Tousignant, Steven2015-11-062015-11-062015-08https://hdl.handle.net/11299/175353University of Minnesota Ph.D. dissertation. August 2015. Major: Veterinary Medicine. Advisors: Robert Morrison, Peter Davies. 1 computer file (PDF); x, 129 pages.Given the lack of good epidemiological data regarding the incidence of PRRSV in the US, the objectives of this dissertation were to 1) document and describe spatial and temporal patterns of PRRSV in the US, 2) describe changes in these patterns over time, 3) investigate the frequency of aerosol PRRSV detection under field conditions as a potential means of transmission, 4) identify risk factors of PRRSV and PED infections and 5) identify factors associated with PRRSV introductions on filtered farms. The data in this thesis suggests that PRRSV behaved predictably between 2009 and 2013, when PEDV emerged in the US swine population and PRRS incidence dropped significantly. Additionally, the frequency of detection of aerosolized PRRSV may be a rare, but highly consequential event. High biosecurity is associated with decreased odds of disease, and filtered farms have undergone many modifications in the past decade to further reduce incidence.enEpidemiologyPRRSSwineThesis or Dissertation