Why Are We Not Making More Progress to Decrease PRRS Incidence? - Dr. Clayton Johnson, Director of Health at Carthage Veterinary Service, from the 2017 Allen D. Leman Swine Conference, September 16-19, 2017, St. Paul, Minnesota, USA. More presentations at http://www.swinecast.com/2017-leman-swine-conference-material

1. Why are we not making more progress
to decrease PRRS incidence?
Clayton Johnson
Director of Health
Carthage System
2017 Leman Conference

2. Dr. Bob Morrison’s Legacy
• Collaboration
• Practical Problem Solver
• Mathematical Models
• Actionable Feedback
• Producer Focused
2

3. Evolving Industry PRRSv Infection Status
3

4. Evolving Industry PRRSv Incidence
4

5. Potential Causes
1. We Can’t Prevent PRRSv Infections
2. Tools and Technologies for PRRSv Infection
Management are Improving
3. PRRSv Prevention Strategies Aren’t Cost
Effective
5

6. Preventing PRRSv Introduction
• Biosecurity
– Exclusion
– Segregation
– Hygiene/Sanitation
• Critical Control Points
– Employee Entry
– Supply Entry
– Animal Entry
– Wean/Cull Exit
– Mortality Exit
– Visitor Entry
– Feed/Water Entry
– Air Filtration
6

7. Biosecurity Defined
• A System of Barriers that Enhance the
Economic Output of Independent Production
Units by Reducing the Risk of Novel Pathogen
Introduction1
• Insurance Analogy
71Definition Courtesy of Dr. Jim Lowe

8. Why Aren’t we Preventing PRRSv
Introduction?
• Biosecurity
– Exclusion
– Segregation
– Hygiene/Sanitation
• Critical Control Points
– Employee Entry
– Supply Entry
– Animal Entry
– Wean/Cull Exit
– Mortality Exit
– Visitor Entry
– Feed/Water Entry
– Air Filtration
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9. Why Aren’t we Preventing PRRSv
Introduction?
• Biosecurity
– Exclusion
– Segregation
– Hygiene/Sanitation
• Critical Control Points
– Employee Entry
– Supply Entry
– Animal Entry
– Wean/Cull Exit
– Mortality Exit
– Visitor Entry
– Feed/Water Entry
– Air Filtration
9
2006
2003
1990
1990
2005
1990
2004
2001

10. Biosecurity Background - Compliance with
Hand Hygiene Procedures in Hospitals
Year Setting
Average
compliance Author Reference
1981
Open ward 16%
Preston 11
ICU 30%
1981
ICUs 41%
Albert 5
ICUs 28%
1983 All wards 45% Larson 12
1987 PICU 30% Donowitz 13
1990 ICU 32% Graham 6
1990 ICU 81% Dubbert 14
1991 SICU 51% Pettinger 15
1992 NICU/others 29% Larson 16
1992 ICUs 40% Doebbeling 7
1992 ICUs 40% Zimakoff 17
1994 Emergency room 32% Meengs 18
1999
All wards 48%
Pittet 9
ICUs 36%
ICUs = intensive care units; PICU = pediatric ICU; NICU = neonatal ICU.
Pittet, Emerging Infectious Disease, Vol. 7, No. 2,Mar–Apr 2001

11. Biosecurity Background - Compliance with
Hand Hygiene Procedures in Hospitals
Year Setting
Average
compliance Author Reference
1981
Open ward 16%
Preston 11
ICU 30%
1981
ICUs 41%
Albert 5
ICUs 28%
1983 All wards 45% Larson 12
1987 PICU 30% Donowitz 13
1990 ICU 32% Graham 6
1990 ICU 81% Dubbert 14
1991 SICU 51% Pettinger 15
1992 NICU/others 29% Larson 16
1992 ICUs 40% Doebbeling 7
1992 ICUs 40% Zimakoff 17
1994 Emergency room 32% Meengs 18
1999
All wards 48%
Pittet 9
ICUs 36%
ICUs = intensive care units; PICU = pediatric ICU; NICU = neonatal ICU.
Pittet, Emerging Infectious Disease, Vol. 7, No. 2,Mar–Apr 2001

