The PHGC represents the first-of-its-kind approach to food animal infectious disease research. The NPB, PRRS CAP, ARS, USDA AFRI, private companies, and universities have come together to conduct a multi-year project designed to understand how host genetics influences the outcome of PRRSV infection. The principal activity completed in Year 2 includes the infection of 600 pigs, PHGC4, PHGC5 and PHGC6. The analysis of pig genomic DNA and host RNA gene expression studies are supported by PHGC-stimulated matching funds. Previous results have affirmed that there are genetic components involved in controlling pig responses to PRRSV infection and this research has identified new avenues for other areas of PRRS research, including new diagnostic techniques, new surveillance approaches, and a better understanding of virus ecology. Swine producers will be able to apply the PHGC data to: 1) determine the relationships between PRRS viral levels, weight gain, and underlying pig genetics; 2) develop better management techniques for the control of PRRSV infection and disease; 3) improve surveillance for PRRSV and other infectious diseases; and 4) identify genes and phenotypic markers that are linked to specific infection and growth outcomes. The thorough characterization of PRRS-associated genes or genomic markers will be used in breeding programs to identify pigs that are more resistant to infection, tolerant to infection, produce a desired cytokine response, and/or respond well following vaccination (vaccine ready pigs). With the support of Year 3 funding, the PHGC will have reached the first milestone of infecting approximately 1600 pigs.