Experiences of SVA Elimination in Sow Farms - Dr. Fabio Vannucci, from the 2018 Allen D. Leman Swine Conference, September 15-18, 2018, St. Paul, Minnesota, USA. More presentations at http://www.swinecast.com/2018-leman-swine-conference-material

1. Experiences with SVA elimination in sow farms
Fabio A Vannucci
Leman Conference
September 2018

2. OutlineIT TAKES A TEAM
Dr. Jean Paul Cano Dr. Deb MurrayDr. Laura Bruner Dr. Jer GeigerDr. Steve Tousignant

3. OutlineImpact in the pork supply chain
• Disruption in the processing plants until the diagnosis of FAD has
been ruled out
• Reallocation of resources for diagnostic investigation
• Poor performance due to secondary infections (lameness) in
continuous flow (finishing sites)
• Increased culling rates in affected sows
• Mortality of neonatal piglets

4. OutlineCase 1 – August 2015
• 2,400 sow farrow-to-finish operation
o 2 x 1,200 head sow farms
o PRRSv negative
• Clinical signs at Sow site #1
• No clinical signs at Sow site #2
o About 2 miles away
o PCR and IFA negative

5. OutlineCase 1 – August 2015
• Clinical scenario
o ~80% sows w/snout lesions
o High % lameness
o Neonatal mortality
o Poor milking sows with sore feet(?)
• Production scenario (Piglets)
oPWM: from 10% to 22% - from Aug 15th to 29th
o Stillborn: from 4% to 18% - Sep 5th

6. OutlineCase 1 – August 2015

7. OutlineCase 1 – August 2015
Do nothing (natural exposure) Closure and elimination
Dynamic of infection/shedding
• Animals (individually identified)
o 34 sows in gestation with clinical signs
• Weekly sampling
o Blood, laryngeal swab/scraping, rectal swab, snout lesion swab

8. OutlineCase 1 – August 2015

9. OutlineCase 1 – August 2015
• Exposure protocol
Manure from
bred gilts and
open gilts
collected
Fed back to
Sows in
gestation
barn and
GDU
Feces
collected
from gilts
recently fed
back (GDU)
Fed to new
sows in
Gestation
and GDU

10. OutlineCase 1 – August 2015
• Monitoring of exposure
Date Sample CT
12/22/2015 Feedback 32.34
12/31/2015 Feedback 38.57
1/7/2016 Feedback 35.62
1/12/2016 Feedback 38.86
1/14/2016 Feedback neg
1/22/2016 Feedback neg
1/26/2016 Feedback 39.04
1/28/2016 Feedback 38.36
GDU Testing- Feb 2016
80% SVV IFA Positive

11. OutlineCase 1 – August 2015
• Monitoring of exposure
o March 2016
- PCR negative
o April 2016
- PCR negative
o May 31, 2016
- Naïve Gilt Entry
- Movement from Sow site 1 to Sow site 2
o ~180 days post-exposure
- IFA positive

12. OutlineCase 1 – August 2015
• Lessons learned
o Success exposure and elimination
o Dynamic of shedding
o Fecal/oral shedding (oral fluids) is good sample for monitoring the herd
• Lessons yet to be learned
o Dynamic of transmission
o Environmental persistence
o Impact on downstream flows
o Etc…

13. OutlineCase 2 – September 2016
Sow Farm
User Group
breeding
stock and
byproducts
Contract
breeding stock
North Site
South Site
Quarantine
• 4,000 sow breed-to-wean multiplier
o PRRSv, Mhp, SECs negative
• Clinical signs at Sow farm
o Neonatal scouring/death
o Vesicular disease in sows
• Wean-finish sites
o North: two weeks later
o South: four weeks later

14. OutlineCase 2 – September 2016
Do nothing (natural exposure) Closure and elimination
Sampling/testing model accepted by AASV for PRRSv
• Define population
• Stabilize population immunity
• Close for a period of time
• Monitor to verify success/failure

15. OutlineCase 2 – September 2016
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 wks P.I.
Confirm infection
Whole-herd exposure
Monitor clinical signs
15 sentinel serum
PCR pooled by 5,
IFAs last week
9 weeks “herd closure” prior
to sentinel introduction
Introduce
15 sentinels
Resume gilt
introductions
20 soon-to-wean piglets OF PCR pooled by 5
• Feces from sows
• Gut homogenate from piglets
• Contact with sows (alleys)

16. OutlineCase 2 – September 2016
Sow Farm
User Group
breeding
stock and
byproducts
North Site
25 weeks after
South Site
18 weeks after
QuarantineWean-finish sites
• Stopped all deliveries to customers
• Both sites depopulated as pigs reached
market weight
• Repopulated with weaned pigs

17. Outline
• Lessons learned
o Robust exposure using piglet intestine and contact-affected sows (alleys)
o Relatively short period to wean PCR-negative piglets
• Lessons yet to be learned
o PCR positive (Oral fluids): 90 days after the clinical signs in the North
site (wean-finish)
Case 2 – September 2016
Environmental persistence(?)

