Survival and mitigation strategies of PEDV and SDCoV in feed

P. E. Urriola, G. C. Shurson, F. Sampedro, M. Trudeau, H. Versma, K. Cottingim, and S. Goyal

Objective for today’s presentation

• Overview of the disease

• Evidence of transmission in feed

• Current projects to find solutions to the PEDV feed transmission issue

Contamination incidents in animal feed chemical and biological

Contaminant Year Feed OriginDioxins > 8 events Feed fat,

compound feed, trace minerals

Brazil, EU

Pesticide 2002 Wheatfeed Germany

Hormone 2002 Glucose syrup Ireland

Animal protein 2004, 2006 Corn and sugar beets

EU and USA

Unauthorized GMO

2005, 2006 Corn, gluten feed, rice

USA, China

Melamine 2007, 2008 Pet food, organic soya expeller product

USA, China

Cranshaw (2012)

What is the problem? - Pathogenesis

Source: AASV

PEDV entered the US and spread rapidly

Mole (2013) Nature 499:388

PEDV reached not only US and Canada, but other countries

http://bioportal.ucdavis.edu/

FEED TRANSMISSION Porcine Epidemic Diarrhea Virus

What is the evidence? Case # 1 - Canada

1. January 2014, first cases in Ontario2. Epidemiological investigation ruled out several routes of

transmissionTrucks (n = 60) were all negative

3. Several lots of nursery pig diet and one lot of spray dried plasma tested positive for PEDV RNA

4. Three feed samples and three spray dried plasma were tested for PCR and all sample tested positive

5. Therefore, a bioassay was conducted

How did they tested for PEDV in the suspected feed?

Pasik et al. (2014) Transb Emerging Diseases`

Experimental group Inoculum

PEDV N gene PEDV S gene

RRT-PCR results RT-PCR results

Negative controln = 10

PBS NA NA

Positive controln = 10

PEDV positive colon emulsion

Ct = 25.45 +++

Spray-dried plasman = 12

Plasma sample 1 Ct = 36.35 ++Plasma sample 2 Ct = 36.65 ++Plasma sample 3 Ct = 36.69 ++

Feedn = 8

Feed sample 1 Cts of 39–40 +Feed sample 2 Cts of 37-42.88 −

Pasik et al. (2014) Transb Emerging Diseases`

Pigs consuming PCR+ SDPP became ill and excreted the virus

Treatment 0 7 14 28

Neg-Control 0/8 0/5 0/5 0/5

SDPP-Control 0/8 0/5 0/5 0/5

PEDV-Control 0/8 8/8 5/5 1/5

SDPP-PEDV 0/8 5/5 4/5 0/5

What is the evidence? Cases in the US – Swine Vet Center

• SVC: reported 10 nursery pig farms, where:– Sow farms not infected– Other routes of transmission were ruled out, such as

internal trucking– Batches of feed tested PCR +

• Removed all ingredients of porcine origin, no new cases of PEDV in nursery farms

Yeske (2014) Allen D. Leman Swine Conference

What about environmental sources of the virus? – Pipestone Vet Clinic

Project Title Institution; PIFeasibility of viability of PCR and ex-vivo bioassay to detect viable PED virus in feed

University of Minnesota; Torremorell

Risk assessment of feed ingredients of porcine origin as vehicles for transmission of Porcine Epidemic Diarrhea virus (PEDV)

University of Minnesota; Davies

Interventions to control PEDV (porcine epidemic diarrhea virus) in feed and feed ingredients

University of Minnesota; Goyal

Evaluation of the risk of a feed mill being contaminated with PEDV or SdCV

Carthage Innovative Swine Solutions,

LLC; GreinerDetermining the impact of conditioning time and temperature in pelleted diets on PEDV survivability in complete swine diets

Kansas State University; Jones

A survey of Sturnus vulgaris (common Starlings) near swine premises to determine the potential roles as a vector of PEDV and SDCV

AMVC, LLC; Thomas

Risk pathways associated with ingredients of porcine

originP. Davies, F. Sampedro, T. Snider, P. E.

Urriola, J. Bergeron, and I. Padilla

Structure of OIE based risk analysis

Hazard identification

Risk assessment(data based)

Risk management(Policy, BMP,

HACCP)

Risk communication(Exchange of information and options concerning risk)

Structure of the feed supply chain -greater risk in ingredients of porcine origin

Risk analysis in feed ingredients of porcine origin• Risk analysis process:

– Systematic review of literature

– Consulting with subject matter experts

– Virus inactivation data– Model risk of transmission

• Precautionary vs. data driven

Porcine ingredients

Spray drying – Low to Negligible

Rendering - Negligible

Hydrolyzed proteins - Negligible

Sampedro et al. (2014)

Inactivation of PEDV in SDPP is a combination of heat and storage

PEDV inactivation conditions - objectives

1. Time x temperature x moisture conditions necessary to inactivate PEDV

2. Processes (irradiation, heating, and addition of drying agents, etc.)

3. To develop a sensitive method for the detection of small amounts of PEDV in large amounts of feed and feed ingredients.

