DETECTION AND CONTROL OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS AND EMERGING VIRAL DISEASES OF SWINE

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1005114
• Multistate No.: NC-_old229
• Project Start Date: Oct 21, 2014
• Project End Date: Jun 30, 2017
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF MINNESOTA
(N/A)
ST PAUL,MN 55108

Performing Department
College of Veterinary Medicine

Non Technical Summary
Basic and applied research will be carried out to reveal ways in which key swine pathogens, including PRRSV, influenza virus, and PEDV move around to infect swine farms, and how pigs mount immune responses that control and prevent infection. The resulting basic information will be used to develop and improve methods for disease diagnosis, monitoring and prevention, especially by vaccines. Economic analyses will provide key information to inform producers and veterinarians about the importance of these diseases and the relative benefit of various intervention methods. The findings from the aforementioned research will be communicated to key target groups of veterinarians and producers through the popular press which the target audience reads, through high-quality meetings specifically targeted to producers and veterinarians, and through electronic communication avenues.

Animal Health Component

50%

Research Effort Categories

Basic

50%

Applied

50%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
311	3599	1090	30%
311	3599	1101	20%
311	3510	3010	20%
311	3510	1170	30%

Knowledge Area
311 - Animal Diseases;

Subject Of Investigation
3510 - Swine, live animal; 3599 - Swine, general/other;

Field Of Science
1090 - Immunology; 1101 - Virology; 3010 - Economics; 1170 - Epidemiology;

Keywords

swine

prrsv

pedv

influenza

economics

vaccine

transmission

pathogenesis

immunology

health

Goals / Objectives
The overall objective for this five-year NC-229 project is to reduce the impact PRRS has on producers, and to assess the feasibility and financial acceptability of PRRS area control and/or elimination for producers. To that end, we focus on the following major points, which faithfully represent the current research priorities of the US swine industry (Pork Check off NPB) : 1.1) PRRSV Immunity and Vaccinology: understanding correlates of immunity and mechanisms to broaden protection, 1.2) PRRSV Epidemiology and Surveillance: understanding virus transmission and differential testing of animals (DIVA), 1.3). Economic Impact of Interventions: determining the economic benefit of vaccination in positive herds Develop effective and efficient approaches for detection, prevention and control of pressing viral diseases of swine of recent emergence, which includes the following: 2.1) Porcine Epidemic Diarrhea Virus, 2.2) Swine Influenza Virus, 2.3) African Swine Fever, 2.4) Emerging serotypes of swine rotaviruses

