The invention relates to a method for detecting
nucleic acid of a porcine reproductive and respiratory syndrome (PRRS)
virus by one step, which comprises the following steps of: collecting,
processing and detecting samples, wherein in the collecting step, an animal blood sample is dripped into a full type approval (FTA) card
sample area; and the detecting steps comprises the: (1) designing
specific primers and a probe for general type PRRS
virus, and marking carboxyfluorescein (FAM) and tetramethyl
rhodamine (TAMARA) fluorescent groups on the probe; and (2) preparing and optimizing a detection
system and a reaction condition, wherein a
reaction system comprises 25 or 50 microliters of trihydroxymethyl aminomethane-
hydrogen chloride (HCl) (the pH value is between 7.8 and 9.0), 0.1 to 0.5 micro mol of upstream primer and 0.1 to 0.5 micro mol of downstream primer, 100 to 400 micro mols of deoxynucleotide mixture, 0.1 to 0.5 micro mol of probe, 100 to 300 U of Moloney
murine leukemia virus (M-MLV)
reverse transcriptase, 1 to 5 U of thermostable deoxyribonucleic acid (
DNA)
polymerase, 4 to 8 mols of Mg<2+->, 300 to 500 nano mol of homogenized reference dyes ROX, and 1 to 15 microliters of sample which is re-suspended in trihydroxymethyl aminomethane-
ethylene diamine tetraacetic acid (EDTA)
buffer solution and is added before each time of reaction. In the method, the
sample collection is easy and convenient, so that an FTA card containing s ribonucleic acid (
RNA) sample can be posted to any one central laboratory to be detected according to a form of regular mails; and the
pollution risks are reduced, and the detection sensitivity is improved.