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Zuo X, Peng G, Xia Y, Xu L, Zhao Q, Zhu Y, Wang C, Liu Y, Zhao J, Wang H, Zou X. A quadruple fluorescence quantitative PCR method for the identification of wild strains of african swine fever and gene-deficient strains. Virol J 2023; 20:150. [PMID: 37452402 PMCID: PMC10347796 DOI: 10.1186/s12985-023-02111-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 06/30/2023] [Indexed: 07/18/2023] Open
Abstract
BACKGROUND Originating in Africa, African swine fever (ASF) was introduced to China in 2018. This acute and highly virulent infectious disease affects domestic pigs. The World Organization for Animal Health has listed it as a statutory reportable disease, and China has listed it as a category A infectious disease. METHODS Primers and probes were designed for four ASFV genes (B646L, EP402R, MGF505-3R, and A137R). The primers/probes were highly conserved compared with the gene sequences of 21 ASFV strains. RESULTS After optimization, the calibration curve showed good linearity (R2 > 0.99), the minimum concentration of positive plasmids that could be detected was 50 copies/µL, and the minimum viral load detection limit was 102 HAD50/mL. Furthermore, quadruple quantitative polymerase chain reaction (qPCR) with nucleic acids from three porcine-derived DNA viruses and cDNAs from eight RNA viruses did not show amplification curves, indicating that the method was specific. In addition, 1 × 106, 1 × 105, and 1 × 104 copies/µL of mixed plasmids were used for the quadruple qPCR; the coefficient of variation for triplicate determination between groups was < 2%, indicating the method was reproducible. CONCLUSIONS The results obtained by testing clinical samples containing detectable EP402R, MGF505-3R, and A137R strains with different combinations of gene deletions were as expected. Therefore, the established quadruple qPCR method was validated for the molecular diagnosis of ASF using gene-deleted ASFV strains.
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Affiliation(s)
- Xuezhi Zuo
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China
- China/WOAH Reference Laboratory for Classical Swine Fever, China Institute of Veterinary Drug Control, Beijing, China
| | - Guorui Peng
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China
| | - Yingju Xia
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China
| | - Lu Xu
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China
| | - Qizu Zhao
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China
| | - Yuanyuan Zhu
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China
| | - Cheng Wang
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China
- China/WOAH Reference Laboratory for Classical Swine Fever, China Institute of Veterinary Drug Control, Beijing, China
| | - Yebing Liu
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China
| | - Junjie Zhao
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China
| | - Haidong Wang
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, Shanxi, China.
| | - Xingqi Zou
- China/WOAH Reference Laboratory for Classical Swine Fever, China Institute of Veterinary Drug Control, Beijing, China.
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Zhan Y, Zhang LH, Lin Y, Cai YF, Zou YW, Hao ZY, Luo ZH, Wang ND, Deng ZB, Yang Y, Wang CJ, Yang Q. Development and preliminary testing of a probe-based duplex real-time PCR assay for the detection of African swine fever virus. Mol Cell Probes 2021; 59:101764. [PMID: 34534618 DOI: 10.1016/j.mcp.2021.101764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 08/30/2021] [Accepted: 09/11/2021] [Indexed: 11/23/2022]
Abstract
An outbreak of African swine fever (ASF) in China in 2018 caused substantial economic losses to the swine industry. To accurately diagnose clinical infection with ASF virus (ASFV), we developed a TaqMan probe-based duplex real-time PCR that simultaneously detected two discontinuous genes in the virus genome, thereby preventing the inaccurate results obtained with only one reaction. Two sets of ASFV gene-specific primers, along with two fluorescent TaqMan probes were designed to target conserved regions of the B646L and B438L genes. This method had high sensitivity and specificity, with a limit of detection of 10 copies/μL, and it did not cross-react with the genomes of other viral pathogens that affect pigs (i.e., CSFV, PRRSV, PEDV, PRV, PPV and PCV2). Overall, 180 clinical samples from ASFV-infected pig farms were used to compare this method with a commercial kit, which yielded excellent consistency (98.3%). This new diagnostic method should greatly improve the efficiency of ASFV surveillance and reduce economic losses, providing benefits for both animal and public health.
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