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Development of an oral vaccine against tuberculosis for use in badgers ( Meles meles )

Development of an oral vaccine against tuberculosis for use in badgers ( Meles meles ). Dr Eamonn Gormley, UCD Dublin. Environment. Transmission of Mycobacterium bovis. Badgers in Rep of Ireland. ~ 100,000 badgers Tuberculosis is endemic Approx. 50% badgers with tuberculosis in

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Development of an oral vaccine against tuberculosis for use in badgers ( Meles meles )

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  1. Development of an oral vaccine against tuberculosis for use in badgers (Meles meles) Dr Eamonn Gormley, UCD Dublin

  2. Environment Transmission of Mycobacterium bovis

  3. Badgers in Rep of Ireland ~ 100,000 badgers Tuberculosis is endemic Approx. 50% badgers with tuberculosis in areas associated with chronic cattle TB Approx. 15% badgers with tuberculosis in Areas with no recent history of cattle TB Epidemiological link with infection in cattle Currently controlled by focal reactive culling

  4. Enhanced diagnosis of M. bovis infection in badgers With parallel interpretation of culture/histo, infection prevalence approx 50%

  5. Diagnostics 1998 - 2010 Pen studies 2002 - 2013 Registration 2015 - 2019 Applications 2012 - 2016 Vaccine Development Overview Field trial 2009 - 2013 Field Vaccine 2017

  6. Captive Badger BROC facility

  7. Badger vaccine studies • Developed immuno-diagnostics with AHVLA for Tb in badgers 2. Determined protective efficacy of BCG 3. Tested efficacy of oral BCG vaccine 4 Testing efficacy against natural M. bovis challenge in Field Trial 5 Evaluating AHVLA vaccine candidates for licensing of vaccine

  8. Oral vaccination: 108 cfu oral vaccine / 104M. bovis challenge 12 week vaccination, 14 week challenge

  9. Badger Vaccine Field Trial Principle Objectives Demonstrate BCG is protective in wild badgers under natural transmission conditions Estimate vaccine efficacy Secondary Objectives: Study post-infection vaccination Provide infrastructure for other research – e.g. population dynamics, badger behaviour Address policy / scientific interests

  10. Badger Vaccine Field Trial Structure: • Large area: 700 km² • Population: ≥ 300 badgers • Long term study – 3/4 years • TB prevalence ~ 30%

  11. Vaccine trial design • Area divided into 3 zones • 100%, 50% & 0% vaccination • 3 year duration • Vaccine/placebo blind coded

  12. Vaccine trial design • 2 sweeps per year • Re-vaccinate every 2nd sweep • Monitor population by serology • Case definition: M. bovis isolation Initial results in 2014

  13. Injectable vs oral vaccine Oral vaccine Needs to be licensed Dose never guaranteed Higher variability Injectable vaccine Available now! Defined delivery dose Expectations of protection of individual However: With optimal delivery, can target populations to achieve population immunity However: May be difficult to generate population immunity

  14. What we need to know? For successful vaccination we need fundamental information on badger population structure and epidemiology of Tb transmission

  15. M. bovis prevalence in badgers spatially clusters with reactor rate Chronic Tb Tb free Herds: Std breakdowns

  16. M bovis infection in wild badgers: Infection prevalence in social groups * All badgers captured at a main sett during the 11-day capturing period were deemed to belong to the same social group (Griffin et al 2005). *All badgers captured at a main sett during the 11-day capturing period were deemed to belong to the same social group (Griffin et al 2005).

  17. M bovis infection in wild badgers: Infection status and sex, age, class * The overall prevalence in females (n=77) was 35.1% and in males (n=55) was 54.5%.

  18. Who do we vaccinate? Individual badgers -Have some expectation of vaccine effect • Social groups • - Highest risk of transmission Regional - Targeting populations to achieve ‘herd’ immunity How do we vaccinate? - Develop efficient delivery system

  19. When (how often-) do we vaccinate? Regional - Need to maintain ‘herd’ immunity Individual badgers - duration of immunity When do we stop vaccination? If objective is to control the disease in badgers – no endpoint If objective is to eradicate the disease in badgers – finite endpoint

  20. Acknowledgements UCD Leigh Corner Denise Murphy Simon More- CVERA Lab staff CVRL Eamon Costello Lab staff AHVLA Mark Chambers Glyn Hewinson Sandrine Lesellier DAFM Margaret Good Anthony Duignan Michael Sheridan James O’Keefe Martin Blake Richard Healy

  21. Thank you Photo by: Ian O’Boyle

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