Update on viruses affecting swine production systems ... · (SVD) Picornaviridae, Enterovirus Foot...

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Veterinary Diagnostic LaboratoryIowa State University

Update on viruses affecting swine production systems

Porcine Epidemic Diarrhea Virus (PEDv)Porcine Reproductive and respiratory syndrome virus (PRRSv)

Seneca Virus A (SVA)

Pablo Pineyro, DVM, MVSc, DVSc, PhDAssistant professor, Veterinary Diagnostic and Production Animal Medicine

Iowa State University, Ames, IA

Iowa Swine DayIowa State University

June 29th, 2017

Veterinary Diagnostic LaboratoryIowa State University

Swine Disease Topics of Interest

• Porcine Epidemic Diarrhea Virus (PEDv)

• Porcine Reproductive and respiratory syndrome virus

(PRRSv)

• Seneca Virus A (SVA)

Veterinary Diagnostic LaboratoryIowa State University

Coronavirus

• Positive sense RNA virus

• 7 open Reading frames 4 structural proteins

• Spike protein (S gene )• Membrane (M)• Envelope (E)• Nucleoprotein (N)

http://wwwuser.cnb.csic.es/~webcoron/research.html

Veterinary Diagnostic LaboratoryIowa State University

CoVs detectados en murciélagos son el origen de los géneros Alphacoronavirus y Betacoronavirus, y los CoVs detectados en aves son el origen de los géneros Gammacoronavirus y Deltacoronavirus (Woo et al. 2012)

Veterinary Diagnostic LaboratoryIowa State University

Porcine epidemic diarrhea (PEDv)Porcine transmissible gastroenteritis (TGEv)Porcine respiratory coronavirus (PRCv)

Porcine Deltacoronavirus (PDCoV)

Porcine Hemagglutinating Encephalomyelitis (PHEV)

Veterinary Diagnostic LaboratoryIowa State University

Enteric • Porcine epidemic diarrhea (PEDv)• Porcine transmissible gastroenteritis (TGEv)• Porcine Deltacoronavirus (PDCoV)

• Porcine epidemic diarrhea (PEDv)• Porcine transmissible gastroenteritis (TGEv)• Porcine Deltacoronavirus (PDCoV)

Respiratory  • Porcine respiratory coronavirus (PRCv)• Porcine respiratory coronavirus (PRCv)

SNC and gastro enteric

• Porcine Hemagglutinating Encephalomyelitis (PHEV))• Porcine Hemagglutinating Encephalomyelitis (PHEV))

Clinical signs

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PEDV current situation

Veterinary Diagnostic LaboratoryIowa State University

Emergency of PEDV in the US

Veterinary Diagnostic LaboratoryIowa State University

Emergency of PEDV in the US

Veterinary Diagnostic LaboratoryIowa State University

29/4/13 12/5/13 15/5/1310/5/13 17/5/13 21/5/13

First case description April 30May  6May 8

TGE PCR (‐)Rotavirus PCR (‐)

Pancoronavirus PCR (+)

Viral sequencingISU + NVSL

First official report of PEDV in United State

ISU sequencing  = PEDV (China 2012)

ISU‐VDLSpike‐gen PCR (S‐gene)

Dr. Matt Ackermann

Emergency of PEDV in the US

Veterinary Diagnostic LaboratoryIowa State University

USDA. (SECD) Situation Report – Jun 22, 2017www.aphis.usda.gov/animal‐health/secd. 

PEDV: Cumulative confirmed and presumptive PEDV positive premises since June 5, 2014

Veterinary Diagnostic LaboratoryIowa State University

Number of Confirmed Positive Premises by Week 

Veterinary Diagnostic LaboratoryIowa State University

Material and Methods

• Inoculation and housing• Inoculation and housing• CDCD piglets• Groups separated by room 

• Pigs individually housed in plastic totes

• No contact between pigs• Oro‐gastric inoculation

• 3 hrs post delivery• Challenge 1x10^3 virus• Gastric tube fed milk replacer 3x daily

