Seasonal pasture myopathy - atypical myopathy
Atypical myopathy is a highly fatal muscle disease of grazing horses. Ingestion of the toxin hypoglycin A, found in sycamore seeds, has been identified as the cause of the disease. Clinical signs can vary from mild lethargy and muscle stiffness to sudden death, with numerous horses on the same grazing potentially affected. Early diagnosis and rapid implementation of supportive treatment is vital, however fatality rates remain high.