An improvement of real-time polymerase chain reaction system based on probe modification is required for accurate detection of African swine fever virus in clinical samples in Vietnam

• Published in: Animal bioscience Vol. 33; no. 10; pp. 1683 - 1690
• Main Authors: Tran, Ha Thi Thanh, Dang, Anh Kieu, Ly, Due Viet, Vu, Hao Thi, Van Hoang, Tuan, Nguyen, Chinh Thi, Chu, Nhu Thi, Nguyen, Vinh The, Nguyen, Huyen Thi, Truong, Anh Due, Pham, Ngoc Thi, Dang, Hoang Vu
• Format: Journal Article
• Language: English
• Published: Asian - Australasian Association of Animal Production Societies 01-10-2020; Asian-Australasian Association of Animal Production Societies (AAAP) and Korean Society of Animal Science and Technology (KSAST); Asian-Australasian Association of Animal Production Societies; 아세아·태평양축산학회
• Subjects: african swine fever; conventional polymerase chain reaction; Hog cholera; molecular diagnosis; pams cell; Polymerase chain reaction; Rankings; real-time polymerase chain reaction; Scientific equipment and supplies industry; Scientific equipment industry; Swine; virus isolation; 축산학; United States; Vietnam
• ISSN: 1011-2367; 2765-0189; 1976-5517; 2765-0235
• DOI: 10.5713/ajas.19.0525

Objective: The rapid and reliable detection of the African swine fever virus (ASFV) plays an important role in emergency control and preventive measures of ASF. Some methods have been recommended by FAO/OIE to detect ASFV in clinical samples, including realtime polymerase chain reaction (PCR). However, mismatches in primer and probe binding regions may cause a false-negative result. Here, a slight modification in probe sequence has been conducted to improve the qualification of real-time PCR based on World Organization for Animal Health (OIE) protocol for accurate detection of ASFV in field samples in Vietnam.Methods: Seven positive confirmed samples (four samples have no mismatch, and three samples contained one mutation in probe binding sites) were used to establish novel real-time PCR with slightly modified probe (Y = C or T) in comparison with original probe recommended by OIE.Results: Both real-time PCRs using the OIE-recommended probe and novel modified probe can detect ASFV in clinical samples without mismatch in probe binding site. A high correlation of cycle quantification (Cq) values was observed in which Cq values obtained from both probes arranged from 22 to 25, suggesting that modified probe sequence does not impede the qualification of real-time PCR to detect ASFV in clinical samples. However, the samples with one mutation in probe binding sites were ASFV negative with OIE recommended probe but positive with our modified probe (Cq value ranked between 33.12-35.78).Conclusion: We demonstrated for the first time that a mismatch in probe binding regions caused a false negative result by OIE recommended real-time PCR, and a slightly modified probe is required to enhance the sensitivity and obtain an ASF accurate diagnosis in field samples in Vietnam.