Reverse transcription loop-mediated isothermal amplification combined with lateral flow device (RT-LAMP-LFD) for swine influenza virus detection

Abstract

Swine influenza virus (SIV) causes respiratory disease in pigs leading to economic losses in swine production. Some
SIV subtypes can also infect human and considered as a zoonotic pathogen. The importants of swine influenza are not
only impact on the economic losses but also the human health. The objectives of this study were to develop a reverse
transcription loop-mediated isothermal amplification combined with lateral flow device assay (RT-LAMP-LFD) for the
detection of SIVs and to evaluate the performance, sensitivity and specificity of the assay. Our result showed that RTLAMP-LFD assay was developed with six newly designed primers and with optimum condition at 63oC and 30
minutes. The detection limit of the assay was 7.8 pg/µl, which is comparable to real time RT-PCR assay. RT-LAMPLFD assay is a specific method for the detection of SIV, in which there were no cross reaction with other important
viruses of pigs (PRRSV, PCV2, PRV and PEDV). When evaluation with reference SIVs, field SIVs and other viruses
(n=59), the newly developed RT-LAMP-LFD assay has good performance with 100% sensitivity, 100% specificity and
perfect percentage of agreement (Kappa=1) compared to reference assays. In conclusion, this RT-LAMP-LFD assay has
a potential for a rapid diagnostic test for SIV detection and could be developed for low-cost or in house assay. The RTLAMP-LFD assay could be implemented and applied at first point of care of disease outbreaks to help prevent and
control the spread of SIV in pig farms.