R.B. Baker, DVM, MS Past Director of the Iowa Pork Industry Center, ISU Extension and Outreach

Senior Clinician & Dr. David R. Trask Professorship in Entrepreneurial Studies Food Supply Veterinary Medicine – VDPAM

rbbaker@iastate.edu

A Summary of Our Current PEDV Knowledge

PED virus Update:

Diagnostics, Transmission,

Management, & Reporting

Talk Focus • Brief review of our advancing knowledge

–The PED virus in our herds

–The role of the Iowa State Diagnostic Lab

–Current Research

–Biosecurity Efforts

–Disease Management

–Reporting

Additional Resources: www.pork.org/pedv

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PEDV History in the USA

• First case of PEDV was submitted to Iowa State University Vet Diagnostic Lab (ISUVDL) on April 29

• Initially thought to be transmissible gastroenteritis (TGE)

• Persistence of staff at ISUVDL led to confirmation of PEDV on May 17, 2013

• Retrospective testing of submissions that were saved found positive samples back to mid-April 2013, on a growing pig site in Ohio

PEDV spread rapidly

between and within regions

of the USA

Biosecurity as currently practiced in the U.S. was NOT effective at slowing the spread of the virus

High Health Herds with a long period of disease freedom were affected

Total Positive PEDV Cases (NAHLN)

PDCoV Positive Biological Accessions

Where the Pigs Are Located in US ≈ 500,000 pigs/week imported to IA to be grown

Porcine Epidemic

Diarrhea Virus

• PED is primarily spread by the fecal-

oral route

• Incubation is very short: 12-36 hours

• Vomiting and diarrhea in all ages

• PEDV only infects pigs

Other diseases that cause diarrhea

– don’t automatically assume it is

PEDV if you see loose stools

• Viral

– Transmissible Gastroenteritis Virus (TGEV)

– Porcine rotavirus groups A and B

• Bacterial

– Clostridium, E. coli, Salmonella, Brachyspira, Ileitis.

• Parasitic

– Coccidia, Cryptosporidium, Nematodes

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-21 -19 -17 -15 -13 -11 -9 -7 -5 -3 -1 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29

Farrowing performance related to PEDv infection on 16000 sows

Avg totalborn Avg liveborn

Reproductive Ramifications Pod 1

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Farrowing rate in 16,000 sows bred during the PEDV break

Reproductive Ramifications Pod 1

Stillborn Pod 1

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% Stillborn

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Avg totalborn

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Farrowing Performance related to PEDV Infection on 12,000 sows

Reproductive Ramifications Pod 2

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Farrowing rate in 12,000 Sows post PEDV break

Reproductive Ramifications Pod 2

Pod 2 Stillborn

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

% Stillborn

ISU Diagnostic Lab Serving Food

Animal Agriculture

Comprehensive Diagnostic Service, Teaching, and Discovery (Iowa’s only Full-Service & Fully Accredited Veterinary Diagnostic Laboratory)

Processing 55,000+ cases/year from livestock producers Applying world-class technology to real-world problems

≈ 75% Swine, 10% Bovine, 10% Poultry, + 5% Everything Else

Porcine Coronaviruses in US Swine

TGE: Transmissible Gastroenteritis

PEDV: Porcine Endemic Diarrhea Virus

PDCoV: Porcine Deltacoronavirus

* Field reports suggest it to be a pathogen

* Most reports suggest it is milder than PEDV -----------------------------------------------------------------------------------------------------------------------------

PRCV = Porcine Respiratory Coronavirus

* Seems to be more of a friend than a foe

Porcine enteric disease picture in the US has rapidly become more complex

Porcine Coronavirus Diagnostic Specimens

(TGE, PEDV, & most recently PDCoV)

• Intestine (Fresh & Fixed)

• Feces

• Fecal Swabs

• Oral Fluids

• Serum (Antibody) Antemortem diagnostic tools are increasingly used (especially Oral fluids & Molecular Dx) to monitor the heath status of US swine in real-time.

Oral Fluids

New PEDV

Diagnostic

Tool

Porcine Coronavirus Serology

(Antibody Testing)

• PEDV – IFA (labor intensive, subjective, but it has been fairly robust)

• PEDV-Elisa (only routine @ UMN & ISU)

– Duration of detectable antibody response needs to be understood with PEDV

– Commercially Available PEDV Elisa’s → Very Poor

• TGE-PRCV Differential Elisa

• PDCoV = No Assays Available

Research Efforts to Date

• Great effort to produce and validate diagnostics

for PEDV and PDCoV (milk, feces, serum, saliva)

• Route of spread – transport, slaughter, buying

station roles, heat inactivation, drying etc.

