What you need to know about anthrax

What is Anthrax?

Anthrax is a serious, life-threatening, infectious disease caused by the gram-positive, spore-forming bacteria called Bacillus anthracis. Under the microscope, these bacteria appear like large rods. Once they’re in the soil, where they live, this organism becomes dormant and forms into a spore. These spores are very difficult to destroy and are known to survive in the soil for more than 40 years.

Anthrax normally affects animals, especially goats, cattle, sheep and horses. Infection in humans was initially non-existent in industrialized nations, but not until the threat of bioterrorism became evident in the late 2001. This disease can be transmitted to humans through contact with infected animals, products from infected animals, and intentionally tainted materials. Anthrax, however, does not spread from person to person.

Like any other infectious disease, the incubation period (time between contact with anthrax and the start of symptoms) for anthrax varies, and it may take more than a week before an infected person begins to manifest the symptoms. 

How Can Anthrax Infect Humans?

Anthrax is a potent biological weapon because spores can be spread easily through the mail or other means. This disease can infect humans in three ways. People who are exposed to airborne particles may develop cutaneous, inhalation, or gastrointestinal anthrax, depending on the route of exposure.

The most common form of infection is cutaneous anthrax. After an incubation period of 1 to 12 days, an ugly sore appears, one that may develop into a necrotic ulcer. In some cases, however, the sore will just disappear on its own even without treatment. Other symptoms of cutaneous anthrax include fever, malaise and headache. There may also be involvement of the lymph nodes.

Gastrointestinal anthrax occurs approximately 1 to 7 days after ingestion of contaminated food or undercooked contaminated meat. This can cause a serious, sometimes fatal disease. Symptoms include nausea, loss of appetite, fever, severe abdominal pain, bloody vomiting, and bloody diarrhea. The oropharyngeal form may also occur, manifested by lesions at the base of the tongue, difficulty swallowing, fever, and enlargement of the cervical lymph nodes.

The most fatal form is inhalation anthrax. After an incubation period of several days to 60 days, the infected person may manifest symptoms such as a brief prodromal fever, cough, fatigue, and mild chest discomfort that may quickly progress to severe respiratory distress, sweating, stridor, cyanosis and signs of meningitis (rigidity of the neck, headache, photophobia, altered mental state). If left untreated, it may proceed to shock and after 24 to 36 hours, death may ensue. 

How to Diagnose Anthrax

Tests to diagnose anthrax depend entirely upon the type of disease that is suspected. History-taking, including the person’s occupation, is essential in determining infection. Nasal swab testing may be conducted on several individuals to detect the presence of anthrax in the environment, although this does not confirm infection by anthrax in a person. The bacteria may be found in cultures or smears in cutaneous anthrax or sputum cultures in inhalation anthrax. Chest X-ray or Chest CT scan may also show significant changes in and between the lungs. Once the anthrax spreads inside the body, bacteria can be seen in blood using a microscope. Additional diagnostic tests include spinal fluid cultures (before antibiotics) and polymerase chain reaction testing.

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