Project Overview
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Proposal abstract:
Brucellosis is one of the world’s most widespread zoonoses but ranks as one of the seven most neglected, according to the World Health Organization. There are up to 5,000,000 new human cases of brucellosis annually. In the U.S., the State-Federal Cooperative Brucellosis Eradication Plan, initiated in 1934, was successful in eradicating brucellosis from cattle populations. However, the disease still has a reservoir in elk and bison in the greater Yellowstone area (GYA) with multiple instances of spillover into GYA cattle in the last decade. Positive cases in livestock lead to quarantines that can cost the producer in upwards of $254,000 per outbreak. Additionally, producers may elect, and in some cases be required, to cull their herd and submit them to imperfect and time-consuming diagnostic testing. Producers that are located in the Designated Surveillance Area (DSA), which spans Wyoming, Idaho, and Montana, are also required to undertake increased testing requirements prior to importation to some specific states. This applies to producers that are not under quarantine but conduct their livestock operations within the DSA. Recently, the DSA has been expanded to include areas where wildlife have tested positive for brucellosis. This expansion undoubtedly snares more producers into the DSA and submits them to a higher level of testing requirements for exportation of their livestock. We propose to develop and validate a new molecular assay (polymerase chain reaction) that has increased sensitivity while maintaining the high specificity seen with bacterial culture. Unlike bacterial culture that requires a suspect animal to be euthanized and sampled for testing, we hope to target our assay as an ante-mortem test that can be run on a blood sample. Not only would this test take only hours to complete in comparison to days/weeks with culture, but it would reduce the occupational risk to laboratory personnel from exposure to zoonotic pathogens. Therefore, having reliable testing and a short diagnostic lag time is crucial to eliminating the disease from the GYA. Once validated, we propose to conduct an educational campaign that would educate producers of the testing methods in comparison to these new testing methods. Additionally, we would generate educational materials that would demonstrate the known exposures to livestock and measures that can be taken to prevent the exposures and subsequent infections. We have various producer forums that would allow us to get these educational materials distributed to producers in the DSA. We can utilize the Brucellosis Coordination Team meeting head biannually to disseminate materials, as well as the Wyoming Stock Growers Association, the University of Wyoming Agriculture Extension office, and the Wyoming Livestock Board. With this multi-pronged approach, we hope to move towards eradication and increase the sustainability of our producers.
Project objectives from proposal:
1. Complete whole genome analysis of non-conserved regions in the 95 sequences that are in-house from USDA-NVSL. This entails the identification of a minimum of 10 candidate targets that can be tested against known positive and negative samples.
2. Statistically identify the best performing candidate set of the primers and probes.
3. Reproduce the sensitivity and specificity outside of our research lab in the Wyoming State Veterinary Laboratory to ensure they are achieving the same sensitivity and specificity on diagnostic samples.
4. Implement the new PCR test with the herd plan, which is used in the three states that are included in the DSA.
5. Communicate to our stakeholders (Wyoming Livestock Board, Wyoming Stock Growers Association, Wyoming Game and Fish Department, and United Stated Department of Agriculture – National Veterinary Services Laboratory) about the test availability and sensitivity and specificity in comparison to culture.
6. Conduct informational sessions to our producers in the DSA of this assay as well as distribute fact sheets on brucellosis. This fact sheet will contain information on current testing methodologies and strategies that can be used to decrease risk of wildlife spill over to livestock.