|WANZALA, SYLVIA - University Of Minnesota|
|CARSTENSEN, MICHELLE - Minnesota Department Of Natural Resources|
|TRAVIS, DOMINIC - University Of Minnesota|
|SREEVATSON, SRINAND - University Of Minnesota|
Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2016
Publication Date: 7/1/2017
Citation: Wanzala, S.I., Palmer, M.V., Waters, W.R., Thacker, T.C., Carstensen, M., Travis, D., Sreevatson, S. 2017. Evaluation of pathogen-specific biomarkers for the diagnosis of tuberculosis in white-tailed deer (Odocoileus virginianus). American Journal of Veterinary Research. 78(6):729-734. doi: 10.2460/ajvr.78.6.729.
Interpretive Summary: Bovine tuberculosis (bTB), caused by Mycobacterium bovis, accounts for up to 10% of human TB cases in developing countries and is increasing in cattle in the US and UK. Control of bTB is hindered by the presence of numerous wildlife reservoirs such as white-tailed deer, European badgers, and brush-tailed possums. Reasons for the failure to eradicate the disease are multi-factorial; however, limitations in the availability of accurate and convenient tests are a primary factor. In this study, a biological marker of infection was found in the sera of tuberculosis-infected deer but not in sera from non-infected deer. This information will be useful for development of a new test for the detection of tuberculosis in deer; thereby, benefiting deer producers and possibly regional and federal departments of natural resources.
Technical Abstract: Objective - To develop a noninvasive biomarker based Mycobacterium bovis specific detection system to track infection in domestic and wild animals. Design – Experimental longitudinal study for discovery and cross sectional design for validation Animals - Yearling white-tailed deer fawns (n=8) were experimentally infected at the National Animal Disease Center (NADC) and their sera collected over the period of infection for biomarker detection. White-tailed deer (Odocoileus virginianus) sera (n = 384) was collected by the Minnesota Department of Natural Resources (DNR) from 2007- 2010 in northwest Minnesota were used for validation of biomarkers. Procedures- Deer were experimentally infected with 2 x 108 colony forming units of the virulent M. bovis strain 1315 on day 0. Sera were collected at baseline (pre-infection) and days 19, 48 and 60 post-infection. Non-infected control deer (n=3) received 0.9% saline on day 0 and were bled at each time point as age-matched controls. Three mycobacterium specific biomarkers (MB1895c, MB2515c, and Pks5), previously validated for cattle tuberculosis, were tested using sera from experimentally infected deer with an indirect ELISA. For field validation, the same ELISA was used on sera from 384 deer collected from 2007-2010 in northeast MN, concurrent with bTB outbreak involving cattle and deer in that region. Results- The ELISA using M. bovis specific biomarkers could detect bTB infection as early as 48 days post–infection in experimentally-infected deer. Results from the field deer sera showed disease prevalence decreased over the 4-year period. Conclusions and Clinical Relevance- Prevalence estimates suggest that bTB in deer in MN declined after 2009 but may be persistent at very low levels as subclinical disease, as indicated by the presence of low levels of circulating biomarkers.