Two real-time RT-PCR assays of classical swine fever virus, developed for the genetic differentiation of naturally infected from vaccinated wild boars

Abstract

Classical swine fever virus (CSFV) is the causative agent of classical swine fever (CSF), a disease notifiable to the Office International des Epizooties (OIE). A live marker vaccine would be the ultimate choice for controlling CSF, which enables serological and genetic differentiation of vaccine from wild type CSFV. Recently, a marker vaccine CP7_E2alf has been reported [Koenig, P., Lange, E., Reimann, I., Beer, M., 2007. CP7_E2alf: a safe and efficient marker vaccine strain for oral immunisation of wild boar against classical swine fever virus (CSFV). Vaccine 25, 3391–3399]. A vaccine-specific TaqMan real-time RT-PCR assay was developed and evaluated, and a second, wild type-specific assay was modified from an established one in such a way that both can be performed in two wells side-by-side in a microplate in a single run. The detection limit is 50 viral RNA copies per reaction for the vaccine-specific assay, and 20 copies per reaction for the wild type assay. The two assays have been shown to be highly specific and reproducible, with potential application for genetic differentiation of wild type CSFV from the marker vaccine CP7_E2alf in wild boar vaccination programs.