The Role of Vaccine for PRRS Control in Growing Pigs Iowa Pork Congress Educational Seminar January 23 rd, 2008

PRRSV in Growing Pigs: Economics Most current measures of PRRS control are targeted at breeding herds However; recent reports from NPB and ISU indicate that 88% of the costs associated with PRRS are incurred in growing pigs –PRRS adds $6.01 cost/pig in nursery phase –PRRS adds $ 7.67 cost/pig in finish phase Neumann E., et. al., JAVMA, 2005

PRRS in Pigs: Production Impact The National Pork Board estimates that PRRS adds between $5.60 and $7.60 to the cost of production per head sold. Impact of PRRS Virus in Grow/Finish ADG12% Decrease Feed Efficiency7.5% Decrease Percent Mortality166% Increase Source: Neuman, E.J.; Kliebenstein, J.B.; et.al.; Assessment of the economic impact of porcine reproductive and respiratory syndrome on swine production in the United States; JAVMA, Vol. 227, No. 3, August, 2005.

Key Questions Heterologous Cross-Protection (Efficacy) - Do current MLV vaccines offer cross- protection to current field strains of PRRS? What is optimal timing of vaccination for PRRS control in growing pigs?

Controlled Experimental Studies Halbur et. al. –Independent Research Study at ISU that evaluated Ingelvac® PRRS ATP against challenge with 3 current and highly virulent PRRS field isolates; (JSHAP, Sept-Oct 2005 ) Roof et. al. –Meta-analysis of 16 independent studies evaluating Ingelvac® PRRS MLV and ATP against heterologous challenge to PRRS field isolates; (5th Int. Symp. Emerging & Re-emerging Swine Diseases – 2007)

Meta-analysis conclusions: Vaccine offers consistent and repeatable protection against heterologous challenge in the respiratory model –Significant reduction of magnitude and duration of viremia –Significant reduction of clinical disease –Significant reduction of PRRS induced lung lesions; gross & microscopic –Significant improvement of production performance: ADG; etc. –Vaccination needs to least 4 wks prior to field virus exposure for optimum development of protective immunity

Controlled Experimental Studies Halbur et. al. –Independent Research Study at Iowa State University that evaluated Ingelvac® PRRS ATP against challenge with 3 current and highly virulent PRRS field isolates; (JSHAP, Sept-Oct 2005 )

Halbur Study Design NA 2.0 ml IMIngelvac PRRS ATP 38 NA None107 BIVI / 2.0 ml INNANone106 VR2385 (1-3-4) / 2.0 ml INNANone105 BIVI / 2.0ml INNANone104 BIVI / 2.0 ml IN2.0ml IM Ingelvac PRRS ATP 103 VR2385 (1-3-4) / 2.0 ml IN2.0ml IM Ingelvac PRRS ATP 102 BIVI / 2.0ml IN2.0ml IM Ingelvac PRRS ATP 101 Challenge/RouteDose/ Route TreatmentNGroup

Halbur Study: Improvement in ADG

Halbur Study: Reduction in Lung Lesions

PRRS Efficacy: Take Home Message Independent confirmation of vaccine efficacy at Iowa State University. –Improved ADG –Reduction of Lung Lesions –Reduction of Clinical Disease –Reduction of Post-challenge Viremia Trial conducted by Dr. Pat Halbur Trial used Ingelvac ATP Used 3 recent heterologous challenge isolates –Heterologous Protection Exists

PRRS in Pigs: Return on Investment

Conclusions When used properly, vaccine provides consistent and reproducible benefits (statistically) against heterologous isolates. –Timing is Key! –Vaccine needs to be given 4 weeks prior to field virus exposure for optimum protection!

Key Questions Heterologous Cross-Protection (Efficacy) - Do current MLV vaccines offer cross- protection to current field strains of PRRS? YES What is optimal timing of vaccination for PRRS control in growing pigs? 4 weeks prior to PRRS exposure

Efficacy of Vaccine: Do experiences in the field further confirm what we see in the Lab?