12. • Biosecurity is a Risk Management Continuum
• The value of the farm at risk should define the
biosecurity investment
Biosecurity Goal =
Absolute Disease Prevention
Biosecurity Goal =
No Disease Prevention
Stud FTM
FTM –
Marketing
FTM –
Not Marketing
Sourcing
Commercial
Sourcing
Multiplication
Biosecurity for Individual Farms

13. • Farms should add consistent levels of
investment to optimize risk management
– Example - Wean pig pickups
Sow
Farm
Sow
Farm
Sow
Farm
Sow
Farm
Sow
Farm
Sow
Farm
Sow
Farm
Transfer Station
Maintenance Truck/Tools
Biosecurity for Individual Farms

14. Potential Root Cause #1:
We Can’t Prevent PRRSv Introduction
• Not the Root Cause – We have the tools to
prevent PRRSv introduction
• Individual tools cannot be haphazardly
implemented – Must be a System Approach
• The tools are Expensive
• Older Farms not designed with all tools
• Compliance with tool usage will never be
100%
14

15. Improving PRRSv Management Strategies
• PRRS MLV Vaccination/Acclimation
15
No
Immunity
Prior
Immunity
Weaned Pig Value $40 $40
Lost Weaned Pigs 3575 645
Value Lost $143,000 $25,800
Linhares et al, 2014

16. Improving PRRSv Management Strategies
• “Regarding herd closure, 58 of the 61 herds
were not closed to gilt entries until stability
was achieved…
• And time from 1-7-4 detection to gilt
introduction was not correlated with Time to
Stability”
– Betlach et al, 2016 SHMP

17. Improving PRRSv Management Strategies
• More sensitive diagnostic samples allow
better timing of herd closure & “MCREBEL”
– Decreased cost to the producer
17
Photo Courtesy of Marcelo AlmeidaPhoto Courtesy of Will Lopez

18. Improving PRRSv Management Strategies
• MLV Vaccination of Growing Pigs
– Tremendous Data Sets to Support Efficacy
– Significant reduction in lung lesions
– Significant reduction in fever days
– Decreased shedding of Wild Type PRRSv
• Frequency
• Duration
18

19. Improving PRRSv Management Strategies
• Macrolide Antibiotics
– Tilmicosin Administered at 10 mg/kg bodyweight
for 14 days during LVI
– Dramatic Reduction in Sow Mortality and
Abortions in Treatment Group
– $61.73/Sow Impact
– $13.84/Sow Cost
19

20. • Killed Vaccines
• Nanoparticle Adjuvant Technologies
• DNA Vaccines
• PRRSv Resistant Genotypes
20
Improving PRRSv Management Strategies

21. Potential Root Cause #2: Tools and Technologies for
PRRSv Infection Management are Improving
• Our Tools and Technologies are Improving
• Producers and Veterinarians and Continually
Improving Tool and Technology Implementation
– New Tools are Available
– New Tools are in the Pipeline
– Research Efforts have defined Tool Value Proposition
– Diagnostics allow for Precision Ag Approach
21

22. Understanding the Biosecurity
Improvement Value Proposition
• Put Yourself in the Producers Shoes:
– Understand the PRRS Biosecurity Opportunity
– Appreciate PRRS Cost
– Have Tremendously Diverse Capital Options
– Thorough Economic Evaluation is Appropriate
22

23. Economic Model to Evaluate Impact of
Decreasing PRRSv Incidence
• Cost of Disease (Includes WTF Impact):
– Antibody Positive: $218.16/Sow1
– Antibody Negative: $340.21/Sow1
• Cost of Intervention (Air Filtration):
– Low Cost: $150/Sow
– High Cost: $300/Sow
• Maintenance Cost of Intervention:
– Low Cost: $15/Sow
– High Cost: $20/Sow
23
1Linhares DCL, Johnson C, Morrison RB (2015) Economic
Analysis of Vaccination Strategies for PRRS Control. PLoS ONE
10(12): e0144265. https://doi.org/10.1371/journal.pone.0144265

