Comprehensive Discussion of PEDv

2014 Swine Education In-Service ConferenceOctober 2, 2014

Dr. Harry SnelsonAASV

Disease Discovery

Looks like TGE…Acts like TGE….

Ain’t TGE

Sun Mon Tues Weds Thurs Fri Sat

28 29 30 1 2 3 4

5 1st Phone Call

6 1st Indiana – Sow Farm

7 2nd Indiana – Sow

8Initial TGE PCR neg

9IHC results neg – call vdl

10EM pos for corona

11

12 13 14 15 16 NVSL confirmsPEDV

17USDA announes

18

19 20 21 22 23 24 25

26 27 28 29 30 31 1

Sun Mon Tues Weds Thurs Fri Sat

28 29 30 1 May

2 3 4

5 6 7 8 9 10 11

12 13 14 15 16 174 cases known(3 in IA, 1 in IN)

18

19 20 21 22 23 24 25

26 27 28 29 30 31 1

Veterinary Diagnostic LaboratoryIowa State UniversityOutcome of retrospective testing & on-boarding PEDV PCR

SUNDAY MONDAY TUESDAY WEDNESDAY THURSDAY FRIDAY SATURDAY(TOTALS)

15 APRIL

16OH – GF

17 18 19 20 1 GF

21 22 23 24 25 26IN – GF

27 1 GF

28 29IA (W. Central) – SOW

30IA (NE) – SOW OH – GF IA – GF

1 MAYIA – GF

2IA – GF

3IA – GF

4 4 GF2 SOW

5 6 IA (NW) – SOW

7IA – GF IA – GF

8IN – SOWMN – SOW IA – GF

9IA – GF IA – GFIA – GF

10CO (Eastern) – SOWIA – GF IN – ??IN – ??PA – ??

11 7 GF 4 SOW3 UNKNOWN

12 13MN – GF

14CO – SOW MN – GF

15MN – SOW MN – GF

16IA – SOW

17IA – SOW IA – SOW IA – GF

184 GF 5 SOW(31 actual cases)

19 20IA – SOW IN – SOW IN – SOW IA – GF MN – GF MN – GF

21CO – GF IA – GF IA – GF IA – GF IA – GF IA – GF IA – GF IA – GF IA – GF IA – GF MN – GF OH – GF

22CO – SOW CO – SOW IA – GF IA – GF IA – GF IA – GF IA – GF IA – GF IA – GF OK – GF

23IA – SOW IA – SOW GF OH MN – ??

24IA – GF IA – GF IA – GF IA – GF IA – GF CO – GF CO – GF MN – GF MN – GF MO – GFMN – ??

2534 GF 7 SOW2 UNKNOWN

Veterinary Diagnostic LaboratoryIowa State University

PEDV Positive Cases Ascertained from Multiple VDLs

Week Received

@ VDL

Total Number of PEDv Positive

Diagnostic Case Submissions

(Premises) via PCR or IHC

Farm Type

CO IA IL IN KS MI MN MO NC NY OH OK PA SD ?

Sow Growing Pig ?

4/15/2013 (1), 2 0 1 1

4/22/2013 (1), 1 0 1 1

4/29/2013 (6), 9 2 4 5 1

5/6/2013 (14) , 17 4 7 3 1 8 3 1 1

5/13/2013 (9), 10 5 3 1 1 4 4

5/20/2013 (43), 44 7 33 3 5 25 2 7 1 2 1

Total (74), 83 18 49 7 7 42 6 12 1 11 1 1

* for the weeks prior to 6-17-13, laboratories were able to provide diagnostic case submissions and number of premises testing positive for PEDv. Starting 6-17-13, the data are limited to ONLY diagnostic case submission

numbers (aka Swine Accessions)

Clinical Signs

• Clinically indistinguishable from TGE– Alpha coronavirus– Fecal-oral pathogen– Profuse diarrhea and vomiting– High mortality rates in neonatal pigs– High morbidity, lower mortality as pigs age

• Not zoonotic, not a food safety concern

Diagnostics

• PCR – ready quickly• Serology– IFA– ELISA

• No VI – virus is difficult to grow• Bioassay to prove infectivity/viability– Time consuming– Expensive– Lacks sensitivity

Week 1 Week 2 Week 3 Week 4 Week 5 Week 60%

20%

40%

60%

80%

100%

120%

0% 0%

25%

70%

0.951

Percent Survivability to Day 7

PED virus

• New to North America• In Europe in 1970’s• Current virus present in Asia– U.S. virus 99+ % similar to 2012 isolate from Anhui

Province in China• U.S. swine herd naïve, 100% susceptible• No vaccine• Easily transmitted

Response

• USDA designated PED a “transboundary” disease– Not reportable– Non-regulatory– Production disease like PRRS or PCV– Turned the response over to the swine industry

• NPB, NPPC and AASV coordinated effort with USDA to understand the epidemiology and develop a response strategy

• Transmitted via contaminated manure• Concentrated on elevating biosecurity

AASV Response

• Collaboration with producer groups, state/federal/international animal health officials

• Outreach/education of veterinary members– Meeting at WPX– Website updated weekly– Collaborate with NPB on research efforts and

educational outreach to producers• Epidemiology efforts– Initial introduction survey– RRT participation

Veterinary Survey

• Concern: How did this virus come into the U.S.?• Objective: Identify any risk factors potentially

associated with the introduction of the PEDv into the U.S. swine herd

• Survey designed by AASV, NPB, NPPC & USDA-CEAH• Administered by practitioners, data transferred to

CEAH via link designed by FAZD at Texas A&M• Data analyzed by CEAH • Questionnaire examined > 100 variables• 25 case herds, 18 matched control herds

Survey Results

• Only seven variables were considered significantly likely to have some association with the introduction of PEDv

• These seven risk factors were associated with the process of feeding the animals.