• Pathogenesis

• Feed transmission bioassay development

• Control Interventions in feed

• Understanding Feed Mill contamination

• Conditioning Time and Pelleting – virus

inactivation

• Bird involvement studies

• Duration of Immunity in Sows after initial

infection

• Maternal Immunity and piglet protection

• Many Others

Transport of pigs may be the

most significant way the

virus is moving around

• Lowe, etal, 2013. The Role of Harvest Plant Lairage and Transportation in Propagating …..(PEDV)– Preliminary Results

– 669 trailers sampled over a 2-3 day period from 7 slaughter plants between June 14 and 20, 2013

– Analyzed for the presence of PEDV RNA by a commercially available PCR test at the ISU VDL

What was discovered

• 17.3% of the trailers were contaminated prior to unloading

• Contamination rates ranged from 2.0% to 69.7% between plants

• Of the trailers not contaminated at arrival, 11.4% were contaminated during the unloading process

• Plants with higher contamination rates at arrival tended to have higher rates of trailers that were contaminated during the unloading process (R2=0.98)

• Across all plants, each contaminated trailer at arrival resulted in 0.96 additional trailers that were contaminated during the unloading process

Yoon, Madson, Magstad, Labois, et al – experimentally infected with PEDV.

Porcine Coronavirus Molecular Diagnostic Assays @ ISU VDL Red = New Assays in Past 12-months

• TGE – PCR

• PEDV – PCR

• PEDV Differential – PCR – Original US strain vs. more recently identified variant

• PDCoV – PCR

• Pan-Corona – PCR (Discovery – Yoon et al)

• PEDV Sequencing – S1 Gene (Routine)

– Whole Genome (Research)

• PDCoV Sequencing – Research & diagnostic

↑ Sensitive, Semi-quantitative, Same-day testing, Used Extensively

Dr. Jianqiang Zhang, ISU-VDL

Two Distinctly Different Groups

of PEDVs Circulating in US

• January 2014 – ISU VDL S1 Sequencing

– 15 PEDV positive cases

– 10 cases shared 99.1-100% nucleotide identities to PEDV strains identified in US swine since April 2013

– 5 cases shared 99.6-100% nucleotide identities to each other but only 93.4-94.6% nucleotide identities to the originally identified US strain

PEDV Variant Epidemiology

• January 2014 – ISU VDL retrospective testing – 183 random PEDV PCR positive fecal samples from ISU VDL cases

submitted May to September 2013

– 6 of 183 cases were positive “PEDV variant”

– Five of the 6 PEDV variant positive cases were submitted in May 2013 and the other in early June

• In retrospect, both PEDV strains have been present and circulating in US since April/May 2013. – Earliest PEDV positive case identified in the US was submitted to the

ISU VDL on April 15, 2013.

PDCoV

• PDCoV not PEDV or TGEV or PRCV

– Delta vs. Alpha Coronaviruses

– Doesn’t appear to be any cross-protection

• Vomiting and diarrhea (Field/Diagnostic Reports)

– Similar clinical signs and lesions to PEDV/TGE

– Reportedly more transient &/or less severe

– Koch’s postulates yet to be fulfilled

• ISU-VDL Available Assays

– PDCV PCR is currently offered

– PDCV sequencing available

• Limited retrospective testing on PDCoV completed to date

Alphacoronavirus: PEDV Deltacoronavirus: PDCV

PED Management

• Elimination similar to TGE programs

– reported successful – takes longer

(>90days)

– Failures are reported but little data

• In single site continuous flow farms the

virus often becomes endemic

• A generation II vaccine is on the market

PEDV Elimination

• First Step has been early weaning off site

• Immediate feedback of infected material to the breeding herd

• Herd closure to replacements

Elimination

• If Possible:

• All replacement gilts necessary for a period of four to six months should be in the farm during the feedback exposure period

• Sentinel animals are best to determine if the virus has been eliminated prior to resumption of replacement flow (introduction of naïve animals)

Feedback protocols are

like those for TGEV

• Consist of fecal material and/or the intestinal tracts (viscera) from infected / scouring piglets

• Process the viscera through a garbage disposal/blender etc. to macerate thoroughly

• Cold water may be used to extend/carry the feedback material – The virus is temperature sensitive – warm, hot, or

chlorinated water should be avoided

Keeping PEDV OUT

Biosecurity!

Biosecurity!

Biosecurity!

Bio-Exclusion Considerations

Pest/Wildlife Control

Aerosol – weather

Manure Application

Keeping it out

• Biosecurity Challenges

–Fecal Oral Routes are Numerous

• Pigs (Isolation of new stock)

• Pig Trailers & Truck Drivers

–Rendering, Slaughter, Cull Sows etc.

