Progress 09/01/06 to 08/31/09
Outputs
OUTPUTS: Bighorn sheep-domestic sheep in-contact study: Results from the contact study were presented to scientific audiences (e.g., Conference of Research Workers in Animal Diseases, Chicago, IL, December 6-8, 2009; Schwabe Symposium, Chicago, IL, December 4, 2012). The study's results inform field investigations of natural outbreaks of bighorn sheep pneumonia, with increased focus on the potential importance of Mycoplasma ovipneumoniae as a co-factor. Historically, primacy was accorded Pasteurella multocida and Bibersteinia trehalosi as major etiological agents in BHS pneumonia complex. A recent investigation of 8 BHS pneumonia epizootics in the western United States concluded that M. ovipneumoniae was commonly present in pneumonic lungs. Brucellosis in GYA elk: Test-and-slaughter over five years significantly reduced elk brucellosis seroprevalence. Such an approach could serve as a management tool in a combined arsenal to reduce brucellosis transmission risks amongst elk, and between elk and other wildlife and domestic species (cattle). Identifying elk parturition ranges (and thereby abortion ranges) provided management information for more effective, seasonally relevant segregation of elk and cattle during the brucellosis transmission risk period (February-June). Results were disseminated via peer reviewed publications, meetings with Wyoming Game and Fish department wildlife managers, and WGFD annual reports. PrP in cervid species: Purified protein as well as plasmid-bearing bacterial stocks were disseminated to collaborators for collateral projects including the use of MALDI-MS to analyze alleles present in disease-associated prion from CWD-infected deer and elk. Protein and plasmids were also donated for projects to develop the in vitro conversion assay of Caughey et al (QUIC) using cervid recPrP as template material to allow the investigation of a wide range of tissue and environmental samples for infectious prion, and the compatibility of genetic variants to conversion by homologous and heterologous infectious prions. PARTICIPANTS: Individuals working on project: Dr. Subramaniam Srikumaran; Dr. Todd Cornish; Dr. Jean Jewell. Partner organizations: University of Wyoming; Washington State University. Training or professional development: Master's thesis, University of Wyoming--Ms. Laura Linn. TARGET AUDIENCES: Wildlife managers; veterinarians; diagnosticians; hunters; livestock producers. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
A significant finding was majority survival of bighorn sheep over >100 days of commingling with domestic sheep in the absence of M. ovipneumoniae. The high survival rate is consistent with M. ovipneumoniae being an important component in epidemic pneumonia of bighorn sheep. If correct, the risk of bighorn sheep pneumonia following contact with domestic sheep could be reduced if in-contact sheep are managed to eliminate carriage and shedding of M. ovipneumoniae. Related field studies of bighorn sheep pneumonia suggest that M. ovipneumoniae is the only agent for which data consistently met the criteria for a primary etiologic role in multiple outbreaks. Identification of M. ovipneumoniae as the epizootic agent of bighorn sheep pneumonia may prove a useful focus for control measures. The WGFD elk brucellosis test-and-slaughter program was performed on three elk winter feedgrounds in one elk herd unit (2006 to 2010). Elk from one feedground were trapped and tested for brucellosis twice each winter during this time period. 107 seropositive elk from the feedground were sent to slaughter. Brucellosis seroprevalence decreased significantly on the feedground from 2006 (39%) to 2010 (5%). All slaughtered elk were tested by bacterial culture. 60% were culture-positive for Brucella abortus [57% of pregnant elk (n=83), 71% of non-pregnant elk (n=24), 100% of yearling elk (n=5)]. The serological test panel with highest sensitivity and specificity for predicting culture positive animals was the card test, rivanol, SPT, and FPA (sensitivity = 100%, specificity = 88%). Results of the pilot test-and-slaughter program suggest that this approach may have value in lowering elk brucellosis seroprevalence (and, by proxy, risk of brucellosis transmission to cattle) in select applications. The program was labor intensive and costly (total cost in excess of $1.25 million). We foresee this option as a useful tool when combined with other disease control applications. The associated project using vaginal implant transmitters on pregnant elk that delineated new parturition (and potential abortion) ranges for elk. These data are incorporated into the WGFD elk brucellosis management plans, They resulted in improved segregation of elk and domestic cattle during the brucellosis transmission season (February to June). Physicochemical properties of prion proteins in cervid species: Mule deer cellular prion protein gene (PrP) alleles encoding serine at amino acid position 225 (225S) or phenylalanine at position 225 (225F) were cloned into expression-inducible plasmid vectors, expressed in E coli cultures and purified from inclusion body pellets using metal affinity column liquid chromatography under renaturing conditions. The 209I (isoleucine at codon 209) allele of moose (Alces alces shirasi) cellular prion protein gene was also cloned. Monoclonal antibodies were developed that would be immunoreactive for 225S or 225F. 25 MAbs from the F peptide mice and 19 from the S peptide mice were isolated and screened for allelic specificity. Efforts to secure further funding to continue the project beyond the expiration of the grant were unsuccessful.
Publications
- Maichak, EJ, Scurlock, BM, Rogerson, JD, Meadows, LL, Barbknecht, AE, Edwards, WH, Cross, PC. 2009. Effects of management, behavior, and scavenging on risk of brucellosis transmission in elk of western Wyoming. Journal of Wildlife Diseases 45:398-410.
- Scurlock, BM, Edwards WH, Meadows LL, Cornish, TE. 2011. Using Test and Slaughter to Reduce Prevalence of Brucellosis in Elk Attending Feedgrounds in the Pinedale Elk Herd Unit of Wyoming; Results of a 5 Year Pilot Project. Wyoming Game and Fish Department Annual Report 2011.
- Besser TE, Cassirer EF, Yamada C, Potter KA, Herndon C, Foreyt WJ, Knowles DP, Srikumaran S. 2012. Survival of bighorn sheep (Ovis canadensis) commingled with domestic sheep (Ovis aries) in the absence of Mycoplasma ovipneumoniae. Journal of Wildlife Diseases 48(1):168-72.
- Meadows, LL, Scurlock, BM, Edwards, WH, Tate, CM, Rogerson, JD, Maichak, EJ, Henningsen, JC, Randall, J, Robinson, TJ, and Cornish, TE. 2012. Evaluation of an Elk Brucellosis Test-and-Slaughter Program in Wyoming. Journal of Wildlife Diseases(submitted).
- Meadows, LL. 2011. Evaluation of the Elk Brucellosis Test-and-Slaughter Program and Comparison of Bacteriologic and Serologic Tests for Brucellosis in Elk. Masters Thesis, Animal and Veterinary Sciences, University of Wyoming, Laramie, Wyoming.
- Nichols, TA, Pulford, B, Wyckoff, AC, Meyerett, C, Michel, B, Gertig, K, Hoover, EA, Jewell, JE, Telling, GC, and Zabel, MD. 2009. Detection of protease-resistant cervid prion protein in water from a CWD-endemic area. Prion 3:171-183.
|