Oral and sub-cutaneous vaccination of commercial pigs with a recombinant porcine adenovirus expressing the classical swine fever virus gp55 gene

A recombinant porcine adenovirus expressing the classical swine fever virus (CSFV) gp55/E2 gene was administered to commercially available pigs via or al or subcutaneous routes and their susceptibility to oral and subcutaneous challenge with CSFV was determined. 100% of animals vaccinated and challen ged subcutaneously were protected. In the groups of pigs vaccinated either orally or subcutaneously and then challenged orally, 60% of animals were pr otected. Before challenge, neutralising antibodies to CSFV were detected in 60% of pigs vaccinated subcutaneously, but in none of those given the vacc ine orally. CSFV antigen was found in the spleens of surviving pigs that ha d been vaccinated orally. In contrast, subcutaneous vaccination was shown t o preclude the presence of CSFV in the spleen of animals that survived chal lenge.