Rapid diagnosis of Leishmania infection with a portable loop-mediated isothermal amplification device

Abstract

L. donovani is an intracellular protozoan parasite, that causes visceral leishmaniasis (VL), and consequently, post-kala azar dermal leishmaniasis (PKDL). Diagnosis and treatment of leishmaniasis is crucial for decreasing its transmission. Various diagnostic techniques like microscopy, enzyme-linked immunosorbent assays (ELISA) and PCR-based methods are used to detect leishmaniasis infection. More recently, loop-mediated isothermal amplification (LAMP) assay has emerged as an ideal diagnostic measure for leishmaniasis, primarily due to its accuracy, speed and simplicity. However, point-of-care diagnosis is still not been tested with the LAMP assay. We have developed a portable LAMP device for the monitoring of Leishmania infection. The LAMP assay performed using our device can detect and amplify as little as 100 femtograms of L. donovani DNA. In a preliminary study, we have shown that the device can also amplify L. donovani DNA present in VL and PKDL patient samples with high sensitivity (100%), specificity (98%) and accuracy (99%), and can be used both for diagnostic and prognostic analysis. To our knowledge, this is the first report to describe the development and application of a portable LAMP device which has the potential to evolve as a point-of-care diagnostic and prognostic tool for Leishmania infections in future. Supplementary Information The online version contains supplementary material available at 10.1007/s12038-021-00211-0.

A low‐cost, portable, and practical LAMP device for point‐of‐diagnosis in the field

“…However, microfluidic devices are expensive to fabricate, complex to use, and require trained personnel and stable operation conditions, which makes this technology not feasible for field‐deployable real‐time diagnosis (Almassian et al, 2013, de Oliveira et al, 2021, El‐Tholoth et al, 2021, Ganguli et al, 2020, Kaymaz & Elitas, 2021, Ma et al, 2018, Mori et al, 2001, Wan et al, 2017, Wan et al, 2019). Therefore, portable, rapid, cost‐effective, automated, and remotely controllable LAMP platforms with colorimetric readouts will be the future of field‐ready modern nucleic‐acid‐based detection platforms (Kaygusuz et al, 2019, Ludwing et al, 2021, Puri et al, 2021, Xun et al, 2021).…”

Rapid diagnosis of Plasmodium falciparum malaria using a point-of-care loop-mediated isothermal amplification device

“…For the prediction of parasitemia from the ADC value, the inverse logarithm value was calculated by raising the base10 to the logarithm of the log-transformed parasitemia value corresponding to a different ADC value. The percentage sensitivity, specificity and accuracy with 95% confidence intervals (CI) were calculated using Medcalc software as previously described by Puri et al, 2021.…”

“…LAMP assay was performed in the device as previously described (Puri et al, 2021). Briefly, a working dilution of 10X was prepared from primer stocks (100 µM).…”

“…The LAMP amplification device which can be operated via a mobile application and fluorescent readout unit used in this study were the same as described by Puri et al, 2021. Briefly, the core of the LAMP device consists of a resistive heating block and a system controller placed in a 3D printed casing shown in (Figure 1A).…”

“…The system measures the fluorescence levels at an interval of 3 seconds (1 second on and 2 seconds off). The data is logged into a file where it can be used for further analysis (Puri et al, 2021).…”