Project Methods
Methods for understanding correlates of immunity and mechanisms to broaden protection against PRRSV include:Identifying the strategies by which the efficacy of modified live (PRRSV-MLV) vaccine induces immune response and in design of alternate approaches to effectively control PRRS and reduce its transmission in swine herds. Specifically, identifying molecular features of neutralizing antibodies and conditions that favor production of neutralizing antibodies. Also,understanding virus transmission, assessing the sustainability and cost-benefit of filtration as a means to reduce the risk of airborne viral spread between farms will be actively pursued. The methods to be employed for filtration analysis typically involve cohort studies, for example: a two-cohort study in which farms are classified as exposed (filtered treatment farms) or unexposed (non-filtered control farms). The study then likely involves comparison of infection rates in susceptible populations housed in non-filtered and filtered buildings/farms for periods of at least several weeks in typical clusters of farmland settings. Filtration of incoming air, in combination with standard biosecurity procedures, has been demonstrated to prevent transmission of PRRSV into susceptible herds. To quantify the impact of air filtration on reducing risk of PRRSV outbreaks, the incidence rate of new PRRSV introductions in equivalent numbers of filtered and non-filtered production units (i.e. control sow herds in a swine dense region of North America during a certain study period). Events of novel virus introduction (lateral introduction or new outbreak) are recorded by phylogenetic analysis of PRRSV ORF5 gene sequences of the new isolate. To further complete the picture of thorough biosecurity measures implementation the role of PRRSV-contaminated slurry as a means of viral spread between farms will also be evaluated. To determine economic impacts,economic models will be developed to evaluate alternative interventions. The key inputs in such models are the cost of the intervention and the expected impact on productivity and resource use (for example: feed and antimicrobials). Swine enterprise budgeting models are the preferred approach to evaluate alternative vaccine strategies. The models may be constructed to evaluate multiple interventions (scenarios). Standard market pig prices, input prices and fixed costs must be used for all scenarios so that differences in economic outcomes are due strictly to the impact of the animal health strategies. However, current values for market pig prices, input prices and fixed costs should be used as the economic outcomes are sensitive to the values entered for them.For alternative animal health interventions, the expected impact on productivity and resource use will be estimated using randomized, controlled studies that provide estimates of the productivity impacts of alternative animal health interventions that have a high level of internal validity (ie. the study is well designed and executed). These frequently lack external validity since the field conditions under which the animal health interventions are used may differ greatly. Therefore, large-scale cohort studies of farms using the animal health intervention (exposed) and farms not using the animal health intervention (unexposed) is the preferred approach for estimating values to be included in a swine enterprise budgeting model where the outcome will be used to provide the basis for industry-wide recommendations. As studies are done to evaluate interventions, such as filtering, production and resource use data may be collected at the same time to answer the economic question and leverage the value of these studies.Porcine epidemic diarrhea virus (PEDV) diagnostic for establishing standardized laboratory methods and testing protocol for PEDV and antibodies in various sample matrices will be accomplished through effort to standardize home-made PCR-based assays currently available in various diagnostic laboratories using a set of samples form pigs with known infection status and also evaluate them on unconventional sample matrices such as oral fluid and environmental samples; development of antibody assays in various platforms for characterization of immune responses, effective surveillance and assessing the immune status of animals and populationsUnderstanding correlates of protective immunity is be accomplished by studying the immune ontogeny (kinetics and profile) under both experiment and field conditions. Effort will be made to identify and immune correlates of protective immunity including corresponding viral proteins. Lactogenic immunity and methods to provide better lactogenic immunity will be studied, including feedback, vaccination and passive immunization, will be studied. 3. Vaccines and delivery systems conferring better mucosal immunity will be explored. Also, PEDV epidemiology and surveillance will be studied for understanding of prevalence, virus transmission and molecular evolution. Methods include full-length sequencing on selected viruses, determinaiton of factors affecting transmission of PEDV between and within herds will be characterized focusing on herd management, biosecurity measure, transportation and feed, and determination of prevalence of PEDV in US swine populations, using diagnostic data and surveys using meat juice and/or oral fluids along with assessment of economic impact of PED on US swine industry.For Swine Influenza Virus: factors influencing virus transmission within and between swine farms will be determined to reduce economic losses caused by viral diseases. Identifying the mechanisms by which these pathogens enter, circulate and persist in swine herds will be accomplished by determining the relationships between virus diversity and evolution with the ecology, epidemiology, and virulence properties of influenza A (IAV) virus in swine, including viruses from under-sampled pig populations in North America, at local, regional or national scales. Epidemiologic and ecologic factors such as production system type, population immunity, age of susceptibility, seasonality, and polymicrobial interactions will be assessed to determine how influenza viruses are introduced and persist on farms and how are they moved within and between production systems and globally. The genetic or genomic bases for viral fitness or virulence will be investigated. Methods to study control by vaccination or other interventions include the effectiveness of current and novel practices for preventing IAV infection by identifying immune parameters that are correlates of heterologous protection with traditional and/or new vaccine platforms or evaluating new vaccine strategies such as those targeting different age groups or seasonal whole-herd vaccinations versus vaccinating breeding animals on production schedules. The extent that genetic diversity impacts antigenic diversity and how suboptimal immunity contributes to evolution of influenza viruses in swine will be evaluated. Alternative interventions to prevent new introductions to swine herds will be investigated.

