PRRS Field Applicable Research Update - Dr. Daniel Linhares, Iowa State University,, from the 2017 North American PRRS/National Swine Improvement Federation Joint Meeting, December 1‐3, 2017, Chicago, Illinois, USA. More presentations at http://www.swinecast.com/2017-north-american-prrs-nsif-joint-meeting

1. Monitoring and measuring
PRRS impact: ISU update
Cesar Moura, Giovani Trevisan, Gustavo Silva, Marcelo Almeida, Swami
Jarayaman, Will Lopez, Jeff Zimmerman, Derald Holtkamp, Daniel Linhares
BIVI Symposium @ North American PRRS Symposium. Chicago, 12/3/2017

3. Agenda
PRRS detection in breeding herds
 Processing fluids (great screening method)
 Family oral fluids (assessing due to wean status)
 Automated SPC (early signals / supplement Dx)
PRRS detection in growing pigs
 How many ropes do I need?
Update on the cost of PRRS in the US
SHIC Rapid Response Corps
SHIC Swine disease reporting system (VDL data)
Pipeline @ ISU VDPAM

4. Detecting PRRS:
• MOSS (monitoring and surveillance system) protocols are not
perfect. Important concepts:
• Time to detect outbreak
• Limit of PRRS detection at population level
• False alarm rate
• Optimum MOSS:
• Fast, practical, affordable, effective

5. Swine industry increasingly using population-based
samples for disease monitoring
Individual pig sampling
Serum, blood swab, tonsil scraping
Population-based sampling
Oral fluids, processing fluids
More practical, cheaper,
↑ herd sensitivity

6. Few assumptions that the Industry has made
for disease monitoring
30 DTW sera, 3 consecutive months = poor sensitivity
60 DTW sera, 3 consecutive months = poor sensitivity
90 DTW sera, 3 consecutive months = poor sensitivity
 Due-to-wean (DTW) pigs = breeding herd status
 PRRSv dies out after 90 days < 10% prevalence in DTW
 PRRSv is randomly distributed in the barn
How about individual sows shedding virus for longer time?
Field data: this does not always happen
PRRS is actually clustered, specially when at low prevalence

7. How to improve PRRS
monitoring (↑ pigs, ↑ frequent) in a
practical, affordable and
reliable way?

8. Processing fluids
“Aggregate sample of fluids composed by the
serosanguineous drainage from the tissues removed off
the piglets at the time of castration and tail docking.”
- Will A. Lopez
• Lopez et al., JSHAP 2018 [in press]
• Lopez et al., Proc 2017 James D. McKean Swine Disease Conference. Ames, IA. p 65.
• Lopez et al., Proc 2017 James D. McKean Swine Disease Conference. Ames, IA. p 69.
• Lopez et al., National Hog Farmer. Nov 06, 2017.
• Lopez et al., Pig 333 website. Dec, 2017
• Lopez et al., 2018 AASV meeting, Research Topics.
• Lopez et al. 2018 AASV meeting. Monitoring and Surveillance Systems workshop.

9. Processing fluids studies:
• Sensitivity of PRRS PCR in PF’s
• Comparison of PRRSv RNA detection rate in PF’s vs. serum
• Longitudinal sampling of farms undergoing PRRS elimination
BIG thanks to:
 Drs. Jose Angulo, Eva Jablonski, NPB swine health committee
 Drs. Clayton Johnson, Paul Yeske, Grant Allison, Tom Gillespie, Deb Murray,
Rebecca Robins, Ian Levis, Luc Dufresne, Jean Paul Cano
 Drs. Jeff Zimmerman, Phil Gauger, Karen Harmon, JQ Zhang, Sarah Bade,
Nubia Macedo, Luis Gimenez-Lirola

10. PF: higher PRRSv detection rate, compared to sera
Lopez et al., 2017
Sampling set
Processing fluids
PRRS PCR results
Serum PRRS PCR
results
1 Positive 1/6
2 Positive 1/6
3 Positive 2/6
4 Positive 2/6
5 Positive 1/6
6 Positive 1/6
7 Positive Not detected
8 Positive Not detected
9 Positive 1/6
10 Positive 2/6

