Anthrax is an acute disease caused by the bacteria Bacillus anthracis. B. anthracis is a nonmotile, spore-forming bacterium. Anthrax affects both animals and humans. B. anthracis occurs naturally in the environment and becomes infectious when environmental conditions of soil, temperature, moisture, and nutrition are optimal. When the bacteria are released from an infected animal or exposed to oxygen they form spores that are very resistant to temperature extremes, chemical disinfectants, and desiccation. B. anthracis spores can live in the soil for decades.
What we need to know are the symptoms and how it gets transmitted.
Animals contract anthrax from grazing or eating vegetation grown in contaminated soils, eating contaminated feedstuffs (such as meat and bone meal), or inhaling spores discharged from an infected animal. Humans can contract the disease in the same ways and also by handling infected animals or their wool, hides, leather, or hair. Eating undercooked meat from infected animals can also be a source of transmission (infected animals in the United States are a rare occurrence). Direct contact with a person with anthrax is extremely unlikely to spread the disease. Depending on how the disease was contracted, symptoms will vary, and usually occur within seven days. People can develop three types of anthrax which vary in symptoms: cutaneous, inhalation, and gastrointestinal.
Cutaneous: The most common form, cutaneous anthrax, is contracted by contact with the bacteria which enter through a cut or abrasion on the skin. Symptoms begin as a raised bump that itches followed by a painless ulcer which appears one to two days after infection. The ulcer is usually one to three centimeters in diameter with a black center. If left untreated, the infection can lead to death (in 20% of cases). With treatment, deaths are rare.
Pulmonary or Respiratory (Inhalation): This form is contracted by inhalation of Bacillus anthracis spores. Eight thousand to 10,000 spores must be inhaled to cause illness. Initial symptoms are mild and resemble a cold or the flu. Three to five days later, symptoms become acute with fever, breathing problems, and shock; this form is usually fatal (90% of untreated cases) unless antibiotics can be started soon after infection.
Gastrointestinal: Gastrointestinal anthrax is contracted by ingestion of meat from infected animals. Initial symptoms include nausea, loss of appetite, vomiting, and fever. This is followed by abdominal pain and diarrhea (often with blood). This form causes death in 25-65% of cases.
