Development and Validation of a Universal One-Step RT-PCR Assay for Broad Detection of Duck Tembusu Virus

Development of a Rapid Visual Detection Assay for Duck Tembusu Virus Using RT-LAMP-CRISPR/Cas12a

Duck Tembusu virus (DTMUV) is an emerging flavivirus that has inflicted significant economic losses on China's poultry industry. Rapid and accurate detection of DTMUV is crucial for effective prevention and control measures. In this study, we developed a novel, rapid visual detection assay that combines reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) with the CRISPR/Cas12a system for on-site detection of DTMUV. Our results demonstrate that this assay can sensitively and specifically detect the specific DNA plasmids containing the DTMUV NS3 gene within 100 min, with a limit of detection as low as 19.3 copies/μL. We successfully applied the RT-LAMP-CRISPR/Cas12a assay to diagnose DTMUV in eight duck embryos and 11 chicken embryonic fibroblast samples, and the results obtained with direct visualization by the naked eye were consistent with those obtained using real-time RT-PCR. Overall, our RT-LAMP-CRISPR/Cas12a assay is a reliable, sensitive, specific, and user-friendly method that holds great promise for early on-site detection of DTMUV in clinical samples, facilitating timely interventions and improved disease management in the poultry industry.

Advancements in Research on Duck Tembusu Virus Infections

Duck Tembusu Virus (DTMUV) is a pathogen of the Flaviviridae family that causes infections in poultry, leading to significant economic losses in the duck farming industry in recent years. Ducks infected with this virus exhibit clinical symptoms such as decreased egg production and neurological disorders, along with serious consequences such as ovarian hemorrhage, organ enlargement, and necrosis. Variations in morbidity and mortality rates exist across different age groups of ducks. It is worth noting that DTMUV is not limited to ducks alone; it can also spread to other poultry such as chickens and geese, and antibodies related to DTMUV have even been found in duck farm workers, suggesting a potential risk of zoonotic transmission. This article provides a detailed overview of DTMUV research, delving into its genomic characteristics, vaccines, and the interplay with host immune responses. These in-depth research findings contribute to a more comprehensive understanding of the virus's transmission mechanism and pathogenic process, offering crucial scientific support for epidemic prevention and control.

Reverse transcription recombinase-aided amplification assay combined with a lateral flow dipstick for detection of duck Tembusu virus

Duck Tembusu virus disease, caused by duck Tembusu virus (DTMUV), brings great harm to duck industry. Early diagnosis is of great significance for the prevention and control of this disease. In order to develop a specific and sensitive method for rapid diagnosis of DTMUV, reverse-transcriptase recombinase aided amplification combined with lateral flow dipstick (RT-RAA-LFD) method for detection of DTMUV was established. Firstly, downstream primer was labeled with biotin and probe was labeled with FAM, and primer concentration, reaction time, and reaction temperature were optimized. Then, the specificity and sensitivity of this method was investigated. The results of specificity test showed that it had no cross reaction with other common pathogens such as low pathogenic avian influenza virus (AIV), Newcastle disease virus (NDV), duck hepatitis A virus (DHV), and duck Reovirus. The results of sensitivity test showed that the minimum detection limit of this method was 10 copies/μL, which was 1000 times than conventional RT-PCR (104 copies/μL), and equivalent to that of fluorescent quantitative PCR. Furthermore, this RT-RAA-LFD method demonstrated excellent intragroup and intergroup consistency. Finally, the RT-RAA-LFD assay and real-time PCR were both utilized to examine 58 clinical samples concurrently. The results showed that the RT-RAA-LFD method (5/58) was more sensitive than the fluorescence quantitative PCR method (4/58). In summary, RT-RAA-LFD method established in this study had a strong specificity and high sensitivity, which provided technical support for clinical detection of DTMUV.

Development of a reverse transcription loop-mediated isothermal amplification based clustered regularly interspaced short palindromic repeats Cas12a assay for duck Tembusu virus

Duck Tembusu virus (DTMUV) is an emerging pathogen that poses a serious threat to the duck industry in China. Currently, polymerase chain reaction (PCR), quantitative PCR (qPCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) are commonly used for DTMUV detection. However, these methods require complex steps and special equipment and easily cause false-positive results. Therefore, we urgently need to establish a simple, sensitive and specific method for the clinical field detection of DTMUV. In this study, we developed an RT-LAMP-based CRISPR-Cas12a assay targeting the C gene to detect DTMUV with a limited detection of 3 copies/μL. This assay was specific for DTMUV without cross-reaction with other common avian viruses and only required some simple pieces of equipment, such as a thermostat water bath and blue/UV light transilluminator. Furthermore, this assay showed 100% positive predictive agreement (PPA) and negative predictive agreement (NPA) relative to SYBR Green qPCR for DTMUV detection in 32 cloacal swabs and 22 tissue samples, supporting its application for clinical field detection.