• Feed Trucks and Drivers

• Pig handling equipment – cut boards

etc.

• Employees – hands, shoes, clothing

Bio-Exclusion Considerations

For the Farm • Limiting traffic onto the farm

– People and equipment

• Thoroughly cleaning and disinfecting

potential fomites coming onto the farm

• Enforcing downtime requirements

• Maintaining a log of visitors

The AP Bio-Dry

Truck and trailer are heated to a minimum

of 160°F for 10 minutes to inactivate PED

virus

Keeping it out

• Manure handling equipment and operators

• Service personnel

• Water supply

• Tools

• Supplies

• Any fecal contaminated object that enters

the farm and contacts a pig

A typical site …

tough to have lines of separation ?

Disinfectants?

Antifreeze may

be used with

some disinfectants

RV Antifreeze

1 gal (-50 oF)

to 5/6 gal/water

Keeping it out

oLines of Separation

Bench Entry

A double entrance separates farm personnel

from feed trucks, manure haulers or other

farming equipment

A double entrance separates farm personnel

from feed trucks, manure haulers or other

farming equipment

Daily Biosecurity Priorities

Keeping it out – Other

Risks – Feed ingredients - Plasma Protein?

– Airborne virus ?

– Visitors and employees?

– Birds?

Winter weather greatly

enhances virus spread by all

tracking possibilities

BIOSECURITY

THINK!!

What About Vaccine

• Many in Asia

• One on the market in the USA

• Several in the works in the USA

Mandatory Reporting

• June 5th, Federal order requiring pork producers report cases of Novel Corona virus infections

– Any outbreak that meets the case definition

– National Animal Health Laboratory's required to report positive cases

• Veterinarians may be the reported contact or the owner – This choice is now on accession form when submitting a case

– All other labs – commercial or private

Approved sample types submitted

for PEDV and PDCoV PCR testing

eligible for reimbursement include:

Intestines

Feces

Fecal Swabs

Oral Fluids

Environmental Samples (specifically associated with a farm site and live pigs)

Lab Mandatory Reporting

Requirements

1. Premises Identification number (PIN)

2. Submitter Information (Practitioner etc.)

3. Accession and specimen information

• Barcode must be included

• Diagnostic Test Results

Producer Responsibility

when Diagnosed Positive

• In collaboration with the herd veterinarian (or state vet, APHIS vet) must develop a herd management plan that includes

1. Diagnostic monitoring plan

2. Herd management best practices for PEDV control and/or elimination and biosecurity

a. Employee and visitor

b. Pigs coming onto a site

c. Trucks and trucking personnel

d. Feed components (ingredients, etc.)

3. Maintenance of up-to-date records on pig movements and make them assessable if requested by APHIS vets

CURRENT STATISTICS: SECD Positive Premises Confirmed (July 10–16, 2014) by Case Definition

State

PEDV Confirmed

Positive Premises

PDCoV

Confirmed

Positive

Premises

PEDV and PDCoV mixed

infection Confirmed

Positive Premises

SECD Confirmed

Positive Premises

Totals

SECD Confirmed Positive

Premises with Active Herd

Plans added this period.

IA 5 0 0 5 0

KS 3 0 0 3 0

NC 3 0 0 3 0

OK 7 0 0 7 0

TX 1 0 0 1 0

OH 1 1 2 4 0

NE 2 0 0 2 1

MI 1 0 2 3 0

PA 1 0 0 1 0

Totals 24 1 4 29 1

CUMULATIVE STATISTICS: SECD Positive Premises Confirmed (June 5–July 16, 2014) by Case Definition.

State

PEDV Confirmed

Positive Premises

PDCoV Confirmed

Positive Premises

PEDV and PDCoV mixed

infection Confirmed

Positive Premises

SECD

Confirmed Positive

Premises Totals

SECD

Confirmed Positive

Premises with Active Herd

Plans

IA 16 1 0 17 0

IL 1 0 0 1 1

KS 3 0 0 3 0

MI 1 0 2 3 2

MO 1 0 0 1 0

NC 3 0 0 3 0

NE 2 1 0 3 1

OH 3 1 2 6 0

OK 7 0 0 7 0

PA 1 0 0 1 0

TX 1 0 0 1 0

Total 39 3 4 46 4

Novel Swine Enteric

Coronavirus Disease

• Emergency Management Response System

– EMRS Data Base.

– So far 29 premises entered

– 415 Pending or received for follow-up

• Information Security

– NAHLN Labs have a layer

– USDA adds their Layer

Resources:

NPB http://www.pork.org/filelibrary/PEDfsBook4.pdf

Thank you