Case Reports from Seneca Valley Virus

Case Reports from Senecavirus AChris J. Rademacher, DVMSenior Clinician - ISU Swine Extension Veterinarian ISU College of Veterinary Medicine - VDPAM

Senecavirus A = Seneca Valley Virus

AcknowledgementsDr. Pablo PineyroDr. KJ YoonDr. Darin MadsonDr. Daniel LinaresDr. Rachel DerscheidDr. Kent SchwartzDr. Rodger MainDr. Pat Halbur

Dr. Derald HoltkampDr. Paisley CanningDr. Jessica BatesDr. Abbey CanonDr. Dave BaumDr. JQ ZhangDr. Phil GaugerDr. Karen Harmon

Seneca Virus A (Seneca Valley Virus)Senecavirus A is a non-enveloped single-stranded RNA virus of the family Picronaviradae. Foot and Mouth Disease Virus (FMDV) and swine vesicular disease virus (SVDV) is also a member of this same viral family.This type of infection in swine resulting in snout and coronary band vesicles has also been termed idiopathic vesicular disease in swine.Disease has been reported in the United States, Canada, Australia, Italy, New Zealand and most recently in Brazil. Farm outbreaks in the United States are sporadic (less than 20 have occurred in the last 3 decades), but have been recognized in multiple regions.In the last 5 years and prior to these recent outbreaks, Senecavirus A has been found in North Carolina and Illinois. Senecavirus A has been identified in swine cases from California, Illinois, Iowa, Louisiana, Minnesota, New Jersey, and North Carolina between 1988 and 2001.

Is Senecavirus A really causing Idiopathic Vesicular Disease?Kochs postulates have NOT been fulfilled for Senecavirus A and Idiopathic Vesicular DiseaseSeveral attempts at reproducing the diseaseCan cause seroconversion consistently.But CANNOT reproduce signs consistent with Idiopathic Vesicular Disease.

Senecavirus A CasesStarted with 2 calls about exhibition pigs July 21stReports of sudden lameness, redness around hoofAnecdotal reports of hoof lesionsVeterinarian was contacted and FAD investigation initiated.Both cases occurred after stressful eventTransportation

Exhibition Swine July 8 13 Acute presentation

(Exhibition #1) 7/21/15Pig NumberSample typeTest resultsFMD PCRSV-A (SVV) PCRVI161toe swabNegativePositiveNegativehoof scrapeNegativePositiveNegative162(leg swab LF)NegativePositiveNegativenasal swabNegativeNegative--hoof scrapeNegativePositivePositive

Results of testing at the VDL-ISUPig NumberSampletypeTest resultsSV-A (SVV) rRT-PCRFMD rRT-PCRSVDrRT-PCRVESrRT-PCRVSV (IND1)rRT-PCRVSV (NJ)rRT-PCR161SwabPositiveNegativeNegativeNegativeNegativeNegativeScrapingsPositiveNegativeNegativeNegativeNegativeNegative162SwabPositiveNegativeNegativeNegativeNegativeNegativeSwabPositiveNegativeNegativeNegativeNegativeNegativeScrapingsPositiveNegativeNegativeNegativeNegativeNegative

Results of testing at the National Veterinary Services Laboratories (NVSL)

Exhibition #2, 7/23/15Pig NumberSample typeTest resultsFMD PCRSV-A (SVV) PCRVI42 ZAC 9600Nasal swabNegativeNegative--Vesicular fluidNegativePositivePositive

Results of testing at the VDL-ISUExhibition #2, 7/23/15Pig NumberSample typeTest resultsFMD PCRSV-A (SVV) PCRVI2484Nasal swab 1NegativeNegative--Nasal swab 2NegativeNegative--Vesicular fluidNegativePositivePositive

Results of testing at the VDL-ISU

Commercial Finishing Herd- July 22nd1200 head finishing barn with report of acute lameness and vesicular lesions on snout and feet.20-30% prevalence initially (overnight)Market weight animalsFAD investigation Negative for vesicular diseasesPositive for Seneca Valley Virus (both ISU and FADDL)Herd was also concurrently infected with active M.hyopneumoniaeCo-factor?

Commercial Finishing Herd - July 15thBarn was topped on July 10thDirty market truckCommercial loading crewFirst clinical signs reported on July 15Over next 10-14 days80-90% of pigs had some sort of lesionsVesicular lesions or lamenessPigs crawling to the feeders

Vesicular fluidSwab Nose scrapingSerumOral FluidCommercial Finishing herd, 7/29/15 14 days into outbreak