Progress 10/21/14 to 06/30/17

Outputs
Target Audience: Swine producers, veterinarians, veterinary health scientists, scientists, scientists and veterinarians-in-training, students Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Research and animal experimental studies training and professional development for undergraduate biology and animal science majors, graduate students in animal health and disease disciplines including engineering and environmental sciences, veterinary students, graduate students, DVM-PhD dual degree students, veterinarians, and visiting scientists and scholars. How have the results been disseminated to communities of interest?Publication in peer-reviewed professional journals in the sciences and medicine, including veterinary medicine, non-peer-reviewed publications in industry trade magazines, professional magazines and communications, website posting and blogging activities, workshops, meetings and sessions of veterinary and scientific meetings, posters, etc. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? PRRSV Immunity and Vaccinology: UMN continued work on mechanisms of immune protection and correlates of immunity, particularly in the area of neutralizing antibodies.UMN, in collaboration with cooperating veterinarians and producers, characterized individual variation in anti-PRRSV antibody responses that may have a genetic basis. UMN described genetic variation in antibody gene loci that contributes to immune variation in response to PRRSV. PRRSV Epidemiology and Surveillance: UMN, in collaboration with a cooperating production company, collected from air samples in regions of concentrated swine production during a high incidence season.UMN continues to amass industry-wide data on national PRRSV outbreaks in the Swine Health Monitoring Project with weekly reporting updates to all interested parties. A diminished epidemic wave was noted in 2015-2016 that followed the emergence of the explosive PEDV epidemic. The work is accomplished through a broad collaboration with producers that provide data on outbreak incidence, NPB, veterinarians and scientists inside and outside NC229.UMN has continued work on air filtration and standards to assess filter efficiency in collaboration with UMN Mechanical Engineers, to provide tools to better assess filter longevity to support the long term prevention of airborne PRRSV in farms. UMN has developed a method to evaluate the effect of intervention strategies on the viability of airborne PRRSV. (2)Develop effective and efficient approaches for detection, prevention and control of pressing viral diseases of swine of recent emergence, which includes the following: 2.1) Porcine Epidemic Diarrhea Virus, MN developed an ELISA test for detection of antibodies against PDCoV.MN collaborated with Carthage Vet Clinic and Rensselaer Swine Service to characterize neutralizing antibody responses to PEDV in response to infection and vaccination. 2.2) Swine Influenza Virus,MN identified live animal markets as a potential source for emergence of novel influenza A viruses and interspecies transmission.MN, with NIH and ASPROCER, found novel human-like influenza A viruses circulating in swine in Mexico and Chile.Genome plasticity of triple reassortant H1N1 influenza A virus during infection of vaccinated pigs were identified at MN.Concentration, size distribution, and infectivity of airborne particles carrying swine viruses were characterized by MN.MN characterized the association of the presence of influenza A virus and porcine reproductive and respiratory syndrome virus in sow farms with post-weaning mortality.Comparative virulence of wild-type H1N1pdm09 influenza A isolates in swine was evaluated by collaborative group including MN.MN studied the association between