• Sample collection• Sample collection• Fecal swabs

• Prior to inoculation• Every 12 hrs thereafter

• Necropsy• 12, 24, 48 and 72 hours post infection

• Necropsy samples• Colonic contents• 5 sections of small intestine

• Duodenum, proximal, mid, and distal jejunum and ileum

Veterinary Diagnostic LaboratoryIowa State University

PEDD Clinical signs in experimentally infected animals

• 12 hrs post infection• 30% of animals• Diarrhea and lethargy

• 24, 46, 72 hrs post infection• 100% of piglets• Watery diarrhea and vomiting

dehydration, emaciation

Veterinary Diagnostic LaboratoryIowa State University

Challenge piglets

Gross lesions

Control

Veterinary Diagnostic LaboratoryIowa State UniversityKwonil Jung, et al. 2014

Histological changes associated with PEDV infection

PEDV infects all villi and sporadically  infects crypt enterocytes

Veterinary Diagnostic LaboratoryIowa State University

Histological changes associated with PEDV infection

PEDV infects all villi and sporadically  infects crypt enterocytes

Necrosis of intestinal mucosa

Veterinary Diagnostic LaboratoryIowa State University

Histological changes associated with PEDV infection

PEDV infects all villi and sporadically  infects crypt enterocytes

Necrosis of intestinal mucosa

Atrophy of villi with attenuation, swelling or loss of epithelium on tips of villi, 

lateral bridging of villi

Veterinary Diagnostic LaboratoryIowa State University

• Severe diarrhea and vomiting• All ages affected – Older pigs less severe• No response to antibiotic treatment

• High morbidity, variable mortality• Death = 100% if < 7 d, near 100% < 10 d• Older animals survive but may grow slower, breed less

successfully, and shed virus for an extended time

• 24 hour to 4 day incubation period• Affected pigs observed very quickly• Spreads through herds very fast

PEDV Clinical signs in naturally infected animals

Veterinary Diagnostic LaboratoryIowa State University

Dr. Matt Ackermann

Veterinary Diagnostic LaboratoryIowa State University

Dr. Matt Ackermann

Veterinary Diagnostic LaboratoryIowa State University

Diagnostics

• PCR – ready quickly

• Immunohistochemistry

• Serology• IFA• ELISA

• No VI – virus is difficult to grow

• Bioassay to prove infectivity/viability• Time consuming• Expensive• Lacks sensitivity

Veterinary Diagnostic LaboratoryIowa State University

Take home message

• PEDv infection

• Severe malabsorptive and maldigestive diarrhea

• Starting clinical signs at 12 hours post infection (hpi)

• Affecting 100% of piglets at 24 hpi

• Severe villi blunting and atrophy in neonate piglets

• At 12 hpi – lesions duodenum and ileum

• 24 t 72 hpi - lesions are diffuse throughout small intestine

Veterinary Diagnostic LaboratoryIowa State University

PRRSV$664 

Million USD /year

PEDV$304 

Million USD /year

Dr. Holtkamp‐ ISU

Economic implication of PEDV

Veterinary Diagnostic LaboratoryIowa State University

Swine Disease Topics of Interest

• Porcine Epidemic Diarrhea Virus (PEDv)

• Porcine Reproductive and respiratory syndrome

virus (PRRSv)

• Seneca Virus A (SVA)

Veterinary Diagnostic LaboratoryIowa State University

Swine Respiratory Pathogens

38%

26%

8% 7% 7%3% 3% 2% 2% 2% 1% 1% 1% 0.16% 0.12% 0.07% 0.01%

0%

10%

20%

30%

40%

50%

PERC

ENT OF RE

SPIRAT

ORY

 ACC

ESSIONS

Veterinary Diagnostic LaboratoryIowa State University

Number of Bronchointerstitial Pneumonia. Caused by PRRSV Diagnosed at ISU-VDLN

umbe

r of c

ases

/ ye

arN

umbe

r of c

ases

/ ye

ar

Veterinary Diagnostic LaboratoryIowa State University

Clinical Presentations

Porcine Reproductive and Respiratory Syndrome Virus (PRRSv) Background Information

http://www.elsenburg.com/vets/prrs

Abortions Respiratory Disease

http://www.cvm.umn.edu/sdec/prod/groups/cvm/@pub/@cvmhttp://www.elsenburg.com/vets/prrs

Increase Mortality

Veterinary Diagnostic LaboratoryIowa State University

Histological Lesions

Veterinary Diagnostic LaboratoryIowa State University

Commercially Available

• Modified live-attenuated virus (MLV) vaccines

• Inactivated virus vaccine or killed virus vaccine (KV)

