Epidemics of severe swine disease, termed “Porcine High Fever Disease (PHFD)”, continue to be reported in Southeast Asia, and a specific strain of porcine reproductive and respiratory syndrome virus (PRRSV) has been identified as the primary pathogen in these epidemics. This viral strain has not been identified in the United States, nor has PRRS disease been associated with such severe symptoms as reported in China, Vietnam, and other neighboring countries. The objective of this proposal was to study a Vietnam PRRSV isolate recovered from the epidemic of PHFD by primary genetic analysis of the virus, development of a reverse genetic system, and analysis of the recombinant virus in cell culture. Unfortunately, the transfer of the genetic material of the virus from our collaborators was severely delayed, such that only part of the proposed research has been completed. However, we have determined that the isolate, named SRV-07, aligns with other PHFD PRRSV isolates from other Asian countries, that these isolates still have not been detected in the United States. We have developed the tools to ensure correct diagnoses if/when similar isolates may appear in our country. The insights will benefit the US pork industry by having advanced detection tools for prompt diagnosis, and possible new virulence attributes of the Southeast Asian PRRSV isolate.