What is Botulism? 

Botulism is a progressive, flaccid paralysis resulting from ingestion of a bacterial toxin (from Clostridium botulinum) which can be rapidly fatal if not aggressively treated from the first clincal signs. 

Clinical Signs: Clinical Signs of Botulism include the following: 

  • Severe muscle weakness 
  • Flaccid paralysis with normal mentation 
  • Inability to swallow 
  • Poor tail, tongue and eyelid tone
  • Hypoventilation, respiratory arrest 
  • Paresis/inability to stand for extended periods 
  • Limb paralysis 
  • Progression to muscular weakness and recumbency 
  • Drooling 
  • Muscle trembling 
  • Unexplained mydriasis with sluggish pupillary light reflexes
  • Tachycardia 
  • Colic and decreased gastrointestinal motility 
  • Sudden unexplained death
  • inability to rise after lying down 

Diagnosis: Botulism should be the primary concern for horses suffering from flaccid paralysis without any signs of precipitating conditions. Diagnosis is by elimination of other causes of neurological disease-causing weakness and recumbency such as EPM, EHM, arboviral encephalitis, rabies, metabolic derangements, myopathies and other toxins.  

Treatment:  Treatment with antiserum can be used if administered early in the disease.

Prevention: Vaccination is effective and may be used in environments known for the disease.


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Vermilion County, LA
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December 17, 2022
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December 14, 2022
Vermilion Parish County, LA
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