Botulism: Clinical Description

Risk Groups

  • All persons. Injection drug users are at increased risk for wound botulism.


  • Foodborne botulism: typically 12-36 hours after toxin ingestion, but in rare cases as early as 6 hours or as late as 10 days after ingesting toxin.
  • Wound botulism and infant botulism: it is difficult to estimate incubation period because exposure times cannot be ascertained.
  • Inhalational botulism: same as foodborne botulism.


  • Foodborne Botulism
    • Symmetric cranial neuropathies such as diplopia, drooping eyelids, difficulty swallowing, dry mouth, altered voice, or difficulty speaking
    • Symmetric descending flaccid paralysis in a proximal to distal pattern.
    • Possibly but not necessarily:
      • Abdominal pain
      • Nausea
      • Vomiting
      • Diarrhea
    • May progress to respiratory dysfunction from respiratory muscle paralysis.
  • Infant Botulism
    • Poor feeding
    • Diminished suckling and crying ability
    • Neck and peripheral weakness “floppy baby”
    • Constipation
    • Ventilatory failure
  • Wound Botulism
    • Neurological findings are indistinguishable from food-borne botulism without gastrointestinal symptoms
    • Wounds may not be obviously or grossly infected but are usually deep and contain avascular areas.

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Page last reviewed: October 6, 2006