RESUMO
Three primer were designed based on the consevered area of the genetic of the ATCC VR-2332 strain and LV strain. And the nest RT-PCR of testing porcine reproductive and respiratory syndrome virus were developed. The nest RT-PCR against ATCC VR-2332 strain, LV strain and B13 strain were done by this method.The DNA fragment were obtained specially from the three strains isolated from different region. The size were 430bp (430bp) , 410bp (413bp) and 410 bp (413bp) separately. But the DNA fragment were not obtained from HCV, PPV and PRV. Its sensitivity was 10-2 TCID50. It's sensitivity increased 10000 times than one step RT-PCR. It should make the method of testing porcine reproductive and respiratory syndrome virus more sensitive, fast and accurate.