Mycoplasmal pneumonia in Swine by uer60003

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									                             ABCD

Mycoplasmal pneumonia in
Swine
Immunologic Considerations
Mycoplasmal pneumonia                 ABCD

•Chronic infection of ciliated epithelium

•Increased cost
   • Interventions, fixed cost

•Reduce revenue
   • Reduced growth rate (# sold)
   • Cull/substandard pigs (price penalty)
   • Mortality

                                             2
The “customer”   ABCD




                        3
What is “success”?         ABCD

• Final customer„the pig
  • Welfare & well being

• Producer
  • Biology  financial




                                  4
Maes, et al                             ABCD

• Typical economic impact

•  ADG,  Cull

•  Mortality

• FE



                            Vaccine, 1999
                                               5
Study designs                           ABCD

• Random, blinded evaluations
  • block by source, sex, weight, etc

• Four weeks from vaccination to challenge

• Four week monitoring period




                                               6
Immunity                                         ABCD

• Passive Immunity
  • Protects from challenge
  • May interact with active immunization

• Active Immunity
  • Level/duration of protection




                 Thacker,et al 2000; BIVI 2000
                                                        7
Cellular Immunity                           ABCD

• Dr. E Thacker
  • Various levels of cellular immune
    response

 • Sensitized via vaccination

 • All vaccines protected lungs




                     Swine Health & Production
                                                   8
CMI Relationship                    ABCD

• CMI = Cell mediated immunity

• Peripheral lymphocytes

• Association with growth rate?
  • Higher CMI level at challenge
  • Higher ADG




                                           9
Clinical study                            ABCD

• Higher CMI responses associated with
  • Higher Average Daily Gain

 • Reduced Lung lesions

• Replication of results




                            Roof, AASV 2001
                                                 10
Combination control                   ABCD

• Application of vaccines & therapeutics

• “Complimentary” strategies?

• Sources of active immunity
  • Immunization
  • Field organism exposure




                                             11
Natural exposure                         ABCD

• Slow onset in continuous production
  systems
  • Low level introduction/late spread

• Aerosol spread & dose

• Alone or complicated disease




                                                12
Linkage                                 ABCD

• Several methods to develop immunity

• Prior to vaccines„
  • Strategic medications one week per month

• Study case




                                               13
Prophylaxis &                         ABCD
Metaphylaxis
• Established clinical disease

• “Peri” outbreak
  • Little or no overt clinical disease
  • Exposure has occurred
  • “Incubation” period




                                             14
Metaphylaxis                                ABCD

• Metaphylaxis: e.g. Strategic-Dosing

• natural exposure allows infection and incubation
  immediately prior to short-term medication to
  shut down the incubation process prior to
  expression of disease and associated negative
  biologic and economic consequences

• Exposure may aid development of protective long-
  term active immunity against endemic diseases




                                                     15
Metaphylaxis                            ABCD

• Limited duration of therapeutic
  medication:

• Advantages
  • limits cost
  • organism/antibiotic exposure time
  • development of resistance




                                               16
Potential for
Metaphylactic                          ABCD
Strategic-Dosing
• Inability to exclude infection
  • Disease outbreaks later in production
    • SEW/18-week wall, etc
    • Lawsonia/PPE

• Vaccines not available or only partially
  effective
  • APP
  • Streptococcus
  • Compliance failure
                                              17
Potential                             ABCD

• Change in epidemiology
  • Timing of vaccination prior to exposure
  • Newly diagnosed disease

• Multiple disease challenges require broad
  spectrum intervention tool




                                              18
Case study                            ABCD

• Commercial 3-site production system in
  Midwest
• Consistent history of decreased
  performance 8-12 weeks post-placement in
  finisher (18-22 weeks of age)
    • ADG
    • F/G
    • ADFI
• Inconsistent diagnostic findings


                                             19
Design                                      ABCD

 • 2 animals per pen were serially bled
   every two weeks
 • Serology was initially performed on
   placement and closeout samples to screen
   for M. hyo, PRRS, SIV, TGE, Salmonella
   and Lawsonia activity
 • Additional serology was performed on bi-
   weekly samples for pathogens shown to be
   active in finishing based on screening
   serology


                  Swine Health & Production, 2000
                                                    20
Therapeutic options                   ABCD
• Treatment 1: Denagard +Aureomycin pulsed
  5 times (2, 4, 7, 10, and 13 weeks post-
  placement) and Aureomycin 100g/t given
  weeks 3, 5, 6, 8, 9, 11, and 12
  [“Continuous”]
• Treatment 2: Denagard(35 g/t) +
  Aureomycin(10 mg/lb BW) pulsed 5 times
  (2, 4, 7, 10, and 13 weeks post-
  placement) [“Pulse”]
• Treatment 3: Non-medicated Controls



                                             21
Outcomes                              ABCD

• Consistently observed performance  did
  not occur during any 2-week interval
• Perhaps because 2/3 of the animals in the
  barn/airspace were on systemic
  antibiotics which  infection pressure
• However both med strategies significantly
  improved overall survivability and
  performance




                                              22
              Impact on Mycoplasma                                   ABCD

                                     MYCOPLASMA serology


               0.5                                                   Continuous Med Mhyo


              0.45
                                                                     Pulse Med Mhyo

               0.4
                                                                     Control Mhyo

              0.35


               0.3
Tween 20 OD




              0.25


               0.2


              0.15


               0.1


              0.05


                0
                     0   2   4   6       8     10    12    14   16
                                       Week



                                                                                      23
Immunology                               ABCD

• Both strategic and continuous medication
  strategies significantly improved ADFI,
  ADG, F/G and survivability while being
  cost-effective
• There were no significant performance
  differences between strategic and
  continuous medication strategies
• Strategic medication permitted natural
  Mycoplasma exposure and immune response
  (seroconversion) as w/ NMC’s while
  improving/protecting growth performance


                                                24
Implications                          ABCD

• Therapeutic use of medications or
  biologics

• Goals of model
  • Growth
  • Lungs
    • Defined vs. natural exposure
  • Immunity



                                             25
End consumers                         ABCD

• The pig
  • Reduced clinical disease
  • Maintenance of therapeutic application &
    use
  • Welfare

• Consumer
  • Reduced medication use
    • Residue, resistance
  • More efficient resource use
                                               26
Summary thoughts                         ABCD

• Immunologic advantages in Mycoplasma
  control
  • Single point application
  • Defined investment
  • Limited residue/resistance

• Limitations
  • Incomplete control...



                                                27
Combined approaches                    ABCD

• May enhance control of Mycoplasmal disease

 • Improved total respiratory health

 • “Enhance” active immunity

 • Limit biologic consequences of exposure




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