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A multi-disciplinary research project on PMWS (2008-2012): Aetiology, pathogenesis and immunology of porcine post-weaning multi-systemic wasting syndrome:

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Presentation on theme: "A multi-disciplinary research project on PMWS (2008-2012): Aetiology, pathogenesis and immunology of porcine post-weaning multi-systemic wasting syndrome:"— Presentation transcript:

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2 A multi-disciplinary research project on PMWS ( ): Aetiology, pathogenesis and immunology of porcine post-weaning multi-systemic wasting syndrome: genetic-environmental interactions Presented by Dr. med. vet. Barbara Wieland, PhD Royal Veterinary College

3 Background Epidemiology of PMWS has changed over the years (epidemic vs endemic) Change in affected age groups reported It is still unclear what triggers the onset of typical clinical signs Porcine circovirus 2 (PCV2): necessary agent Multi-factorial disease (environment, genetics, co-infections)

4 Project aims 1.Epidemiology Establish risk factors affecting severity of PMWS on farms 1.Epidemiology Establish risk factors affecting severity of PMWS on farms 2. Immunology Determine the cellular immune response to the putative microbial pathogens in vitro 2. Immunology Determine the cellular immune response to the putative microbial pathogens in vitro 3. Disease model Establish an in vivo model of PMWS to investigate role of environment 3. Disease model Establish an in vivo model of PMWS to investigate role of environment Our hypothesis is that PMWS occurs when the immune function is depressed in pigs with a specific genetic background following infection with PCV2 and i)conjoint infection with a second microbial pathogen, and/or ii)exposure to one or more environmental stressors, which may be either physical or social in nature

5 1c. Epi model: Economic importance for pig industry Cost/benefit of control & preventive measures 1c. Epi model: Economic importance for pig industry Cost/benefit of control & preventive measures 1b. Longitudinal Study: Economic losses over time Recovery factors 1b. Longitudinal Study: Economic losses over time Recovery factors year year year year year Retrospective Analysis- Retrospective Analysis- 1a. Cross-sectional study D. Pfeiffer, B. Wieland, K.Staerk + BPEX 1a. Cross-sectional study D. Pfeiffer, B. Wieland, K.Staerk + BPEX Risk factors Herd management Environmental & social stressors Presence of other pathogens Reproduction (Genetics) 3. Disease model M. Nevel, C. Wathes, T. Demmers +VLA Establish disease model Environmental stressors PCV-2 x Environment interaction PCV-2 + Co-infection with other pathogens x Environment interaction 3. Disease model M. Nevel, C. Wathes, T. Demmers +VLA Establish disease model Environmental stressors PCV-2 x Environment interaction PCV-2 + Co-infection with other pathogens x Environment interaction 2. Immunology D. Werling + Pfizer, Ark Genomics, IAH (Compton & Pirbright) a. Signalling pathways Effect of PCV-2 infection b. Secondary Infection c. Importance of host genetics 2. Immunology D. Werling + Pfizer, Ark Genomics, IAH (Compton & Pirbright) a. Signalling pathways Effect of PCV-2 infection b. Secondary Infection c. Importance of host genetics Knowledge Transfer & Data sharing Pig industry: BPEX Pfizer Knowledge Transfer & Data sharing Pig industry: BPEX Pfizer Timeline of the project and interactions between the different parts

6 Objectives of Part 1, Epidemiology Understand the impact of potential risk factors, and combinations of these, on the severity level of PMWS observed in English farms Provide base-line data on the current endemic situation to assess the efficacy of PCV-2 vaccines Develop epidemiological and economic models to identify appropriate and cost-efficient control strategies

7 Economic models Investigation of risk factors affecting severity of PMWS observed on farms: outline of studies carried out Cross-sectional study ( ) 149 farms across England Definition of PMWS severity Severity category 1 Severity category 2 Severity category 3 Non- vaccinating Follow-up visits on 50 farms (June 2009-January 2010) Follow-up visits on 50 farms (June 2009-January 2010) approx 12. farms approx. 12 farms

8 Cross-sectional study: 149 farm visits carried out 3182 pigs sampled before PCV2 vaccination Representing sows (17% of pig herd) Locations of all farms included in the study, overlaid on a map of total pig numbers throughout England, aggregated into 10km squares (pig density data taken from the 2004 UK agricultural census).

9 Questionnaire Farm assessment Farm visit General information Productivity over time Environment Management Reproduction PMWS over time Health status Animal Welfare Environment PMWS present (incl. post mortem) Blood samples Age groups: Sows Weaners Growers Finisher s PCV-2 Elisa PCV-2 PCR PPV PRRS EP APP 20 samples

10 Severity of PMWS observed by producers in different age groups from 2001 to 2008

11 Mortality: Records In age groups Mortality: Records In age groups Morbidity: % in age groups Qualitative and quantitative over time Morbidity: % in age groups Qualitative and quantitative over time Productivity: FCR age at slaughter data Productivity: FCR age at slaughter data Risk factorsPMWS severity Correlated data explore using factor analysis:basis to define PMWS severity at herd level Test for associated with PMWS severity Pathogens PRRS, PPV, EP, APP, Salmonella Pathogens PRRS, PPV, EP, APP, Salmonella Health Other diseases, medication, vaccination Health Other diseases, medication, vaccination Reproduction AI, replacements parity of sows Reproduction AI, replacements parity of sows Genetics % of different breeds Supplier, parent generation Genetics % of different breeds Supplier, parent generation Environment housing, ventilation, light farm type Environment housing, ventilation, light farm type Social stressors Stocking density, batch system, cross-fostering Social stressors Stocking density, batch system, cross-fostering PCV-2 prevalence: PCR Data collected

12 Laboratory results: Herd level Includes results of 147 farms PCV-2 Ab negative farms were PCR positive Test + farms% PCV-2 Elisa (Synbiotics Serelisa®) PCV-2 qPCR APP (Swinecheck APP 3, 6 & 8 ) EP (Biobest in-house test) PPV (Svanova ELISA) PRRS (Biobest in-house test)6644.9

13 Objectives of Part 2, Immunology The objectives are : Assess differences in cell type-specific signalling pathways perturbed by PCV2 infection Analyse secondary responses of PCV2-infected cells isolated from different tissues; and Investigate whether differences in PCV2/PMWS susceptibility are based on a genetic link attributable to a specific signalling pathway.

14 Objectives of Part 3, Disease model The aim is to develop an in vivo disease model of PMWS to investigate the aetiology and pathogenesis of PMWS under controlled environmental conditions. The objectives are: to measure environmental effects on the aetiology and pathogenesis of PMWS; to determine whether infection, immune and production responses to combined physical and social stressors in PMWS are additive or multiplicative; and to quantify performance effects of PMWS, thereby informing the economic model developed in Part 1

15 Pablo Alarcon Martina Velasova Barbara Wieland Mandy Nevel Dirk Pfeiffer Katharina Staerk Christopher Wathes Bettina Schmidt Dirk Werling


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