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<ul> <LI> Investigate alterations in the immune system of pigs infected with Porcine Circovirus Type 2 (PCV2) and/or Porcine Reproductive and Respiratory Syndrome Virus (PRRSv). <LI> Examine the role of cell-mediated immunity in pig response to homologous and heterologous viral challenge after immunization or infection with PRRSv. <LI> Evaluate the influence of management factors on the introduction, changes in strain, virulence and relationship between PRRSv and PCV2. <LI> Determine the impact of PCV2 and/or PRRSv on pig health/productivity in commercial farms. <LI> Determine if activated phagocytes, mast cells, cytokines and reactive oxygen metabolites induce prostaglandin synthesis in piglet ileum, and if the PGs and nitric oxide enhance barrier function of the gut epithelium. <LI> Evaluate the influence of weaning age on gut epithelium and select immune cells. <LI> Assess the prevalence and significance of bacterial pathogens in swine waste with emphasis on the potential public health risks.
NON-TECHNICAL SUMMARY: The North Carolina pork industry experienced rapid growth and continues to change methods of pork production. The changes in production have not eliminated infectious diseases, and thus, this project incorporates molecular/genomic approaches with epidemiologic methods to investigate PCV2 and PRRS virus and other significant pathogens. The project also will initiate studies to assess the potential public health concerns of bacterial pathogens in swine waste. Project examines infectious diseases in pork production Purpose is to investigate PCV2 and PRRS virus. Will study the potential public health concerns of bacterial pathogens in swine waste.
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APPROACH: Quantitative RT-PCR and gene sequencing will be used to detect and assess differences in PRRSv strains and response to wild-type and vaccine challenge, cytokine messages in macrophages and lymphocytes. Real-time PCR methods to quantify PCV2 load in infected pigs and ELISA's and SN's to characterize antibody response to vaccination, virus exposure and infection in commercial pig farms. Immunohistochemical or in situ hybridization to confirm the presence of viral antigen in pigs affected with PCV2. Epidemiological methods and controlled studies will determine the role of management factors on the introduction and control of PRRSv and/or PCV2 strains in commercial farms. Study mechanisms of gut healing using acutely injured and piglet intestine in Ussing chambers in vitro. The trans-epithelial electrical resistance, permeability, and cytokine and PG production rates will be determined with this tissue. Applied epidemiology and molecular methods (RT-PCR, sequencing) will be combined to determine the presence and significance of porcine bacterial pathogens in swine lagoons and wastewater.