Detection and Control of Porcine Reproductive and Respiratory Syndrome Virus and Emerging Viral Diseases of Swine

<p>NON-TECHNICAL SUMMARY:<br/> Outcomes or Projected Impacts: Production of value-added swine and pork products through the diagnosis and control of PRRSV and emerging viral disease in breeding herds and genetic stocks. (GPRA obj G1.1) Increased global competitiveness of the U.S. swine industry by eliminating the cost of PRRS and by producing PRRS-free pigs. (obj. G1.2) Improved access to affordable and healthful pork and pork products. (obj. G2.1) Improved food safety by elimination of disease agents most impactful on health in swine. (G2.2) Promotion of greater harmony between agriculture and the environment by the development of more efficient and sustainable swine production practices through elimination of the most significant health hazard to swine. (G4.1) Increased capacity of communities and families to enhance their own economic well-being through more profitable
management of swine farms. (G5.1) Increased capacity of communities, families and individuals to improve their own quality of life and job satisfaction by raising healthier pigs. (G5.2)
<p>APPROACH:<br/> Objective 1a. Basic research studies, including functional immunology and signal transduction pathways in cytokine production will be investigated in PRRSV-infected and uninfected pigs in vivo and in primary macrophage cell cultures in vitro. Recombinant viral proteins will be used to evaluate cell proliferation and IFN production. Objective 1b.Animal challenge studies using infectious clones for different viruses (developed in Obj.3) will be conducted in the selected institutions. Objective 1c. To understand the immunological basis for viral co-infections on respiratory disease pathogenesis the disease model proposed will incorporate a combination of two or more viral pathogens, such as PCV2 and PRRSV (the most common co-factor associated with PCV2) administered to gnotobiotic or specific pathogen free pigs. We will measure the functional properties of
humoral and cellular responses during viral co-infection and development of disease in comparison to the single pathogen infection or as a response to vaccination for one or both pathogens. Objective 2a. Methods used to study these components will include risk factor assessment such as the AASV PRRSV risk assessment tool and should include large field-based investigations. Objective 2b. Evaluation of the effectiveness of current and novel practices for preventing pathogen infection in a herd will be part of the research conducted. Objective 2c. Collaborate with researchers in the basic sciences to identify the role and impact of virus diversity and evolution on the ecology, epidemiology, and virulence of and other emerging viral infections of swine in production settings and in different countries (USA, Mexico, China, Spain). Objective 2d.Develop models of infection and disease at the
herd, production system, and meta-population levels for the purpose of identifying ecologic and epidemiologic critical control points that may be used to prevent infection, reduce their impact on the swine health, or eliminate them from the U.S. swine herd. Objective 3a. Humoral and cellular immunity associated with long-term protective immunological memory defines the efficacy of a given vaccine formulation (and will be assessed in Obj.1). Objective 3b. Full-length infectious cDNA clones are available for type 1 and 2 genotypes of PRRSV, so it is now possible to alter the PRRSV genome to create rationally defined vaccine candidates. Objective 3c.The development of novel antiviral drugs and therapeutics will be approached based on RNA interference (RNAi); silencing of PRRSV replication will be guided by small interfering RNAs (siRNAs). Objective 3d. While current diagnostic methods are
generally very good, both PCR and ELISA assays require monitoring and modification of probes, diagnostic laboratory resources, and can be improved. Current diagnostic methods will be improved.
<p>PROGRESS: 2013/01 TO 2013/09<br/>Target Audience: veterinary researchers and diagnosticians, veterinary practitioners, pork producers, veterinary biologics and diagnostic companies Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Training was provided for 2 Research Associates, 2 PhD candidates at SDSU How have the results been disseminated to communities of interest? Many abstracts were submitted and presentedto the National Pork Producers, American Association of Swine Veterinarians, other researchers (Conference for Research Worker's In Animal Diseases, American Association of Virology, American Association of Veterinary Laboratory Diagnosticians, American Association of Microbiology), locally to the SD PRRSV Area Regional Control Group, and internationally to the International PRRSV
Symposium in Beijing China. What do you plan to do during the next reporting period to accomplish the goals? Continue work on PRRSV host interaction with focus on the role of innate immunity (eg. PKR against PRRSV infection). We will also continue to explore the utility of using virus-like particles for PRRSV vaccine development. We will continue efforts to develop improved diagnostic and control methods to reduce the impact of PEDV on the US swine industry.
