First report on foot disease in the endangered huemul deer (Hippocamelus bisulcus)

The huemul deer (Hippocamelus bisulcus) is an endangered neotropical cervid endemic to southern Argentina and Chile. Here we report foot lesions of unknown etiology in 24 huemul deer from Bernardo O’Higgins National Park,... [ view full abstract ]

The huemul deer (Hippocamelus bisulcus) is an endangered neotropical cervid endemic to southern Argentina and Chile. Here we report foot lesions of unknown etiology in 24 huemul deer from Bernardo O’Higgins National Park, Chile, recorded from April 2005 to August 2010. All affected deer displayed similar but varying degrees of clinical signs, including lameness and soft tissue swelling in one or more limbs proximal to the hoof or in the interdigital space and, in some cases, ulceration of the swollen areas and/or abnormal wear or growth of one or both of the claws. Some cases spontaneously and completely resolved; others progressed to more severe, proliferative and/or suppurative forms in which partial or complete loss of the hoof structure occurred. Animals showed signs of intense pain such as marked lameness, reluctance to bear weight on the affected feet, and reduced mobility followed by loss of body condition and prolonged recumbency, which often preceded death. The disease affected both genders and all age categories. The severity of clinical disease was variable and in a third of affected animals, resulted in complete incapacitation and death. Morbidity and mortality rates ranged from 40 to 80% and 13 to 40%, respectively. Diagnostics were limited to a single case from which samples were available. Histology revealed severe papillomatous hyperplasia and dermatitis. Bovine papillomavirus immunohistochemistry and PCR for papillomaviruses, herpesviruses, poxviruses, adenoviruses, flaviviruses and iridovirus were negative. Silver staining revealed superficial organisms suggestive of Treponeme spp. infection, an additional differential that is also being pursued. Despite severe limitations in outbreak investigation, this is the first documentation of a disease which might pose a considerable conservation threat for huemul deer in Chilean Patagonia. Furthermore, this report illustrates the need for improved monitoring of huemul deer and synergistic, rapid response efforts, to adequately address disease events threatening this species.