Porcine reproductive and respiratory syndrome virus continues to be a significant problem for pork producers. The aim of this body of work was to help stakeholders control and prevention infection with this virus. A literature review of currently available diagnostic tests and guidelines for their interpretation serves as a resource for producers, practitioners, and researchers. The research focus was to evaluate two novel methods to develop improved modified live vaccines. The efficacy of viral chimeras constructed from a commercially available vaccine and a virulent wild-type isolate and the ability to attenuate wild-type isolates with a unique cell passage process are reported. Both techniques proved to be capable of developing potential vaccine candidates.