Experimental Vaccines

• Viral vector vaccines

• DNA vectors vaccines

• Subunit vaccines

Current Status and Future Direction of PRRSV Vaccine

Veterinary Diagnostic LaboratoryIowa State University

PRRSV diagnosis

Veterinary Diagnostic LaboratoryIowa State University

PRRS Information

16

2 4 26

1317

22

715

19

30

9

76

3745

56 56

101

114

96

81

94

6368

0

20

40

60

80

100

120

May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May

Qtr2 Qtr3 Qtr4 Qtr1 Qtr2

2015 2016

1‐3‐4

1‐7‐4

Total cases analyzed 10401-3-4 pattern: 1441-7-4 patter: 896

Veterinary Diagnostic LaboratoryIowa State University

PRRS MLV PCR

PCR - PRRSV BIVI MLV-likeAnimal ID Specimen Ct / Result CommentB, OF, Tube #2 Oral fluid >40 / Negative

Sequencing and Analysis - PRRSVAnimal ID Specimen Target Gene RFLP CommentB, OF, Tube #2 Oral fluid ORF5 1-3-4 Wild type

Sequence HomologyReference VirusInglevac ATP Lelystad Prime Pac Inglevac MLV FosteraPercent Identity 84.6% 62.7% 85.4% 84.8% 85.6%

NucleotideATGTTGGGGAAATGCTTGACCGCGGGTTATTACTCGCAATTGCTTTTTTTGTGGTGTATCGTGCCATTCTGTCTTGTTGCGCTCGCCAACGCCAACAACGGCAGCAGCTCTCATTTACAGTTGATTTATAACCTGACGATATGTGAGCTGAACGGCACAGATTGGCTGAACGATCATTTCAGCTGGGCGGTGGAGACTTTCGTCATCTTCCCTGCGTTGACCCACATTGTCTCTTATGGCGCCCTCACCACTAGCCATTTTCTTGACACGGTCGGCCTGATCACTGTGTCCACCGCCGGATATTATCACAAGCGGTATGTATTGAGCAGCATTTACGCTGTTTGTGCCCTGGCTGCGTTGGTTTGCTTCGCCATTAGGTTGGCGAAAAATTGCATGTCCTGGCGCTACTCGTGTACTAGATATACCAATTTTCTCCTGGACACTAAGGGCAAACTCTACCGCTGGCGGTCACCCGTCATCATAGAGAAGGGGGGTAAAGTTGATGTTGAGGGCCATTTGATTGACCTCAAAAGAGTTGTGCTTGATGGTTCCGCGGCAACTCCTGTAACCAAAGTTTCAGCGGAACAATGGGGTCGTCCTTAG

PCR Applied Biosystems - PRRSVAnimal ID Specimen US Ct / Result EU Ct / Result CommentB, OF, Tube #2 Oral fluid 25.3 / Positive >=37 / Negative

PCR has primers to MLV vaccine virusPositive indicates vaccine virus

Note:Can’t rule out wild‐type infection in addition to vaccine virus

Slide courtesy of Dr. Darin Madson

Veterinary Diagnostic LaboratoryIowa State University

PRRS Sequencing

• Can there be more than 1 PRRS isolate within a clinical sample?• When you sequence the PCR product, which isolate do you get?• Is the most predominate (highest titered sample) sequenced?• Is that virus the issue?

• PRRS sequencing primers are close to MLV vaccine virus; preferential will sequence this virus even if there are other present

• If near somewhat equal quantities

• May need to use Next Generation Sequencing(NGS) to determine

Slide courtesy of Dr. Darin Madson

Veterinary Diagnostic LaboratoryIowa State University

Swine Disease Topics of Interest

• Porcine Epidemic Diarrhea Virus (PEDv)

• Porcine Reproductive and respiratory syndrome virus

(PRRSv)

• Seneca Virus A (SVA)

Veterinary Diagnostic LaboratoryIowa State University

Swine Vesicular disease

Foot and mouth disease (FMD)                                                                 

Picornaviridae, Aphthovirus

Swine Vesicular disease

Foot and mouth disease (FMD)                                                                 

Picornaviridae, Aphthovirus

Swine vesicular disease (SVD)

Picornaviridae, Enterovirus

Swine Vesicular disease

Foot and mouth disease (FMD)                                                                 

Picornaviridae, Aphthovirus

Swine vesicular disease (SVD)

Picornaviridae, Enterovirus

Vesicular Stomatis(VS)

Rhabdoviridae, Vesiculovirus

Swine Vesicular disease

Foot and mouth disease (FMD)                                                                 

Picornaviridae, Aphthovirus

Swine vesicular disease (SVD)

Picornaviridae, Enterovirus

Vesicular Stomatis(VS)

Rhabdoviridae, Vesiculovirus

Vesicular exanthema of swine(VESV)

Calicivirdae, Vesivirus

Swine Vesicular disease

Veterinary Diagnostic LaboratoryIowa State University

Foot and Mouth Disease Swine Vesicular Disease

Vesicular ExanthemaVesicular Stomatitis

Clinical Comparison: Snout

Center for Food Security and Public Health, Iowa State University, 2011

Veterinary Diagnostic LaboratoryIowa State University

Idiopathic vesicular disease and neonatal mortality associated (Seneca Virus A)

Veterinary Diagnostic LaboratoryIowa State University

Introduction- Clinical Signs & Lesions

• Vesicular lesions of the snout and feet of sows, lameness• No additional lesions found on necropsy

Canning et al. 2016.

