Update on PED Research Lisa Becton, DVM, MS, DACVPM Dir. Swine Health Information & Research National Pork Board
History of PEDV PEDV was confirmed in the US on May 16 th, 2013 by diagnostic tests at the USDA National Veterinary Services Laboratory (NVSL) in Ames, IA –Found in multiple farms simultaneously and then additional farms diagnosed positive potentially from lateral spread In May of 2013, PEDV was new to the US and no existing information regarding basics of disease pathogenicity, virulence, epidemiology etc., existed. To address this urgent need, the Board has since approved >$2 million for use for research of PEDV. And, just recently approved an additional $886,500 for continued research focus.
Current Status of PEDV PEDV continues to be a major health challenge for U.S. producers into 2014 Since it was first diagnosed in May of 2013, there have been a total of >6804 cases reported: –CASE reports are different than SITE reports. –30 states (VA most recent state with positive case) –Data can be found at www.aasv.orgwww.aasv.org
National Pork Board Focus Research focus - New virus therefore needed research on PEDV and impact for US producers Development and communication of producer information/resources Containment/management strategies –Work with USDA/stakeholders and develop next steps for emerging disease response –Rapid Response Team pilot/Surveillance activities
Development of Research Priorities *Swine Health Committee – producers, veterinarians, advisors (university, government, industry) PED Strategic Task Force Input from AASV and NPPC membership State Pork Associations input
PEDV Research Priorities June 2013 Initial Research Priorities: Needed to get answers quickly! (<6months) Basic understanding of the characteristics and pathogenesis of PEDV Development & validation of diagnostic tests (antigen and antibody) Environmental stability on various surfaces and substrates and effectiveness of sanitation efforts Epidemiology of the disease Funded 8 proposals early June for 2013 – “basics” research for PEDV 7
PEDV Research for Fall 2013 Understanding sow immunity was high priority for the fall call and the Committee funded 3 proposals addressing multiple aspects of sow immunity: –Duration of immunity; Optimizing feedback protocols; Diagnostic tests to assess sow and piglet immunity to PEDV Other areas of concern and focus for fall 2013: –Assessment of feed as a source of viable/infective virus –Ability of disinfectants to denature PEDV
What we now know about the “basics” of PEDV “Basic knowledge” for PEDV: Clinical signs: diarrhea starts at 2-3 dpi & stops after 10 dpi Severity of disease is age dependent Virus shed (fecal) starts at 24-48 hrs & peaks at 5-6 days post- challenge Pigs, in general, appear to stop shedding virus by 35 days post- infection *Important to understand for clean-up and management post-outbreak – long-time between stop of shedding vs. clinical signs PEDV did not shed via the air in the aerosol in the lab setting when pigs were housed in the same room but with no other direct contact
Development and Support for Diagnostic Tests Researchers have been able to develop a method to propagate the virus in cell culture **This step is critical for future diagnostic tests and for vaccine development Development and validation of key diagnostic tests for PEDV: virus detection (PCR); exposure (ELISA); immunity (IFA/FFN) Sequencing the genome of PEDV – is it changing? Evaluate diagnostic tests that can look for more than one disease: TGE; PEDV; Rotatvirus Validate samples for PEDV – oral fluids (screening test); feed; environmental samples
Survival of PEDV in various materials/surfaces Fresh feces (humidity dependent) –14 days @ 104ºF & 122ºF; 7 days @ 140ºF Manure Slurry –14 days @ 77ºF; >28 day @ 39ºF and -4ºF Feed –Dry feed: 1 week survival but not @ 2 weeks –Slurry: PCR+ @ 28 days; no diarrhea in weeks 1-3
Survival of PEDV in various materials/surfaces Amount of virus needed for infection: LOW –Virus is shed in very high amounts in piglets Metal surfaces –Virus can be killed at 160 F for 10 minutes OR maintaining them at room temperature (68 F) for at least 7 days.
Survival of PEDV in Drinking and Recycled Water Drinking Water: –By rRT-PCR, PEDV RNA was detected for >7 weeks. –Bioassay results show that PEDV was infectious for 2 weeks. –TGEV was also infectious for 7 weeks. Recycled Water: –By rRT-PCR, PEDV RNA was detected for >7 weeks. –Bioassay results show that PEDV was infectious for 1 week. –TGEV was infectious for 7 weeks.
Analysis of the Risk Factors for the Spread of PEDV Study done through the Swine Health Monitoring Project: http://www.cvm.umn.edu/sdec/SwineDiseases/pedv/index.htm NC Cluster: Type of farm: Fw – Fin (48.8%) vs. individual site (31.6%) Location of POS farm and risk of being infected 1 mile – 8.4 2 miles – 6.3 >3 miles – no Î risk Other risks that are being evaluated include the increased frequency of trash hauling, dead removal, animal movements etc.