11. Lopez et al., 2017
PRRSv detection by
qPCR: higher in PF,
compared to
matched individual
blood
 18% Serum tested positive
 85% PF tested positive

12. Processing fluids volume: ~2.1ml/litter, 180μl/pig:
Sample
match
P.F. fluids
volume
(ml)
Litters in
sample
Pigs in
sample
Average
volume
per litter
(ml)
Average
volume per
pig (μl)
1 30 21 262 1.43 115
2 45 21 250 2.14 180
3 48 18 174 2.67 276
4 50 20 226 2.50 221
5 55 25 265 2.20 208
6 45 37 466 1.22 97
7 80 35 438 2.29 183
8 110 50 650 2.20 169
9 90 37 481 2.43 187
10 110 40 525 2.75 210
Lopezetal.,2017

13. Also detected in PF:
 Anti-PRRSv antibodies (Dr. Luis Gimenez-Lirola)
 PRRSV ORF-5 sequences
 PCV2 DNA
Lopez et al., 2017

14. Lopez et al., 2017

15. Time to test 3 consecutive negative weeks, byPRRS PCR
week
Time to 3 consecutive negative weekly PCRs on PF testing (n=30 herds):
0 10 20 30
100%
80%
60%
40%
20%
0%
Proportionofherdstestingnegative
25th percentile: 26 weeks
50th percentile: 28 weeks
75th percentile: 31 weeks

16. Processing Fluids: key findings
Obtaining PF (100-720 pigs): easy and practical
PRRSV detection in PF > matching 30 sera
ORF 5, and antibodies in processing fluids
Longitudinal sampling (~ 30 herds)
Started testing negative after >16 weeks post exposure
Near zero prevalence, missed before?
Continue to optimizing molecular / serologic methods
!

17. Optimizing oral
fluid collection
from due-to-
wean pigs
Marcelo Almeida et al,
…work in progress

18. Family oral fluids
=success rate ~ 90%
Dr. Marcelo Almeida
Litter oral fluids
= poor reproducibility

19. Study design:
72 matching sets of FOF, & sera from all piglets in the litter
PRRSV RNA by rRT-PCR
Almeida et al., work in progress

20. ROOM 10
37
33 34 25 21 28 26
31 26 26 19 27
24
NO PIGLETS - NOT SAMPLED
PIGLETS MIXED WITH NEXT CRATE - NOT SAMPLED
PIGLETS MIXED WITH NEXT CRATE - NOT SAMPLED
FAIL TO COLLECT FOF
FAIL TO COLLECT FOFFAIL TO COLLECT FOF
EMPTY CRATE
ROOM 11
32 31 30 35 32 29
29 27 33 33
18 24 35 21 26
20 27 30 34
24
25 21 26 27 27
28 20 27 28
FAIL TO COLLECT FOF
ROOM 9
26 24 27 29 25 26 25
31 27 36 32 23 32 23 31
26
25 32 31
22 29 18
26 26 23
24 25
25 23 26 23
32 35 32 31 33 33
32 25 30 32 28
27 21 26 31 22 28 27
28 30 26 20 27 29 27
23 23 24 22 25
24 33 21
22 27 21 25 24 24 24 27 27
25 30 27 24 30 24 23 33
30 28 21 29 28
33 30 22 25
EMPTY CRATE
ONLY PIGLETS - NOT SAMPLED
FAIL TO COLLECT FOF
Piglet prevalence: 6.3%
Litter prevalence: 19.0%
FOF-positive litters = 9.5%
Piglet Prev: 57.3%
Litter Prev: 82.4%
FOF Pos = 82.4%
Piglet Prev: 19.0%
Litter Prev: 29.4%
FOF Pos = 17.6%
NOT randomly
distributed
NOT randomly
distributed
Results
Almeida et al., work in progress. Iowa State University.
Room A Room B Room C

