Comprehensive Discussion of
PEDv
2014 Swine Education In-Service Conference
October 2, 2014
Dr. Harry Snelson
AASV
Disease Discovery
Looks like TGE…
Acts like TGE….
Ain’t TGE
Sun
Mon
28
29
5 1st
Phone
Call
Tues
30
Weds
Thurs
Fri
Sat
1
2
3
4
6 1st
7 2nd
Indiana Indiana
– Sow
– Sow
Farm
8
Initial
TGE PCR
neg
9
IHC
results
neg –
call vdl
10
11
EM pos
for
corona
12
13
14
15
16 NVSL 17
confirms USDA
PEDV
annou
nes
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
17
18
4 cases known
(3 in IA, 1 in
IN)
19
20
21
22
23
24
25
26
27
28
29
30
31
1
SUNDAY
MONDAY
15 APRIL
TUESDAY
16
OH – GF
23
WEDNESDAY
THURSDAY
FRIDAY
17
18
19
24
25
26
IN – GF
3
IA – GF
SATURDAY
(TOTALS)
20
1 GF
27
1 GF
4
4 GF
2 SOW
21
22
28
29
30
IA (W. Central) – SOW IA (NE) – SOW
OH – GF
IA – GF
6
7
IA (NW) – SOW
IA – GF
IA – GF
1 MAY
IA – GF
2
IA – GF
8
IN – SOW
MN – SOW
IA – GF
9
IA – GF
IA – GF
IA – GF
10
CO (Eastern) – SOW
IA – GF
IN – ??
IN – ??
PA – ??
11
7 GF
4 SOW
3 UNKNOWN
12
13
MN – GF
14
CO – SOW
MN – GF
15
MN – SOW
MN – GF
16
IA – SOW
17
IA – SOW
IA – SOW
IA – GF
19
20
IA – SOW
IN – SOW
IN – SOW
IA – GF
MN – GF
MN – GF
21
CO – GF
IA – GF
IA – GF
IA – GF
IA – GF
IA – GF
IA – GF
IA – GF
IA – GF
IA – GF
MN – GF
OH – GF
22
CO – SOW
CO – SOW
IA – GF
IA – GF
IA – GF
IA – GF
IA – GF
IA – GF
IA – GF
OK – GF
23
IA – SOW
IA – SOW
GF OH
MN – ??
24
IA – GF
IA – GF
IA – GF
IA – GF
IA – GF
CO – GF
CO – GF
MN – GF
MN – GF
MO – GF
MN – ??
18
4 GF
5 SOW
(31 actual
cases)
25
34 GF
7 SOW
2 UNKNOWN
5
Veterinary Diagnostic Laboratory
Outcome of retrospective testing & on-boarding PEDV PCR
Iowa State University
PEDV Positive Cases Ascertained from Multiple VDLs
Total Number of
Farm Type
PEDv Positive
Week
Diagnostic Case
CO IA IL IN KS MI MN MO NC NY OH OK PA SD ?
Received
Submissions
@ VDL
(Premises) via Sow Growing ?
Pig
PCR or IHC
4/15/2013
4/22/2013
4/29/2013
5/6/2013
5/13/2013
5/20/2013
Total
(1), 2
(1), 1
(6), 9
(14) , 17
(9), 10
(43), 44
(74), 83
0
1
1
0
1
2
4
4
7
3
1
8
5
3
1
1
4
7
33
3
5 25
2
7
1
2
18
49
7
7 42
6
12
1
11 1
1
5
1
3
1
1
4
* 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)
1
1
Veterinary Diagnostic Laboratory
Iowa State University
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
120%
95%
100%
80%
100%
70%
60%
40%
25%
20%
0%
0%
Week 1
0%
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.
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
Plant
A
B
C
D
E
G
All
Courtesy Dr. Jim Lowe
Contaminated
at entry
2.25%
7.00%
10.84%
2.00%
14.56%
3.00%
5.98%
Contaminated Contamination
at Plant
Ratio
8.05%
3.58
4.30%
0.61
10.81%
1.00
0.00%
0.00
3.08%
0.62
1.03%
0.34
4.31%
0.72
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
Guidelines for Diagnosis of PED Virus
• Lab diagnosis needed
for determining site
status
• Managing biosecurity
or biocontainment
• Specifics of specimen
collection
• Feces
• Oral fluids
30
PED Biosecurity Guidelines
31
PED Biosecurity Guidelines
32
Current Status
as 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