Diagnosis: Necrohemorrhagic enterocolitis (swine dysentery)
Etiology: Brachyspira hyodysenteriae (note black spirochetal organisms along the apical surface of cryptal enterocytes; large intestine; modified silver stain)
Other enteric diseases of pigs: Lawsonia intracellularis (porcine proliferative enteritis – usually affects the ileum), Escherichia coli (especially young piglets with edema in the mesocolon), Salmonella Choleraesuis (associated with rectal stenosis), coronaviruses (TGEV, SADS-CoV, PDCoV, PEDV), rotaviruses (neonatal piglets with failure of passive transfer), and nematodes (ascarids and milk spot liver due to parasitic migration)