Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Mar 25;18(1):98.
doi: 10.1186/s12936-019-2722-1.

Field evaluation of malaria malachite green loop-mediated isothermal amplification in health posts in Roraima state, Brazil

Heather M Kudyba  1 , Jaime Louzada  2 , Dragan Ljolje  3 , Karl A Kudyba  1 , Vasant Muralidharan  4 , Joseli Oliveira-Ferreira  5   6 , Naomi W Lucchi  7
Affiliations

Field evaluation of malaria malachite green loop-mediated isothermal amplification in health posts in Roraima state, Brazil

Heather M Kudyba et al. Malar J. .

Abstract

Background: Microscopic detection of malaria parasites is the standard method for clinical diagnosis of malaria in Brazil. However, malaria epidemiological surveillance studies specifically aimed at the detection of low-density infection and asymptomatic cases will require more sensitive and field-usable tools. The diagnostic accuracy of the colorimetric malachite green, loop-mediated, isothermal amplification (MG-LAMP) assay was evaluated in remote health posts in Roraima state, Brazil.

Methods: Study participants were prospectively enrolled from health posts (healthcare-seeking patients) and from nearby villages (healthy participants) in three different study sites. The MG-LAMP assay and microscopy were performed in the health posts. Two independent readers scored the MG-LAMP tests as positive (blue/green) or negative (clear). Sensitivity and specificity of local microscopy and MG-LAMP were calculated using results of PET-PCR as a reference.

Results: A total of 91 participants were enrolled. There was 100% agreement between the two MG-LAMP readers (Kappa = 1). The overall sensitivity and specificity of MG-LAMP were 90.0% (95% confidence interval (CI) 76.34-97.21%) and 94% (95% CI 83.76-98.77%), respectively. The sensitivity and specificity of local microscopy were 83% (95% CI 67.22-92.66%) and 100% (95% CI 93.02-100.00%), respectively. PET-PCR detected six mixed infections (infection with both Plasmodium falciparum and Plasmodium vivax); two of these were also detected by MG-LAMP and one by microscopy. Microscopy did not detect any Plasmodium infection in the 26 healthy participants; MG-LAMP detected Plasmodium in five of these and PET-PCR assay detected infection in three. Overall, performing the MG-LAMP in this setting did not present any particular challenges.

Conclusion: MG-LAMP is a sensitive and specific assay that may be useful for the detection of malaria parasites in remote healthcare settings. These findings suggest that it is possible to implement simple molecular tests in facilities with limited resources.

Keywords: Diagnosis; Malachite green loop-mediated isothermal amplification; Malaria; Plasmodium.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Summary of enrolled patients and sample processing
Fig. 2
Fig. 2
Summary of positive results by microscopy, MG-LAMP and PET-PCR
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. WHO . World malaria report. Geneva: World Health Organization; 2018.
    1. PAHO . Epidemiological alert: increase of malaria in the Americas. Washington: Pan American Health Organization; 2018.
    1. Wongsrichanalai C, Barcus MJ, Muth S, Sutamihardja A, Wernsdorfer WH. A review of malaria diagnostic tools: microscopy and rapid diagnostic test (RDT) Am J Trop Med Hyg. 2007;77:119–127. doi: 10.4269/ajtmh.2007.77.119. - DOI - PubMed
    1. Tajebe A, Magoma G, Aemero M, Kimani F. Detection of mixed infection level of Plasmodium falciparum and Plasmodium vivax by SYBR Green I-based real-time PCR in North Gondar, north-west Ethiopia. Malar J. 2014;3:411. doi: 10.1186/1475-2875-13-411. - DOI - PMC - PubMed
    1. Ehtesham R, Fazaeli A, Raeisi A, Keshavarz H, Heidari A. Detection of mixed-species infections of Plasmodium falciparum and Plasmodium vivax by nested PCR and rapid diagnostic tests in southeastern Iran. Am J Trop Med Hyg. 2015;93:181–185. doi: 10.4269/ajtmh.14-0650. - DOI - PMC - PubMed

MeSH terms

LinkOut - more resources