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Mycoplasmal pneumonia in Swine. Immunologic Considerations. Mycoplasmal pneumonia. Chronic infection of ciliated epithelium Increased cost Interventions, fixed cost Reduce revenue Reduced growth rate (# sold) Cull/substandard pigs (price penalty) Mortality. The “customer”.

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mycoplasmal pneumonia in swine

Mycoplasmal pneumonia in Swine

Immunologic Considerations

mycoplasmal pneumonia
Mycoplasmal pneumonia
  • Chronic infection of ciliated epithelium
  • Increased cost
    • Interventions, fixed cost
  • Reduce revenue
    • Reduced growth rate (# sold)
    • Cull/substandard pigs (price penalty)
    • Mortality
what is success
What is “success”?
  • Final customer…the pig
    • Welfare & well being
  • Producer
    • Biology  financial
maes et al
Maes, et al
  • Typical economic impact
  •  ADG,  Cull
  •  Mortality
  • FE

Vaccine, 1999

study designs
Study designs
  • Random, blinded evaluations
    • block by source, sex, weight, etc
  • Four weeks from vaccination to challenge
  • Four week monitoring period
immunity
Immunity
  • Passive Immunity
    • Protects from challenge
    • May interact with active immunization
  • Active Immunity
    • Level/duration of protection
  • Thacker,et al 2000; BIVI 2000
cellular immunity
Cellular Immunity
  • Dr. E Thacker
    • Various levels of cellular immune response
    • Sensitized via vaccination
    • All vaccines protected lungs

Swine Health & Production

cmi relationship
CMI Relationship
  • CMI = Cell mediated immunity
  • Peripheral lymphocytes
  • Association with growth rate?
    • Higher CMI level at challenge
    • Higher ADG
clinical study
Clinical study
  • Higher CMI responses associated with
    • Higher Average Daily Gain
    • Reduced Lung lesions
  • Replication of results

Roof, AASV 2001

combination control
Combination control
  • Application of vaccines & therapeutics
  • “Complimentary” strategies?
  • Sources of active immunity
    • Immunization
    • Field organism exposure
natural exposure
Natural exposure
  • Slow onset in continuous production systems
    • Low level introduction/late spread
  • Aerosol spread & dose
  • Alone or complicated disease
linkage
Linkage
  • Several methods to develop immunity
  • Prior to vaccines…
    • Strategic medications one week per month
  • Study case
prophylaxis metaphylaxis
Prophylaxis & Metaphylaxis
  • Established clinical disease
  • “Peri” outbreak
    • Little or no overt clinical disease
    • Exposure has occurred
    • “Incubation” period
metaphylaxis
Metaphylaxis
  • Metaphylaxis: e.g. Strategic-Dosing
  • natural exposure allows infection and incubation immediately prior to short-termmedicationto shut down the incubation process prior to expression of disease and associated negative biologic and economic consequences
  • Exposure may aid development of protective long-termactive immunity against endemic diseases
metaphylaxis1
Metaphylaxis
  • Limited duration of therapeutic medication:
  • Advantages
    • limits cost
    • organism/antibiotic exposure time
    • development of resistance
potential for metaphylactic strategic dosing
Potential for Metaphylactic 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
potential
Potential
  • Change in epidemiology
    • Timing of vaccination prior to exposure
    • Newly diagnosed disease
  • Multiple disease challenges require broad spectrum intervention tool
case study
Case study
  • 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
design
Design
  • 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

therapeutic options
Therapeutic options
  • 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
outcomes
Outcomes
  • 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
immunology
Immunology
  • 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
implications
Implications
  • Therapeutic use of medications or biologics
  • Goals of model
    • Growth
    • Lungs
      • Defined vs. natural exposure
    • Immunity
end consumers
End consumers
  • The pig
    • Reduced clinical disease
    • Maintenance of therapeutic application & use
    • Welfare
  • Consumer
    • Reduced medication use
      • Residue, resistance
    • More efficient resource use
summary thoughts
Summary thoughts
  • Immunologic advantages in Mycoplasma control
    • Single point application
    • Defined investment
    • Limited residue/resistance
  • Limitations
    • Incomplete control...
combined approaches
Combined approaches
  • May enhance control of Mycoplasmal disease
    • Improved total respiratory health
    • “Enhance” active immunity
    • Limit biologic consequences of exposure