The Role of Vaccine for PRRS Control in Growing Pigs
Iowa Pork Congress
Educational Seminar
January 23rd, 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 thecost of production perhead sold.
Impact of PRRS Virus in Grow/Finish
ADG 12% Decrease
Feed Efficiency 7.5% Decrease
Percent Mortality 166% 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 occur @ 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
NA2.0 ml IMIngelvac PRRS ATP38
NANANone107
BIVI 1-8-4 / 2.0 ml INNANone106
VR2385 (1-3-4) / 2.0 ml INNANone105
BIVI 1-4-4 / 2.0ml INNANone104
BIVI 1-8-4 / 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 1-4-4 / 2.0ml IN2.0ml IM
Ingelvac PRRS ATP
101
Challenge/RouteDose/ Route
TreatmentN Group
Halbur Study:Improvement in ADG
1.73
1.281.41
0.69
1.12
0.65
1.42
0.87
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
ATP2385ch
NONVX2385ch
ATP144ch
NONVX144ch
ATP184ch
NONVX184ch
ATPallch
NONVXallch
p<0.05
p<0.01p<0.01
p<0.01
Halbur Study: Reduction in Lung Lesions
8.4
18.4
4.2
41.6
3.6
49.2
5.4
36.4
0
10
20
30
40
50
60
ATP2385ch
NONVX2385ch
ATP144ch
NONVX144ch
ATP184ch
NONVX184ch
ATP allch NONVXallch
p<0.01 p<0.01p<0.01
p<0.05
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?
YESWhat 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
BreedingHerd
Nursery Grow-Finish
VaccinateGrowing Pigs
for PRRS?
Initiate a SowStabilization
Program?Vaccination and other measures
1 -(not infected)
_ _ NO NO
2 -(not infected)
_ + YES NO
3 +(infected & stable)
_ _ NO MaintainProgram
4 +(infected & stable)
-/+ + YES MaintainProgram
5 +(infected & unstable)
+ + NO YES
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 PRRS @ entry to PRRS positive nurseries reduced mortality from >9% to <3%
• Vaccinated PRRS positive nursery sites performed equally to PRRS negative nursery sites
Impact of PRRS Vaccination in PRRS Positive Nurseries% Mortality
Individ.: cl: 2.53941 ucl: 6.04506 lcl: -.96624 * Rule violationRange: cl: 1.31813 ucl: 4.30669 lcl: 0 Subgrp Size 1
OO
O
O
O
O
OO
OO
O OO
O
OO O O
OO O
OO
O
OO
Individ.
cllil
uil
lwl
uwl
lcl
ucl
0
5
10
15
O
O
O
O
O
O
OO
O
O
O
O
O O OO
O O OO
O
O O O
O
O
Range
cl
lil
uil
lwl
uwl
lcl
ucl
0
2
4
6
8
DAY:MONTH:YEAR:
7105
11205
18205
3305
12305
27305
28305
1405
13505
27505
4605
22605
10705
20705
22705
10805
25805
2905
13905
28905
131005
261005
21105
21105
251105
271205
301205
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. ADG FE
PRRS PositiveVaccinated Nursery
331,462 2.65% 13.73 54.94 0.89 1.56
PRRS NegativeNon-vaccinated Nursery
337,810 3.04% 13.61 54.01 0.88 1.62
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
% Mortality ADG FE
PRRS PositiveVaccinated Nursery: 2005
331,462 2.65% 0.89 1.56
PRRS NegativeNon-vaccinated Nursery: 2005
337,810 3.04% 0.88 1.62
2006 Nursery Performance: All PRRS Vaccinated
513,797 1.92% 0.86 1.67
•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?