Start Date: Jul 01, 2008
End Date: Feb 15, 2011
PRRSV is the cause of the number one disease concern for US pork producers and the available vaccines have failed to produce an adequate control strategy. Biological studies have so far revealed that this virus has developed a number of methods to evade the swine host immune response including high frequency viral recombination to produce tremendous strain variation, attachment of sugars to mask key neutralization domains and an ambiguous dampening of an effective immune response. To produce a more robust control program for PRRSV, our approach is to modify the virus through reverse genetics such that the innate and/or acquired immune response is improved or repaired. Other swine viruses, such as porcine circovirus and swine influenza virus, have been shown to exacerbate PRDC in swine production systems. Modification of a PRRSV reverse genetic system to incorporate immunogenic regions of other pathogens may be considered. Combining immunogenic regions of other pathogens may produce a multivalent vaccine that would be advantageous in PRDC control programs. Thus, our approach will involve interactions between clinical professionals at ISU-CVM and scientists at NADC to uncover novel PRRSV strains and develop advanced vaccine prototypes that may include genetic regions of other pathogens. Scientists from the NADC and ISU-CVM will conduct the proposed collaborative research. The research will focus on in vitro and in vivo studies that will 1) explore how PRRSV replicates and investigate mechanisms of virulence, 2) test effects of genetic mutations in putative virulence domains, and 3) maintain a surveillance program looking for unique PRRSV isolates in the field.