Evaluation of non-instrumented nucleic acid amplification by loop-mediated isothermal amplification (NINA-LAMP) for the diagnosis of malaria in Northwest Ethiopia

Abstract

BackgroundMalaria is a major public health problem in sub-Saharan African countries including Ethiopia. Early and accurate diagnosis followed by prompt and effective treatment is among the various tools available for prevention, control and elimination of malaria. This study aimed to evaluate the performance of non-instrumented nucleic acid amplification loop-mediated isothermal amplification (NINA-LAMP) compared to standard thick and thin film microscopy and nested PCR as gold standard for the sensitive diagnosis of malaria in Northwest Ethiopia.MethodsA cross-sectional study was conducted in North Gondar, Ethiopia from March to July 2014. Eighty-two blood samples were collected from malaria suspected patients visiting Kola Diba Health Centre and analysed for Plasmodium parasites by microscopy, NINA-LAMP and nested PCR. The NINA-LAMP method was performed using the Loopamp™ Malaria Pan/Pf detection kits for detecting DNA of the genus Plasmodium and more specifically Plasmodium falciparum using an electricity-free heater. Diagnostic accuracy outcome measures (analytical sensitivity, specificity, predictive values, and Kappa scores) of NINA-LAMP and microscopy were compared to nested PCR.ResultsA total of 82 samples were tested in the primary analysis. Using nested PCR as reference, the sensitivity and specificity of the primary NINA-LAMP assay were 96.8% (95% confidence interval (CI), 83.2% - 99.5%) and 84.3% (95% CI, 71.4% - 92.9%), respectively for detection of Plasmodium genus, and 100% (95% CI, 75.1% - 100%) and 81.2% (95% CI, 69.9% - 89.6%), respectively for detection of P. falciparum parasite. Microscopy demonstrated sensitivity and specificity of 93.6% (95% CI, 78.5% - 99.0%) and 98.0% (95% CI, 89.5% - 99.7%), respectively for the detection of Plasmodium parasites. Post-hoc repeat NINA-LAMP analysis showed improvement in diagnostic accuracy, which was comparable to nested PCR performance and superior to microscopy for detection at both the Plasmodium genus level and P. falciparum parasites.ConclusionNINA-LAMP is highly sensitive for the diagnosis of malaria and detection of Plasmodium parasite infection at both the genus and species level when compared to nested PCR. NINA-LAMP is more sensitive than microscopy for the detection of P. falciparum and differentiation from non-falciparum species and may be a critical diagnostic modality in efforts to eradicate malaria from areas of low endemicity.

A Unique Plasmodium falciparum K13 Gene Mutation in Northwest Ethiopia

“…Giemsa staining and microscopy was performed as described previously. 11 Only those with mono-infection with P. falciparum were included in this study. Finger prick blood samples were collected on Whatman 903 filter paper (GE Healthcare, Mississauga, Canada) at the time of diagnosis, air-dried, individually inserted in a zip-lock bag, and transported to University of Calgary, Canada, for molecular analysis.…”

“…Genomic DNA extraction from the filter paper blood spots was performed as described previously in a study. 11 Plasmodium falciparum kelch 13 was amplified from the genomic DNA samples using nested polymerase chain reaction (PCR) with slight modification.…”

Single-use paper-based hydrogen fuel cells for point-of-care diagnostic applications

“…The duration of the power delivery can be extended as these devices use up to 20x more MgFe for a single test (and consequently, produce as much hydrogen) than the amount used in the fuel cells presented here. [39][40][41][42] This approach implies reusability of the fuel cells for more than one measurement, thus reducing the overall cost per test.…”

“…the corrosion of magnesium iron particles. [36][37][38][39][40][41][42] This chemistry is very convenient, as it , requires only the addition of water to achieve 100°C (a reason why it has also been widely used to heat portable meals). During the course of the chemical reaction the magnesium is oxidized, releasing hydrogen gas as a byproduct, which previously was simply vented off to the atmosphere.…”

Diagnosing Neglected Tropical Diseases in HIV Coinfection

“…The LAMP assays commonly present diagnostic efficacy similar to the nested PCR assays, considered by many articles the gold standard. [41][42][43] These reports showed that LAMP assays enable detection of P. falciparum and P. vivax at the species level and diagnose asymptomatic infections or low parasitic loads. 41,43,44 Molecular diagnosis may also facilitate the detection and identification of malaria cases in nonendemic countries, where individuals may become infected when traveling for business or tourism.…”