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

Sisay Getie,Dylan R. Pillai,Abu Naser Mohon,Banchamlak Tegegne,Wossenseged Lemma

doi:10.1186/s12936-017-1692-4

Abstract

BackgroundMalaria 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.MethodsA 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.ResultsUsing 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.ConclusionsThis 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.

Highlights

Malaria is a major public health problem and an important cause of maternal and infant morbidity in sub-Saharan Africa, including Ethiopia
A higher positivity rate of both single and mixed Plasmodium species infection were reported by loop-mediated isothermal amplification (LAMP) than other diagnostic techniques used in this study (Table 2)
Using nested polymerase chain reaction (nPCR) as the gold standard, LAMP had the highest sensitivity (100%; 95% CI 100) compared to microscopy (90%; 95% CI 66.3–113.7) and rapid diagnostic test (RDT) (70%; 95% CI 33.8–106.2)

Summary

Introduction

Malaria is a major public health problem and an important cause of maternal and infant morbidity in sub-Saharan Africa, including Ethiopia. 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. Every year about 30 million African women in malariaendemic areas become pregnant and are at risk of infection with malaria, and an estimated 75,000–200,000 infant deaths are reported due to malaria infection in pregnancy [5, 6]. Due to P. falciparum, in pregnant women increases the risk of maternal death, miscarriage, stillbirth and neonatal death [7, 8]. In areas of stable malaria, adult pregnant women would have considerable acquired immunity and infection during pregnancy typically does not cause symptomatic malaria. The effect of malaria in pregnancy is primarily low birth weight and maternal anaemia [9, 10]

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