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

Abstract

LAMP diagnosis of malaria is simple and cost-effective with acceptable sensitivity and specificity as compared to standard diagnostic modules such as microscopy, RDTs and nested PCR, and thus its deployment for onsite screening of malaria in resource-limited regions is under consideration. However, the requirement of an electricity-operated dry bath and bulky read-out unit is still a major concern. In an effort to simplify this limitation, we have developed a portable LAMP device and fluorescence readout unit which can be used in the rapid point-of-care diagnosis of malaria. We have developed a point-of-care diagnostic LAMP device that is easy to operate by a mobile application, and the results can be quantified with a fluorescent readout unit. The diagnostic performance of the device was evaluated in 90 P. falciparum-infected clinical isolates stored at 4°C for 6-7 years and 10 freshly collected isolates from healthy volunteers. The LOD and quantitative ability of LAMP in estimating parasitemia levels were revealed with laboratory-grown P. falciparum strain (3D7). The LAMP assay performed in our device was exclusive for P. falciparum detection with sensitivity and specificity determined to be 98.89% and 100%, respectively, in clinical isolates. The LOD was documented to be 1 parasite/µl at the cut-off ADC value of 20. Parasite density estimated from ADC values showed concordance with microscopically determined parasite density of the cultured P. falciparum 3D7 strain. The LAMP assay performed in our device provides a possible portable platform for its deployment in the point-of-care diagnosis of malaria. Further validation of the quantitative ability of the assay with freshly collected or properly stored clinical samples of known parasitemia is necessary for field applicability.

Rapid Detection of Malaria Based on Hairpin-Mediated Amplification and Lateral Flow Detection

“…The results of this work show that the detection sensitivity of HMA-LFD is approximately five copies/µL based on the detection of different concentrations of the recombinant plasmid under gradient dilution, and this sensitivity is comparable to the sensitivity of the LAMP technique reported in previous literature [36,37]. HMA-LFD was used to detect the nucleic acids of three pathogens, which commonly cause febrile diseases in inbound and outbound personnel, and the results showed that only the nucleic acid of Plasmodium was positively detected, while the samples containing the other two pathogens remained negative.…”

Enhancing malaria detection in resource-limited areas: A high-performance colorimetric LAMP assay for Plasmodium falciparum screening

“…Since then, several studies have been conducted to enhance the efficiency of LAMP diagnosis. Among those, some studies have targeted the S-type of the 18S rRNA genes for parasite detection [15,38]. However, the S-types of the 18S rRNA were found to be abundant in the gametocyte for S1-type and in sporozoites within the mosquito salivary gland for S2-type [30].…”

Advanced Techniques and Unusual Samples for Malaria Diagnosis

“…Detailed procedures and protocol of LAMP technique for malaria diagnosis heavily depend on the specific type of kit used, as there are different commercially available LAMP kits and each with its specifications, for example, Illumigene (Alethia), malaria LAMP, and Loopamp malaria amplification kit [66]. One of the short-comings of this technique it is qualitative, not quantitative, but has a very good sensitivity similar to other sensitive molecular techniques like PCR [67].…”