausea and vomiting
  • Headache
  • Sweats (often extreme)
  • Extreme fatigue
  • Body aches

Gastrointestinal anthrax occurs after eating contaminated meat:

  • Nausea and vomiting, often with blood
  • Loss of appetite
  • Fever
  • Stomach pain
  • Severe diarrhea
  • Swollen neck or neck glands

Injection anthrax has been seen in people who inject drugs:

  • Fever
  • Groups of small blisters or bumps that may itch
  • A painless sore with a black center
  • Swelling around the injection site

When to Get Medical Help

Get medical care right away if you think you’ve been exposed to anthrax or develop symptoms after possible exposure. Anthrax is a serious illness that needs quick treatment.

Call your doctor immediately if you:

  • Develop a skin sore that forms a black center, especially after handling animals or animal products
  • Have flu-like symptoms after possible exposure to anthrax
  • Experience breathing problems, chest pain, or fever after inhaling dust or particles in high-risk settings

Early treatment with antibiotics can greatly increase your chances of recovery. Don’t wait for severe symptoms to appear before seeking medical attention.

Tell your healthcare provider about any recent activities that might have exposed you to anthrax, such as:

  • Working with animals or animal products
  • Visiting countries where anthrax is more common

Causes

Anthrax infections happen when people come into contact with the bacteria Bacillus anthracis. This bacteria forms spores that can survive in the environment for many years. These tough spores activate when they enter a suitable host.

There are three main ways people get infected with anthrax:

  • Contact with Infected Animals: Farmers, veterinarians, and people who handle animal products like wool or hides face higher risks.
  • Consuming Contaminated Food: Eating undercooked meat from infected animals can cause gastrointestinal anthrax.
  • Inhaling Anthrax Spores: This is the most dangerous form and often happens in industrial settings that process animal products.

Anthrax does not typically spread from person to person. Most natural infections occur in regions where anthrax is common in animals, particularly parts of Africa, Asia, and the Middle East.

Soil contaminated with anthrax spores can remain infectious for decades.

Humans rarely develop anthrax without direct exposure to infected animals or their products. However, anthrax has been used as a biological weapon, as seen in the 2001 mail attacks in the United States.

Risk Factors

Several factors may increase a person’s chance of getting anthrax. People who work with animals or animal products have a higher risk, especially those handling livestock or processing animal hides, wool, or bones from areas where anthrax is common.

Veterinarians, farmers, and laboratory workers who handle Bacillus anthracis also face increased exposure risk.

Travel to regions where anthrax outbreaks occur frequently can raise risk levels. These areas include parts of Africa, Central Asia, and the Middle East where anthrax is more common in animals.

Military personnel deployed to these regions may also have a higher exposure risk.

Some activities, like handling certain imported animal products, might increase risk. Items such as:

  • Goat hair drums
  • Animal hides
  • Wool products from high-risk regions
  • Bone meal fertilizer

Individuals with weakened immune systems might experience more severe symptoms if exposed to anthrax.

Complications

Anthrax infection can lead to several serious complications if not treated promptly. The specific complications depend on how a person gets infected (skin, inhalation, gastrointestinal, or injection).

Untreated cutaneous (skin) anthrax can spread to the bloodstream and become life-threatening. The infection may cause large, painless ulcers with black centers that leave permanent scars.

Inhalation anthrax has the highest risk of severe complications. It can cause:

  • Bleeding in the chest cavity
  • Meningitis (brain and spinal cord inflammation)
  • Shock
  • Respiratory failure
  • Death (mortality rates can exceed 75% even with treatment)

Gastrointestinal anthrax may lead to:

  • Severe intestinal bleeding
  • Fluid buildup in the abdomen
  • Intestinal tissue death
  • Shock

Pregnant women with anthrax face additional risks of pregnancy loss or spreading the infection to their babies.

Prevention

Taking steps to prevent anthrax exposure is important, especially for those in high-risk settings.

Livestock farmers and veterinarians should vaccinate animals annually against anthrax. People who work with animal products from areas where anthrax is common should practice good hygiene and use protective equipment.

For laboratory workers handling the bacteria, proper safety protocols are essential. These include using biosafety cabinets, wearing gloves, and following decontamination procedures. Some workers in high-risk settings may receive the anthrax vaccine.

Protective measures in high-risk settings include:

  • Wearing protective clothing and equipment
  • Proper handwashing after handling animals or animal products
  • Cooking meat thoroughly to kill possible bacteria
  • Avoiding contact with soil or animals in areas with known outbreaks

Mail handling safety became important after the 2001 bioterrorism incidents. Suspicious packages—those with excessive postage, strange odors, or powder—should be reported immediately to authorities.

Public health systems monitor for anthrax cases to detect outbreaks quickly.


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Health Writer

Janis's areas of expertise include nutrition, exercise, stress management, and mental health. She is passionate about educating and empowering people to take control of their health and make positive changes that can last a lifetime. Janis believes that small, sustainable changes are the key to long-term success, and she works with her clients to develop personalized plans that fit their individual needs and lifestyles.