Comprehensive Discussion of PEDv

2014 Pork Management ConferenceJune 19, 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 2ndIndiana – Sow

8InitialTGE PCR neg

9IHC results neg –call vdl

10EM posfor corona

11

12 13 14 15 16 NVSL confirmsPEDV

17USDA announes

18

19 20 21 22 23 24 25

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 19 201 GF

21 22 23 24 25 26IN – GF

271 GF

28 29IA (W. Central) – SOW

30IA (NE) – SOW OH – GF IA – GF

1 MAYIA – GF

2IA – GF

3IA – GF

44 GF2 SOW

5 6 IA (NW) – SOW

7IA – GF IA – GF

8IN – SOWMN – SOWIA – GF

9IA – GF IA – GFIA – GF

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

117 GF 4 SOW3 UNKNOWN

12 13MN – GF

14CO – SOWMN – GF

15MN – SOW MN – GF

16IA – SOW

17IA – SOW IA – SOW IA – GF

184 GF 5 SOW(31 actualcases)

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

21CO – GFIA – GF IA – GF IA – GF IA – GF IA – GF IA – GF IA – GF IA – GF IA – GF MN – GFOH – 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 – GFMN – GFMO – 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 ?

SowGrowing

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

0% 0%

25%

70%

95%100%

0%

20%

40%

60%

80%

100%

120%

Week 1 Week 2 Week 3 Week 4 Week 5 Week 6

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.

Epidemiology – Observational Study

Question topic Type of VariableOdds

Ratiop value Interpretation

How many pelleted rations were fed to

sows during the last 90 daysContinuous 0.45 0.001

When the number of pelleted rations fed to sows goes

up by 1, the odds of being a case goes down 55%.

Origin of sow feed used in the last 90 days Categorical 2.33 0.002

When sow feed was custom mixed off farm compared

to being purchased complete, the odds of being a case

goes up 2.3X.

What grain was mixed with in sow feed in

the past 90 days.Categorical 0.44 0.002

When grain was mixed with an amino acid source,

salt, calcium, phosphorus and a premix in sow feed

compared to only an amino acid source and a base

mix, the odds of being a case goes down 56%

How many meal/mash rations were fed to

nursery pigs during the last 90 daysContinuous 1.65 0.05

When the number of meal/ mash rations fed to nursery

pigs goes up by 1, the odds of being a case goes up

65%.

How many meal/mash rations were fed to

finishers during the last 90 daysContinuous 1.51 0.004

When the number of meal/ mash rations fed to

finishing pigs goes up by 1, the odds of being a case

goes up 51%.

Total number of rations fed to finishers

during the last 90 daysContinuous 1.36 0.04

When the total number of rations fed to finishing pigs

goes up by 1, the odds of being a case goes up 36%.

What grain was mixed with in finisher feed

in the past 90 days.Categorical 0.50 <0.001

When grain was mixed with a supplement in finisher

feed compared to with an amino acid source and a

base mix, the odds of being a case goes down 50%

Contents of premix in the most recent

finisher dietCategorical 3.50 0.02

When vitamin and trace mineral premix was in the

same premix in the most recent finisher diet the odds

of being a case goes up 3.5X.

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 -- $800,000 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

Ratio

A 2.25% 8.05% 3.58

B 7.00% 4.30% 0.61

C 10.84% 10.81% 1.00

D 2.00% 0.00% 0.00

E 14.56% 3.08% 0.62

G 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 TestingMay-June, 2013: NVSL tested feed, mineral and vitamin premixes and dried plasma samples. Laboratory testing results (PCR) were negative except for dried plasma products.

June, 2013: NVSL conducted a bioassay using a vitamin premix and plasma.The bioassay pigs did not show evidence of infection through testing of the feces and serology.

July, 2013: NVSL conducted a bioassay using dried plasma that was obtainedfrom the blender. The bioassay pigs did not show evidence of infection throughtesting of the feces and serology.

Feb., 2014: NVSL tested dried plasma from the manufacturer.The samples were positive utilizing the real time PCR assay, and confirmatory testing is being conducted utilizing the nested PCR.

March, 2014: The bioassay for the last group of plasma samples is currently on test.

Feed as a possible vector

• Dr. Scott Dee – has been able to transmit PEDvvia feed to naïve pigs

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

AASV FEEDBACK SURVEY

Preliminary Results

Feedback Survey

• Asked vets that have attempted feedback to respond

• Approx. 83 herds represented

• 50/50 success vs failure

– Success = no “re-break” following feedback

– Failure = clinical signs never went away or came back following feedback.

% Sows with diarrhea

% Anorexic sows % IFA + % ELISA +

Feedback Success/Failure

65 100 100 S100 95 100 F80 40 95 F

100 100 100 F90 95 86 63 F70 90 100 F80 90 80 F30 30 100 S50 90 100 F50 90 100 F50 80 100 F35 35 92.5 99 F30 85 100 100 F95 70 98 F35 35 100 S50 40 100 S75 100 98 S

Educational Outreach

• AASV.org

• Pork.org

• Lab diagnosis needed for determining site status

• Managing biosecurity or biocontainment

• Specifics of specimen collection

• Feces

• Oral fluids

36

Guidelines for Diagnosis of PED Virus

37

PED Biosecurity Guidelines

38

PED Biosecurity Guidelines

Current Statusas of 5/10/14

Test Results Cumulative

PEDv Positive Accessions 6,617

Total Accessions Tested 18,326

Percent PED Positive Accessions 36.1%

Number of States Reporting Positive Accessions

29*

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 and one each in Quebec, Manitoba, 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 transboundarydiseases

• 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

Acknowledgements

• Dr. Matt Ackerman – Swine Vet Services

• Dr. Rodger Main – ISU VDL

• Dr. Brian McCluskey – USDA CEAH

• Dr. Paul Sundberg -- NPB