Anthrax: Causes, Risk Factors, Symptoms, Treatment


Anthrax is a bacterial infection caused by Bacillus anthracis. It primarily affects animals but can infect humans through contact with contaminated animals or their products. Symptoms depend on the route of exposure and can range from skin ulcers to severe respiratory or gastrointestinal illness.

If you experience flu-like symptoms with the sudden onset of high fever, accompanied by skin lesions or respiratory distress, consult urgently with an Infectious Disease specialist or a General Practitioner in the Internal Medicine department to evaluate the possibility of Anthrax exposure.


Bacterial Infection: Anthrax is caused by the bacterium Bacillus anthracis.

Spore Formation: The bacterium forms hardy spores that can survive in the environment for years.

Transmission: Humans typically contract anthrax through contact with infected animals or their products (e.g., hides, wool, meat).

Three Primary Forms: Anthrax can manifest in three main forms depending on the route of entry: cutaneous, inhalation, and gastrointestinal.

Cutaneous Anthrax: Most common form, results from spores entering through a cut or abrasion on the skin.

Inhalation Anthrax: Rare but severe, occurs from inhaling spores typically from contaminated animal products or deliberate release.

Gastrointestinal Anthrax: Rare, occurs from consuming contaminated meat.

Industrial Exposure: Workers in industries processing animal products (e.g., wool, hides) are at higher risk.

Biological Weapon: Can be used as a bioterrorism agent due to ease of spore production and potential lethality.

Prevention: Vaccination is available for high-risk individuals, and antibiotics can treat anthrax if diagnosed early.

Risk Factors

  • Occupational Exposure: Veterinarians, farmers, and laboratory workers handling animals or animal products.
  • Environmental Exposure: Living in or visiting areas with anthrax-contaminated soil.
  • Biological Warfare: Potential exposure in regions of conflict or terrorism.
  • Injection Drug Use: Sharing needles contaminated with anthrax spores.
  • Wool Sorting: Handling wool, hair, or hides from infected animals.
  • Travel: Visiting countries with endemic anthrax or outbreaks.
  • Improperly Cooked Meat: Consuming undercooked meat from infected animals.
  • Military Service: Military personnel deployed to areas with anthrax risk.
  • Immune Compromise: Individuals with weakened immune systems are more susceptible.


Cutaneous Anthrax:

  • Begins with a small, itchy bump resembling an insect bite.
  • Develops into a painless sore with a black center.
  • Swelling around the sore may occur.

Pulmonary Anthrax:

  • Initial symptoms mimic a common cold or flu.
  • Progresses rapidly to severe breathing difficulties.
  • Shock and meningitis can develop quickly.

Gastrointestinal Anthrax:

  • Nausea, loss of appetite, and fever are early signs.
  • Abdominal pain, vomiting of blood, and severe diarrhea follow.
  • Inflammation and tissue death in the intestines are critical.

Injection Anthrax:

  • Presents as localized swelling at the injection site.
  • High fever and severe illness may follow rapidly.

General Symptoms:

  • Fever, chills, and extreme fatigue are common across all types.
  • Rapid progression from mild symptoms to severe illness.
  • Without treatment, mortality rates can be high.

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Clinical Presentation: Look for symptoms such as fever, chills, fatigue, cough, and difficulty breathing.

Exposure History: Inquire about recent contact with animals, animal products, or contaminated soil.

Physical Examination: Check for signs like skin lesions (especially painless ulcers with a black center), swollen lymph nodes, and abnormal breath sounds.

Laboratory Tests: Collect samples (blood, skin swabs, respiratory secretions) for culture and PCR testing to identify Bacillus anthracis.

Imaging: Use imaging (X-ray, CT scan) to assess for signs of respiratory or mediastinal involvement.

Serology: Perform serologic tests to detect anthrax-specific antibodies.

Differential Diagnosis: Rule out other infections or diseases with similar symptoms (e.g., other bacterial pneumonias, plague).

Public Health Notification: Notify local health authorities promptly to initiate public health measures and surveillance.

Biopsy: Consider tissue biopsy for definitive diagnosis, especially for cutaneous anthrax.

Treatment Initiation: Start empiric antibiotic therapy (e.g., ciprofloxacin, doxycycline) promptly while awaiting diagnostic confirmation.


  • Antibiotics: Such as ciprofloxacin, doxycycline, or penicillin, are effective in treating anthrax infections.
  • Antitoxin: Administered in combination with antibiotics, it neutralizes the toxins produced by anthrax bacteria.
  • Supportive Therapy: Includes intravenous fluids and oxygen therapy to maintain vital functions.
  • Surgery: May be necessary to drain fluid collections or remove dead tissue in severe cases like inhalational anthrax.
  • Vaccination: Pre-exposure vaccination is available for individuals at high risk, such as military personnel and certain laboratory workers.
  • Isolation: Infected individuals should be isolated to prevent the spread of the disease.
  • Monitoring: Close monitoring of symptoms and response to treatment is essential for adjusting therapy as needed.
  • Public Health Measures: Contact tracing, prophylactic antibiotics for exposed individuals, and decontamination of affected areas are crucial to prevent outbreaks.

Preventive Measures

Vaccination: Ensure livestock and potentially exposed individuals are vaccinated against anthrax.

Hygiene Practices: Maintain good hygiene standards when handling animal products or carcasses.

Quarantine: Implement quarantine measures for suspected or confirmed anthrax cases in animals.

Monitoring: Regularly monitor livestock and wildlife populations for signs of anthrax outbreaks.

Avoid Consumption: Refrain from consuming meat from animals suspected to have died from anthrax.

Protective Clothing: Wear appropriate protective clothing and gear when handling potentially infected animals or contaminated materials.

Education: Educate communities and healthcare providers about the risks, symptoms, and preventive measures of anthrax.

Reporting: Report suspected cases promptly to local health authorities for swift intervention.

Environmental Management: Manage and dispose of animal carcasses properly to prevent environmental contamination.

Control Measures: Implement control measures such as disinfection of affected areas and insect control to minimize the spread of anthrax spores.

Do's & Don’t's

Do's Don't
Ensure domestic farm animals are vaccinated at 3 months, 6 months, and annually.  Neglect vaccinations for domestic farm animals. 
Quarantine oneself if infected with anthrax to prevent spread.  Ignore the need for self-quarantine when infected.
Report anthrax infection to local authorities promptly.  Delay or avoid notifying local authorities of anthrax infection.

If you experience flu-like symptoms with the sudden onset of high fever, accompanied by skin lesions or respiratory distress, consult urgently with an Infectious Disease specialist or a General Practitioner in the Internal Medicine department to evaluate the possibility of Anthrax exposure.

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