| Anthrax | ||
|---|---|---|
| ICD-10 code: | A22 | |
| ICD-9 code: | 022 | |
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Anthrax, also referred to as splenic fever, is an acute infectious disease caused by the bacteria Bacillus anthracis and is highly lethal in its most virulent form. Anthrax most commonly occurs in wild and domestic herbivores, but it can also occur in humans when they are exposed to infected animals, tissue from infected animals, or high concentrations of anthrax spores. Still there are no cases of people who got sick through contact with a diseased person. Anthrax means "Coal" in Greek, and is used because victims develop black skin lesions.
Anthrax infection is rare but not remarkably so 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.
Anthrax comes in 89 known strains. The best known is the virulent Ames strain, used in the 2001 anthrax attacks in the United States. The Vollum (also incorrectly refered to as Vellum) strain, another one suitable for use as a biological weapon, was isolated in 1935 from a cow in Oxfordshire, UK, and used (specifically the Vollum 1B strain) during 1960s in the US and UK bioweapon programs; Iraq also attempted to acquire it during 1980s, together with Ames. Other strains are eg. Sterne (a Benign form used for inoculations, named after a South African researcher), ANR-1, δAmes, A-3, RP4 and RP42. The strains differ in presence and activity of various genes, determining their Virulence and production of antigens and toxins. See the list of strains.
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.
In recent years there have been a number of attempts to develop new drugs against anthrax. One such drug is currently (2005) being developed by Professor Timor Baasov of the Technion in Israel and Professor Chi-Huey Wong of the Scripps Research Institute in California. The antibiotics attacks not only the bacillus itself but also the toxic protein that the Anthrax releases into the bloodstream of the infected person. It is also able to neutralize the toxic protein, even if the bacillus has already been released into the bloodstream.
To speed up the process, trace amounts of a non-toxic Catalyst composed of Iron and tetro-amido macrocyclic ligands is combined with Sodium carbonate and Bicarbonate and made into a spray. This spray is applied to an infected area and is followed by another spray containing tertiary-butyl hydroperoxide.
Using the catalyst method a complete kill of all the spores takes 30 minutes. A standard catalyst-free spray destroys fewer than half the spores in the same amount of time.
Bacillus anthracis is a rod-shaped Gram-positive bacterium of size about 1 by 6 micrometres. 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 an 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 such that they cannot phagocytose bacteria.
Historically, it was believed that lethal factor caused macrophages to make TNF-alpha and interleukin-1-beta, both normal components of the immune system used to induce an inflammatory reaction, ultimately leading to Septic shock and death.
However, recent evidence indicates that anthrax also targets endothelial cells, causing vascular leakage (similar to hemorrhagic bleeding), and ultimately hypovalemic shock, not septic shock.
The virulence of a strain of anthrax is dependent on multiple factors, primarily which include its poly-D-glutamic acid capsule which protects the bacterium from phagocytocis by host macrophages, and its toxins, Edema Toxin and Lethal Toxin.
Vollum B1 was the strain used in the US and UK biological warfare programs. The weaponized stocks in the US were destroyed in 1969 after Nixon dismantled the US program.
British tests in 1942 contaminated Gruinard Island in Scotland with anthrax spores of the Vollum/14578 strain, and rendered it unusable for the following 48 years. The trial was a test of effectivity of a submunition of an "N-bomb", a retaliatory biological weapon. In addition, five million "cattle cakes" impregnated with anthrax were prepared and stored in Porton for being dropped over Germany by the Royal Air Force as an anti-livestock weapon; however both the cakes and the bomb were never used.
An accidental release of anthrax in a research lab at Fort Detrick in Frederick, Maryland in the United States led to the permanent sealing of a building with plastics and glues.
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 can take minimal equipment and about a first-year collegiate microbiological education. However, to make an Aerosol form of anthrax suitable for biological warfare (a process called "weaponizing") requires extensive training and highly developed equipment. It is important to note, however, that simply knowing how to cultivate anthrax spores is useless, unless one actually has the anthrax species to cultivate in the first place.
High quality weaponized anthrax spores were used in Bioterrorism, in the 2001 anthrax attacks, performed by mailing letters containing the spores. These events also spawned numerous Anthrax hoaxes.