influenza A virus infection and pigs subpopulations in endemically infected breeding herds.MN characterized viral load, viability and persistence of influenza A virus in air and on surfaces of swine production facilities.MN evaluated an electrostatic particle ionization technology for decreasing airborne pathogens in pigs.MN investigated the airborne transmission of H5N2 high pathogenic avian influenza (HPAI) virus during the spring outbreaks that occurred in the Midwestern U.S.MN tested 800 sera from swine co-located in or near counties with H5N2 HPAI infected poultry for antibodies to H5N2 HPAI. All were negative for antibodies against A/Turkey/Minnesota/9845-4/2015 H5N2 HPAI by hemagglutination inhibition assays.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Alonso, C.; Olson, B.; Goyal, B.; Raynor, P.; Davies, P.; Torremorell, M. 2016. Comparison of two size-differentiating air samplers for detecting airborne swine viruses under experimental conditions. Aerosols Science and Technology; DOI: 10.1080/02786826.2016.1249278
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Davies, B., X. Wang, C.M.T. Dvorak, D. Marthaler, and M.P. Murtaugh. 2016. Diagnostic phylogenetics reveals a new porcine circovirus 2 cluster. Virus Res. 217:32-37.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Dvorak, C.M.T., Y. Yang, C. Haley, N. Sharma and M.P. Murtaugh. 2016. National reduction in porcine circovirus type 2 prevalence following introduction of vaccination. Vet. Micro. 189:86-90.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Guo, X., J.C. Schwartz, and M.P. Murtaugh. 2016. Genomic variation in the porcine immunoglobulin lambda variable region. Immunogenetics, 68:285-293.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Alkhamis, M.A., A.M. Perez, M.P. Murtaugh, X. Wang and R.B. Morrison. 2016. Applications of Bayesian phylodynamic methods in a recent U.S. porcine reproductive and respiratory syndrome virus outbreak. Frontiers Microbiol. 7:67,1-10.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Jarvis, M.C., H.C. Lam, Y. Zhang, L. Wang, R.A. Hesse, B.M. Hause, A. Vlasova, Q. Wang, J. Zhang, M.I. Nelson, M.P. Murtaugh and D. Marthaler. 2016. Genomic and evolutionary inferences between American and global strains of porcine epidemic diarrhea virus. Prev. Vet. Med. 123:175-184.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Neira V, Rabinowitz P, Rendahl A, Paccha B, Gibbs SG, Torremorell M (2016). Characterization of viral load, viability and persistence of influenza A virus in air and on surfaces of swine production facilities. PlosOne. 11(1): e0146616. doi:10.1371/ journal.pone.0146616
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Paccha B, Jones RM, Gibbs S, Kane MJ, Torremorell M, Neira-Ramirez V, Rabinowitz PM (2016). Modeling risk of occupational zoonotic influenza infection in swine workers. J of Occupational Environmental Hygiene, 13:8, 577-587, DOI 10.1080/15459624.2016.1159688
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Song, Q., S. Stone, D. Drebes, L.L. Greiner, C.M.T. Dvorak and M.P. Murtaugh. 2016. Characterization of anti-porcine epidemic diarrhea virus neutralizing activity in mammary secretions. Virus Res. 226:85-92.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Torremorell M, Alonso C, Davies P, Raynor PC, Patnayak D, Torchetti MK, McCluskey B (2016). Investigation into the airborne dissemination of H5N2 highly pathogenic avian influenza virus during the 2015 spring outbreaks in the Midwestern U.S. Avian Diseases 60:637-643.
• Type: Theses/Dissertations Status: Published Year Published: 2015 Citation: Robinson SRR. 2015. Mechanisms of immune protection against porcine reproductive and respiratory syndrome virus (PRRSV). PhD Thesis, University of Minnesota.

