TABLE 12.5.

Differentials and Diagnosis of Some Causes of Acute Diarrhea in Adult Horses

Category	Differentials	Diagnosis
Infectious	Salmonellosis	Fecal culture (five consecutive) Fecal PCR
	Clostridium perfringens	Quantitative fecal culture Fecal toxin immunoassay or PCR
	C. difficile	Fecal culture Fecal toxin immunoassay or PCR
	Neorickettsia risticii	Fecal or blood PCR Serology
	Coronavirus	Fecal PCR
Parasitic	Strongylosis	Fecal egg counts Cranial mesenteric artery palpation Serum IgG(T)
	Cyathostominosis	Fecal egg count Rectal biopsy Cecal or colonic biopsy
Toxic	NSAID	History and clinical signs Right dorsal colon ultrasonography Laparoscopy or laparotomy
	Cantharidin	History of exposure Fecal or urine cantharidin concentrations
	Arsenic	History of exposure Fecal, blood, urine, or tissue arsenic concentrations
Miscellaneous	Carbohydrate overload	History of inappropriate ingestion of carbohydrate Blood lactate concentration
	Sand enteropathy	Auscultation of ventral colon Fecal sand content Abdominal radiography

Ig, Immunoglobulin; NSAID, nonsteroidal antiinflammatory drugs; PCR, polymerase chain reaction.