Introduction
Bacillus anthracis is a rod-shaped, gram-positive bacteria that has the ability to cause infectious diseases. The bacteria is found naturally in soil and affects both domestic as well as wild animals all over the world when they come in contact with contaminated water, soil, or plants. When individuals come in contact with these infected animals or products of infected animals, they can get seriously sick. Individuals can contract the infection through different routes, including skin contact with the spores, breathing in, or through raw or undercooked meat of infected animals. Although animal-to-human transmission is possible, there are no reported cases of anthrax transmission from an infected human to a healthy human being.
What Is Cutaneous Anthrax?
Cutaneous anthrax is the most common form of anthrax infection. When individuals come into contact with the infected animals or their products through skin contact, it results in cutaneous anthrax. Cutaneous anthrax can occur when the spores come in contact with scrapes or open wounds of the skin.
Who Is at Risk of Getting Cutaneous Anthrax?
Individuals who work closely with animals such as farmers, wool workers, veterinarians, etc are at an increased risk of being exposed to anthrax spores and developing cutaneous anthrax unless proper precautionary measures are taken. Coming into contact with the wool, fur, hair, bones, or blood of the infected animals is the main source by which one may get exposed to anthrax spores. Laboratory workers may also be exposed if they fail to take precautionary measures when handling the blood or skin sample of infected individuals while testing.
What Are the Symptoms of Cutaneous Anthrax?
Once the bacteria enters the skin, it multiples and germinates at the site and produces toxins. The toxin then causes changes to the site of infection of the skin. The symptoms of cutaneous anthrax usually occur within one to ten days after exposure to anthrax spores. Symptoms usually include:
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A small painless, bump, or blister at the site of infection which is often the face, arm, hand, or neck.
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Sometimes, the blisters may also be filled with fluid.
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The bump or blister then progresses to form a painless sore or ulcer with a dark or black necrotic center (eschar).
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The surrounding area of the sore or ulcer (although painless) may be red and swollen.
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Some may experience itching of the blister.
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Within two weeks, the ulcer heals into a dry scab and eventually falls off.
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Individuals may also experience mild fever, headache, and general weakness.
How to Diagnose Cutaneous Anthrax?
Diagnosis of cutaneous anthrax includes physical examination and laboratory tests for further confirmation. Samples of the skin lesion are taken before any medications (especially antibiotics) are given to the individual as a treatment measure as medications may give false negative test results.
Physical Examination - The doctor will access the site of infection, and the lesion and check for the characteristic black necrotic center (eschar).
Blood Test - A blood sample from the individual is tested for the presence of antibodies against Bacillus anthracis bacteria.
Culture Test - A sample of the skin lesion or fluid from the lesion is sent for a culture test to a laboratory where the growth of bacillus anthracis bacteria confirms the diagnosis of anthrax.
Methylene Blue Stain Test - This test is done to identify and visualize bacteria under a microscope after staining the lesion sample with methylene blue. In the case of Bacillus anthracis, a non-motile, rod-shaped gram-positive bacteria is seen.
Polymerize Chain Reaction (PCR) Test - The polymerize chain reaction test is done to detect the presence of the DNA sequence specific to Bacillus anthracis in the collected blood sample.
Skin Biopsy - Blood tests and culture tests can help diagnose cutaneous anthrax. However, a biopsy of the skin sore or ulcer may be done to diagnose cutaneous anthrax and to rule out other possible skin lesions.
How to Treat Cutaneous Anthrax?
Appropriate treatment measures must be followed by individuals with cutaneous anthrax for proper recovery and healing of the lesion. Improper management can cause the anthrax toxin to reach into the bloodstream which can be fatal. Treatment measures to follow for cutaneous anthrax are:
Medications - Antibiotics such as Doxycycline or Ciprofloxacin are often effective in treating infections caused by bacillus anthracis. Antibiotics are usually prescribed orally for seven to ten days depending on the lesion. If the skin lesion spreads deeper or involves the lymph nodes in the site of infection, then intravenous administration of Doxycycline or Ciprofloxacin is done. The lesions are usually painless, however, in case of pain or discomfort, Ibuprofen may be given to alleviate the pain.
Lesion Care - The lesion has to be kept clean and dry to avoid further infection of the lesion and prevent it from spreading to deeper layers of the skin, or adjacent lymph nodes or leeching into the bloodstream as it can cause serious complications.
How to Prevent Cutaneous Anthrax?
There are no reported cases of spread of cutaneous anthrax from human to human. However, care must be taken when handling infected individuals, or infected animals, or when visiting a country with active anthrax cases. Some of the preventive measures are as follows:
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One must wear protective gears such as gloves and masks and appropriate protective clothing and footwear when working (farmers or veterinarians) in close proximity with infected animals or infected animal products.
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If one is aware of being exposed to anthrax spores and has not developed any symptoms then one must take antibiotics (Doxycycline or Ciprofloxacin) as a preventive measure.
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Laboratory personnel must be careful when handling blood and skin lesion samples and must do so only with proper gloves and masks.
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Anthrax vaccine is not included among the mandatory vaccinations. However, the anthrax vaccine is available for laboratory workers, veterinarians, and some military members of the united states (who may be at a higher risk of exposure to anthrax). The vaccine is given as five intramuscular shots over a period of eighteen months. Annual boosters are also recommended for maximum protection from anthrax for these individuals.
Conclusion
World Health Organization (WHO) estimates around two thousand to twenty thousand cases of anthrax infections all over the world every year. Individuals are generally found to be resistant to cutaneous anthrax. However, any break in the skin barrier gives the anthrax spores direct access to cause localized skin infections. Early diagnosis and appropriate treatment measures are important for a favorable outcome.
