Analysis of ORF 1 in European porcine reproductive and respiratory syndrome virus by long RT-PCR and restriction fragment length polymorphism (RFLP) analysis

A rapid method was developed for partial characterization of the replicase- encoding open reading frame 1 (ORF 1) of porcine reproductive and respirato ry syndrome virus (PRRSV). It comprised long RT-PCR amplification of 11.1 k b (94%) of ORF 1, followed by restriction fragment length polymorphism anal ysis. The method was used to compare ORF 1 sequences of two divergent Europ ean-type PRRSV strains. Our results indicated that the structural and repli case parts of these two strains had evolved at overall similar rates. (C) 2 000 Elsevier Science B.V. All rights reserved.