Redirected from Anthrax
Anthrax infection is rare but not remarkable in herbivores such as cattle, sheep, goats, camels, and antelopes. Anthrax can be found globally. It is more common in developing countries or countries without veterinary public health programs. Certain regions of the world (South and Central America, Southern and Eastern Europe, Asia, Africa, the Caribbean, and the Middle East) report more anthrax in animals than others.
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Pulmonary (pneumonic, respiratory, inhalation) anthrax infection initially presents with cold or flu-like symptoms for several days, followed by severe (and often fatal) respiratory problems. If not treated soon after exposure, inhalation infection is the most deadly, with a nearly 100% mortality rate. A lethal case of anthrax is reported to result from inhaling 10,000-20,000 spores. This form of the disease has also been known as Woolsorters' disease. Other routes have included the slicing up of imported animal horns for the manufacture of buttons, and handling bristles used for the manufacturing of brushes.
Gastrointestinal (gastroenteric) anthrax infection often presents with serious gastrointestinal difficulty, vomiting of blood, and severe diarrhea. Untreated, intestinal infection results in a 25-60% death rate.
Cutaneous (skin) anthrax infection presents with a large, painless necrotic ulcer (beginning as a irritating and itchy skin lesion or blister which is dark in color, usually concentrated as a black dot, somewhat resembling bread mold) at the site of infection, forming about a week or two after exposure. Unlike bruises or most other lesions, cutaneous anthrax does not cause pain. Cutaneous infection is the least deadly; without treatment, approximately 20% of all skin infection cases are fatal. Treated cutaneous anthrax is rarely fatal.
A vaccine, produced from one component of the toxin of a non-virulent strand, is also available. The vaccine must be given at least four weeks before exposure to Anthrax; annual booster injections are required to maintain immunity.
The spores can be trapped with a simple HEPA or P100 filter. Anthrax as an airborne threat can be prevented with a full-face mask. Unbroken skin is decontaminated simply with soap and water.
Bacillus anthracis is a rod-size gram-positive bacterium of size about 1 by 6 microns. It was the first bacterium ever to be shown to cause disease, by Robert Koch in 1877. The bacteria normally rest in spore form in the soil, and can survive for decades in this state. Once taken in by a herbivore, the bacteria start multiplying inside the animal and eventually kill it, then continue to reproduce in the carcass. Once they run out of nutrients there, they revert back to the dormant spore state.
The infection of herbivores (and humans) proceeds as follows: the spore is located and engulfed by scavenger cells of the immune system specialized to deal with invaders. Inside the scavenger cell, the spore turns into a bacillus, multiplies, and eventually bursts the cell, releasing bacilli into the bloodstream. There they release a protein toxin which has macrophages as its principal target. The toxin has two components: edema factor and lethal factor. Edema factor inactivates macrophages so that they cannot participate in the fight against the infection; lethal factor causes the macrophage to make TNF-alpha[?] and interleukin-1-beta[?], both normal components of the immune system used to induce an inflammatory reaction. The excessive inflammation throughout the body ultimately leads to septic shock and death.
The virulence of a strain of anthrax is dependent on its enclosing capsule and its toxin; both are determined by different genes.
The simplest method of obtaining an anthrax sample would be to get it from an animal killed by anthrax; this source is rare in developed countries but common in underdeveloped countries.
Cultivating anthrax spores takes minimal equipment and about a first-year collegiate microbiological education. However, to make an aerosol form of anthrax suitable for biological warfare requires extensive training and highly developed equipment. The major problem is to prevent the spores from forming clumps too large for effective infection.
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