Oral FluidCT 18-22

Site Visit 4 weeks post-break

Deep nail bed hemorrhages

Oral Fluids 4 weeks into break

Commercial Finisher Pig Submission 4 weeks postPig Act valuePig Bct valuePig Cct valuePig Dct valuePig Ect valueNS 39.2942NS36.5697NSNSNS39.2237IG LN 27.1985IG LN26.2969IG LN26.4305IG LN23.9951IG LN37.6992LUNG 33.0138LUNG 38.1958LUNG LUNG LUNG TONSIL 25.4314TONSIL 29.1689TONSIL 26.2243TONSIL 26.7544TONSIL 31.9282KIDNEY KIDNEY KIDNEY 34.4317KIDNEY KIDNEY DUODENUM 37.174DUODENUM DUODENUM DUODENUM DUODENUM COLON 31.7546COLON 39.5719COLON 35.636COLON COLON 32.7871PANCREAS 35.3174PANCREAS 37.5111PANCREAS 39.4825PANCREAS PANCREAS JEJUNUM JEJUNUM JEJUNUM JEJUNUM JEJUNUM ILEUM ILEUM 35.8979ILEUM 37.7044ILEUM 34.4255ILEUM 36.9822CECUM 35.7437CECUM 34.4668CECUM 36.6959CECUM CECUM HEART HEART HEART HEART 39.5658HEART TB LNTB LN35.3208TB LN36.4787TB LN34.315TB LNSPLEEN32.2124SPLEEN33.518SPLEEN35.7303SPLEEN32.6254SPLEENBRAIN BRAIN BRAIN BRAIN BRAIN LIVER 34.2664LIVER36.1441LIVER 37.2877LIVER LIVER SERUMSERUMSERUMSERUMSERUMR FRONT VES SW32.8268R FRONT RUPT VES26.5174 L FRONT RUPT VES26.2915L FRONT VESICLE25.3493FECES31.5441R HIND VES SW29.3093NOSE VES SWL HIND CLAW24.7197FECES36.6384FECES33.8502FECES35.0188FECES33.5528

No significant gross or histologic lesions, other than the claw lesions

Senecavirus A in Sow Farms

Seneca Virus Breeding Herd CasesWeek of August 17thReports of high neonatal morbidity and mortality in pigs less than 7 days.With or without diarrhea (more common with diarrhea)Not usually finding much for other diarrhea agentsSome sows with high fevers early on (104-106oF)Some sows not eating fully (not much for off feed)Mortality is short lived (4-7 days)

Seneca Virus Breeding Herd CasesWith descriptions similar to these, pathologists began to run SVV PCR on various samples from submitted cases started finding positives!!Upon further investigation, then finding evidence of vesicular disease in breeding age animals.10-40% prevalenceVesicles or coronary band lesionsNO LESIONS in young pigsGross or Histologically.

Breeding Herd LesionsLesions in sows in farrowing roomsAffected littersSows had a few vesicles on the noseLots of lesions on the feetCoronary band ulcerationsInterdigital ulcersDeep nail hemorrhagesSaw similar lesions in unaffected litters, just not as severe.MOST ARE ON THE FRONT FEETNo lesions in the pigs at allGestationAll vesicular lesions+ or feet lesions

Senecavirus A in neonatal pigs

Senecavirus A in neonatal pigs

SVV PCR on neonatal pigs (less than 7 days)NO DISTINCT HISTOLOGIC LESIONS

Other Neonatal PCR (less than 7 days of age)Sample TypeCT Value of SVV PCRLN, Tonsil, Liver pool22.05Feces 24.1Feces25.5

NO DISTINCT HISTOLOGIC LESIONSSome cases report gross findings of mesocolonic edema

Sow Serial Shedding StudyCurrently being completed in MN and IAFollowing clinically affected and unaffected sows and pigs from that litterPCR on serum, rectal, tonsil swabsInitial plan is to follow for 6 weeks, then reassess.Follow pigs to the nursery and then do oral fluids on rooms they are placed in.

Whats been the impact on % Pre-Wean Mortality?Small increase (2-5%) in % PWM for 1 week.May double % PWM if there are other agents presentC. difficileRota

ISU VDL Case Summary (as of 9.17.15)StateNumber of CasesIA16MO10IL4SD1Unknown1

Production TypeNumber of casesSow14Nursery3Finish2Exhibition5Gilts3Truckwash1Unknown4

ISU LIMS and personal communicationRetrospectively now found in neonatal diarrhea cases as far back as 7/29/1532 sites32 sites

Oral Fluid Survey (1108 samples from 241 cases)1.2 % of cases and 0.45% of samples tested positiveFrom 8.24.15 through 8.31.15State of OriginTotal Number of Positive Samples in CaseTube #IL21,2IA12IN21,2

241 cases with 1108 samples

Testing Available at ISUReal Time PCRSame day if samples arrive by 11amVirus IsolationSequencingWhole genome and VP1Next generation sequencingSerologySN and IFA Currently being validatedELISA Under developmentIHC/ISH Under development

What should you do if you suspect SVA??If you see suspect lesions on nose and/or coronary bands?Contact your veterinarian and State/Federal OfficialsThey will determine the next course of actionsDO NOT attempt to sell pigs with active lesions.Wait until they are completely resolved.See an increase in % PWM in neonatal pigs (less than 7 days)Look for vesicular lesions contact State/Federal Officials

SummarySeen a significant increase in cases of Idiopathic Vesicular DiseaseHave founds Senecavirus A in all casesAlso seeing Senecavirus A in cases of increases in % PWM in neonatal pigsShort duration (4-7 days)Clinical pictures match description of cases in Brazil over the past year.Appears that the virus may have changed from historical isolates.Must continue to be vigilent to work up cases as Foreign Animal Disease (FAD) to continue to rule out vesicular diseases that are FAD

Questions??