An outbreak of equine botulism type A associated with feeding grass clippings

Stephanie R. Ostrowski, Steven V. Kubiski, Joanie Palmero, Christopher M. Reilly, Jamie K. Higgins, Sheri Cook-Cronin, Snehal N. Tawde, Beate M. Crossley, Paula Yant, Ray Cazarez, Francisco A. Uzal

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


In September 2010, an outbreak of type A botulism involved 4 horses in northern California that were fed grass clippings obtained from a nearby park. All 4 animals developed a progressive flaccid paralysis syndrome clinically consistent with exposure to preformed Clostridium botulinum neurotoxin (BoNT). Within 48 hr of consuming the grass clippings, all 4 horses showed marked cervical weakness (inability to raise their heads to a normal position) and died or were euthanized within 96 hr. One horse was submitted for diagnostic examination and subsequent necropsy. At necropsy, extensive edema was observed in areas of the nuchal ligament and inguinal fascia. A sample of the grass clippings tested positive for preformed BoNT type A by the mouse bioassay test. Emphasis should be placed on early case recognition, rapid initiation of treatment with the trivalent antitoxin product, and preventing exposure to BoNT in spoiled forages.

Original languageEnglish (US)
Pages (from-to)601-603
Number of pages3
JournalJournal of Veterinary Diagnostic Investigation
Issue number3
StatePublished - May 2012


  • Botulism
  • Clostridium botulinum
  • grass
  • neurotoxin
  • type A

ASJC Scopus subject areas

  • veterinary(all)


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