24. Economic Model to Evaluate Impact of
Decreasing PRRSv Incidence
24
Variable Assumptions:
Intervention Cost - High ($300) Fixed Assumptions: Per sow for 10 years
Intervention Cost - Low ($150) 2 10 Yr V Bank Replacements/Mated $ 100.00 $25,000 for 3000 prefilters
Maintenance Cost - High ($20) 24 10 Yr Pre-Filter Replacements/Mated $ 3.84 $0.032/sow/month electricity
Maintenance Cost - Low ($15) $ 4.00 Cost/Pre-Filter $ 100.00 V-Bank Replacements (every 4 years)
Outbreak Cost - Ab Pos $218 $ 90.00 Cost/V-Bank
Outbreak Cost - Ab Neg $340
Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10
High-High
Intervention Cost ($300)
Maintenance Cost ($20) ($20) ($20) ($20) ($20) ($20) ($20) ($20) ($20) ($20)
Net Cost ($320) ($340) ($360) ($380) ($400) ($420) ($440) ($460) ($480) ($500) -2.29 -1.47
-4.3632 -6.8042
Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10
High-Low
Intervention Cost ($300)
Maintenance Cost ($15) ($15) ($15) ($15) ($15) ($15) ($15) ($15) ($15) ($15)
Net Cost ($315) ($330) ($345) ($360) ($375) ($390) ($405) ($420) ($435) ($450) -2.06 -1.32
-4.848 -7.56022
Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10
Low-High
Intervention Cost ($150)
Maintenance Cost ($20) ($20) ($20) ($20) ($20) ($20) ($20) ($20) ($20) ($20)
Net Cost ($170) ($190) ($210) ($230) ($250) ($270) ($290) ($310) ($330) ($350) -1.60 -1.03
-6.23314 -9.72029
Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10
Low-Low
Intervention Cost ($150)
Maintenance Cost ($15) ($15) ($15) ($15) ($15) ($15) ($15) ($15) ($15) ($15)
Net Cost ($165) ($180) ($195) ($210) ($225) ($240) ($255) ($270) ($285) ($300) -1.38 -0.88
-7.272 -11.3403

25. Economic Model to Evaluate Impact of
Decreasing PRRSv Incidence
• 10 Year Intervention Costs:
– High/High: $500/Sow
– High/Low: $450/Sow
– Low/High: $350/Sow
– Low/Low: $300/Sow
• Outbreak Prevention Breakeven:
– High/High: 4.4-6.8 Years
– High/Low: 4.8-7.6 Years
– Low/High: 6.2-9.7 Years
– Low/Low: 7.3-11.3 Years
25

26. Potential Root Cause #3:
PRRSv Prevention Strategies Aren’t Cost Effective
• This is True for Some Farms
– Farm Outbreak Frequency
– Cost of PRRSv Biosecurity Improvements
• Producers Have Tremendous Capital Options
– Expansion
– Packer Ownership
– Diversified Investments
• Even if Cost Effective, Capital isn’t Always Available
26

27. Take Homes
1. System Biosecurity Improvements will Decrease PRRS
Incidence
– Partial Improvement may not Impact Outbreak Rate
– Compliance Remains Critical – Training & Auditing
2. PRRS Management Tools are Improving
– New Technology & Tools
– Better Understanding of Old Technology & Tools
– Better Diagnostics Allow Precision Implementation
3. Biosecurity is Not Always Cost Effective for Producers
– Cost of Biosecurity Improvements – New Outbreak Rate
– Impact of PRRSv Outbreak – Herd Cost x Outbreak Rate
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28. 28
Thank You!
johnson@hogvet.com