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Development of Vaccine Approaches for Bovine Tuberculosis in Free-Ranging White-tailed Deer

Development of Vaccine Approaches for Bovine Tuberculosis in Free-Ranging White-tailed Deer. Mitchell Palmer, Ray Waters, Tyler Thacker National Animal Disease Center, ARS, USDA Ames, IA. Wildlife Vaccines. P ublic health: rabies, plague, Lyme disease

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Development of Vaccine Approaches for Bovine Tuberculosis in Free-Ranging White-tailed Deer

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  1. Development of Vaccine Approaches for Bovine Tuberculosis in Free-Ranging White-tailed Deer Mitchell Palmer, Ray Waters, Tyler Thacker National Animal Disease Center, ARS, USDA Ames, IA

  2. Wildlife Vaccines • Public health: rabies, plague, Lyme disease • Livestock production: bovine TB, brucellosis, pseudorabies • Iconic or endangered species: pasteurellosis (Bighorn sheep), anthrax (Black rhino)

  3. Wildlife Vaccines-Challenges- • Multiple species in natural transmission cycle • Effective oral vaccine • Safety of non-target species • Fastidious feeding behavior • Instability of vaccine in prevailing environmental conditions • High reproductive rates and population turnover • Requirement for low unit cost • Government funding (development, purchase, delivery)

  4. Agent • Mycobacterium tuberculosis complex > 99.95% sequence homology • M. tuberculosis • M. bovis – broadest host range • M. caprae • M. africanum • M. canetti • M. microti • M. pinnipedii • M. mungi

  5. Cattle are often the original source of M. bovis in wildlife. As the prevalence of bovine tuberculosis decreases in livestock, the relative importance of wildlife reservoirs increases.

  6. Tuberculosis Eradication • 1900- tuberculosis leading cause of death • 10-25% of human tuberculosis due to M. bovis • 1917- USDA eradication program • 15,000 deaths to M. bovis • 3x- number of foodborne deaths today • Current surveillance is slaughter surveillance

  7. Obstacles to Bovine Tuberculosis Eradication • Importation of infected cattle • Need rapid, reliable and inexpensive test to at border crossings. • Inability to Test and Remove Cattle • Need reliable, accurate tests to remove infected cattle without whole herd depopulation. • Wildlife Reservoirs • Need for vaccines for wildlife. • Safe vaccines • Vaccine delivery systems • Need for vaccines for cattle. • Infected vs Vaccinated

  8. Tuberculosis in Wildlife • Traditional eradication methods used for livestock DO NOT work with wildlife reservoirs. • No country with an established wildlife reservoir of tuberculosis has successfully eradicated tuberculosis from domestic livestock. • Vaccines viewed as possible control measure.

  9. Mycobacterium bovisbacille Calmette-Guerín (BCG) • BCG was developed 1906-1919. • Originally isolated from a cow. • Continuous passage led to decreased virulence • Oldest of vaccines in use today. • World’s most widely used vaccine (3 billion doses since 1920). • Vaccinated individual may have positive skin test. Camille Guerin Albert Calmette

  10. Vaccination in the US

  11. Efficacy Does vaccination prevent infection? Does vaccination prevent disease (lesion development)? Does vaccination decrease transmission?

  12. Stage 1 Stage 2 Stage 4 Stage 3

  13. Medial retropharyngeal LN Total Score

  14. Lung BCG Danish: Stages I-III BCG Pasteur: Stages I- III Non-vaccinates: Stages I-IV Medial retropharyngeal LN BCG Danish: no lesions BCG Pasteur and non-vaccinates: Stages I-V

  15. Mediastinal LN Lung

  16. Oral vaccination of white-tailed deer with M. bovis BCG

  17. Is it safe? • Adverse reactions • Non-target species • Public health concerns • Possible exposure through venison consumption

  18. Will vaccination of deer interfere with cattle testing? • Possible cattle exposure to BCG • False positive skin test results • False positive IFN-gamma test results

  19. Cattle (n=12): no conversion on skin test or Bovigam, all culture results negative Unvaccinated sentinel deer (n=10) BCG SC vaccinated deer (n=19)

  20. 13 vaccinated deer 9 in-contact deer 7 calves 27 weeks of indirect contact No residual BCG No evidence of transmission of BCG from Vaccinated deer to cattle Immunological evidence of deer to deer transmission of BCG

  21. White-tailed deer- US Possums- NZ Badgers- UK, Ireland Wild boar- Spain

  22. Testing a molasses-based bait for oral vaccination of white-tailed deer (Odocoileus virginianus) against Mycobacterium bovis- M. R. Stafne, BS, Iowa State University, College of Veterinary Medicine Physical stability Observations BCG Survivability

  23. Future • Bait • Alternative Baits • Vaccine Delivery Mechanism • More field testing (attraction, stability,non-targets) • Vaccine • Duration of immunity • Protection through secondary vaccination • Effect of high doses on protection • Red tape • USDA, Michigan DNR, Michigan Department of Agriculture Approval for BCG in deer • Environmental impact statement, etc.

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