Veterinary Diagnostic LaboratoryIowa State University

Senecavirus A in neonatal pigs

Slide courtesy of Dr. Chris Rademacher

• Piglets- death of weakness, lethargy, diarrhea, hyperemia

Veterinary Diagnostic LaboratoryIowa State University

(Case 4) South Dakota, Finishing herd, 7/29/15. Gross findings

Veterinary Diagnostic LaboratoryIowa State University

(Case 4) South Dakota, Finishing herd, 7/29/15. Gross findings

Veterinary Diagnostic LaboratoryIowa State University

(Case 4) South Dakota, Finishing herd, 7/29/15. Market Pig Shedding Study

Veterinary Diagnostic LaboratoryIowa State University

Senecavirus A diagnosis

Veterinary Diagnostic LaboratoryIowa State University

Detection Methods

• RT‐PCR of vesicular fluid, nasal swabs, serum, oral fluids, tissue• Found in tissues with no pathologic changes

Veterinary Diagnostic LaboratoryIowa State University

Detection Methods

• RT‐PCR of vesicular fluid, nasal swabs, serum, oral fluids, tissue• Found in tissues with no pathologic changes

• Immunohistochemistry (IHC)

• In situ hybridization (ISH)

• Virus isolation 

• Electron microscopyJianqiang Zhang, et al

Veterinary Diagnostic LaboratoryIowa State University

• ELISA

• IFA

• Virus neutralization 

Detection Methods

Veterinary Diagnostic LaboratoryIowa State University

(Case 5) Neonatal mortality in a sow farm, 9/17/15.

Reports of high neonatal morbidity and increment in mortality rate in pigs less than 7 days.

With or without diarrhea (more common with diarrhea)No significant diagnostic lesions Occasional smooth/mucoid E. Coli isolated and rotavirus detected

Veterinary Diagnostic LaboratoryIowa State University

11 Clinically affected sows 22 piglets11 Clinically normal sows 11 piglets

18%36%

55%9%

18%

27%

0%

20%

40%

60%

80%

100%

Serum Feces Tonsil

Percentage of positive sows

Clinically affetcted Clinically normal

33% 33% 33%

18%36% 27%

0%

20%

40%

60%

80%

100%

Serum Feces Tonsil

Percentage of positive piglets

Clinically affetcted Clinically normal

Field investigation

Veterinary Diagnostic LaboratoryIowa State University

SVA

det

ectio

n ra

te b

y R

T-qP

CR

(%)

Detection of Senecavirus A (SVA) by RT-qPCR in a SVA-affected swine breeding farm

Veterinary Diagnostic LaboratoryIowa State University

IgG

S/P

ratio

Senecavirus A recombinant VP1 protein ELISA sample-to-positive (S/P) IgG antibody response

Veterinary Diagnostic LaboratoryIowa State UniversitySlide courtesy of Jordan Kraft

Senecavirus A PCR Positive Cases by Farm Type

0

2

4

6

8

10

12

14

# SV

A PC

R PO

SITIVE

 CAS

ES

DATE BY WEEK

Senecavirus A PCR Positive Cases by Farm Type

Sow Growing Pig Unknown/Other

Veterinary Diagnostic LaboratoryIowa State University

• Increment in cases of Idiopathic Vesicular Disease associate with the presence of SV-A in show and finisher pigs

• Increment in cases of PWM associated with Idiopathic Vesicular Disease in sow and associate with the presence of SV-A

• We identified a new SV-A contemporary strain genetically different from the historical SV-A US strain

Summary

Veterinary Diagnostic LaboratoryIowa State University

• Viral mutation origin

• Host-pathogen interaction

• Predisposing factors

• Clinical, serological and viral prevalence

• Viral persistence in the environment

• Viral inactivation

Question to be answered

Veterinary Diagnostic LaboratoryIowa State University

Thanks for your attention

Questions?

Veterinary Diagnostic LaboratoryIowa State University