Update on PRRS stability studies…and quick updates on PRRS detection and

biosecurity

Daniel LinharesVeterinary Diagnostic and Production Animal Medicine [VDPAM]

Iowa State University

Agenda: Update on PRRS stability

| SHMP 1-7-4 project

| Next steps to decrease stability?

Oral fluids-based slaughter surveillance [preliminary]

Oral fluids from suckling pigs [for breeding herd monitoring]

Detecting outbreaks a few weeks earlier…

What’s new on measuring “anti-PRRS biosecurity”?

What’s on the pipeline?

Controlling PRRS

Detecting PRRS

Preventing PRRSMore PRRS…

Couple field studies on PRRS stability…

2009-2013 study• Acutely infected breeding herds• Load + close + expose program• Agreement to test (30 litters/month)

• Key demographic info:• 50% infected with 1-4-4 PRRSv• 50% prior PRRS history (3 years)• 61 farms, 16 systems

2014-2016 study• Infected breeding herds• Not required to close or to expose• Agreement to test (30 litters/month)

• Key demographic info:• All infected with “1-7-4” virus• 107 farms, 5 systems

PRRS control

Linhares, Cano, Torremorell, Morrison. Prev Vet Med, 2013 Betlach, Linhares, Morrison. in prep.

Early TTS is possible

PRRS control

44weeksTTS50

38 weeks

TTBP50

Success rate to reach Stable

Main outcomes, 2013 and 2016 studies (TTS @ last testing)

Early ones: 24-28 weeks

2013 2016

18 weeks

2016

25 weeks

2013

80%49/61

2013

62%67/107

2016

PRRS control

Median TTS (95th confidence interval):2013 study 38.3 (35 – 42) weeks2016 study 44 .0 (41 – 52) weeks

2013 cohort achieved TTS sooner than 2016 herds1/3 of 2016 herds did not reach TTS by 52 weeks

TTS

Prob

abili

tyPRRS control

All herds: closure was associated with faster TTSPRRS control

TTS at Birth

Hunter & Morrison, 2016

TTS @ BirthMedian time: 21.2 weeksRange: 8 to 32 weeks

PRRSv RNA RT-PCR from blood, tail blood swabs, or placental umbilical cord serum (PUCS)

Litters < 24 hrs old No cross-fostering

PRRS control

Project to reach Stable: • 60 to 80% success rate• 24 to 60 weeks to reach the 4th negative testTTS and Probability to reach Stable were better in the 2009-2013 cohort (61 herds) compared to the 2014-2016 cohort (107 herds):• Herd closure? Whole-herd exposure? PRRSv itself?TTS at farrowing: • 20 weeks (best= 8wks) answer in farrowing room?

PRRS control

Summary data from 168 sow farmsattempting to achieve stability

What else to (consistently) reduce TTS?

Biosecurity (to reduce re-breaks)

Boost (herd) immunity

Reduce within-herd transmission

PRRS control

PRRS detection

Oral fluids-based slaughter surveillance

Marcelo Almeida, Jeff Zimmerman, Daniel Linhares

At the farm PRRS RNA Positive (PCR)

PRRS RNANegative (PCR)

Oral fluids 79 (25%) 240 (75%)Serum 6 (2%) 310 (98%)

Oral Fluids PRRS RNA Positive (PCR)

PRRS RNANegative (PCR)

Farm 79 (25%) 240 (75%)Abattoir 33 (34%) 63 (66%)

VDL Serum OF Farm OF Abattoir

Lab1 295/316 (93.35) 319/319 (100.0) 96/96 (100.0)

Lab2 291/315 (92.38) 320/320 (100.0) 96/96 (100.0)

Lab3 299/316 (94.62) 319/319 (100.0) 96/96 (100.0)

PRRS ELISA by sample: 93% serum, 100% oral fluids were positive

VDL Serum OF Farm OF Abattoir

Lab1 32/32 (100.0) 32/32 (100.0) 32/32 (100.0)

Lab2 32/32 (100.0) 32/32 (100.0) 32/32 (100.0)

Lab3 32/32 (100.0) 32/32 (100.0) 32/32 (100.0)

PRRS ELISA by group: 100% of groups were positive

PRRS detection

VDL Serum OF Farm OF Abattoir

Lab1 5/32 (15.63) 22/32 (68.75) 17/32 (53.13)

Lab2 8/32 (25.00) 21/32 (65.63) 12/32 (37.50)

Lab3 5/32 (15.63) 24/32 (75.00) 11/32 (34.37)

VDL Serum OF Farm OF Abattoir

Lab1 6/316 (1.90) 79/319 (24.76) 33/96 (34.38)

Lab2 10/315 (3.17) 67/320 (20.94) 26/96 (27.08)

Lab3 6/316 (1.90) 80/319 (25.08) 21/96 (21.88)

PRRS PCR by sample: ~2% serum, ~24% Farm OF, ~28% Abattoir OF

PRRS PCR by group: ~ 18% serum, ~65% Farm OF, ~40% Abattoir OF

PRRS detection

Serum: 97.5 – 99.1% agreement between VDLsOral Fluids: 82.3 – 88.5% agreement between VDLs

