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Matamoros G, Escobar D, Pinto A, Serrano D, Ksandrová E, Grimaldi N, Juárez-Fontecha G, Moncada M, Valdivia HO, Fontecha G. PET-PCR reveals low parasitaemia and submicroscopic malarial infections in Honduran Moskitia. Malar J 2023; 22:110. [PMID: 36978056 PMCID: PMC10053754 DOI: 10.1186/s12936-023-04538-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 03/18/2023] [Indexed: 03/30/2023] Open
Abstract
BACKGROUND Malaria remains a main parasitic disease of humans. Although the largest number of cases is reported in the African region, there are still endemic foci in the Americas. Central America reported 36,000 malaria cases in 2020, which represents 5.5% of cases in the Americas and 0.015% of cases globally. Most malaria infections in Central America are reported in La Moskitia, shared by Honduras and Nicaragua. In the Honduran Moskitia, less than 800 cases were registered in 2020, considering it an area of low endemicity. In low endemicity settings, the number of submicroscopic and asymptomatic infections tends to increase, leaving many cases undetected and untreated. These reservoirs challenge national malaria elimination programmes. This study aimed to assess the diagnostic performance of Light Microscopy (LM), a nested PCR test and a photoinduced electron transfer polymerase chain reaction (PET-PCR) in a population of febrile patients from La Moskitia. METHODS A total of 309 febrile participants were recruited using a passive surveillance approach at the Puerto Lempira hospital. Blood samples were analysed by LM, nested PCR, and PET-PCR. Diagnostic performance including sensitivity, specificity, negative and positive predictive values, kappa index, accuracy, and ROC analysis was evaluated. The parasitaemia of the positive samples was quantified by both LM and PET-PCR. RESULTS The overall prevalence of malaria was 19.1% by LM, 27.8% by nPCR, and 31.1% by PET-PCR. The sensitivity of LM was 67.4% compared to nPCR, and the sensitivity of LM and nPCR was 59.6% and 80.8%, respectively, compared to PET-PCR. LM showed a kappa index of 0.67, with a moderate level of agreement. Forty positive cases by PET-PCR were not detected by LM. CONCLUSIONS This study demonstrated that LM is unable to detect parasitaemia at low levels and that there is a high degree of submicroscopic infections in the Honduran Moskitia.
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Affiliation(s)
- Gabriela Matamoros
- Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Denis Escobar
- Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Alejandra Pinto
- Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Delmy Serrano
- Hospital de Puerto Lempira, Secretaría de Salud de Honduras, Gracias a Dios, Honduras
| | - Eliška Ksandrová
- Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Nicole Grimaldi
- Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Gabriel Juárez-Fontecha
- Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Marcela Moncada
- Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | - Hugo O Valdivia
- Department of Parasitology, U.S. Naval Medical Research Unit 6 (NAMRU-6), 07006, Lima, Peru
| | - Gustavo Fontecha
- Microbiology Research Institute, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras.
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2
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Herman C, Leonard CM, Uhomoibhi P, Maire M, Moss D, Inyang U, Abubakar A, Ogunniyi A, Mba N, Greby SM, Okoye MI, Iriemenam NC, Maikore I, Steinhardt L, Rogier E. Non-falciparum malaria infection and IgG seroprevalence among children under 15 years in Nigeria, 2018. Nat Commun 2023; 14:1360. [PMID: 36914649 PMCID: PMC10011577 DOI: 10.1038/s41467-023-37010-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 02/27/2023] [Indexed: 03/16/2023] Open
Abstract
Plasmodium falciparum (Pf) is the dominant malaria parasite in Nigeria though P. vivax (Pv), P. ovale (Po), and P. malariae (Pm) are also endemic. Blood samples (n = 31,234) were collected from children aged 0-14 years during a 2018 nationwide HIV survey and assayed for Plasmodium antigenemia, Plasmodium DNA, and IgG against Plasmodium MSP1-19 antigens. Of all children, 6.6% were estimated to have Pm infection and 1.4% Po infection with no Pv infections detected. The highest household wealth quintile was strongly protective against infection with Pm (aOR: 0.11, 95% CI: 0.05-0.22) or Po (aOR= 0.01, 0.00-0.10). Overall Pm seroprevalence was 34.2% (95% CI: 33.3-35.2) with lower estimates for Po (12.1%, 11.6-12.5) and Pv (6.3%, 6.0-6.7). Pm seropositivity was detected throughout the country with several local government areas showing >50% seroprevalence. Serological and DNA indicators show widespread exposure of Nigerian children to Pm with lower rates to Po and Pv.
