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

Abstract

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.

Management of Animal Botulism Outbreaks: From Clinical Suspicion to Practical Countermeasures to Prevent or Minimize Outbreaks

“…Differential diagnosis includes toxic plant poisoning, organophosphate intoxication, equine viral encephalitis, central nervous system trauma, equine protozoal myeloencephalitis, aberrant larval migration, and hyperammonemia. 35 In horses that feed in a group, the dominant horse eats first and is therefore usually the first one to develop clinical signs and shows most rapid progression of the neurotoxic syndrome. 35 …”

“…35 In horses that feed in a group, the dominant horse eats first and is therefore usually the first one to develop clinical signs and shows most rapid progression of the neurotoxic syndrome. 35 …”

“…[31][32][33] Typically, type C and D toxins are associated with carrion of birds or small animals that have contaminated water, feed, or the environment, while noncarrion-associated botulism is caused by type A and B toxins. 4,[33][34][35] A second form of animal botulism is associated with the absorption of BoNTs produced in vivo in the intestinal tract. This form of botulism, seen in chickens and horses, can be categorized as a toxicoinfection.…”

Surto de botulismo tipo C em equinos no Rio Grande do Sul

“…Kinde et al (1991), Pabilonia (2003) e Ostrowski et al (2012), descreveram alguns achados necroscópicos proeminentes, como enterite catarral e hemorrágica e edemas intramusculares multifocais, principalmente na cabeça e pescoço, relatados em surtos de botulismo em equinos na Améri-ca do Norte; entretanto, se tratam de lesões inespecíficas e nem sempre relacionadas ao botulismo. Nos casos analisados, a apresentação clínica, associada com a ausência de lesões no exame anatomopatológico, corroboram com o descrito por outros autores (Ricketts et al 1984, Kelly et al 1984, Schoenbaum et al 2000.…”

Botulism

“…El botulismo por ingestión de alimentos es causada habitualmente por ingestión de toxinas de C.botulinum y otras especies ; una pequeña cantidad de neurotoxina (aproximadamente 30 ng) puede llegar a ser fatal 74 . La vía de contaminación más frecuente es el consumo de alimentos (carne en descomposición, carcasas, conservas en mal estado) o pastos contaminados con la neurotoxina ya producida; es la principal fuente de intoxicación en los animales domésticos 68,70 . La tasa de mortalidad general es de 5-10% 69 , y puede llegar hasta el 80% en los rumiantes 73 .…”