BW Agents: Botulinum toxin

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BW Agents Botulinum toxin

• J.A. Sliman, MD, MPH
• LCDR MC(FS) USN
• Preventive Medicine Resident
• Johns Hopkins Bloomberg
• School of Public Health

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Toxins

• Different from chemical weapons
• Naturally occurring
• Non-volatile
• Non-persistent no person-to-person spread
• Utility mostly limited by low toxicity
• More effective as terrorist devices

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Botulinum

• Produced by Clostridium botulinum
• 7 related neurotoxins, types A through G
• Usually seen as a food-borne illness
• Aerosol attack will produce similar symptoms
• Toxins are easily obtained from cultures and
  easily aerosolized

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BW History

• Numerous cases of food-borne outbreak
• Usually resulting from ingestion of improperly
  canned foods
• Weaponized by FSU, researched extensively
• Weaponized by Iraq
• Admitted in 1991, weapons found in 1995

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BW/BT Significance

• Easy to produce weaponize
• Can be aerosolized or placed into food
• Most toxic BW/BT agent by weight
• LD50 0.001mg/kg body weight
• 15,000x more toxic than VX
• 100,000x more toxic than Sarin

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Mechanism

• Binds presynaptic nerve terminals at NMJ at
  cholinergic autonomic sites
• Prevent release of acetylcholine
• Opposite of organophosphate nerve agents
• Bulbar palsies skeletal muscle weakness

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Clinical botulism

• Symptoms start 24-36 hours after inhalation
• Ingestion shorter time of onset
• Onset determined by dose
• Early bulbar signs followed by progressive,
  descending, symmetric skeletal muscle weakness
  paralysis

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Clinical botulism

• Culminates abruptly in respiratory failure
• Can happen within 24 hours of onset
• Patients remain afebrile throughout
• CSF clear, no MSE changes
• Distinguishes it clinically from meningitis

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Diagnosis

• No antibody response (usually)
• Serum or gastric bioassay may be positive
• Usually a clinical diagnosis
• No cholinergic symptoms

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Management

• CFR 100 if not treated
• Ventilatory assistance cuts CFR to 5
• Intensive nursing imperative
• Recovery may take months but is usually complete

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Antitoxin

• Equine antitoxin highly effective
• Useful against food-borne illness
• Useful against aerosol attack as post-attack
  prophylaxis prior to symptom onset
• Must do skin testing prior to use
• Desensitization is effective if skin test is ()

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Vaccine

• Experimental, not FDA approved
• Available for use in case of suspected attack
• 0, 2, 12 weeks booster every year

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Botulinum toxin

• Bulbar signs progressive, descending symmetric
  flaccid paralysis
• Afebrile, no anticholinergic or CSF signs
• Use antitoxin in case of attack