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Affiliation(s)
- Camelia Herman
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30029, USA.,BeVera Solutions, Atlanta, GA, 30341, USA
| | - Colleen M Leonard
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30029, USA.,Oak Ridge Institute for Science and Education, US. Department of Energy, Oak Ridge, TN, 37831, USA
| | - Perpetua Uhomoibhi
- National Malaria Elimination Programme, Federal Ministry of Health, Abuja, Nigeria
| | - Mark Maire
- U.S. President's Malaria Initiative, Malaria Branch, Division of Parasitic Diseases and Malaria, U.S. Centers for Disease Control and Prevention, Abuja, Nigeria
| | - Delynn Moss
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Uwem Inyang
- U.S. President's Malaria Initiative, United States Agency for International Development (USAID), Abuja, Nigeria
| | - Ado Abubakar
- Institute of Human Virology (IHVN), Abuja, Nigeria
| | | | - Nwando Mba
- Nigeria Centre for Disease Control (NCDC), Abuja, Nigeria
| | - Stacie M Greby
- Division of Global HIV and Tuberculosis, Center for Global Health, Centers for Disease Control and Prevention, Abuja, Nigeria
| | - McPaul I Okoye
- Division of Global HIV and Tuberculosis, Center for Global Health, Centers for Disease Control and Prevention, Abuja, Nigeria
| | - Nnaemeka C Iriemenam
- Division of Global HIV and Tuberculosis, Center for Global Health, Centers for Disease Control and Prevention, Abuja, Nigeria
| | - Ibrahim Maikore
- World Health Organization, Nigeria Country Office, Abuja, Nigeria
| | - Laura Steinhardt
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30029, USA
| | - Eric Rogier
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30029, USA.
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3
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Tavakoli-Koopaei R, Javadi-Zarnaghi F, Aboutalebian S, Mirhendi H. Malachite Green-Based Detection of SARS-CoV-2 by One-Step Reverse Transcription Loop-Mediated Isothermal Amplification. IRANIAN JOURNAL OF SCIENCE 2023. [PMCID: PMC9898859 DOI: 10.1007/s40995-022-01392-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The pandemic of severe acute respiratory syndrome 2 (SARS-CoV-2) revealed the necessity of diagnosis of the infected people to prevent the prevalence infection cycle. Many commercial pathogen diagnosis methods are based on the detection of genomic materials. Isothermal amplification methods such as loop-mediated-isothermal amplification (LAMP) are the method of choice in these cases. Reverse transcription steps are efficiently coupled to LAMP for the detection of pathogens with genomic RNAs such as SARS-CoV-2. Many detection systems for LAMP include fluorescent readout systems. Although such systems result in desirable limits of detection, the need for special instrumentation is the main dispute of such systems to become real point of care assays. In contrast, colorimetric detection methods would reduce costs and improve the applicability of the system. In this study one-step reverse transcription-LAMP reaction was established that enables visual detection of the SARS-CoV-2 genome. Nasopharyngeal RNA samples were first validated by reverse transcription quantitative polymerase chain reaction and then subjected to RT-LAMP. To lower the cost associated with the readout system equipment, malachite green (MG) was used. The color change of MG to blue allowed visual detection of the virus. Firstly, experiments were set up as two-step RT-LAMP reaction to identify the best primer sets. In addition, MG concentration was optimized with the significant colorimetric signal for the positive samples. Next, a one-step colorimetric method was developed for the detection of SARS-CoV-2 based on MG color shift in 2 h.