• Did not implicate any specific finished feed, feed ingredient, feed manufacturer or ingredient supplier.

Response

• Development of 3 working groups– Biocontainment

• How to limit spread off an infected premises

– Biosecurity Transport• Review, modify, recommend biosecurity plans for transport,

shows/exhibitions, producers

– Packing Plant• Recommend biosecurity principles for packing plants, buying

stations, etc

• These working groups have developed a number of guides targeting biosecurity published on NPB website

Research

• Pork Board -- $3 million for PEDv research– Rapid response to research call– Research objectives

• Diagnosis• Pathogenesis• Environmental stability• Epidemiology• surveillance

– Shortened timeline• 13 days to identify and initiate research projects• Progress updates every two weeks• Six month deadline

Research

• NPB, NPPC and AASV funded a study by Dr. Jim Lowe to look at transmission in harvest plant lairage.

Lairage Study

• Trailers do become contaminated at packing plants due in part to movement of drivers

• The more contact that occurs, the higher the rate of contamination

One positive trailer in means 1.7 positive trailers at exit

PlantContaminated

at entryContaminated

at PlantContamination

RatioA 2.25% 8.05% 3.58B 7.00% 4.30% 0.61C 10.84% 10.81% 1.00D 2.00% 0.00% 0.00E 14.56% 3.08% 0.62G 3.00% 1.03% 0.34

All 5.98% 4.31% 0.72

Courtesy Dr. Jim Lowe

Research

• Dr. Matthew Turner surveyed cull sow buying stations in NC– Minimal biosecurity in place– Virus present, likely transmission occurring– Willingness on the part of the managers to make

changes

Future research focus for PED• Funding:

– NPB - $650,000– AFIA - $100,000– Genome Alberta - $500,000– NGFA - $60,000

• Formation and duration of immunity after infection; What level of immunity is needed for full protection?

• Can immunity be overwhelmed?

• Continued development and implementation of surveillance strategies for PED

• Evaluate strategies for trailer disinfection

Feed as a possible vector

• AASV survey identified feed as likely associated with the introduction

• Feed has anecdotally been associated with outbreaks

• Numerous bioassays on suspect feed and ingredients have been unable to confirm feed as a source

Feed as a possible vector

• Private research– has been able to transmit PEDv via feed to naïve pigs

• Canada achieved a positive bioassay using spray dried porcine blood plasma but not feed pellets

Educational Outreach

• AASV.org• Pork.org

• Lab diagnosis needed for determining site status

• Managing biosecurity or biocontainment

• Specifics of specimen collection• Feces• Oral fluids

30

Guidelines for Diagnosis of PED Virus

31

PED Biosecurity Guidelines

32

PED Biosecurity Guidelines

Current Statusas of 10/01/14

Test Results Cumulative

PEDv Positive Accessions 8,506

Total Accessions Tested 33,727

Percent PED Positive Accessions 25.2%

Number of States Reporting Positive Accessions

31

Courtesy of NAHLN

Courtesy of NAHLN

Canadian Experience

• January 23 – PEDv confirmed in Ontario• February – CFIA announces PCR positive feed– Positive bioassay with U.S. origin porcine blood

plasma– Negative feed bioassay

• Has since spread to multiple farms in Ontario (60+), Manitoba (5), and one each in Quebec, and PEI

What We’ve Learned• Although similar to TGE, PEDv is a different bug– More active in warmer environments– More difficult to control in a sow herd– Clinical picture can be more severe– Apparently no cross protection with TGE or PRCV– Huge amounts of virus are present

• Holes in our defense layers – obviously exist but hard to identify– Biosecurity at all levels should be evaluated– Particular emphasis on transport, packing plants

What We’ve Learned• VDLs responded quickly but challenges with

ability to communicate effectively– Tools exist today to facilitate this communication• FAZD has done an excellent job working with industry

to facilitate the transfer of information

– VDLs and NAHLN have stepped up to try to provide weekly data on new cases but…• Without PINs the data is suspect• Current mechanism is too labor intensive and archaic

What We’ve Learned

• The use and ability to capture PINs would significantly improve data sharing

• Challenges exist with defining roles government and industry with transboundary diseases

• We are seeing “rebreaks” in 30 – 40% of herds• Swine Deltacoronavirus introduction???

Swine Deltacoronavirus

• Clinically looks like TGE/PED but tests negative– Differential PCR available

• 1st seen in Hong Kong in 2012• Identified in Ohio in February• Identified in Canada in March

PDCoV Results (as of October 1, 2014)

Courtesy of NAHLN

Acknowledgements

• Dr. Matt Ackerman – Swine Vet Services• Dr. Rodger Main – ISU VDL• Dr. Brian McCluskey – USDA CEAH