von Ostertag,Robert, German veterinarian, 1864-1940.
Ostertagia - genus of stomach worms that are found primarily in cattle.
ostertagiasis - infection caused by Ostertagia. Synonym(s): ostertagiosis
a disease of ruminants caused by invasion of the abomasum by Ostertagia spp. Two forms occur. Type I is in lambs or calves in their first summer at pasture and is characterized by the presence of large numbers of adult worms in the abomasum, profuse watery diarrhea, depressed appetite and a high morbidity rate. Type II occurs in cattle in the late winter after that first summer and sometimes in adults. It is characterized by emergence of large numbers of inhibited larvae from the abomasal mucosa, by chronic diarrhea, emaciation, a high death rate and a greatly thickened and edematous abomasal mucosa, subcutaneous edema and high plasma pepsinogen levels. The timing of the two forms varies between countries.
The disease is more properly referred to as ostertagiosis but common usage is ostertagiasis.