Heinen, P.P.

virus strain /swine swine fluenza netherland vaccine author antigenic sequence nucleotide variant table difference titre fluenza viruses antigenic drift outbreak nucleotide sequences study animal antigenic heterogeneity 1995/1996 hi titres heterogeneity reference 4452–4464 fluenza vaccines fi ve strains h 1n virus position pthyr season number virology drift cluster infection ef ficacy assay fluenza centre jong jc fluenza virus strains nucleotide sequences range antisera antiserum hi tests disease phylogenetic nucleoprotein genes scale bar vaccine strain biology laboratory fluenza virus european post-infection serum antibody europe nding dilution university inhibition vaccinated genbank neuraminidase fi ndings fluenza virus vaccines fi ve clusters italic type fi ve swine van nieuwstadt ap erasmus university rotterdam fi nishing pigs isolation vaccination hi variants vaccine strains vaccinated pigs ronde-verloop fm