Skip to main content
Bovine TB vaccination trial

Bovine TB vaccination trial

white tailed deer herd in a forest opening

Michigan has been dedicated to eradicating bovine tuberculosis (bTB) for nearly three decades, achieving progress in lowering the disease's prevalence in free-ranging white-tailed deer and reducing infection rates in cattle. Despite these advancements, current management strategies have maximized their effectiveness. There's a need for the development of additional tools that can complement ongoing efforts in the state. A unified and sustained approach to protecting human, wildlife, and domestic animal health is critical to further progress toward bTB eradication.

Study summary

From late February to April 2024, the United States Department of Agriculture – Wildlife Services (USDA-WS) is deploying vaccine delivery units (VDUs) at selected sites in part of Alpena County, Michigan, to evaluate the ability to deliver an oral bovine tuberculosis (bTB) vaccine to wild deer. With landowner consent, approximately 15 sites are being used for this field trial. The VDUs, consisting of alfalfa and molasses cubes containing an edible sphere with the liquid vaccine, are systematically placed in crop fields frequented by deer. These units remain in place for up to two days, during which the sites will be monitored, followed by the retrieval of any units not consumed by the deer. Several weeks after VDU deployment, USDA-WS will harvest deer from the trial area under permits issued by the Michigan Department of Natural Resources (DNR) and submit samples for analyses by the State of Michigan and USDA. Conducted under the guidance of a licensed Michigan veterinarian and approved by the USDA, this field trial is the next step in understanding oral bTB vaccination of wild deer. The DNR will not allow vaccination of deer beyond the scope of this trial until broader-scale testing of deer for the vaccine becomes practical.

Frequently asked questions

  • Deer are being orally vaccinated by consuming vaccine delivery units (VDUs) that contain encapsulated liquid bacillus Calmette Guerin (BCG), a weakened strain of Mycobacterium bovis. BCG has been used for over 100 years to protect children from TB and is one of the most widely used vaccines in people around the world.

  • At this time, there is not an approved test the Michigan Department of Agriculture and Rural Development can use to differentiate between BCG vaccinated cattle and those that have been exposed to virulent bovine tuberculosis. Vaccinated cattle would come up positive on bTB testing. Once the amount of bTB becomes low in a species (which is the case in cattle), a vaccine is not used because it can mask the disease and hinder eradication.

  • There are no physical markers identifying deer that have ingested the vaccine. Hunters cannot submit deer heads to be tested for BCG, but they can submit heads to determine if the deer is infected with bTB. Hunters close to the vaccination sites could potentially come in contact with BCG while field dressing a vaccinated deer when they handle its organs or lymphoid tissue 1,2. The DNR always encourages hunters to protect themselves from potential disease exposure by wearing latex or rubber gloves when field dressing deer. While the risk is low, this precaution will protect hunters concerned about exposure to BCG as well.

  • Work conducted with penned deer prior to this trial has shown that BCG was not found in deer muscle tissue at any time it was tested, including 12 months after oral vaccination. In these studies, BCG was only detected in lymphoid tissue and intestinal organs 1,3. If you are concerned, avoid consuming organs and cook venison to 140oF for six minutes, or until juices run clear to kill the bacteria that causes bTB and BCG as well 2,4.

  • Vaccinated deer are not immune or fully protected from a bTB infection. In research trials using penned deer, BCG vaccination reduced severity of the disease 6, 7. This means vaccinated deer are less likely to actively transmit bTB to other deer and livestock, reducing spread. It is unknown exactly how long a deer would be protected, but a single vaccination would not last a deer's lifetime. Protection in deer has been shown to last 4 months, however, it hasn’t been tested past that point. Protection in cattle at one year has been demonstrated 8. The same duration is expected in deer, but cannot be confirmed without additional testing.

  • Vaccination sites are not near homes or yards and unconsumed vaccine delivery units will be recovered. No serious side effects have been observed after ingesting BCG in multiple species 5.

  • No negative side effects or adverse reactions have been reported in multiple species vaccinated with BCG including deer, brushtail possum, badgers, and wild boar 9,10,11,12,13.

  • In general living in an area where bTB is found in deer and cattle increases the risk of exposure to bTB, compared to other areas of the state where the disease has not been detected. There is no additional risk as a result of this field trial. Field trial locations have been selected based on habitat and landscape factors, not because of a higher prevalence of bTB in deer there.

