Abomasal parasite syndrome in North American elk (Cervus elaphus canadensis).

CASE HISTORY An 18-month clinical course of chronic ill-thrift, weight loss and emaciation, and eventual death occurred in a group of 520 translocated elk of mixed age and sex. Translocation was carried out without regard to animal welfare or health risks associated with the translocation. Mortality was approximately 84% (436/520) despite supportive nutritional and medical treatment. PATHOLOGICAL FINDINGS General clinical and postmortem examinations indicated only Se and Cu imbalances and nutritional inadequacy. Additional purposeful post-mortem examination and histological evaluation of tissue sections from four of the affected adult elk demonstrated elevated abomasal pH and proliferative abomasal lesions as the most significant findings, consistent with Type-II ostertagiosis; intra-lesional nematodes were seen in the abomasum of two animals. DIAGNOSIS Fading elk syndrome, or abomasal parasite syndrome in elk. CLINICAL RELEVANCE Abomasal parasite syndrome initiated by Type-II ostertagiosis should be considered as a differential diagnosis in cases of ill-thrift and wasting in elk or elk-red deer hybrids. Changes to the architecture and secretory function of the abomasal wall lead to apparently irreversible digestive pathophysiology and nutritional disease.