Handheld Ultra-Fast Duplex Polymerase Chain Reaction Assays and Lateral Flow Detection and Identification of Leishmania Parasites for Cutaneous Leishmaniases Diagnosis

Early and accurate detection of infectious diseases is a key step for surveillance, epidemiology and control, notably timely disease diagnosis, patient management and follow-up. In this study, we aimed to develop handheld ultra-fast duplex PCR assays coupled to amplicon detection by lateral flow (LF) immunoassay to deliver a rapid and simple molecular diagnostic test for concomitant detection and identification of the main Leishmania parasites encountered in Tunisia. We selected two DNA targets to amplify L. major/L. tropica and L. infantum/L. tropica groups of species DNAs, respectively. We optimized the experimental conditions of a duplex ultra-fast PCR. The amplification is performed using a portable Palm convection PCR machine within 18 min, and the products are detected using an LF cassette within 10 min. The test allows the identification of the infecting species according to the position and number of test lines revealed. Tested on a selection of DNAs of representative Leishmania strains of the three studied species (N = 37), the ultra-fast duplex PCR–LF showed consistent, stable and reproducible results. The analytical limit of detection of the test was 0.4 pg for L. major, 4 pg for L. infantum and 40 pg for L. tropica.