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

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

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

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

BW/BT Significance Easy to produce & weaponize Can be aerosolized or placed into food Most toxic BW/BT agent by weight –LD 50 =  g/kg body weight –15,000x more toxic than VX –100,000x more toxic than Sarin

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

Clinical botulism Symptoms start hours after inhalation –Ingestion = shorter time of onset –Onset determined by dose Early bulbar signs followed by progressive, descending, symmetric skeletal muscle weakness & paralysis

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

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

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

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 (+)

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

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