Anthrax

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Anthrax

• The Worlds Most Famous Bacteria

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History

• Anthrax has afflicted humans throughout recorded
  history. The fifth and sixth plagues of Egypt
  described in Exodus are widely believed to have
  been anthrax. The disease was featured in the
  writings of Virgil in 25 BC and was familiar in
  medieval times as the Black Bane. It was from
  studies on anthrax that Koch established his
  famous postulates in 1876, and vaccines against
  anthrax the best known being that of Pasteur
  (1881)were among the first bacterial vaccines
  developed.

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What is it?

• Anthrax is caused by Bacillus anthracis.
• Bacillus species are rod-shaped,
  endospore-forming aerobic or facultatively
  anaerobic
• The spores are resistant to heat, cold,
  radiation, desiccation, and disinfectants.
  Bacillus anthracis needs oxygen to sporulate
  this constraint has important consequences for
  epidemiology and control. In vivo, B anthracis
  produces a polypeptide (polyglutamic acid)
  capsule that protects it from phagocytosis.

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How Can You Get It?

• Humans acquire the disease directly from contact
  with infected herbivores or indirectly via their
  products. The clinical forms include ( 1 )
  cutaneous anthrax ,from handling infected
  material (this accounts for more than 95 percent
  of cases) (2) intestinal anthrax, from eating
  infected meat and (3) pulmonary anthrax, from
  inhaling spore-laden dust.

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Cutaneous Anthrax

• Cutaneous anthrax usually occurs through
  contamination of a cut or abrasion, although in
  some countries biting flies may also transmit the
  disease. After a 2- to 3-day incubation period, a
  small pimple or papule appears at the inoculation
  site. A surrounding ring of vesicles develops.

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Cutaneous Anthrax

• Over the next few days, the central papule
  ulcerates, dries, and blackens to form the
  characteristic eschar .The lesion is painless and
  is surrounded by marked edema that may extend for
  some distance. Pus and pain appear only if the
  lesion becomes infected by a pyogenic organism.

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Cutaneous Anthrax

• In most cases the disease remains limited to the
  initial lesion and resolves spontaneously. The
  main dangers are that a lesion on the face or
  neck may swell to occlude the airway or may give
  rise to secondary meningitis. Approximately 20
  percent of untreated cases of cutaneous anthrax
  progress to fatal septicemia.

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Cutaneous Anthrax
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Cutaneous Anthrax
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Cutaneous Anthrax
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Gastrointestinal Anthrax

• Gastrointestinal and pulmonary anthrax are both
  more dangerous than the cutaneous form because
  they are usually identified too late for
  treatment to be effective.
• If the spores enter a lesion in the
  gastrointestinal mucosa, they germinate and are
  taken into the bloodstream and lymphatics,
  finally producing systemic anthrax, which is
  usually fatal.

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Symptoms

• Intestinal The intestinal disease form of
  anthrax may follow the consumption of
  contaminated meat and is characterized by an
  acute inflammation of the intestinal tract.
  Initial signs of nausea, loss of appetite,
  vomiting, fever are followed by abdominal pain,
  vomiting of blood, and severe diarrhea.
  Intestinal anthrax results in death in 25 to 60
  of cases.

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Pulmonary Anthrax

• inhaling anthrax spores from contaminated animal
  products. In pulmonary anthrax, inhaled spores
  are transported by alveolar macrophages to the
  mediastinal lymph nodes, where they germinate and
  multiply to initiate systemic disease.
• Pulmonary Anthrax is usually fatal.

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Pulmonary Anthrax

• Initial symptoms may resemble a common cold.
  After several days, the symptoms may progress to
  severe breathing problems and shock. Inhalation
  anthrax is usually fatal.

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Treatment

• Doctors can prescribe effective antibiotics,
  Anthrax is readily treated with penicillin,
  tetracycline, chloramphenicol, gentamicin, or
  erythromycin. To be effective, treatment should
  be initiated early. If left untreated, the
  disease can be fatal.

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Anthrax as a Biological Warfare Agent

• Anthrax is the preferred biological warfare agent
  because
• It is highly lethal.
• 100 million lethal doses per gram of anthrax
  material (100,000 times deadlier than the
  deadliest chemical warfare agent).
• Silent, invisible killer.
• Inhalational anthrax is virtually always fatal.

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Anthrax as a Biological Warfare Agent

• There are low barriers to production.
• Low cost of producing the anthrax material.
• Not high-technology. Knowledge is widely
  available.
• Easy to produce in large quantities.
• It is easy to weaponize.
• It is extremely stable. It can be stored almost
  indefinitely as a dry powder.
• It can be loaded, in a freeze-dried condition, in
  munitions or disseminated as an aerosol with
  crude sprayers.