Development and Application of Fluorescent and Lateral Flow Dipstick Recombinase-Aided Amplification for Rapid Detection of Glaesserella parasuis

<i>Glaesserella parasuis</i> (<i>G. parasuis</i>) is a bacterial respiratory pathogen from pigs, which can cause high morbidity and mortality in weaned piglets in piggery. An accurate and rapid detection for <i>G. parasuis</i> is crucial for the effective control of Glässer's disease. In the present study, two distinct Recombinase-Aided Amplification (RAA) techniques, utilizing fluorescence and lateral flow dipstick, were developed for the detection of <i>G. parasuis</i>. The two RAA assays, namely the fluorescent RAA (Fluo-RAA) and lateral flow dipstick RAA (LFD-RAA) assays, prioritize specificity and are capable of detecting <i>G. parasuis</i> with sensitivities of 10 copies and 100 copies, respectively. Both assays are capable of utilizing boiled nasal swab samples as DNA templates, demonstrating sensitivity comparable to that of commercial DNA extraction kits. Sensitivity tests had revealed that the Fluo-RAA assay exhibited greater sensitivity than the LFD-RAA assay. While the Fluo-RAA assay is more sensitive than the LFD-RAA assay, it is also more labor-intensive and better-suited for laboratory use than for field conditions. The entire process for the LFD-RAA assay can be completed within one hour without the need for professional equipment, making it more suitable for field use.