Progress 10/21/14 to 09/30/15

Outputs
Target Audience: Thetargetaudienceis swine producers, swine veterinarians, swine health researchers,and consumers nationally in the U.S. andinternationally in various countries of SouthAmerica, Europe, and Asia. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Sally Robinson earned the PhD degree, John Schwartz earned the PhD degree, and Michael Raye is being mentored for the PhD degree. How have the results been disseminated to communities of interest?Results have been disseminated through peer-reviewed primary research articles in the scientific and veterinary medical literature, lay publications in producer magazines, presentations to producers and veterinarians, and presentations to producer groups. What do you plan to do during the next reporting period to accomplish the goals?Research will continue in the priority areas of the project, and publication and communication activities will be maintained at current levels.

Impacts
What was accomplished under these goals? Accomplishments in the area of PRRSV immunity and vaccinology included discovery of broadly neutralizing antibodies against the rapidly evolving porcine reproductive and respiratory syndrome virus (PRRSV), which opens the door to identification of molecular bases for protection. Also, Innate and adaptive immunity against PRRSV was summarized in a review article that is expected to help guide future research. Accomplishments in the area of PRRSV epidemiology and surveillanceincluded assessment of variation in porcine reproductive and respiratory syndrome virus open reading frame 5 diagnostic sequencing, which showed that inter-laboratory can occur, so that positive control samples are advisable. Emergence of a virulent PRRSV was shown in vaccinated herds in the US, showing that the virus continues to evolve. Evolutionary diversification of type 2 PRRSV further demonstrates this continuing pattern of change. Accomplishments in improved approaches to control and prevention of emerging viral diseases included demonstration of cross-protective immunity by infection of sows with a mild strain of PEDV to provide protection against infection with a severe strain. Also, PEDV was detected in air samples, indicating that airborne transmission was a route of transmission. Economic impacts of interventions to PRRS include a ground-breaking study comparing time to PRRSv-stability and production losses between two exposure programs to control PRRSv in sow herds. Mathematical modeling of influenza A virus dynamics within swine farms showed that the effects of vaccination reduced severity of field virus infection.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Loving, C., F.A. Osorio, M.P. Murtaugh and F.A. Zuckermann. 2015. Innate and adaptive immunity against porcine reproductive and respiratory syndrome virus. Vet. Immunol. Immunopath. 167:1-14.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Brar, M.S., M. Shi, M.P. Murtaugh, and F.C. Leung. 2015. Evolutionary diversification of type 2 porcine reproductive and respiratory syndrome virus. J. Gen. Virol. 96:1570-1580.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Wang, X., D. Marthaler, A. Rovira, S. Rossow, and M.P. Murtaugh. 2015. Emergence of a virulent porcine reproductive and respiratory syndrome virus in vaccinated herds in the United States. Virus Res. 210:34-41.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Robinson, S.R., J. Li, E.A. Nelson, and M.P. Murtaugh. 2015. Broadly neutralizing antibodies against the rapidly evolving porcine reproductive and respiratory syndrome virus. Virus Res. 203:56-65.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Balka, G., X. Wang, A. Balint, I. Kiss, F. Olasz, K. Banai, M. Rusvai, T. Stadejek, D. Marthaler, M.P. Murtaugh, and Z. Zadori. 2015. Full genome sequence analysis of a wild, non-MLV-related type 2 Hungarian PRRSV variant isolated in Europe. Virus Res. 200:1-8.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Goede, D., M.P. Murtaugh, J. Nerem, P. Yeske, K. Rossow, and R. Morrison. 2015. Previous infection of sows with a mild strain of Porcine Epidemic Diarrhea Virus confers protection against infection with a severe strain. Vet Micro. 176:161-164.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Stricker, A.M., D.D. Polson, M.P. Murtaugh, J. Christopher-Hennings, and T. Clement. 2015. Variation in porcine reproductive and respiratory syndrome virus open reading frame 5 diagnostic sequencing. J. Swine Health Prod. 23:18-27.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Diaz A, Perez A, Sreevatsan S, Davies P, Culhane M, Torremorell M (2015). Association between influenza A virus infection and pigs subpopulations in endemically infected breeding herds. PLoSOne, 10(6):e0129213. doi: 10.1371/journal.pone.0129213
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Alvarez J, Torremorell M, Morrison R, Perez A (2015). Association of the presence of influenza A virus and porcine reproductive and respiratory syndrome virus in sow farms with post-weaning mortality. Prev Vet Med. pii: S0167-5877(15)00235-4. doi: 10.1016/j.prevetmed.2015.07.003.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Alonso C, Raynor PC, Davies PR, Torremorell M (2015). Concentration, size distribution, and infectivity of airborne particles carrying swine viruses. PLoS One. 10(8):e0135675. doi: 10.1371/journal.pone.0135675. eCollection 2015.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Diaz A, Enomoto S, Romagosa A, Sreevatsan S, Nelson M, Culhane M, Torremorell M (2015). Genome plasticity of triple reassortant H1N1 influenza A virus during infection of vaccinated pigs. J Gen Virol. doi: 10.1099/jgv.0.000258.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Nelson MI, Culhane MR, Rovira A, Torremorell M, Guerrero P, Norambuena J (2015). Novel human-like influenza A viruses circulate in swine in Mexico and Chile. PLOS Currents: Outbreaks. Edition 1. doi: 10.1371/currents.outbreaks.c8b3207c9bad98474eca3013fa933ca6.