  • Yes. Since 1977 several oral rabies vaccine programs have been implemented in the U.S. The U.S. Department of Agriculture Animal and Plant Health Inspection Service-Wildlife Services has worked with local and state governments and other partners to control rabies through the use of oral rabies vaccination (ORV) of wildlife. ORV baits containing the vaccine are distributed by fixed-wing aircraft or by hand in targeted areas. A large-scale ORV program in the eastern U.S. has reduced the cases of raccoons infected with rabies and slowed or stopped the spread west. Other success includes elimination of the dog-coyote rabies virus variant (RVV) along the U.S. – Mexico border. An ORV program targeted coyotes in this area after the dog-coyote RVV affected domestic dogs and caused two human deaths 14 .

Literature cited in FAQs

1 Palmer MV, Thacker TC, Waters WR, Robbe-Austerman S, and Aldwell FE. (2014). Persistence of Mycobacterium bovis bacillus Calmette–Guerin (BCG) Danish In White tailed Deer (Odocoileus virginianus) Vaccinated with a Lipid-Formulated Oral Vaccine. Transboundary and Emerging Diseases 61: 266-272.

2 Palmer MV, and Thacker TC. (2018). Use of the human vaccine, Mycobacterium bovis bacillus Calmette guérin in Deer. Frontier in Veterinary Science 5:244

3 Palmer MV, Thacker TC, Waters WR, Robbe-Austerman S, Lebepe-Mazur SM, and Harris NB. (2010A). Persistence of Mycobacterium bovis Bacillus Calmette-Gue´rin in White-Tailed Deer (Odocoileus Virginianus) after Oral or Parenteral Vaccination. Zoonoses and Public Health 57:e206-e212.

4 Merkal RS and Whipple DL. (1980). Inactivation of Mycobacterium bovis in meat products. Applied and Environmental Microbiology 40(2):282-284

5 Buddle BM, Vordermeier HM, Chambers MA and de Klerk-Lorist L-M. (2018). Efficacy and Safety of BCG Vaccine for Control of Tuberculosis in Domestic Livestock and Wildlife. Frontiers of Veterinary Science 5:259. doi: 10.3389/fvets.2018.00259

6 Nol P, Palmer MV, Waters WR, Aldwell FE, Buddle BM, Triantis JM, Linke LM, Phillips GE, Thacker TC, Rhyan JC, Dunbar MR, and Salman MD. (2008). Efficacy of oral and parenteral routes of Mycobacterium bovis bacille Calmette-Guerin vaccination against experimental bovine tuberculosis in white-tailed deer (Odocoileus virginianus): a feasibility study. Journal of Wildlife Diseases 44(2):247- 259.

7 Palmer MV, Thacker TC, and Waters WR. (2009). Vaccination with Mycobacterium bovis strains Danish and Pasteur in white-tailed deer (Odocoileus virginianus) experimentally challenged with Mycobacterium bovis. Zoonoses Public Health. 56: 243-251

8 Thomas Holder et al., Vaccine, https://doi.org/10.1016/j.vaccine.2023.10.060

9 Griffin JF, Hesketh JB, Mackintosh CG, Shi YE, Buchan GS. (1993). BCG vaccination in deer: distinctions between delayed type hypersensitivity and laboratory parameters of immunity. Immunol Cell Biol. 71:559–70. doi: 10.1038/icb.1993.62

10 Aldwell FE, Pfeffer A, DeLisle GW, Jowett G, Heslop J, Keen D, et al. (1995). Effectiveness of BCG vaccination in protecting possums against bovine tuberculosis. Res. Vet. Sci. 58:90–5. doi: 10.1016/0034-5288(95)90095-0

11 Corner LA, Costello E, Lesellier S, O'Meara D, Gormley E. (2008). Vaccination of European badgers (Meles meles) with BCG by the subcutaneous and mucosal routes induces protective immunity against endobronchial challenge with Mycobacterium bovis. Tuberculosis. 88:601–9. doi: 10.1016/j.tube.2008.03.002

12 Nol P, Robbe-Austerman S, Rhyan JC, McCollan MP, Triantis JM, Beltrán-Beck B, et al. (2016). Determining the persistence of Mycobacterium bovis bacille Calmette-Guérin Danish in select tissues of orally vaccinated feral swine (Sus scrofa spp.) Res Vet Sci. 104:50–2. doi: 10.1016/j.rvsc.2015.11.007

13 Buddle BM, Vordermeier HM, Chambers MA and de Klerk-Lorist LM. (2018). Efficacy and Safety of BCG Vaccine for Control of Tuberculosis in Domestic Livestock and Wildlife. Frontiers of Veterinary Science 5:259. doi: 10.3389/fvets.2018.00259

14 U.S. National Plan for Wildlife Rabies Management 2023-2027. U.S Department of Agriculture[1]Animal Plant Health Inspection Services.