Botulism intoxication — toxin type: The clinical illness of botulism results from ingestion of which class of toxin produced by Clostridium botulinum?
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AAn enterotoxin
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BNeurotoxin
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CMycotoxin
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DAll of these
Answer
Correct Answer: Neurotoxin
Explanation
Introduction / Context:Botulism presents with neurologic signs such as diplopia, dysphagia, flaccid paralysis, and in severe cases respiratory failure. The mechanism is a neuroparalytic toxin blocking neuromuscular transmission.
Given Data / Assumptions:
- Agent: Clostridium botulinum.
- Toxin: protein neurotoxin types A–G.
- Exposure: preformed toxin in foods or in vivo production in wound/infant botulism.
Concept / Approach:The botulinum neurotoxin cleaves SNARE proteins in cholinergic nerve terminals, preventing acetylcholine release and causing flaccid paralysis. It is not an enterotoxin or a fungal mycotoxin.
Step-by-Step Solution:Identify hallmark: neuroparalysis.Match to toxin class: neurotoxin.Select ‘‘Neurotoxin.’’
Verification / Alternative check:Clinical antitoxin therapy targets circulating neurotoxin, confirming the mechanism.
Why Other Options Are Wrong:
- Enterotoxin: would primarily cause secretory diarrhea, not paralysis.
- Mycotoxin: produced by fungi, not Clostridium.
- All of these: overinclusive and incorrect.
Common Pitfalls:Assuming gastrointestinal symptoms are predominant; neurological findings are diagnostic.
Final Answer:Neurotoxin