Poster Presentation 64th International Conference of the Wildlife Disease Association 2015

Clinical findings in free-ranging elk (Cervus elaphus) affected with treponeme-associated hoof disease (TAHD) in southwest Washington state, USA (#170)

Kristin Mansfield 1 , Brock Hoenes 1 , Stefanie Bergh 1 , Rachel Cook 2 , Brooke George 1 , Eric Holman 1 , Nicholle Stephens 1 , Jennifer Wilson-Welder 3
  1. Washington Department of Fish and Wildlife, Olympia, WA, USA
  2. National Council for Air and Stream Improvement, La Grande, OR, USA
  3. Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, USDA-ARS, Ames, IA, USA

Treponeme-associated hoof disease (TAHD) has emerged as a significant disease of elk (Cervus elaphus) in southwest Washington state during the past decade. While severely affected individuals and an apparently high prevalence of disease are readily observable in the TAHD-endemic area, the population effects of this disease are unknown.  In order to inform management of elk in the TAHD-endemic area, during February 2015 the Washington Department of Fish and Wildlife initiated a 5-year study to investigate the potential effects of TAHD on adult female (>2 years old) elk survival and reproduction.  A total of 78 animals were radio-collared:  58 with visual evidence of TAHD, and 20 with normal-appearing hooves and no evidence of lameness at the time of capture.  In conjunction with marking the animals for this study, samples were collected for the following analyses:  whole blood for measurement of lymphocyte response to known hoof disease pathogens and for complete blood counts; serum for measurement of antibodies to known hoof disease pathogens;  and hoof swabs for bacterial culture, polymerase chain reaction, and metagenomic microbial studies.  In addition, nutritional status was assessed using elk-specific body condition scoring methods and pregnancy status was determined via transrectal ultrasound.  Lymphocytes from affected elk exhibited significant proliferation to pathogenic Treponema sp. antigens compared to elk from outside the TAHD-endemic area, but did not differ in response to Fusobacterium necrophorum or Dichelobacter nodosus antigens.  Within the endemic area, preliminary analyses suggest that elk with TAHD had higher neutrophil/lymphocyte ratios than unaffected elk. Remaining analyses are ongoing at the time of abstract submission and will be included in the conference presentation.