Causes include the ingestion of forages, particularly clovers, infected with the fungus Rhizoctonia leguminicola, which produces the toxic alkaloid slaframine. Profuse ptyalism is often the only clinical sign. Affected animals have no evidence of oral ulceration or other oral lesions. Ptyalism resolves once the animal is removed from the affected forage. The differential diagnoses for large animals (particularly ruminants) include bluetongue, vesicular stomatitis, vesicular exanthema, and foot-and-mouth disease.
Last full review/revision April 2012 by Jan F. Hawkins, DVM, DACVS