Dr. Chris Rademacher - Seneca Valley Virus - Field Experiences In Iowa

Information about Dr. Chris Rademacher - Seneca Valley Virus - Field Experiences In Iowa

Published on February 11, 2016

Author: trufflemedia

Source: slideshare.net

Content

1. Case Reports from Senecavirus A Chris J. Rademacher, DVM Senior Clinician - ISU Swine Extension Veterinarian ISU College of Veterinary Medicine - VDPAM Senecavirus A = Seneca Valley Virus

2. Acknowledgements • Dr. Pablo Pineyro • Dr. KJ Yoon • Dr. Darin Madson • Dr. Daniel Linares • Dr. Rachel Derscheid • Dr. Kent Schwartz • Dr. Rodger Main • Dr. Pat Halbur • Dr. Derald Holtkamp • Dr. Paisley Canning • Dr. Jessica Bates • Dr. Abbey Canon • Dr. Dave Baum • Dr. JQ Zhang • Dr. Phil Gauger • Dr. Karen Harmon

3. 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.

4. Is Senecavirus A really causing Idiopathic Vesicular Disease? • Koch’s postulates have NOT been fulfilled for Senecavirus A and Idiopathic Vesicular Disease • Several attempts at reproducing the disease – Can cause seroconversion consistently. – But CANNOT reproduce signs consistent with Idiopathic Vesicular Disease.

5. Senecavirus A Cases • Started with 2 calls about exhibition pigs – July 21st – Reports of sudden lameness, redness around hoof • Anecdotal reports of hoof lesions • Veterinarian was contacted and FAD investigation initiated. • Both cases occurred after stressful event – Transportation

6. Exhibition Swine July 8 – 13 – Acute presentation

7. • (Exhibition #1) 7/21/15 Pig Number Sample type Test results FMD PCR SV-A (SVV) PCR VI 161 toe swab Negative Positive Negative hoof scrape Negative Positive Negative 162 (leg swab LF) Negative Positive Negative nasal swab Negative Negative -- hoof scrape Negative Positive Positive Results of testing at the VDL-ISU Pig Number Sample type Test results SV-A (SVV) rRT-PCR FMD rRT-PCR SVD rRT-PCR VES rRT-PCR VSV (IND1) rRT-PCR VSV (NJ) rRT-PCR 161 Swab Positive Negative Negative Negative Negative Negative Scrapings Positive Negative Negative Negative Negative Negative 162 Swab Positive Negative Negative Negative Negative Negative Swab Positive Negative Negative Negative Negative Negative Scrapings Positive Negative Negative Negative Negative Negative Results of testing at the National Veterinary Services Laboratories (NVSL)

8. • Exhibition #2, 7/23/15 Pig Number Sample type Test results FMD PCR SV-A (SVV) PCR VI 42 ZAC 9600 Nasal swab Negative Negative -- Vesicular fluid Negative Positive Positive Results of testing at the VDL-ISU • Exhibition #2, 7/23/15 Pig Number Sample type Test results FMD PCR SV-A (SVV) PCR VI 2484 Nasal swab 1 Negative Negative -- Nasal swab 2 Negative Negative -- Vesicular fluid Negative Positive Positive Results of testing at the VDL-ISU

9. Commercial Finishing Herd- July 22nd • 1200 head finishing barn with report of acute lameness and vesicular lesions on snout and feet. – 20-30% prevalence initially (overnight) – Market weight animals • FAD investigation – Negative for vesicular diseases – Positive for Seneca Valley Virus (both ISU and FADDL) • Herd was also concurrently infected with active M.hyopneumoniae – Co-factor?

10. Commercial Finishing Herd - July 15th • Barn was topped on July 10th – Dirty market truck – Commercial loading crew • First clinical signs reported on July 15 • Over next 10-14 days – 80-90% of pigs had some sort of lesions • Vesicular lesions or lameness • “Pigs crawling to the feeders”

11. A B C A B C A B C A B C A B C D 0 1 0 2 0 3 0 4 0 CtValues Commercial Finishing herd, 7/29/15 – 14 days into outbreak Oral Fluid CT 18-22

12. Site Visit – 4 weeks post-break

13. Deep nail bed hemorrhages

14. Oral Fluids – 4 weeks into break 27.2 25.5 27.3 28.3 25.7 28.7 28.2 28.7 26.6 27.6 26.3 29.2 27.6 23.4 26.7 28.4 27.1 28.6 26.2 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 North 6 North 1 South 5 North 9 South 1 North 10 South 6 North 4 North 5 North 2 North 3 North 7 North 8 South 3 South 4 South 2 South 7 South 9 South 8 Oral Fluid CT - 4 weeks post break

