Performance of loop-mediated isothermal amplification (LAMP) for the diagnosis of malaria among malaria suspected pregnant women in Northwest Ethiopia

Abstract

Background: Malaria is a major public health problem and an important cause of maternal and infant morbidity in sub-Saharan Africa, including Ethiopia. Early and accurate diagnosis of malaria with effective treatment is the best strategy for prevention and control of complications during pregnancy and infant morbidity and mortality. However, laboratory diagnosis has relied on the identification of malaria parasites and parasite antigens in peripheral blood using Giemsa-stained microscopy or rapid diagnostic tests (RDTs) which lack analytical and clinical sensitivity. The aim of this study was to evaluate the performance of loop-mediated isothermal amplification (LAMP) for the diagnosis of malaria among malaria suspected pregnant women in Northwest Ethiopia. Methods:A cross sectional study was conducted from January to April 2016. Pregnant women (n = 87) suspected of having malaria at six health centres were enrolled. A venous blood sample was collected from each study subject, and analysed for Plasmodium parasites by microscopy, RDT, and LAMP. Diagnostic accuracy outcome measures (sensitivity, specificity, predictive values, and Kappa scores) of microscopy, RDT and LAMP were compared to nested polymerase chain reaction (nPCR) as the gold standard. Specimen processing and reporting times were documented.Results: Using nPCR as the gold standard technique, the sensitivity of microscopy and RDT was 90 and 70%, and the specificity was 98.7 and 97.4%, respectively. LAMP assay was 100% sensitive and 93.5% specific compared to nPCR. Conclusions:This study showed higher sensitivity of LAMP compared to microscopy and RDT for the detection of malaria in pregnancy. Increased sensitivity and ease of use with LAMP in point-of-care testing for malaria in pregnancy was noted. LAMP warrants further evaluation in intermittent screening and treatment programmes in pregnancy.

Detection of Plasmodium Infection by the illumigene Malaria Assay Compared to Reference Microscopy and Real-Time PCR

“…However, RDTs lack analytical sensitivity with limits of detection higher than 100 parasites/l, resulting in low sensitivities reported especially for non-falciparum Plasmodium species (12). Molecular-based isothermal tests for field diagnosis of malaria have recently been well studied in resourcelimited settings with acceptable clinical results (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24).…”

Evaluation of Visual LAMP detection of Plasmodium falciparum and non-Plasmodium falciparum

“…Sensitivity of LAMP is several orders of magnitude higher than by microscope and RDT [21] . As worldwide countries set targets of malaria elimination, accurate diagnosis, optimal treatment, stop of transmission, and reducing mortality of malaria are becoming critical [25,26] . As a result of the sudden decline in local patients and the gradual elimination of malaria, there are a trend of degradation in the clinical diagnosis and screening capacity of malaria.…”

Applying Loop-mediated Isothermal Amplification (LAMP) in the Diagnosis of Malaria, Leishmaniasis and Trypanosomiasis as Point-of-Care Tests (POCTs)

“…In Colombia, this test has been used to differentiate P.falciparum from P.vivax [53]. In Ethiopia, mtDNA based-LAMP has been applied in the early detection of malaria in pregnant women leading to high sensibility [54]. In a larger study in Papua New Guinea, Malaysia, Ghana and Gambia, hydroxynaphthol blue was used as a colorimetric indicator in order to optimise the detection of malaria parasites [55].…”