Case report: fading elk syndrome in a herd of captive elk (Cervus elaphus) in the North American midwest

Authors: Boggiatto, Paola; CRAWFORD, LAUREN - Orise Fellow; KANIPE, CARLY - Orise Fellow; Palmer, Mitchell; Olsen, Steven

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2020
Publication Date: 8/21/2020
Citation: Boggiatto, P.M., Crawford, L.S., Kanipe, C., Palmer, M.V., Olsen, S.C. 2020. Case report: fading elk syndrome in a herd of captive elk (Cervus elaphus) in the North American midwest. Frontiers in Veterinary Science. 7:497. https://doi.org/10.3389/fvets.2020.00497.
DOI: https://doi.org/10.3389/fvets.2020.00497

Interpretive Summary: The work presented here sheds light on fading elk syndrome, a seldom reported disease of elk in North America. This highly debilitating, and often fatal condition can have a detrimental effect on captive elk herds, in both in terms of production and animal loss. Diagnosis of fading elk syndrome can be difficult, and therapeutic intervention is not always successful. Fatal elk syndrome is associated with abomasal parasitism with Ostertagia parasites, a common parasite of domestic ruminants, such as cattle and sheep. To our knowledge, this is only the second report of fading elk syndrome in the United States. The information presented will be of interest to veterinarians working with wildlife ruminants, and to elk and deer producers.

Technical Abstract: Seven, 2 year-old elk (Cervus elaphus) hinds presented as dull and depressed with severe weight loss in summer of 2019, in a herd of 34 animals, located in Ames, Iowa, at the National Animal Disease Center. Complete blood counts were unremarkable, but blood chemistry showed a severe hypoalbuminemia. Fecal floatations were also unremarkable, and non-diagnostic. Histological examination of tissues collected at necropsy revealed proliferative abomasitis and nematodes consistent with Ostertagia spp. Anthelmintic treatment consisting of a combination of pour-on Cydectin® and injectable Noromectin Plus®, at double the recommended dose for cattle, was started immediately following presentation of clinical signs. This particular treatment regimen showed positive results, as all remaining animals in the herd recovered. Albumin levels had improved within 5 weeks of starting treatment, and were within normal limits by 10 weeks after the identification of clinical signs. Fading elk syndrome, or chronic ill-thrift of elk, is characterized by progressive weight loss, severe cachexia, and it is often fatal. While this syndrome has been extensively reported to affect wapiti-type red deer hybrids farmed in New Zealand since the mid 1980’s, there is only a single report of this disease in North America. The disease is associated with abomasal parasitism with Ostertagia species, of which elk appear to be particularly susceptible.