Submitted to: National Hog Farmer
Publication Type: Popular Publication
Publication Acceptance Date: November 22, 2006
Publication Date: January 15, 2007
Citation: Not published as seperate article but integrated as part of article: J. Vansickle. 2007. Facing Chronic Disease. National Hog Farmwer Jan 15, 2007. Available: http://nationalhogfarmer.com/mag/farming_facing_chronic_disease/
The most important disease affecting US pork production is porcine reproductive and respiratory syndrome (PRRS). National Pork Board has estimated losses due to PRRS cost producers $600M each year. This article highlights the “Big Pig” project that demonstrates the advantages in using a multi-institutional (university and commercial), multi-disciplinary approach to analyze pig disease responses. “Big Pig” represents the first comprehensive study of porcine reproductive and respiratory syndrome (PRRS) virus replication and immunity within a single, relatively large population of experimentally infected pigs. For this study 109 pigs were infected with PRRSV at Iowa State University and sampled every two weeks up to 203 days. There were 56 litter matched, uninfected controls. All pigs were donated for this study. Over the course of the study, more than 20,000 pig samples were distributed to five institutions (Iowa State University, Kansas State University, South Dakota State University, IDEXX Laboratories, USDA BARC). There is now a depository of samples at Kansas State for other research projects; samples have already gone to the University of Michigan, University of Minnesota, and USDA NADC. This will be a resource for samples for validating new diagnostic tests.
What has been learned so far from this research? 1) Virus replication is extensive during the growth-finish phase; 2) PRRSV negatively impacts growth performance; 3) There is no correlation between acquired immunity and virus load; 4) There is discordance between molecular tests and bioassays used to detect PRRSV; 5) IDEXX was able to further validate their commercial ELISA for PRRS; and 6) Tests to predict PRRSV persistence are still unavailable.