Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 14 1 2019 08 03 1256 1256 Faezeh Houmansadr Department of Cellular and Molecular Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran Mohammad Soleimani Department of Microbiology, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran AND Tasnim Biotechnology Research Center, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran Saied Reza Naddaf Department of Parasitology, Pasteur Institute of Iran, Tehran, Iran 2020 03 22 Background: This study aimed to develop a loop-mediated isothermal amplification (LAMP) assay for the rapid detec­tion of tick-borne relapsing fever in resource-limited areas. Methods: A set of six primers were designed based on the conserved regions of the Glycerophosphodiester phos­phodiesterase (glpQ) gene of Borrelia species. For sensitivity assay, serial dilutions of a recombinant plasmid contain­ing a 219bp sequence of the glpQ were prepared and used as the template DNA. The LAMP reactions containing the six primers and the reagents required for amplification were incubated at 60–65 °C for 60min in a Loopamp real-time tur­bidimeter. For the specificity test, DNA from 14 other bacteria were included in the assays, and double-distilled water was used as the negative control. Also, DNA from dried blood spots (DBSs) of spirochetemic mice, and blood samples from relapsing fever-suspected patients were examined by the LAMP along a Borrelia-specific nested PCR that targets the rrs-rrl-IGS region. Results: The LAMP detected as low as 90glpQ copies in reactions. The primers reacted with DNA from DBS of spi­rochetemic mice showing spirochete concentrations of ≤ one per a 1000X microscopic field. In clinical samples, the LAMP assay showed a higher sensitivity compared to nested-PCR. The LAMP specificity was 100%, as the primers did not react with other bacteria DNA. Conclusion: The high sensitivity and specificity of the test, along with the simplicity of the DNA extraction procedure, make the LAMP a reliable and adaptable tool for the diagnosis of tick-borne relapsing fever in rural endemic areas. https://jad.tums.ac.ir/index.php/jad/article/view/1256 https://jad.tums.ac.ir/index.php/jad/article/download/1256/482