Porvac^® Subunit Vaccine Protects Against Three Field Isolates of Classical Swine Fever Virus

The control of classical swine fever (CSF) in endemic areas has been attempted with modified live vaccines. However, in some regions, the implementation of imperfect vaccination programs has led to a reduction in the genetic diversity of the circulating CSF virus (CSFV) strains and a change in their virulence. Porvac^® subunit vaccine has been shown to provide a rapid onset of protection against the "Margarita" strain. The aim of this study was to evaluate whether the immune response induced by Porvac^® is also effective against autochthonous CSFV isolates of low, medium or high virulence. All pigs vaccinated with Porvac^® were protected against the disease after challenge. PR-11/10-3 isolate caused a very mild disease in controls, whilst Holguin_2009 isolate produced mild to moderate signs of CSF and one of the pigs died. Finally, controls inoculated with PR-2016 isolate developed moderate to severe signs of CSF and two of them died. Viral replication was detected in controls, but not in pigs immunized with Porvac^®. Finally, anti-E^rns antibodies were induced in five out of six control pigs but not in any of the vaccinated pigs. These results support the use of Porvac^® for the control and elimination of CSF in Cuba and other endemic regions.