Frequency of PRRS live vaccine virus (European and North American genotype) in vaccinated and non-vaccinated pigs submitted for respiratory tract diagnostics in North-Western Germany

A basic requirement of live vaccine virus strains is that natural transmission of vaccine virus is minimal or non-existent (3). The objectives of this study were (a) to determine the frequency of the EU and the NA genotype PRRS vaccine viruses in a large sample of pigs from North-Western Germany, (b) to assess the association between vaccine isolate detection and vaccination history and (c) to characterise the identified vaccine isolates considering their origin.   Elisabeth Grosse Beilag