Available online 7 December 2023, 105633

Developing and validation of a loop-mediated isothermal amplification for clinical diagnosis of WNV

Amplifications on extracted viral RNA and on crude samples with Thermal Cycler and Pebble Device

RT-LAMP for WNV detection can be used at point of care in hospital setting or small laboratories

RT-LAMP assay is an efficient consistent technique for detecting WNV.

RT-lamp requires extracted RNA and have lower sensitivity when run directly on crude material.

West Nile Virus (WNV) causes a serious public health concern in many countries around the world. Virus detection in pathological samples is a key component of WNV infection diagnostic, classically performed by real-time PCR. In outbreak situation, rapid detection of the virus, in peripheral laboratories or at point of care, is crucial to guide decision makers and for the establishment of adequate action plans to prevent virus dissemination. Here, we evaluate a Loop-mediated isothermal amplification (LAMP) tool for WNV detection. Amplifications were performed comparatively on extracted viral RNA and on crude samples using a classical thermal cycler and a portable device (pebble device). qRT-PCR was used as gold standard and two sets of urine samples (n=62 and n=74) were used to evaluate the retained amplification protocols and assess their sensitivity and specificity. RT-LAMP on RNA extracts and crude samples showed a sensitivity of 90% and 87%, respectively. The specificity was 100% for extracts and 97% for crude samples. Using the device, the RT-LAMP on extracted RNA was comparable to the gold standard results (100% sensitivity and specificity) and it was a bit lower on crude samples (65% sensitivity and 94% specificity). These results show that RT-LAMP is an efficient technique to detect WNV. RT-LAMP provides a rapid, sensitive, high-throughput and portable tool for accurate WNV detection and has potentials to facilitate diagnostic and surveillance efforts both in the laboratory and in the field, especially in developing countries.

West Nile Virus

RT-LAMP test

Pebble device

crude samples

rapid diagnosis

© 2023 The Author(s). Published by Elsevier B.V.