21. FOF: high herd sensitivity to detect PRRSv in DTW
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10 11 12
ProbabilitytodetectPRRSVinFOF
Number of PRRSv-positive pigs in the litter
Almeida et al., work in progress
Number of
viremic pigs in
the litter
Frequency of
FOF-positive
samples
0 0%
1 or 2 50%
3 or more 100%

22. # Viremic
piglets
Prevalence Individual samples FOF samples
4 1.0% 211 38
8 2.0% 124 21
20 5.0% 55 15
40 10.0% 28 12
How many FOF samples to detect PRRSv in a farrowing room?
Work in
progress…

23. Time
Herds undergoing PRRSv elimination:
1) negative @ birth; 2) remain negative @ weaning
PRRS @ weaning: + + + + + + + + - - - - -
+ + + - - - - - - - - - -PRRS @ birth:
We spread PRRSV to pigs/litters born negative (through
management practices)
BIG OPPORTUNITY WINDOW
“you can only manage what you measure”

24. Ongoing automated
production data screening for PRRS
detection
Cesar Moura, Swaminathan Jarayaman, Cory Farver,
Gustavo Silva, Mark Schwartz, Daniel Linhares

25. Applied SPC to detect herd level signs of PRRS
VDPAM
Silva, Schwartz, Morrison, Linhares, Preventive Veterinary Medicine 2017

26. Increased Not increased
Yes 10 (100%) 0 (0%)
No 7 (0.5%) 1,381 (99.5%)
Number of aborts
Outbreak
Increased Not increased
Yes 10 (100%) 0 (0%)
No 5 (0.4%) 1,353 (99.6%)
Pct preweaning mortality
Outbreak
Silva et al., 2017. Prev Vet Med.
Time to detect
PRRS: = “zero”
weeks
Results
Time to detect PRRS
(# weeks):
-4 -2 0 2 4

27. SPC project take homes
• Screening production data = supplement MOSS
• Weekly monitoring aborts and PWM: great herd sensitivity and
specificity relative to the Morrison’s Swine Health Monitoring
Project (MSHMP)
• Ongoing, automated SPC screening of breeding herds

28. Web-application for secure data
collection:
 Farm-specific login/password
 Data encryption
 Uploaded directly to ISU server
 User does not access the
database
 Automated SPC, automated
notification
Ongoing SPC with automated notifications:

31. Monitoring and Surveillance Systems (MOSS):
take home messages
• MOSS 2.0 is based on population-based samples:
• More practical, easier, cheaper, better performance compared to
“conventional” (individual pig-based sampling)
• MOSS:
−Methods depend on The Question:
−PF: neonates
−FOF: due-to-wean
−SPC: early signs of disease
Mix n’ match
to answer your
question

32. How many oral fluid samples do I need to
detect PRRSv in growing-finishing pigs?
Rotolo, Zimmerman, et al. Vet. Microbiol. (2017):

33. Rotolo, Zimmerman, et al.:
Rope allocation in the barn
Frequency of sample collection
Sample size (per barn, per site)

35. Rapid Response to Emerging Disease Program
Slides courtesy from Dr. Derald Holtkamp, the PI from this project
Objective:
Develop a Rapid Response Program for
epidemiological investigations of emerging,
transboundary and endemic swine diseases with
known etiology.

