Presentation on theme: "Comprehensive Discussion of PEDv 2014 Swine Education In-Service Conference October 2, 2014 Dr. Harry Snelson AASV."— Presentation transcript:
Comprehensive Discussion of PEDv 2014 Swine Education In-Service Conference October 2, 2014 Dr. Harry Snelson AASV
Disease Discovery Looks like TGE… Acts like TGE…. Ain’t TGE
SunMonTuesWedsThursFriSat 2829301234 5 1 st Phone Call 6 1 st Indiana – Sow Farm 7 2nd Indiana – Sow 8 Initial TGE PCR neg 9 IHC results neg – call vdl 10 EM pos for corona 11 1213141516 NVSL confirms PEDV 17 USDA annou nes 18 19202122232425 2627282930311
SunMonTuesWedsThursFriSat 2829301 May 234 567891011 121314151617 4 cases known (3 in IA, 1 in IN) 18 19202122232425 2627282930311
Veterinary Diagnostic Laboratory Iowa State University Outcome of retrospective testing & on-boarding PEDV PCR SUNDAYMONDAYTUESDAYWEDNESDAYTHURSDAYFRIDAYSATURDAY (TOTALS) 15 APRIL 16 OH – GF 17181920 1 GF 212223242526 IN – GF 27 1 GF 2829 IA (W. Central) – SOW 30 IA (NE) – SOW OH – GF IA – GF 1 MAY IA – GF 2 IA – GF 3 IA – GF 4 4 GF 2 SOW 56 IA (NW) – SOW 7 IA – GF 8 IN – SOW MN – SOW IA – GF 9 IA – GF 10 CO (Eastern) – SOW IA – GF IN – ?? PA – ?? 11 7 GF 4 SOW 3 UNKNOWN 1213 MN – GF 14 CO – SOW MN – GF 15 MN – SOW MN – GF 16 IA – SOW 17 IA – SOW IA – GF 18 4 GF 5 SOW (31 actual cases) 1920 IA – SOW IN – SOW IA – GF MN – GF 21 CO – GF IA – GF MN – GF OH – GF 22 CO – SOW IA – GF OK – GF 23 IA – SOW GF OH MN – ?? 24 IA – GF CO – GF MN – GF MO – GF MN – ?? 25 34 GF 7 SOW 2 UNKNOWN
Veterinary Diagnostic Laboratory Iowa State University PEDV Positive Cases Ascertained from Multiple VDLs Week Received @ VDL Total Number of PEDv Positive Diagnostic Case Submissions (Premises) via PCR or IHC Farm Type COIAILINKSMIMNMONCNYOHOKPASD? Sow Growing Pig ? 4/15/2013 (1), 2 01 1 4/22/2013 (1), 1 01 1 4/29/2013 (6), 9 24 5 1 5/6/2013 (14), 17 47318 3 1 1 5/13/2013 (9), 10 53114 4 5/20/2013 (43), 44 7333525 2 71 21 Total (74), 83 1849774261211111 * for the weeks prior to 6-17-13, laboratories were able to provide diagnostic case submissions and number of premises testing positive for PEDv. Starting 6-17-13, the data are limited to ONLY diagnostic case submission numbers (aka Swine Accessions)
Clinical Signs Clinically indistinguishable from TGE – Alpha coronavirus – Fecal-oral pathogen – Profuse diarrhea and vomiting – High mortality rates in neonatal pigs – High morbidity, lower mortality as pigs age Not zoonotic, not a food safety concern
Diagnostics PCR – ready quickly Serology – IFA – ELISA No VI – virus is difficult to grow Bioassay to prove infectivity/viability – Time consuming – Expensive – Lacks sensitivity
PED virus New to North America In Europe in 1970’s Current virus present in Asia – U.S. virus 99+ % similar to 2012 isolate from Anhui Province in China U.S. swine herd naïve, 100% susceptible No vaccine Easily transmitted
Response USDA designated PED a “transboundary” disease – Not reportable – Non-regulatory – Production disease like PRRS or PCV – Turned the response over to the swine industry NPB, NPPC and AASV coordinated effort with USDA to understand the epidemiology and develop a response strategy Transmitted via contaminated manure Concentrated on elevating biosecurity
AASV Response Collaboration with producer groups, state/federal/international animal health officials Outreach/education of veterinary members – Meeting at WPX – Website updated weekly – Collaborate with NPB on research efforts and educational outreach to producers Epidemiology efforts – Initial introduction survey – RRT participation
Veterinary Survey Concern: How did this virus come into the U.S.? Objective: Identify any risk factors potentially associated with the introduction of the PEDv into the U.S. swine herd Survey designed by AASV, NPB, NPPC & USDA-CEAH Administered by practitioners, data transferred to CEAH via link designed by FAZD at Texas A&M Data analyzed by CEAH Questionnaire examined > 100 variables 25 case herds, 18 matched control herds
Survey Results Only seven variables were considered significantly likely to have some association with the introduction of PEDv These seven risk factors were associated with the process of feeding the animals. Did not implicate any specific finished feed, feed ingredient, feed manufacturer or ingredient supplier.
