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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #299456
Title: Targeted genetic research offers clues to PRRS resistance

Author
item Lunney, Joan
item ROWLAND, RR - Kansas State University
item DEKKERS, J - Iowa State University

Submitted to: National Hog Farmer
Publication Type: Popular Publication
Publication Acceptance Date: 11/29/2012
Publication Date: 12/15/2012
Citation: Lunney, J.K., Rowland, R.R., Dekkers, J. 2012. Targeted genetic research offers clues to PRRS resistance. National Hog Farmer. p. 21.

Interpretive Summary:

Technical Abstract: Infection with porcine reproductive and respiratory syndrome (PRRS) virus elicits a weak immune response in pigs that is not fully protective and which often results in persistent infection in a subset of pigs. Despite substantial research efforts, the exact components of a protective anti-PRRS virus immune response are not known, particularly as it affects viral persistence. In a national effort to assess the role of genetics in determining pig resistance/susceptibility to PRRS virus infection and related pathology and growth effects, the PRRS Host Genetics Consortium (PHGC) was formed. By collecting data on large numbers of PRRS virus-infected pigs, researchers aim to identify and verify important genotypes and phenotypes that predict resistance, tolerance or susceptibility to the viral infection. To date, 13 PRRS virus infection trials of about 200 pigs each have been performed. Numerous samples were collected and stored in duplicate locations at Kansas State University and at the Beltsville Area Research Center. Using this data, genome-wide association analysis (GWAS), performed at Iowa State University, has identified that a region on swine chromosome 4 (SSC4) has major effects on virus load and weight gain following infection with the PRRS virus. The effect of the favorable "B" allele at a target SNP (single-nucleotide polymorphism or snip) in this region, WUR10000125, is dominant, so pigs that have at least 1 copy of this allele are less susceptible to PRRS as seen by the decreased viral levels and improved weight gain for AB as compared to AA pigs (see Figure). These studies have begun to identify genetic alleles that could help predict which pigs will clear PRRS virus faster and grow better following infection. This work sets the stage for targeting the genetic region to identify the exact genes involved and the mechanism that induces the early anti-PRRS virus response. These efforts could potentially lead to new anti-PRRSV biotherapeutics or vaccines. The PHGC is a multi-year project funded by Pork Checkoff, USDA, universities and private companies. The consortium represents the first-of-its-kind approach to food animal infectious disease research.