Field Experiences System Background: Large North American Commercial Swine System Breeding herds have mixed PRRS Status –PRRS negative/naïve –PRRS positive stable and unstable Weaned pigs sourced to nurseries based on PRRS status –3-site production flow management –PRRS positive (stable & unstable) flow to positive nurseries –PRRS negative flow to separate PRRS negative nurseries

PRRS Profile & Vaccination Criteria Breeding Herd NurseryGrow- Finish Vaccinate Growing Pigs for PRRS? Initiate a Sow Stabilization Program? Vaccination and other measures 1 - (not infected) __NO 2 - (not infected) _+YESNO 3 + (infected & stable) __NO Maintain Program 4 + (infected & stable) -/++YES Maintain Program 5 + (infected & unstable) ++NOYES

Intervention Vaccination w/ Ingelvac PRRS ATP implemented Feb/March 2005 to pigs at entry to PRRS positive nursery sites No PRRS vaccination used/needed at PRRS negative nursery sites

Results Compared to historical pre-vaccination performance, vaccination for entry to PRRS positive nurseries reduced mortality from >9% to <3% Vaccinated PRRS positive nursery sites performed equally to PRRS negative nursery sites

Vaccination of all Positive Nurseries Started in Feb/March of 2005 Data points represent Nursery close-out data Non-vax Vaccinated

Total # Out % Mortality In Wt.Out Wt.ADGFE PRRS Positive Vaccinated Nursery 331, % PRRS Negative Non-vaccinated Nursery 337, % Performance of PRRS Positive Vaccinated Nurseries vs. PRRS Negative Nurseries (2005 Annualized Data)

Take Home Message: Appropriate vaccination with a MLV PRRS vaccine prior to field virus exposure can dramatically reduce mortality and improve performance in nursery pigs Vaccinated pigs in PRRSv positive nurseries performed equally to pigs reared in PRRS negative nurseries

Implications Changes made in “negative” flows in 2006 to immunize for PRRS and M. hyo The largest finishing sites receive these pigs and PRRS exposure risks dictate need for vaccination –Allows for flexibility and functionality of nursery flow management –YTD nursery performance shows continued reduction in mortality & performance at target levels

Total # Out % MortalityADGFE PRRS Positive Vaccinated Nursery: , % PRRS Negative Non-vaccinated Nursery: , % Nursery Performance: All PRRS Vaccinated 513, % Performance of PRRS Positive Vaccinated Nurseries & PRRS Negative Nurseries in 2005 Performance of All Nurseries Vaccinated in 2006

Why Vaccine? The system was severely “broken”. –Some nurseries mortalities were over 15% The science was incontrovertible: In the growing pig model, the vaccine works! We knew there were other issues but believed that PRRS was the primary initiating co-factor. Desperate times call for desperate measures!

Lessons Learned First and foremost: There are no magic bullets! The solution to all problems is not entirely in a bottle or given via a needle! MLV PRRS vaccine has been a great tool but success was aided with a “systems approach”

Help Me to Help You! Mass Vaccination at weaning (immediately upon arrival at the nursery) All vaccines are given with a needle-free syringe (to reduce pig to pig transmission of field virus) Sow farms are monitored monthly for presence of PRRS virus circulation Initiate biosecurity measures with the goal of reducing transmission of PRRS virus

Biosecurity Improvements All pigs are moved via dedicated trucks from sow sites to transfer stations Needle free injectors for all piglet vaccines Biosecurity procedures formalized Mortality removal process Perimeter fencing/entry gating/signage All vehicles washed and “baked” Biosecurity Pyramid Attention to detail PRRS Risk Assessments

Aggressive Preventative Approach: PRRS ATP (PRRS modified live) HP One (H. parasuis bacterin) M.Hyo (Mycoplasma hyopneumoniae vaccine) Lawsonia intracellularis (ileitis vaccine) Ery ALC (Erysipelas)

Barriers/Hurdles to Success Multi-sourced nurseries Unstable sow farm sources blended with pigs from naïve/stable flows PRRS vaccine could not be administered until pigs were weaned and delivered to the nurseries Multiple PRRS strains existed in the system Wean age

Field Experience Conclusions Nursery mortality was out of control PRRS virus leaks were common and unpredictable PRRS ATP vaccination (among other things) resulted in immediate reduction of mortality Needle-less technology allowed the use of the vaccine in multi-sourced nurseries at weaning Vaccination gave the confidence to combine all the flows

Thank-you for your attention! Any Questions?