Epidemiology – Observational Study Question topicType of Variable Odds Ratio p valueInterpretation How many pelleted rations were fed to sows during the last 90 days Continuous0.450.001 When the number of pelleted rations fed to sows goes up by 1, the odds of being a case goes down 55%. Origin of sow feed used in the last 90 daysCategorical2.330.002 When sow feed was custom mixed off farm compared to being purchased complete, the odds of being a case goes up 2.3X. What grain was mixed with in sow feed in the past 90 days. Categorical0.440.002 When grain was mixed with an amino acid source, salt, calcium, phosphorus and a premix in sow feed compared to only an amino acid source and a base mix, the odds of being a case goes down 56% How many meal/mash rations were fed to nursery pigs during the last 90 days Continuous1.650.05 When the number of meal/ mash rations fed to nursery pigs goes up by 1, the odds of being a case goes up 65%. How many meal/mash rations were fed to finishers during the last 90 days Continuous1.510.004 When the number of meal/ mash rations fed to finishing pigs goes up by 1, the odds of being a case goes up 51%. Total number of rations fed to finishers during the last 90 days Continuous1.360.04 When the total number of rations fed to finishing pigs goes up by 1, the odds of being a case goes up 36%. What grain was mixed with in finisher feed in the past 90 days. Categorical0.50<0.001 When grain was mixed with a supplement in finisher feed compared to with an amino acid source and a base mix, the odds of being a case goes down 50% Contents of premix in the most recent finisher diet Categorical3.500.02 When vitamin and trace mineral premix was in the same premix in the most recent finisher diet the odds of being a case goes up 3.5X.
Response Development of 3 working groups – Biocontainment How to limit spread off an infected premises – Biosecurity Transport Review, modify, recommend biosecurity plans for transport, shows/exhibitions, producers – Packing Plant Recommend biosecurity principles for packing plants, buying stations, etc These working groups have developed a number of guides targeting biosecurity published on NPB website
Research Pork Board -- $3 million for PEDv research – Rapid response to research call – Research objectives Diagnosis Pathogenesis Environmental stability Epidemiology surveillance – Shortened timeline 13 days to identify and initiate research projects Progress updates every two weeks Six month deadline
Research NPB, NPPC and AASV funded a study by Dr. Jim Lowe to look at transmission in harvest plant lairage.
Lairage Study Trailers do become contaminated at packing plants due in part to movement of drivers The more contact that occurs, the higher the rate of contamination
One positive trailer in means 1.7 positive trailers at exit Plant Contaminated at entry Contaminated at Plant Contamination Ratio A2.25%8.05%3.58 B7.00%4.30%0.61 C10.84%10.81%1.00 D2.00%0.00%0.00 E14.56%3.08%0.62 G3.00%1.03%0.34 All5.98%4.31%0.72 Courtesy Dr. Jim Lowe
Research Dr. Matthew Turner surveyed cull sow buying stations in NC – Minimal biosecurity in place – Virus present, likely transmission occurring – Willingness on the part of the managers to make changes
Future research focus for PED Funding: – NPB - $650,000 – AFIA - $100,000 – Genome Alberta - $500,000 – NGFA - $60,000 Formation and duration of immunity after infection; What level of immunity is needed for full protection? Can immunity be overwhelmed? Continued development and implementation of surveillance strategies for PED Evaluate strategies for trailer disinfection
Feed as a possible vector AASV survey identified feed as likely associated with the introduction Feed has anecdotally been associated with outbreaks Numerous bioassays on suspect feed and ingredients have been unable to confirm feed as a source
Feed Testing May-June, 2013: NVSL tested feed, mineral and vitamin premixes and dried plasma samples. Laboratory testing results (PCR) were negative except for dried plasma products. June, 2013: NVSL conducted a bioassay using a vitamin premix and plasma. The bioassay pigs did not show evidence of infection through testing of the feces and serology. July, 2013: NVSL conducted a bioassay using dried plasma that was obtained from the blender. The bioassay pigs did not show evidence of infection through testing of the feces and serology. Feb., 2014: NVSL tested dried plasma from the manufacturer. The samples were positive utilizing the real time PCR assay, and confirmatory testing is being conducted utilizing the nested PCR. March, 2014: The bioassay for the last group of plasma samples is currently on test.
Feed as a possible vector Private research– has been able to transmit PEDv via feed to naïve pigs Canada achieved a positive bioassay using spray dried porcine blood plasma but not feed pellets
Current Status as of 10/01/14 Test ResultsCumulative PEDv Positive Accessions8,506 Total Accessions Tested33,727 Percent PED Positive Accessions25.2% Number of States Reporting Positive Accessions 31 Courtesy of NAHLN
Canadian Experience January 23 – PEDv confirmed in Ontario February – CFIA announces PCR positive feed – Positive bioassay with U.S. origin porcine blood plasma – Negative feed bioassay Has since spread to multiple farms in Ontario (60+), Manitoba (5), and one each in Quebec, and PEI
What We’ve Learned Although similar to TGE, PEDv is a different bug – More active in warmer environments – More difficult to control in a sow herd – Clinical picture can be more severe – Apparently no cross protection with TGE or PRCV – Huge amounts of virus are present Holes in our defense layers – obviously exist but hard to identify – Biosecurity at all levels should be evaluated – Particular emphasis on transport, packing plants
What We’ve Learned VDLs responded quickly but challenges with ability to communicate effectively – Tools exist today to facilitate this communication FAZD has done an excellent job working with industry to facilitate the transfer of information – VDLs and NAHLN have stepped up to try to provide weekly data on new cases but… Without PINs the data is suspect Current mechanism is too labor intensive and archaic
What We’ve Learned The use and ability to capture PINs would significantly improve data sharing Challenges exist with defining roles government and industry with transboundary diseases We are seeing “rebreaks” in 30 – 40% of herds Swine Deltacoronavirus introduction???
Swine Deltacoronavirus Clinically looks like TGE/PED but tests negative – Differential PCR available 1 st seen in Hong Kong in 2012 Identified in Ohio in February Identified in Canada in March
PDCoV Results (as of October 1, 2014) Courtesy of NAHLN
Acknowledgements Dr. Matt Ackerman – Swine Vet Services Dr. Rodger Main – ISU VDL Dr. Brian McCluskey – USDA CEAH