Meslo Sema
Wollo University, Ethiopia
Title: Evaluation of Non-Instrumented Nucleic acid Amplifi cation- Loop Mediated Isothermal Amplifi cation (NINA-LAMP) for the diagnosis of malaria in Northwest Ethiopia
Biography
Biography: Meslo Sema
Abstract
Background: Malaria is the major public health problem in sub-Saharan African countries including Ethiopia. Early and accurate diagnosis followed by prompt and effective treatment is the main strategy for prevention, control and elimination of malaria. Hence, highly sensitive, specific and rapid molecular methods are urgently needed for diagnosing malaria and differentiating Plasmodium spp. parasite infections. However, high cost and infrastructure limitations are significant hurdles to the introduction of molecular diagnostics in low-resource settings in endemic areas. Therefore, 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 films and nested PCR as gold standard for the diagnosis of malaria in Northwest Ethiopia.
Methods: A 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 Center and analyzed for Plasmodium parasites by Giemsa microscopy, NINA-LAMP and nested PCR. The LAMP method was performed using the LoopampTM Malaria Pan/Pf detection kits (Eiken Chemical, Japan) and a NINA heater (PATH, Seattle, WA) for detecting DNA of the genus Plasmodium and more specifically Plasmodium falciparum. Data were analyzed by SPSS version 20 and MedCalc online software. Diagnostic accuracy outcome measures (sensitivity, specificity, and predictive value and Kappa value) of NINA-LAMP and Giemsa microscopy were compared to nested PCR as reference method.
Results: A total of 82 samples were tested in the primary analysis. Using nested PCR as a reference, the sensitivity and specificity of the primary NINA-LAMP assay were 96.77% and 84.31%, respectively for detection of Plasmodium genus, and 100% and 81.16%, respectively for detection of P. falciparum parasite. Microscopy demonstrated sensitivity and specificity of 93.55%, 98.04%, respectively for the detection of Plasmodium parasites. Post hoc repeat NINA-LAMP analysis showed significantly improved 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.
Conclusion: In our study, NINA-LAMP is highly sensitive and specific 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 likely more sensitive for the detection and differentiation of P. falciparum from non-falciparum species compared to Giemsa microscopy and may be a critical diagnostic modality in efforts to eradicate malaria from areas of low endemicity.