Quantitative Detection of Swine Influenza Virus RNA

Lung and NT were homogenized in brain heart infusion medium (10% weight/volume) with TissueLyser II (Qiagen, Düsseldorf, Germany). RNA from nasal swab, BALF, lung and NT samples were extracted using the MagAttract 96 Cador Pathogen kit ^® (Qiagen, Düsseldorf, Germany) according to manufacturer’s instructions. To detect and quantify swine IAV RNA on each sample a RT-qPCR based on M segment amplification was performed in the Fast7500 equipment (Applied Biosystem) (Spackman et al., 2002 (link)). Samples with a cycle threshold (Ct) value under 40 were considered positive whereas no fluorescence detection were considered negative (Spackman et al., 2002 (link); López-Valiñas et al., 2021 (link)).