ISOLATION AND IDENTIFICATION OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS IN CELL-CULTURES

Three strains of porcine reproductive and respiratory syndrome virus ( PRRSV) were isolated in porcine lung macrophage (PLM) cultures from th ree swine herds. This has been the first successful isolation of PRRSV in the Czech Republic and the strains received the designations CAPM V-501, CAPM V-502 and CAPM V-503, respectively. All the three isolates in PLM were identified by immunofluorescence and immunoperoxidase tes ts and the strain CAPM V-502 also by electron microscopy using the ult rathin section technique. The strain CAPM V-502 has been adapted to th e cell line MARC-145. Viral RNA in PLM cultures infected with any of t he isolated PRRSV strains was demonstrated by RT-PCR targeted to the m ore conserved ORF 7 genomic region encoding the nucleocapsid protein. The assessment of PCR products in agarose gel revealed a uniform size of 394 bp in all the three isolates and the European prototype strain Lelystad used as positive control.