Souto S, Olveira JG, López-Vázquez C, Bandín I, Dopazo CP. Designing and Validation of a Droplet Digital PCR Procedure for Diagnosis and Accurate Quantification of Nervous Necrosis Virus in the Mediterranean Area.
Pathogens 2023;
12:1155. [PMID:
37764963 PMCID:
PMC10536565 DOI:
10.3390/pathogens12091155]
[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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/31/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
The viral nervous necrosis virus (VNNV) is the causative agent of an important disease affecting fish species cultured worldwide. Early and accurate diagnosis is, at present, the most effective control and prevention tool, and molecular techniques have been strongly introduced and accepted by official organizations. Among those, real-time quantitative polymerase chain reaction (rt-qPCR) is nowadays displacing other molecular techniques. However, another PCR-based technology, droplet digital PCR (ddPCR), is on the increase. It has many advantages over qPCR, such as higher sensitivity and more reliability of the quantification. Therefore, we decided to design and validate a protocol for the diagnosis and quantification of SJ and RG type VNNV using reverse transcription-ddPCR (RT-ddPCR). We obtained an extremely low limit of detection, 10- to 100-fold lower than with RT-qPCR. Quantification by RT-ddPCR, with a dynamic range of 6.8-6.8 × 104 (SJ type) or 1.04 × 101-1.04 × 105 (RG type) cps/rctn, was more reliable than with RT-qPCR. The procedure was tested and validated in field samples, providing high clinical sensitivity and negative predictive values. In conclusion, we propose this method to substitute RT-qPCR protocols because it exceeds the expectations of qPCR in the diagnosis and quantification of VNNV.
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