Farm PRRS PCR OF

Farm PRRS PCR serum

↑ PRRSv @ farm = ↑ PRRSv @ abattoir

PRRS detection

Take home messages [preliminary]• OF easily collected at abattoir

• PRRSv antibodies + SVA/PRRSv RNA can be detected on oral fluids collected at abattoir

• PRRSv RNA detection: higher in OF compared to serum

• Variation in agreement between labs (SVA and PRRSv PCRs)

• Need to further explore farm-abattoir agreement: farm prevalence, number of ropes, pig behavior, summer vs winter conditions

Example chart to detect outbreaks using # aborts/week:Note spikes in abortions & changes in SHMP status over time

VDPAM

weeks

PRRS detection

Increased Not increased

Yes 10 (100%) 0 (0%)No 7 (0.5%) 1,381 (99.5%)

Number of abortsPR

RSO

utbr

eak

Increased Not increased

Yes 10 (100%) 0 (0%)No 5 (0.4%) 1,353 (99.6%)

Pct preweaning mortality

PRRS

Out

brea

k

Increased Not increased

Yes 5 (100%) 0 (0%)No 5 (0.4%) 1,363 (99.6%)

Pct preweaning mortality

PED

Out

brea

k Notes:Abortion wave was also detected in one PED outbreak (1 week before changing status to PED 1)

Time to detect PRRS = “zero”: PWM used to define outbreak?

PRRS detection

Analytic Hierarchy Process to measure biosecurity

Level 11. Pig movements2. Pickup/Deliveries 3. People movement 4. Pork/food product entry 5. Manure removal6. Domestic animals, feral swine, other wild animals and insects7. Air and water

Level 2

a. Semen deliveryb. Replacement pigsc. Cull pigs from premisesd. Weaning

Level 3

a. Semen itselfb. Semen packagingc. Vehicle and driver

A) Structure biosecurity risk by categories of events (Holtkamp)B) Relative importance of each categoryC) Relative importance of sub-categories

0.449

0.028

0.1890.052

0.125

0.069

0.089

1.00

0.23

0.570.12

0.08

1.00

0.770.08

0.15

1.00

Frequency of events * risk of events = Score

Gustavo Silva, Derald Holtkamp, Daniel Linhares

PRRS prevention

Analytic Hierarchy Process to measure biosecurity

A) Structure biosecurity risk by categories of events (Holtkamp)B) Relative importance of each categoryC) Relative importance of sub-categories

Gustavo Silva, Derald Holtkamp, Daniel Linhares

PRRS prevention

Pilot data, 30 farms:Score was positively correlated (0.65) with frequency of outbreaks.

Number of PRRS outbreaks, last 5 years

Fina

l sco

re

Description of biosecurity aspects of herds with low or high PRRS incidence and comparison within and between production systems

Linhares, Holtkamp, Morrison, Arruda, Silva & Vilalta

density # key events

selected practices

Infra-structure

Differences, commonalities?

Trends?Scores associated with

frequency outbreaks?

PRRS prevention

Thank you:

Daniel Linhares DVM MBA PhDVDPAM, Iowa State UniversityLinhares@iastate.edu http://field-prrs.blogspot.com/

Abattoir study:Dr Dion Dr DonovanDr MurrayDr WisemanDr Sundberg

Evaluation of methods for oral fluid collection on due-to-wean

pigletsMarcelo Almeida and Daniel Linhares

Source: Yeske-Livermore, L (2014) Source: Graham, J (2013)

PRRS detection

Factors associated with obtainingoral fluids from suckling pigs:

(Marcelo Almeida)

Piglet age: 3 wks old pigs more active than younger pigs Time of the day: the earlier it was the rope exposure, the higher it

was the success rate (Best ~ 6 AM; Poor ≥ 8 AM) Substrate: peanut butter slightly improved success rate (extra work) Rope height from floor: better when rope is close to floor Family sampling: superior (>80%) than litter sampling (~40%) Prior training: improved the litter sampling success rate (+20%).

PRRS detection

Litter Sampling

Family Sampling

Dr Marcelo Almeida

PRRS detection

10%

90%

CTRL-FAMILY/CTRL-LITTER

20%

80%

ctrl-LITTER/ctrl-LITTER

15.07 ± 11.08 mL

14.42 ± 13.17 mL

2.35 ± 1.87 mL

3.44 ± 2.68 mL

4.13 ± 2.98 mL

3.63 ± 1.58 mL

Succ

ess C

riter

ion

= 0.

5 m

L =

91.6

6% S

ucce

ss

100%

PEANUT-FAMILY/PEANUT-FAMILY

100%

CTRL-FAMILY/CTRL-FAMILY

10%

90%

PEANUT-FAMILY/PEANUT-LITTER

10%

90%

PEANUT-LITTER/PEANUT-LITTER

30%

70%

No training/PEANUT-LITTER

40%

60%

No training/control-LITTER

4.70 ± 4.11 mL

4.87 ± 2.23 mL

Thank you:

Daniel Linhares DVM MBA PhDVDPAM, Iowa State UniversityLinhares@iastate.edu http://field-prrs.blogspot.com/

Abattoir study:Dr Dion Dr DonovanDr MurrayDr WisemanDr Sundberg