4. Minimum infectious dose (MID50) of a standard inoculum of PEDV (cell culture- grown) and PEDV mixed with feed and feed ingredients.

Conditions (time x temperature) that are common in feed processing

Process Heat Pressure Time

Pelleting 65-95 °C Steam pressure of 30 PSIG 30-90 s

    Die pressure 75-600 kg/cm2

Extrusion Stream: 70-90 °C Steam: 345 kPa 10-90 s

  Chamber: 100-150 °C  

Spray-drying Inlet: 240 °C No change variable

  Outlet: 80- 90 °C  

Rendering Cooking 115-145 °C

If pressure cocker is used 40-90 min

1.

2.

3.

4.What conditions inactivate the virus?

0.00

2.00

4.00

6.00

8.00

10.00

12.00

0.001.002.003.004.005.00

Time

Log1

0(N

)

Feed ingredients:• Spray dried plasma• Meat and bone meal• Corn• Soybean meal• Distillers grains

Additives:• Organic and inorganic acids

Cottingim et al. (2015); Trudeau et al. (2015)

Mathematical models of virus survival• Virus inactivation was tested with log linear and Weibull models

• Delta value and D value measure the amount of time to reduce virus concentration by 1 log

• Data fit using the Weibull model (higher R2 values)

• Weibull• Log linear

0.00 5.00 10.00 15.00 20.00 25.000.000.501.001.502.002.503.003.50

Measured Identified

Time

Log1

0(N)

0.00 5.00 10.00 15.00 20.00 25.000.00

1.00

2.00

3.00

4.00

5.00

Measured Identified

Time

Log1

0(N)

0 5 10 15 20 250.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

Incubation period in days

Log TCID50/mL

Results - Novus Activate DA

Additive delta value = 0.44 Control delta value = 16.31

Control observed

− Control predicted

Additive observed

− Additive predicted

PEDV is inactivated at increasing temperatures

0 5 10 15 20 250.00

1.00

2.00

3.00

4.00

120130140145

Time (min)

Viru

s (lo

g TC

ID50

/mL)

Trudeau et al. (2015)

Survival of PEDV varies among feed ingredients even at high temperatures

Comple

te Fe

ed

Soyb

ean M

eal

Corn

Dried D

istille

rs Grai

ns

Pre-m

ix

Spray

Dried P

lasma

Blood m

eal

Meat m

eal

Meat a

nd bo

ne m

eal

02468

60° C70° C80° C90° CD

elta

(min

)

Trudeau et al. (2015)

Survival of PDCoV varies among feed ingredient at room temperature

Trudeau et al. (2015)

Survival of PEDV in complete feed at room temperature

Additives Log Reduction (21 days) Delta1 (days)

Control nursery diet 1.4 17.23bc ± 0.78

UltraAcid P (Nutriad)(orthophosphoric, citric, fumaric, and malic acid)

1.6 13.00ac ± 3.41

Acid Booster (Agri-Nutrition) (phosphoric, citric, and lactic acid)

1.6 7.24a ± 3.71

KEMGEST (Kemin Agrifoods )(phosphoric, fumaric, lactic, and citric acid)

3.8 3.28a ± 2.05

Activate DA (Novus )(organic acids and 2-hydroxy-4-methylthiobutanoic acid)

2.0 0.81a ± 0.52

a, b, c Means with different superscripts differ at P < 0.05

Trudeau et al. (2015)

Survival of PEDV and SDCoV is different

AdditivesLog Virus Reduction (21 days)

PEDv Delta1

(days)

Log Virus Reduction (21 days)

PDCoV Delta1

(days)

Control 1.4 17.23bc ± 0.78 2.7 1.60 ± 0.00

Ultracid P 1.6 13.00ac ± 3.41 2.8 0.81 ± 0.65

Acid Booster 1.6 7.24a ± 3.71 2.8 2.34 ± 1.07

KEMGEST 3.8 3.28a ± 2.05 2.8 1.34 ± 0.36

Activate DA 2.0 0.81a ± 0.52 2.8 1.34 ± 0.36

Sugar 3.8 5.66a ± 0.00 2.8 1.34 ± 0.36

Salt 3.4 11.42ac ± 4.43 2.8 1.84 ± 0.94a, b, c Means with different superscripts differ at P<0.05

Summary

• Inactivation conditions differ between PEDV and SDCoV

• Viruses are inactivated by combinations of organic acids with variable effectiveness

• Models of virus inactivation suggest non-linear inactivation conditions

Assay variability• Lack of model fit:

– Kinetics of inactivation – Log reduction

• Experimental error– Variability in cell growth– Variability in virus titers

• Alternative to bioassay:– Low sensitivity of bioassays– Experimental unit?

Thanks!