A real-time colourimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for the rapid detection of highly pathogenic H5 clade 2.3.4.4b avian influenza viruses

ABSTRACT

Highly pathogenic avian influenza viruses (HPAIV) are a major threat to the global poultry industry and public health due to their zoonotic potential. Since 2016, Europe and France have faced major epizootics caused by clade 2.3.4.4b H5 HPAIV. To reduce sample-to-result times, point-of-care testing is urgently needed to help prevent further outbreaks and the propagation of the virus. This study presents the design of a novel real-time colourimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for the detection of clade 2.3.4.4b H5 HPAIV. A clinical validation of this RT-LAMP assay was performed on 198 pools of clinical swabs sampled in 52 poultry flocks during the H5 HPAI 2020–2022 epizootics in France. This RT-LAMP assay allowed the specific detection of HPAIV H5Nx clade 2.3.4.4b within 30 min with a sensitivity of 86.11%. This rapid, easy-to-perform, inexpensive, molecular detection assay could be included in the HPAIV surveillance toolbox.

KEYWORDS:

• RT-LAMP
• highly pathogenic avian influenza virus
• clade 2.3.4.4b molecular detection
• clinical diagnostic
• field detection

Acknowledgements

This study was performed in the framework of the Chaire de Biosécurité & Santé Aviaires, hosted by the National Veterinary College of Toulouse (ENVT). We would like to thank the farm holders for their collaboration with sampling of their flocks and show our gratitude to Sebastien Mathieu Soubies for comments and constructive criticism on an earlier version of the manuscript. Finally, all authors acknowledge GISAID contributors.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by the Direction Generale de l’Alimentation, Ministère de l’Agriculture et de la Souveraineté Alimentaire, France. Fabien Filaire’s PhD position is funded by Theseo France and Lanxess biosecurity from the Lanxess group. The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.