Specific, simple and rapid detection of porcine circovirus type 2 using the loop-mediated isothermal amplification method

A loop-mediated isothermal amplification (LAMP) assay was used to detect PCV2 in this study. Three pairs of primers were specially designed for recognizing eight distinct sequences of the ORF2 gene. This gene lies in the PCV2 virus genome sequence, and encodes the Rep protein that is involved in virus replication. Time and temperature conditions for amplification of PCV2 genes were optimized to be 55 min at 59°C. The analysis of clinical samples indicated that the LAMP method was highly sensitive. The detection limit for PCV2 by the LAMP assay was 10 copies, whereas the limit by conventional PCR was 1000 copies. The assay did not cross-react with PCV1, porcine reproductive and respiratory syndrome virus, porcine epidemic diarrhea virus, transmissible gastroenteritis of pigs virus or rotavirus. When 110 samples were tested using the established LAMP system, 95 were detected as positive.The newly developed LAMP detection method for PCV2 was more specific, sensitive, rapid and simple than before. It complements and extends previous methods for PCV2 detection and provides an alternative approach for detection of PCV2.Porcine circovirus type 2 (PCV2) is a non-enveloped, circular, single-stranded DNA virus that belongs to the Circoviridiae family [1]. This virus is widespread in the commercial swine population, and is accepted as the causative agent of a number of diseases in these animals, such as postweaning multisystemic wasting syndrome (PMWS) [2], and porcine dermatitis and nephropathy syndrome (PDNS). These syndromes cause great losses to the pig industry. As a result, it is necessary to develop an effective method for detecting PCV2 to prevent these diseases. At present, many methods have been developed for the detection of this virus; among which, conventional PCR is commonly used [3]. However, the usefulness of PCR is limited by the presence of PCR inhibitors in the analysis of real biological samples. The wide range of inhibitors (including organic and inorganic