Anthrax is an acute disease caused by Bacillus anthracis.
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Bacillus Anthracis
Bacillus anthracis
can form dormant spores
that are able to survive in harsh conditions for extremely long periods of timeā€”even decades or centuries
.

When spores are inhaled, ingested, or come into contact with a skin lesion on a host they may reactivate and multiply rapidly.


Bacillus anthracis virulence factors
The lethality of the anthrax disease owes itself to the bacterium's two principle virulence factors:the poly-D-glutamic acid capsule, which protects the bacterium from phagocytosis by host neutrophils, and the tripartite protein toxin, called anthrax toxin.

Anthrax toxin is a mixture of three protein components: protective anigen (PA), edema factor (EF), and lethal factor (LF). toxinPA plus LF produces lethal toxin, and PA plus EF produces edema .
These toxins cause death and tissue swelling (edema), respectively.

Exposure
Occupational exposure to infected animals or their products (such as skin wool and meat) is the usual pathway of exposure for humans. Workers who are exposed to dead animals and animal products are at the highest risk, especially in countries where anthrax is more common. Anthrax in livestock grazing on open range where they mix with wild animals still occasionally occurs in the United States and elsewhere. Many workers who deal with wool and animal hides are routinely exposed to low levels of anthrax spores but most exposures are not sufficient to develop anthrax infections.

Mode of infection
Anthrax can enter the human body through the intestines (ingestion), lungs (inhalation), or skin (cutaneous) and causes distinct clinical symptoms based on its site of entry. An infected human will generally be quarantined. However, anthrax does not usually spread from an infected human to a noninfected human.
Pulmonary (pneumonic, respiratory, or inhalational) anthrax
Respiratory infection in humans initially presents with cold or flu-like symptoms for several da
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Inhalational anthrax, mediastinal widening
ys, followed by severe (and often fatal) respiratory collapse.


Gastrointestinal (gastroenteric) anthrax

Gastrointestinal infection in humans is most often caused by eating anthrax-infected meat and is characterized by serious gastrointestinal difficulty, vomiting of blood, severe diarrhea, acute inflammation of the intestinal tract, and loss of appetite. Some lesions have been found in the intestines and in the mouth and throat. After the bacteria invades the bowel system, it spreads through the bloodstream throughout the body, making even more toxins on the way.
Cutaneous (skin) anthrax

Cutaneous (on the skin) anthrax infection in humans shows up as a boil-like skin lesion that eventually forms an ulcer with a black center (escachar).The black eschar often shows up as a large, painless necrotic ulcer at the site of infection. Cutaneous infections generally form within the site of spore penetration between 2 and 5 days after exposure. Unlike bruises or most other lesions, cutaneous anthrax infections normally do not cause pain.



Treatment and prevention

Anthrax cannot be spread directly from person to person, but a patient's clothing and body may be contaminated with anthrax spores. Effective decontamination of people can be accomplished by a thorough wash down with antimicrobial effective soap and water.Effective decontamination of articles can be accomplished by boiling contaminated articles in water for 30 minutes or longer. Chlorine bleach is ineffective in destroying spores and vegetative cells on surfaces, though formaldehyde is effective. Burning clothing is very effective in destroying spores.
Anthrax vaccines
An anthrax vaccine licensed by the U.S. Food and Drug Administration (FDA) and produced from one non-virulent strain of the anthrax bacterium, is manufactured by BioPort Corporation, subsidiary of Emergent BioSolutions. The trade name is BioThrax, although it is commonly called Anthrax Vaccine Adsorbed (AVA). It is administered in a six-dose primary series at 0, 2, 4 weeks and 6, 12, 18 months; annual booster injections are required thereafter to maintain immunity