Periódicos Brasileiros em Medicina Veterinária e Zootecnia

Synchronous detection of BPV and BVDV with duplex Taqman qPCR method

Gong, Zhuan-diGeng, Jin-jingLiang, Hao-qinLin, Guo-zhenShen, Xiao-yunLi, Qion-yiFeng, Ruo-feiWei, Suo-cheng

Background: Bovine parvovirus (BPV) and bovine viral diarrhea virus (BVDV) are commonly etiologies causing diarrheain dairy herds. BPV is a member of Bocaparvovirus genus with a non-enveloped capsid. BVDV, belonging to Pestivirusgenus in Flaviviridae, possesses a single-stranded RNA, and is classified into BVDV-1 and BVDV-2 genotypes accordingto the 5’UTR sequence. 21 genetic groups of BVDV-1 and four groups of BVDV-2 have been found. Diagnosis of viraldiarrhea is often relied on virus detection by isolation or detection of serum antibody. The main objective of the presentstudy was to establish a duplex real time PCR (qPCR) based on Taqman probe to detect synchronously BPV and BVDV.Materials, Methods & Results: TaqMan probe and primers were designed and synthesized from the sequences of conserved5′ - untranslated regions (5′ UTR) of Haden strain of BPV and NADL strain of BVDV. The cDNAs were transcribed invitro to make standard curves before optimizing the assay. DNA/PCR products were ligated into pMD18-T vector, andthen used to transfer BL-21 competent cells to acquire the recombinant plasmids of pMD18-T-BPV and pMD18-T-BVDV.Optimum reaction conditions were comparatively selected. The sensitivity, specificity and reproducibility of TaqMan probeqRT-PCR were evaluated respectively. The results showed the concentrations of pMD18-T-BPV or pMD18-T-BVDV were2.0 × 1010 DNA copies/μL, respectively. A duplex Taqman qPCR method was developed by optimizing the amplificationconditions to simultaneously detect BPV and BVDV. The assay targets at highly conserved VP2 gene of BPV and 5′ UTRgene of BVDV. This qPCR assay was assessed for specificity and sensitivity using DNA of BPV and cDNA of BVDV. Forclinical validation, 308 samples were tested from clinically diarrhea calves. The results showed that optimum annealingtemperature was achieved in 43.2 for duplex BPV and BVDV. Dynamic curves and standard...(AU)

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