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Wood ME, Griebel P, Huizenga ML, Lockwood S, Hansen C, Potter A, Cashman N, Mapletoft JW, Napper S. Accelerated onset of chronic wasting disease in elk (Cervus canadensis) vaccinated with a PrP Sc-specific vaccine and housed in a prion contaminated environment. Vaccine 2018; 36:7737-7743. [PMID: 30414779 DOI: 10.1016/j.vaccine.2018.10.057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/07/2018] [Accepted: 10/14/2018] [Indexed: 10/27/2022]
Abstract
Chronic wasting disease (CWD) is a fatal prion disease affecting multiple cervid species. Effective management tools for this disease, particularly in free-ranging populations, are currently limited. We evaluated a novel CWD vaccine in elk (Cervus canadensis) naturally exposed to CWD through a prion-contaminated environment. The vaccine targets a YYR disease-specific epitope to induce antibody responses specific to the misfolded (PrPSc) conformation. Female elk calves (n = 41) were captured from western Wyoming and transported to the Thorne-Williams Wildlife Research Center where CWD has been documented since 1979. Elk were held in contaminated pens for 14 to 20 days before being alternately assigned to either a vaccine (n = 21) or control group (n = 20). Vaccinated animals initially received two vaccinations approximately 42 days apart and annual vaccinations thereafter. Vaccination induced elevated YYR-specific antibody titers in all animals. Elk were genotyped for the prion protein gene at codon 132, monitored for clinical signs of CWD through daily observation, for disease status through periodic biopsy of rrectoanal mucosa-associated lympoid tissue (RAMALT), and monitored for YYR-specific serum antibody titres. Mean survival of vaccinated elk with the 132MM genotype (n = 15) was significantly shorter (800 days) than unvaccinated elk (n = 13) of the same genotype (1062 days; p = 0.003). Mean days until positive RAMALT biopsy for 132MM vaccinated elk (6 7 8) were significantly shorter than unvaccinated 132MM elk (990; p = 0.012). There was, however, no significant difference in survival between vaccinated (n = 4) and control (n = 5) elk with the 132ML genotype (p = 0.35) or in timing of positive RAMALT biopsies of 132ML elk (p = 0.66). There was no strong (p = 0.17) correlation between YYR-specific antibody titers and survival time. Determining the mechanism by which this vaccine accelerates onset of CWD will be important to direct further CWD vaccine research.
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Affiliation(s)
- Mary E Wood
- Wyoming Game and Fish Department, 1212 South Adams St, Laramie, WY, USA; Wyoming Game and Fish Department, Thorne-Williams Wildlife Research Center, 2362 HWY 34 Wheatland, WY, USA.
| | - Philip Griebel
- Vaccine and Infectious Disease Organization-International Vaccine Research Center, University of Saskatchewan, 120 Veterinary Road, S7N 5E3 Saskatoon, Saskatchewan, Canada; School of Public Health, University of Saskatchewan, 104 Clinic Place, S7N 2Z4 Saskatoon, Saskatchewan, Canada
| | - Matthew L Huizenga
- Wyoming Game and Fish Department, Thorne-Williams Wildlife Research Center, 2362 HWY 34 Wheatland, WY, USA
| | - Samuel Lockwood
- Wyoming Game and Fish Department, Thorne-Williams Wildlife Research Center, 2362 HWY 34 Wheatland, WY, USA
| | - Cole Hansen
- Wyoming Game and Fish Department, Thorne-Williams Wildlife Research Center, 2362 HWY 34 Wheatland, WY, USA
| | - Andrew Potter
- Vaccine and Infectious Disease Organization-International Vaccine Research Center, University of Saskatchewan, 120 Veterinary Road, S7N 5E3 Saskatoon, Saskatchewan, Canada
| | - Neil Cashman
- Department of Neurology, University of British Columbia, S192 - 2211 Wesbrook Mall, V6T 2B5 Vancouver, BC, Canada
| | - John W Mapletoft
- Pan-Provincial Vaccine Enterprise Inc. University of Saskatchewan, 120 Veterinary Road, S7N 5E3 Saskatoon, Saskatchewan, Canada
| | - Scott Napper
- Vaccine and Infectious Disease Organization-International Vaccine Research Center, University of Saskatchewan, 120 Veterinary Road, S7N 5E3 Saskatoon, Saskatchewan, Canada; Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, S7N 5E5 Saskatoon, Saskatchewan, Canada
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