Atypical porcine pestivirus (APPV) is a single-stranded, positive-sense, enveloped RNA virus approximately 11.4 kb in length belonging to the Pestivirus genus and Flaviviridae family. APPV is a genetically distinct pestivirus that infects swine and has been observed in four continents: North America, South America, Europe, and Asia. The genome is highly diverse between viral strains detected in different countries, forming independent clusters according to geographic region. Symptoms of APPV infection have been observed in piglets to include congenital tremors and possibly splay leg syndrome. The virus has been detected in clinically healthy adult pigs.