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BW Agents: Botulinum toxin

BW Agents: Botulinum toxin

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BW Agents: Botulinum toxin

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  1. BW Agents: Botulinum toxin J.A. Sliman, MD, MPH LCDR MC(FS) USN Preventive Medicine Resident Johns Hopkins Bloomberg School of Public Health

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

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

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

  11. 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 (+)

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

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