ostertagiasis

os·ter·ta·gi·a·sis (os″tər-tə-jiґə-sis) infection of the abomasum of a ruminant by nematodes of the genus Ostertagia. In lambs and calves, if there are large numbers of adult worms the host may suffer from anorexia and diarrhea. In older animals, when the resident worm population yields large numbers of larvae, the result is edema and thickening of the abomasal mucosa, with chronic diarrhea and emaciation that can be fatal.