<p>PROGRESS: 2012/01/01 TO 2012/12/31<br/>OUTPUTS: A multiplex swine immune effector molecule assay was licensed to Life Technologies, Inc. and is now commercially available. This assay will be useful to vaccine companies, researchers and others that want to evaluate swine cytokine responses in the development of new PRRSV control measures. Validation of oral fluids for the detection of PRRSV and swine influenza by PCR methods has been performed and optimized extraction and PCR procedures are currently being used for field samples. The use of oral fluids for PRRSV serology has also been fully validated and is widely available to swine producers and practitioners. Development of the fluorescent microsphere immunoassay (FMIA) for detection of antibodies against PRRSV using oral fluid samples provides a framework from which a more robust assay could be developed to profile
the immune response to multiple PRRSV antigens in a single test. The development of oral fluid-based diagnostic tests will change the way we survey diseases in swine herds and improve our ability to cheaply and efficiently track PRRSV infections in both populations and individual animals. The study of interferon expression using PRRSV as a vector demonstrated that the recombinant PRRSV can be a useful tool to study the role of different cytokines in disease progression and immune responses, which represents a new strategy for future therapeutic application and vaccine development. The study of interaction between PRRSV nsp2 and host innate immune response suggests that virus-specific immunity could be enhanced by modifying certain regions within or upstream of the PLP2-DUB domain. This study represents a step forward in elucidating the role of nsp2 in PRRS pathogenesis. A better
understanding of PRRSV-host interactions and innate immune mechanisms is essential for the future development of novel antiviral therapies. PARTICIPANTS: Molecular Virology Research Laboratory: Ying Fang, Associate Professor; Steven Lawson, Post-doc Research Associate; Zhi Sun, Post-doc Research Associate; Robert Langenhorst, Graduate Research Assistant; Russell Ransburgh, Graduate Research Assistant; Yanhua Li, Graduate Research Assistant. Molecular Diagnostic Laboratory: Jane Christopher-Hennings, Professor; Travis Clement, Research Associate. Serology Laboratory: Eric Nelson, Professor; Aaron Singrey, Senior Microbiologist; Xiaodong Liu, Microbiologist. Primary collaborators at Iowa State University: Jeff Zimmerman, Professor; Apisit Kittawornrat, PhD Student; Chris Olsen, PhD Student. Primary collaborators at Kansas State University: Richard Hesse, Professor; Jianfa Bai, Assistant
Professor; Raymond Rowland, Professor. Training and education opportunities were provided for multiple graduate and undergraduate students. TARGET AUDIENCES: Target audiences include veterinarians, researchers, biomedical companies and others interested in collaborations and information on control and detection of PRRSV and viral respiratory diseases of swine. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
<p>PROGRESS:2011/01/01 TO 2011/12/31<br/>OUTPUTS: The project outputs have been presented and are listed in the abstracts under "publications" below. The NC229 project is a multi-collaborative, multi-state, multi-university project entitled, "Detection and control of porcine reproductive and respiratory syndrome virus and emerging viral diseases of swine". There are 5 objectives for this research including 1) Research related to pathogenesis/persistence 2) Research related to virus evolution 3) Research related to mechanisms of transmission 4) Research related to viral Immunity and cross-protection 5) Research related to epidemiology. There are 4 laboratories represented in this project from South Dakota State University with some independent and collaborative projects to achieve these objectives. Outputs included a panel of monoclonal and polyclonal antibodies to
non-structural proteins of PRRSV which will be important tools in studies of PRRSV replication and pathogenesis (Objective 1). An understanding that recombinant PRRSV can be produced whereby IL1B expression or modifications in nsp2 can enhance viral specific immunity. These are important modifications to further vaccine design (Objective 4). A multiplex fluorescent microsphere immunoassay for antibodies against PRRSV differentiates types I and II and can be used for multiplexing for serological profiling (Objective 4 & 5). PARTICIPANTS: Graduate Students were trained during this project: (Y. Fang)Robert Langenhorst, Yanhua Li, Zhi Sun; (J. Christopher-Hennings) Mike Dunn Post doctoral training: S. Lawson (Y. Fang) Other collaborators: Irwin C, (ISU): Zimmerman J, (ISU): Harmon K, (ISU); Kittawornrat A., (ISU); Young, Alan J. (SDSU); Knudsen, David (SDSU); Furhman M. (SD Industry);
Vincent, A. (NVSL); Hesse R (KSU); Rowland B. (KSU); Snijder E, (Leiden University, Netherlands);Xie, Lij (visiting scholar, SDSU); Xie, Zhixun (Collaborator, Guangxi Veterinary Research Institute); Otterson T (U of MN); McGill J (NVSL); Shah R (Life Technologies); Rauh R. (Tetracore, Inc.) TARGET AUDIENCES: Target audiences included: Other researchers nationally and internationally: Intl. PRRSV Symposium, Intl. Nidovirus Meeting, Veterinary Laboratory Diagnosticians: AAVLD meeting, N. Central Conference of the Veterinary Laboratory Diagnosticians meeting. Swine Veterinarians: Am. Assoc. of Swine Veterinarian's meeting PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.