18. OutlineCase 3 – January 2017
• 3000 sow farm, farrow to wean
• PRRSV negative, Mhyo stable
• Being run as a 6000 paired up with a
3000 head sow farm ¼ mile away
• Parity segregated, with P1+ eligible to
move into this farm
• Gilts housed off site about ¼ mile away

19. OutlineCase 3 – January 2017
• Clinical scenario
o Dec 31st 2016: diarrhea and neonatal mortality
o Jan 2nd 2017: blisters in 2 sows
o Jan 9th 2017: vesicular disease throughout the farm

20. OutlineCase 3 – January 2017
Do nothing (natural exposure) Closure and elimination
Environmental persistence
• Weekly monitoring
o 54 sows – oral swab, feces and serum
o Air sample and environmental swabs
- Farrowing and gestation crates

21. OutlineCase 3 – January 2017
• Exposure plan
o Filled with 96 animals: 46 gilts and 50 sows mid-term gestation
o Exposure: contact + inoculation
- Nose-to-nose contact with heat-check boar
- Inoculation: 14 ml of 13ct (~2.6x106 SVA/ml) diluted into 650ml PBS: 0.5ml intranasally

22. OutlineCase 3 – January 2017

23. OutlineCase 3 – January 2017
• Monitoring exposure
o Day 7 post-exposure
- 5 animals showed clinical signs (blisters, off-feed)
- 54/54 (100%) PCR+ feces and oral swabs
- 47/54 (87%) PCR+ serum - viremia
- 0/54 (0%) IFA+
o Day 24 post-exposure
- 28/54 (52%) PCR+ feces
- 8/54 (15%) PCR+ oral swabs
- 0/54 (0%) PCR+ serum
- 52/54 (96%) IFA+

24. OutlineCase 3 – January 2017
oGestation and farrowing oWeaning piglets (n=30)
Disinfection (hydrogen peroxide)
0
5
10
15
20
25
30
35
40
1 2 3 4 5 6 7 8 9 10
Ct
Weeks
Crate Farrowing Crate Gestation
Air Farrowing Air Gestation

25. OutlineCase 3 – January 2017
o Boars (n=2)
- Feces ● - Serum ●
- Oral swab ● - Semen ●
0
5
10
15
20
25
30
35
40
1 2 3 4 5 6 7 8 9 10
Ct
Weeks
* Virus isolation
*
*
• Euthanize the boars
• Weekly environmental sampling
• Tested sentinel animals (IFA)
• Herd re-opened April 13, 2017

26. OutlineCase 3 – January 2017
• Lessons learned
o Environmental persistence of viable virus (~10 weeks)
o Potential aerosol transmission (~2weeks)
o Decay on antibodies titters (~70 days) – susceptibility at the finishing site
• Lessons yet to be learned
o Positive tonsils in teasing boars euthanized 90 days post- clinical signs
- Potential carrier state
- Transmissible virus

27. OutlineSummary
PRRS
Status
Type of farm
First clinical
signs
reported
Event prior to
break
Exposure Period
of time
Clinical
disease
Closure
Case 1
1,200
sows
Free Commercial
Vesicular
lesions
Transport of
gilts using cull
sow truck
Feces from
sows/gilts
6 weeks No
20 weeks
(~150d)
Case 2
4,000
sows
Free Multiplier
Neonatal
mortality
Not identified
Feces from
sows/gilts
Gut homogenate
from piglets
Direct contact
(alleys)
3 weeks No
17 weeks
(~120d)
Case 3
3,000
sows
Free Commercial
Neonatal
mortality
Delivery
semen from a
external
source
Vesicular fluids
Direct contact
(alleys)
1 day Yes
17 weeks
(~120d)

28. OutlineSummary
PRRS
Status
Type of farm
First clinical
signs
reported
Event prior to
break
Exposure Period
of time
Clinical
disease
Closure
Case 1
1,200
sows
Free Commercial
Vesicular
lesions
Transport of
gilts using cull
sow truck
Feces from
sows/gilts
6 weeks No
20 weeks
(~150d)
Case 2
4,000
sows
Free Multiplier
Neonatal
mortality
Not identified
Feces from
sows/gilts
Gut homogenate
from piglets
Direct contact
(alleys)
3 weeks No
17 weeks
(~120d)
Case 3
3,000
sows
Free Commercial
Neonatal
mortality
Delivery
semen from a
external
source
Vesicular fluids
Direct contact
(alleys)
1 day Yes
17 weeks
(~120d)

29. OutlineSummary
PRRS
Status
Type of farm
First clinical
signs
reported
Event prior to
break
Exposure Period
of time
Clinical
disease
Closure
Case 1
1,200
sows
Free Commercial
Vesicular
lesions
Transport of
gilts using cull
sow truck
Feces from
sows/gilts
6 weeks No
20 weeks
(~150d)
Case 2
4,000
sows
Free Multiplier
Neonatal
mortality
Not identified
Feces from
sows/gilts
Gut homogenate
from piglets
Direct contact
(alleys)
3 weeks No
17 weeks
(~120d)
Case 3
3,000
sows
Free Commercial
Neonatal
mortality
Delivery
semen from a
external
source
Vesicular fluids
Direct contact
(alleys)
1 day Yes
17 weeks
(~120d)

30. OutlineAcknowledgments
Fabio Vannucci
vannu008@umn.edu