36. Standardized methodology for
epidemiological investigations
• Standard forms, and summary
reports
• Based on experiences from the PRRS
outbreak investigation pilot project
funded by the Iowa Pork Producers
• In the event of an emerging or
transboundary disease outbreak,
forms and reports will be adapted as
necessary

37. Investigation summary report
•RRC members will draft and
submit a final investigation
summary
•Subjective, qualitative assessment
of the likelihood that each event
was responsible for introduction
of pathogen
• Low
• Medium
• High

38. A regional approach
•RRC members (26 to date) have signed up to participate
• Quickly travel to where they are needed to conduct
investigations in a timely manner
• Need more members in regions 1, 2, 4, 6

39. Online Training…

40. … and Resources

41. To learn more about the Rapid Response Program, or to join the
RRC, visit the SHIC website (http://www.swinehealth.org/) or
contact:
Dr. Derald Holtkamp, Associate Professor
Iowa State University, College of Veterinary
Medicine
holtkamp@iastate.edu

42. Monitoring and updating the
value of productivity losses due
to PRRSV
Slides courtesy from Dr. Derald Holtkamp, Iowa State University
Funding:

43. Objective of this study
• Provide semi-annual updates of the cost of PRRSV in the US.
• Reporting five-year moving average
• October 2016 report: October 2011 to September 2016

44. Features of all studies
• Only the value of lost productivity was estimated
• Other costs not assessed
• Treatment costs, variation, other losses in genetic
herds and boar studs
Impact on supply of pork and
market hog prices was not assessed

45. The value of productivity losses due to PRRSV has declined since 2010
$560.32
$663.91
$638.13
$500
$520
$540
$560
$580
$600
$620
$640
$660
$680
2005 STUDY 2010 STUDY OCTOBER 2016 UPDATE
Holtkamp
et.al. 2013
Holtkamp
et.al. 2016
Neumann
et.al. 2005

46. $560.32
$663.91
$638.13
$580.62
$500
$520
$540
$560
$580
$600
$620
$640
$660
$680
2005 STUDY 2010 STUDY OCTOBER 2016 UPDATE
Adjusted for
price changes
and national
herd size
Holtkamp
et.al. 2013
Holtkamp
et.al. 2016
Neumann
et.al. 2005
The value of productivity losses due to PRRSV has declined since 2010

47. To assess the why, factors contributing to the value of lost productivity
due to PRRSV were assessed independently
• Herd distribution
• Percentage of breeding females and growing pigs in PRRSV affected and PRRSV
unaffected herds
• Productivity
• Productivity of breeding herds and growing pigs in PRRSV affected relative to PRRSV
unaffected herds
• Prices and costs
• Pig prices, input prices and costs
• National herd inventory
• Size of the national herd

48. Frp
(FromtheMSHMPproject)

49. [CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
$400
$450
$500
$550
$600
$650
$700
$750
Herd
distribtion
Productivity Prices and
costs
National
herd
inventory
Herd
distribution
and
productivity
combined
All factors
combined
$(Millions)/year
2010 study (Baseline) October 2016 Update
Since 2010, changes in productivity have reduced
the impact of PRRSV – changes in the other factors
increased the impact
Values in bars are changes from 2010 ($M)

50. The impact of PRRSV has declined by $83 million
annually compared to the 2010 study
Progress,
62%
Remaining,
38%
GOAL by 2020: 20%
($133 million)
Adjusted for changes
in prices and the size
of the national herd
since 2010

51. All of the progress was due to reductions in
productivity losses in PRRSV affected herds,
relative to unaffected herds
• Improvement in the productivity of PRRSV
affected breeding herds relative to PRRSV
unaffected herds
• Especially in breeding herds that are PRRS virus
positive but have not had an outbreak for at least 12
months (BH-C)
• Why?
• Shift from LVI to vaccine
• Improvements in bio-management (sanitation, limiting cross fostering,
etc.)

52. Acknowledgements
• National Pork Board for funding
(Project # 15-212)
• Principal investigator: Dr. Derald Holtkamp
• Co-investigators
• Daniel Linhares, Gustavo de Sousa e Silva, Will Lopez, Iowa State University
• Collaborators
• Robert Morrison and Carles Vilalta, University of Minnesota

53. Development and implementation of a domestic swine bio-
surveillance monitoring and surveillance system. Part 1:
Establishing a swine disease reporting system in the USA
ISU: Trevisan, Linhares, Crim, Main, Linhares
UMN: Torrison, Perez, Vannucci, Thurn
Funding:

54. No.ofcases
Distribution of PCR prevalence by age group
= Gather, aggregate (confidentiality
preserved!), digest, report VDL data
 What are people testing for?
 What are they finding?
 Over time?
 Region (State level)?
 Age group, specimen, …
 Incorporate this info in MSHMP

60. Acknowledgements
Collaborators
Drs. Derald Holtkamp, Jeff Zimmerman, Chris Rademacher, Luis Gimenez-Lirola, Leticia Linhares,
Rodger Main, Bret Crim, Poonam Dubey, Bob Morrison, Clayton Johnson, Carles Vilalta.
Graduate Students
Marcelo Almeida, Will Lopez, Gustavo Silva, Gaurav Rawal, Cesar Moura, Giovani Trevisan,
Joel Miranda, Daniel Torrents, Kim Baker, Swaminathan Jayaraman.
Veterinarians and Producers
~ 3 M sows in the US swine industry
Funding
National Pork Board, Swine Health Information Center, ISU VDPAM, AASV Foundation,
Phibro Animal Health, Zoetis, Boehringer Ingelheim Vetmedica, Laboratorios Hipra.

61. Daniel Linhares, DVM, MBA, PhD
Vet. Diagnostic and Production Animal Med
Iowa State University College of Vet Med.
http://field-prrs.blogspot.com/
Gustavo Silva
Will Lopez
Marcelo Almeida
Cesar Moura
Giovani Trevisan
Gaurav Rawal
Sam Baker
Daniel Torrents
“Evaluation of strategies to prevent, detect, or manage swine infectious diseases under field conditions”
Swami Jayaraman
> Identifying biosecurity aspects associated with outbreaks
> Assessing PRRS stability project
> Field studies on best PRRS management practices [breeding herds]
> Decision tree on PRRS vaccination in growing pigs
> Update of the estimated cost of PRRS in the US swine industry
> Field studies with MJ technology (PRRS typing and immunization)
> Impact of MLV on breeding herd productivity
> Economic benefit of eliminating Mycoplasma hyopneumoniae
> Real-time automated production records to detect outbreaks
> Ecology of type I PRRSv in Europe
> Predictors of growing pig performance
> Processing fluids for improved PRRS detection [newborn pigs]
> Family oral fluids for improved PRRS detection [due-to-wean pigs]
Thank you!

62. Thank you Bob

64. PRRSvprevalence
Time
Threshold of
virus detection
(e.g. 10%
prevalence with
30 random
samples)
A
B
C D
“Re-break”
Event favoring PRRSv transmission
(e.g. cross fostering, or introduction of susceptible gilts)
Scenarios for PRRSv prevalence over time:

65. PRRSvprevalence
Time
Threshold of
virus detection
(e.g. 10%
prevalence with
30 random
samples)
A
B
C D
“Re-break”
Event favoring PRRSv transmission
(e.g. cross fostering, or introduction of susceptible gilts)
Multiple
reports of herds
infected with
near-zero
PRRSv
prevalence
(Linhares et al., 2013,
Graham et al., 2013;
Kittawornrat et al 2014)
Scenarios for PRRSv prevalence over time:

66. Does increasing the sampling frequency
(e.g. from monthly to weekly) increase
probability to detect virus at a low
prevalence?
NO, the “detection limit bar” does not move!
 The sampled population is different every week.

67. PRRSvprevalence
Time
Threshold of
virus detection
(e.g. 10%
prevalence with
30 random
samples)
A
B
C D
“Re-break”
Event favoring PRRSv transmission
(e.g. cross fostering, or introduction of susceptible gilts)
Multiple
reports of herds
infected with
near-zero
PRRSv
prevalence
(Linhares et al., 2013,
Graham et al., 2013;
Kittawornrat et al 2014)
Need to
improve our
monitoring
system:
more pigs,
more
frequently
Scenarios for PRRSv prevalence over time:

68. Courtesy Dr. Ramirez & Almeida