15. Commercial Finisher Pig Submission – 4 weeks post Pig A ct value Pig B ct value Pig C ct value Pig D ct value Pig E ct value NS 39.2942 NS 36.5697 NS NS NS 39.2237 IG LN 27.1985 IG LN 26.2969 IG LN 26.4305 IG LN 23.9951 IG LN 37.6992 LUNG 33.0138 LUNG 38.1958 LUNG LUNG LUNG TONSIL 25.4314 TONSIL 29.1689 TONSIL 26.2243 TONSIL 26.7544 TONSIL 31.9282 KIDNEY KIDNEY KIDNEY 34.4317 KIDNEY KIDNEY DUODENUM 37.174 DUODENUM DUODENUM DUODENUM DUODENUM COLON 31.7546 COLON 39.5719 COLON 35.636 COLON COLON 32.7871 PANCREAS 35.3174 PANCREAS 37.5111 PANCREAS 39.4825 PANCREAS PANCREAS JEJUNUM JEJUNUM JEJUNUM JEJUNUM JEJUNUM ILEUM ILEUM 35.8979 ILEUM 37.7044 ILEUM 34.4255 ILEUM 36.9822 CECUM 35.7437 CECUM 34.4668 CECUM 36.6959 CECUM CECUM HEART HEART HEART HEART 39.5658 HEART TB LN TB LN 35.3208 TB LN 36.4787 TB LN 34.315 TB LN SPLEEN 32.2124 SPLEEN 33.518 SPLEEN 35.7303 SPLEEN 32.6254 SPLEEN BRAIN BRAIN BRAIN BRAIN BRAIN LIVER 34.2664 LIVER 36.1441 LIVER 37.2877 LIVER LIVER SERUM SERUM SERUM SERUM SERUM R FRONT VES SW 32.8268 R FRONT RUPT VES 26.5174 L FRONT RUPT VES 26.2915 L FRONT VESICLE 25.3493 FECES 31.5441 R HIND VES SW 29.3093 NOSE VES SW L HIND CLAW 24.7197 FECES 36.6384 FECES 33.8502 FECES 35.0188 FECES 33.5528 No significant gross or histologic lesions, other than the claw lesions

16. Senecavirus A in Sow Farms

17. Seneca Virus Breeding Herd Cases • Week of August 17th – Reports 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 agents – Some sows with high fevers early on (104-106 o F) – Some sows not eating fully (not much for off feed) – Mortality is short lived (4-7 days)

18. Seneca Virus Breeding Herd Cases • With 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% prevalence • Vesicles or coronary band lesions – NO LESIONS in young pigs • Gross or Histologically.

19. Breeding Herd Lesions • Lesions in sows in farrowing rooms – Affected litters • Sows had a few vesicles on the nose • Lots of lesions on the feet – Coronary band ulcerations – Interdigital ulcers – Deep nail hemorrhages • Saw similar lesions in unaffected litters, just not as severe. • MOST ARE ON THE FRONT FEET – No lesions in the pigs at all • Gestation – All vesicular lesions • + or – feet lesions

20. Senecavirus A in neonatal pigs

21. Senecavirus A in neonatal pigs

22. SVV PCR on neonatal pigs (less than 7 days) 18 24.2 21.6 16.5 22.9 27 20.5 20.4 24.6 20.1 20.89 25.22 0 5 10 15 20 25 30 A1 serum A2 serum A3 serum A4 serum B1 serum B2 serum B3 serum B4 serum Feces A Feces B Skin Coronary band Seneca Valley Virus PCR testing on neonatal piglets (less than 7 days of age) NO DISTINCT HISTOLOGIC LESIONS

23. Other Neonatal PCR (less than 7 days of age) Sample Type CT Value of SVV PCR LN, Tonsil, Liver pool 22.05 Feces 24.1 Feces 25.5 NO DISTINCT HISTOLOGIC LESIONS Some cases report gross findings of mesocolonic edema

24. Sow Serial Shedding Study • Currently being completed in MN and IA • Following clinically affected and unaffected sows and pigs from that litter – PCR on serum, rectal, tonsil swabs • Initial 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.

25. What’s been the impact on % Pre-Wean Mortality? • Small increase (2-5%) in % PWM for 1 week. • May double % PWM if there are other agents present – C. difficile – Rota

26. ISU VDL Case Summary (as of 9.17.15) State Number of Cases IA 16 MO 10 IL 4 SD 1 Unknown 1 Production Type Number of cases Sow 14 Nursery 3 Finish 2 Exhibition 5 Gilts 3 Truckwash 1 Unknown 4 ISU LIMS and personal communication Retrospectively now found in neonatal diarrhea cases as far back as 7/29/15 32 sites 32 sites

27. Oral Fluid Survey (1108 samples from 241 cases) 1.2 % of cases and 0.45% of samples tested positive From 8.24.15 through 8.31.15 State of Origin Total Number of Positive Samples in Case Tube # IL 2 1,2 IA 1 2 IN 2 1,2 241 cases with 1108 samples

28. Testing Available at ISU • Real Time PCR – Same day if samples arrive by 11am • Virus Isolation • Sequencing – Whole genome and VP1 – Next generation sequencing • Serology – SN and IFA – Currently being validated – ELISA – Under development – IHC/ISH – Under development

29. 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 Officials – They will determine the next course of actions • DO 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

30. Summary • Seen a significant increase in cases of Idiopathic Vesicular Disease – Have founds Senecavirus A in all cases • Also seeing Senecavirus A in cases of increases in % PWM in neonatal pigs – Short 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

31. Questions??

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