Anthrax

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Anthrax

• Sung Chul Hwang, M.D.
• Dept. of Pulmonary and Critical Care Medicine
• Ajou University School of Medicine

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Definition

• Acute bacterial disease caused by Bacillus
  anthracis, occurrs most frequently in
  herbivourous animals
• Humans become infected when the spores are
  introduced into the body by direct contact with
  infected animals or contaminated animal products
• Very rarely by consumption of contaminated meat
  products

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Three Human forms of Anthrax
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Etiology

• Bacillus Anthracis
• Large 1.5 m x 4-10
• Non motile
• Encapsulated, chain forming, aerobic gram
  positive rods
• Forms centrally located , oval spores
• Oxygen required for sporulation but not for
  germination
• Sporulation does not take place in living animals

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Epidemiology

• The distribution is world wide
• Most prevalent among domestivc herbivores
  (cattle, sheep, horses, goats)
• Spores? Grazing in contaminated area? Severe
  anthrax with bacteremia ? bleeding from nose,
  mouth, GI tracts? contamination of soil and
  water? subsequent sporulation

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(No Transcript)
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Virulence factors (1)

• Anthrax toxins? lethal in sterile state
• Protective Antigen (PA)
• Encoded by pX01plasmid ? 184.5 kbp
• binds plasma membrane and cleaves into two
  fragments ( PA 20 PA 63). PA63 provides
  binding entry sites for EF and LF
• Edema Factor (EF) Calmodulin dependent
  adenylcyclase, depress PMN
• Lethal Factor (LF) cell deaths by inhibiting
  MAP kinase 1 2

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Virulence Factor (2)

• Capsular polypeptide poly D-glutamic acids
• Encoded by pX02 plasmid ? 95.3 kbp
• Avidly phagocytized by PMN cells
• Antiphagocytic activity

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Cutaneous Anthrax

• Introduction of spores through the skin by cuts
  or abrasions or biting flies
• Most common (95)
• Small red macule? papule, vesicle, pustular
  stage? formation of an ulcer? blackened eschar
  with expanding zone of brawny edema
• Painful reactive lymphadenitis
• Afebrile or mild constitutional symptoms

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Inhalation Anthrax

• About 5 of cases
• Woolsorters Disease
• Similar symptoms with severe viral URI
• In 1 to 3 days increasing fever, dyspnea,
  stridor, hypoxia, and hypotension
• Lesding to death within 24 hours
• Hemorrhagic mediastinitis

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Gastrointestinal Anthrax

• Variable symptoms
• Fever, nausea, vomiting, abdominal pain, rapidly
  developing ascites
• Occasionally, massive diarrhea
• Hemoconcentration and hypotension
• Grave prognosis

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Cutaneous Anthrax
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Diagnosis of Anthrax

• Gram staining
• Direct Fluorescent Antibody staining
• Cultures of cutaneous lesion, blood
• Bloody CSF containing large number of B.
  anthracis
• ELISA test for B. anthracis

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Treatment of Anthrax

• Cutaneous Penicillin G 2 million Unit q 6 hrs
  until edema subsides? oral penicillin 7 to 10
  days
• Inhalation or GI anthrax High dose Penicillin?
  2 million Unit q 2 hrs

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Prevention

• Control animal anthrax with live avirulent
  vaccine( Pasteur spore vaccine-loss of PA plasmid
  or Sterne spore vaccine- loss of plasmid for
  capsular poly peptide)
• Proper disposal of infected animals
• PA toxoid and PA produced vaccine for humans for
  the protection
• Good personal hygienic measures
• Use of protective clothing and respirators
• Proper cooking of meat

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Prognosis

• Untreated cutaneous anthrax 10 20 mortality
• Treated cutaneopus anthrax very low
• Inhalation anthrax 100
• Gastrointestinal anthrax 50