Efficacy of an orally administered classical swine fever live marker vaccine (Flc-LOM-BErns strain) in pigs

Abstract

In several countries, classical swine fever (CSF) has not been detected in domestic pigs, but has been detected in wild boars, making the disease difficult to control. To overcome this problem, we inoculated pigs with a CSF live marker vaccine (Flc-LOM-BE^rns strain), which has "distinguish infection from vaccinated animals (DIVA)" function, to determine whether it is suitable as an oral vaccine specifically for wild boars. Pigs inoculated intramuscularly or orally with the Flc-LOM-BE^rns vaccine were challenged 2 or 4 weeks later, respectively, with virulent CSFV. Pigs administered the oral Flc-LOM-BE^rns strain (10^{5.0 and 6.0} TCID₅₀/dose), and those vaccinated intramuscularly (10^3.0 TCID₅₀/dose), had normal numbers of leukocytes and normal body temperature. Also, they generated protective neutralizing antibodies and anti-BVDV E^rns antibodies. In addition, all pigs in these groups survived, with no CSFV RNA detected in feces, spleen, or other organs. Thus, the Flc-LOM-BE^rns vaccine shows excellent safety and efficacy, while having DIVA function and suitability for oral inoculation.

Keywords: CSFV; DIVA; Flc-LOM-BE(rns); Oral; Pig.