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Anthrax

Anthrax is an infection caused by Bacillus anthracis that occurs primarily in cattle and other herbivores. Humans become infected when Bacillus anthracis spores are introduced into the body by contact with infected animals or contaminated animal products, insect bites, ingestion, or inhalation. Aerosolized spores of Bacillus anthracis have the potential for use in biological warfare or bioterrorism. Cutaneous anthrax is most common and is characterized by the development of a localized skin lesion with a central eschar surrounded by marked nonpitting edema. Inhalation anthrax (woolsorters' disease) typically involves hemorrhagic mediastinitis, rapidly progressive systemic infection, and a very high mortality rate. Gastrointestinal anthrax is rare and is associated with a high mortality rate.

Clinical symptoms

There are 4 types of presentation:

  1. Cutaneous (skin) anthrax:  A small red macule (red area) develops within days after inoculation of B. anthracis spores into skin. During the next week, the lesion typically progresses through papular and vesicular or pustular stages to the formation of an ulcer with a blackened necrotic eschar surrounded by a highly characteristic expanding zone of edema.
  2. Hemorrhagic pneumonia (wool sorter?s disease): The presenting symptoms of inhalational anthrax (woolsorters' disease) resemble those of severe viral respiratory diseases. Early diagnosis of inhalational anthrax that occurs naturally or as a consequence of biological warfare or bioterrorism is difficult. After 1 to 3 days the patient presents with increasing fever, dyspnea, stridor, hypoxia, and hypotension usually leading to death within 24 h.
  3. Gastrointestinal anthrax: Symptoms of gastrointestinal anthrax are variable and include fever, nausea and vomiting, abdominal pain, bloody diarrhea, and sometimes rapidly developing ascites. Diarrhea is occasionally massive in volume. The major features of oropharyngeal anthrax are fever, sore throat, dysphagia, painful regional lymphadenopathy, and toxemia; respiratory distress may be evident. The primary lesion is most often located on the tonsils.
  4. Blood spread in rare cases may lead to meningitis with bloody CSF.

Diagnosis

Bacterial examination of the blood or skin smear from skin anthrax may reveal the diagnosis. Serology with examination of the antibody levels in blood will also confirm anthrax.

Treatment

Antibiotics are indicated depending on the severity and type of infection. Ciprofloxacin, penicillin are the most active antibiotics against Bacillus anthracis. Infected dead animals should be burnt and their housing area disinfected.

Vaccines are available for exposed workers and animals. 

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