Analysis of the Risk Factors for the Spread of PEDV OK Cluster: Analysis is suggestive of airborne spread due to location of positives and wind direction Additional research needs to be done to evaluate fully Swine Health Monitoring Project: 718 premises signed up and project is ongoing and includes summaries from additional research projects within the industry http://www.cvm.umn.edu/sdec/SwineDiseases/PEDV/index.htm (Morrison and Goede)http://www.cvm.umn.edu/sdec/SwineDiseases/PEDV/index.htm
Transportation Research Completed in June 2013, an initial survey performed at 7 market hog plants in the Midwest (Lowe et al.) –669 environmental samples collected and found PEDV –“Swiffered” trucks at entry to a plant and at exit from the plant June 2013: Buying station survey in NC – 4 locations (Turner) –Swabbed chutes and pigs
Results of Transportation Surveys Virus was found in all 7 plants, but not all plants were equally contaminated Virus was found in the NC buying stations both in the facilities and from animals with clinical diarrhea Transportation activities pose a real risk for the spread of PEDV!! –More contact time within plant is a high risk –Cross-contamination between plant and farms occurs –Vehicles can serve as transfer vector for PEDV
What we learned in 2013 1.PEDV is a fecal-oral spread disease 2.PEDV can survive a fairly long time in different conditions and temperatures – best in cold/damp conditions 3.Transportation is a big risk for spreading the virus. More contact between trailer and plant is associated with higher rates of PEDV spread. 4.The virus can be killed at high temps or over long time. 5.Limit or eliminate contact with areas that could be contaminated from other pigs: packing plant, cull markets, other farms: Provide a barrier between you and the plant (boots/coveralls) Change your clothes/footwear before going into your farm 6.Focus needs to continue to be on clean and disinfected equipment/supplies/trailers coming into your farm to limit PEDV spread Removal of all organic material is critical!!! Allow for downtime if at all possible
What do we still need to know? Key Questions in 2014: How is sow immunity developed? How long does it last? How do we measure those levels? Are feed/feed systems an issue for PEDV spread? What is the best way to test feed/feed samples for PEDV? What steps can you take to make feed/feed systems safe?
PEDV Research Funded for 2014 For the Spring call for proposals, the Committee selected projects for funding focusing on: –Validation of new diagnostic tests: continue to dig into PEDV and start to look at immunity vs. just present or not –Continuation of a surveillance project to monitor incidence and track transmission –Assessment of efficacy of disinfectant to denature proteins and provide negative PCR result
Sow Immunity – What do we know? Sow immunity is developed for PEDV and can be measured by diagnostic testing Immunity does not appear to be as long-lived as assumed (NOT similar to TGE) New tests are being developed to assess protocols for developing immunity
PEDV Research For 2014 Late fall, questions arose as to whether or not PEDV can be transmitted via feed and research focus for feed was a high priority for 2014. March 19 th : Feed Consortium meeting in Iowa to discuss immediate needs for feed research; collaboration and $$ support by feed industry Additional research focus, collaboration and $$ leverage with Genome Alberta $500K on research priority needs and focused RFP for PEDV
PED Feed RFP 2014 Investigate effectiveness and cost of feed or feed ingredient treatments that could be used to mitigate viral survival. Develop a viral dose-infection curve showing viral dose by time and by temperature for both pelleted and milled feed. Develop diagnostic procedures for determining potential live virus contamination of feed or feedstuffs.
PED Feed RFP 2014 Feed-focused research: the Swine Health Committee selected 8 proposals for funding: –Risk assessment of feed ingredient as potential to transmit PEDV –Evaluation of feedmills for risk of transmission –Look at birds as a potential mechanism for spread –Look at the impact of pelleting time/temp and other feed interventions on PEDV –Look at alternatives to the current bioassay methods other than the live-pig model –Additional support from the feed industry to help fund this critical research NGFA AFIA Cargill State Associations: IA, IL
PEDV/PDCoV Focus PDCoV assessment for research needs –Worked with diagnostic labs on immediate needs for research: capabilities, pathogenesis, diagnosis etc. PEDV research RFP – finalized to be posted April 15 th with proposals due April 22 nd. –Working with Genome Alberta on priorities and funding resources
Animal-based Research for 2014 Additional questions arose due to the identification of PDCoV and PEDV Focused on understanding more about PDCoV and pathogenesis in the pig Develop additional diagnostic tests specifically for PDCoV
Additional funded research The Committee funded 7 projects: –PEDV antibody-based diagnostic test improvement for evaluation of immunity in milk, feces and serum –PDCoV ELISA development –Development of pseudotyped reporter viruses for detection and characterization of neutralizing antibody response to PEDV and Deltacoronavirus –Development of reagents and serological assays for Porcine Deltacoronavirus (PDCoV) –Development of pig oral fluid based virus neutralization assay and mucosal B cell responses to PEDV: potential tools to monitor herd immune status –The pathogenesis and characterization of porcine epidemic diarrhea virus (PEDV) and porcine enteric deltacoronavirus (PdCoV) in neonatal gnotobiotic swine –Determination of the sites of tissue localization, routes of viral shedding, duration of virus carriage, kinetics of antibody response, and potential of aerosol transmission of Porcine Deltacoronavirus (PDCoV) following inoculation of nursing pigs
PEDV Research Information and updates on funded projects available at www.pork.org/PED www.pork.org/PED
Communication of Research Results (All research information is posted at www.pork.org/PEDV )www.pork.org/PEDV Wanted to provide producers with as close to “real time” results as possible Utilized PEDV specific site for all information Research updates available bi-weekly until project completion
Development of Producer Resources Objective: Put together the best people possible to provide recommendations to address PEDV biosecurity and biocontainment; develop key areas of focus, and utilize current knowledge of the virus PED Strategic Task Force –Review, advise, guide –Urgency PED Working Groups NPB Staff Communications Collaborative efforts – NPB/NPPC/AASV/SAHO/etc.: target respective audiences
Other PED Resources Recommendations available for: –Exhibit Organizer Biosecurity –Exhibitor Biosecurity –Positive in Breeding Herd –Positive in Nursery/Grow-Finish –Line of Separation –Create Clean Crossing –Additional resources…
Summary PEDV and PDCoV are emerging diseases of swine that have proven to be very costly to producers Cooperation and collaboration between all sectors of industry and government is a must Need to continue to focus efforts for collaboration and cooperation on key research questions for disease management and control