Loop-Mediated Isothermal Amplification Assay for Rapid Diagnosis of Malaria Infections in an Area of Endemicity in Thailand

Abstract

The loop-mediated isothermal amplification (LAMP) method, developed by our group for diagnosis of four human malaria parasites, was evaluated on a large scale at a remote clinic in Thailand where malaria is endemic. A total of 899 febrile patients were analyzed in this study. LAMP was first evaluated in 219 patients, and the result was compared to those of two histidine-rich protein (HRP)-2 rapid diagnostic tests (RDTs) and microscopy as a gold standard. LAMP DNA extraction was conducted by a simple boiling method, and the test results were assessed visually. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 95.7%, 100%, 100%, and 98%, respectively, for LAMP and 98.6%, 98%, 95.8%, and 99.3%, respectively, for RDTs. Since RDT-positive results were based on one out of two RDTs, the sensitivity of RDTs was slightly higher than that of LAMP. However, LAMP tended to be more specific than RDTs. LAMP next was evaluated in 680 patients, and the result was compared to that of microscopy as a gold standard. Sensitivity, specificity, PPV, NPV, and diagnostic accuracy of LAMP were 88.9%, 96.9%, 92.2%, 95.5%, and 94.6%, respectively. Nested PCR was used to confirm the discrepant results. Malaria LAMP in a remote clinic in Thailand achieved an acceptable result, indicating that LAMP malaria diagnosis is feasible in a field setting with limited technical resources. Additionally, the rapid boiling method for extracting DNA from dried blood spots proved to be simple, fast, and suitable for use in the field.

Infectivity of symptomatic and asymptomatic Plasmodium vivax infections to a Southeast Asian vector, Anopheles dirus

“…The sample was then centrifuged for 3 min at 13,000 g . A total volume of 5.5 μl of the supernatant containing genomic DNA was used as the template in a 25 μl LAMP reaction, using the Loopamp DNA amplification kit (Eiken Chemical Co, Japan) and an appropriate primer set as previously described (Han et al, 2007; Sattabongkot et al, 2014). Only samples that were free of P. falciparum were included in the final data analysis.…”

The Point-of-Care Laboratory in Clinical Microbiology

“…LAMP eliminates the need for a thermocycler, hence making NAATs cheap, energy-saving, and easy to perform in the POC laboratory (14). Current developments include the rapid diagnosis of malaria (15), tuberculosis, and Buruli ulcer (16). One of the advantages of NAATs is that they have greater sensitivity than the ICT, but they require a higher on April 30, 2020 by guest http://cmr.asm.org/ degree of technicality and training.…”

Development of Visually Improved Loop Mediated Isothermal Amplification for the Diagnosis of Plasmodium vivax Malaria in a Tertiary Hospital in Chandigarh, North India

“…39 Because of the low parasitemia present in P. vivax patients and volatility of LDH at higher temperatures the RDT dependent P. vivax poses difficulties. 40 In the endemic settings where both the P. falciparum and P. vivax are known to cause the severe form of malaria a combined PfHRP2/aldolase RDT test performed better regardless of any clinical manifestation. In the present study, detection was based on HRP-II antigen of P. falciparum and pLDH of P. vivax in whole blood and the sensitivity and specificity of RDT was found to be 96.6% and 85% for P. vivax.…”