Botulism is a neuroparalytic disease caused by neurotoxins produced by the 
bacteria Clostridium botulinum. Botulinum neurotoxins (BoNTs) are among the most 
potent naturally occurring toxins and are a category A biological threat agent. 
The 7 toxin serotypes of BoNTs (serotypes A-G) have different toxicities, act 
through 3 different intracellular protein targets, and exhibit different 
durations of effect. Botulism may follow ingestion of food contaminated with 
BoNT, from toxin production of C botulinum present in the intestine or wounds, 
or from inhalation of aerosolized toxin. Intoxication classically presents as an 
acute, symmetrical, descending flaccid paralysis. Early diagnosis is important 
because antitoxin therapy is most effective when administered early. 
Confirmatory testing of botulism with BoNT assays or C botulinum cultures is 
time-consuming, and may be insensitive in the diagnosis of inhalational botulism 
and in as many as 32% of food-borne botulism cases. Therefore, the decision to 
initiate botulinum antitoxin therapy is primarily based on symptoms and physical 
examination findings that are consistent with botulism, with support of 
epidemiological history and electrophysiological testing. Modern clinical 
practice and antitoxin treatment has reduced botulism mortality rates from 
approximately 60% to < or =10%. The pentavalent botulinum toxoid is an 
investigational product and has been used for more than 45 years in at-risk 
laboratory workers to protect against toxin serotypes A to E. Due to declining 
immunogenicity and potency of the pentavalent botulinum toxoid, novel vaccine 
candidates are being developed.