Joint Research Unit IRTA-UAB in Animal Health, Animal Health Research Centre (CReSA), Autonomous University of Barcelona (UAB), Catalonia, Spain; Institute of Agrifood Research and Technology (IRTA), Animal Health Program (CReSA), WOAH Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe, Autonomous University of Barcelona (UAB), Catalonia, Spain.