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Affiliation(s)
- Reyhaneh Tavakoli-Koopaei
- grid.411750.60000 0001 0454 365XDepartment of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Fatemeh Javadi-Zarnaghi
- grid.411750.60000 0001 0454 365XDepartment of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran
| | - Shima Aboutalebian
- grid.411036.10000 0001 1498 685XDepartment of Medical Parasitology and Mycology, School of Medicine, Research Core Facilities Laboratory, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hossein Mirhendi
- grid.411036.10000 0001 1498 685XDepartment of Medical Parasitology and Mycology, School of Medicine, Research Core Facilities Laboratory, Isfahan University of Medical Sciences, Isfahan, Iran
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Mannier C, Yoon JY. Progression of LAMP as a Result of the COVID-19 Pandemic: Is PCR Finally Rivaled? BIOSENSORS 2022; 12:bios12070492. [PMID: 35884295 PMCID: PMC9312731 DOI: 10.3390/bios12070492] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 07/01/2022] [Accepted: 07/02/2022] [Indexed: 06/01/2023]
Abstract
Reflecting on the past three years and the coronavirus disease 19 (COVID-19) pandemic, varying global tactics offer insights into the most effective public-health responses. In the US, specifically, rapid and widespread testing was quickly prioritized to lower restrictions sooner. Essentially, only two types of COVID-19 diagnostic tests were publicly employed during the peak pandemic: the rapid antigen test and reverse transcription polymerase chain reaction (RT-PCR). However, neither test ideally suited the situation, as rapid antigen tests are far too inaccurate, and RT-PCR tests require skilled personnel and sophisticated equipment, leading to long wait times. Loop-mediated isothermal amplification (LAMP) is another exceptionally accurate nucleic acid amplification test (NAAT) that offers far quicker time to results. However, RT-LAMP COVID-19 tests have not been embraced as extensively as rapid antigen tests or RT-PCR. This review will investigate the performance of current RT-LAMP-based COVID-19 tests and summarize the reasons behind the hesitancy to embrace RT-LAMP instead of RT-PCR. We will also look at other LAMP platforms to explore possible improvements in the accuracy and portability of LAMP, which could be applied to COVID-19 diagnostics and future public-health outbreaks.
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5
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Martín-Ramírez A, Lanza-Suárez M, Muñoz-García C, Hisam SR, Perez-Ayala A, Rubio JM. Usefulness of Malachite-Green LAMP for Diagnosis of Plasmodium and Five Human Malaria Species in a Nonendemic Setting. Am J Trop Med Hyg 2022; 106:tpmd211151. [PMID: 35292597 PMCID: PMC9128691 DOI: 10.4269/ajtmh.21-1151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/22/2021] [Indexed: 11/07/2022] Open
Abstract
Molecular methods are necessary to detect low-density malaria infections. The purpose of this study was to assess the diagnostic performance of six malachite-green loop-mediated amplification method (MG-LAMP) assays (MG-LAMP-Pf, MG-LAMP-Pv, MG-LAMP-Po, MG-LAMP-Pm, MG-LAMP-Pk, and MG-LAMP-Pspp) for the species-specific detection of each human Plasmodium, including P. knowlesi, and the Plasmodium genus compared with the nested-multiplex malaria polymerase chain reaction (NM-PCR), using 161 malaria-positive and 274 malaria-negative samples. MG-LAMP-Pspp assay detected the five human Plasmodium species and each species-specific MG-LAMP assay detected only its corresponding species. Sensitivity, specificity, and predictive values of MG-LAMP assays, compared with NM-PCR, were > 90%, except in the case of the MG-LAMP-Pm assay, which dropped to 47%. Limit of detection for MG-LAMP-Pspp assay ranged from 0.1 parasites/µL for P. falciparum to 16.9 parasites/µL for P. malariae samples, and it was similar for the rest of MG-LAMP assays except for the MG-LAMP-Pm assay. Turnaround time was estimated to be 2 hours and 35 minutes for one MG-LAMP assay and 4 hours and 15 minutes if all species-specific MG-LAMP is set up, whereas for the NM-PCR, turnaround time was ∼6 hours and 15 minutes. Costs per determination ranged from 1 to 6 euros for MG-LAMP assays and 5 euros for NM-PCR. Therefore, MG-LAMP assays appear to have good concordance compared with the reference method, except for the MG-LAMP-Pm assay. They can detect low parasitemia and identify malaria species, with lower costs and shorter time to obtain results, and they are suitable tools to be used in endemic and non-endemic countries for malaria detection.
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Affiliation(s)
- Alexandra Martín-Ramírez
- Malaria and Emerging Parasitic Diseases Laboratory, National Microbiology Centre, Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Lanza-Suárez
- Malaria and Emerging Parasitic Diseases Laboratory, National Microbiology Centre, Instituto de Salud Carlos III, Madrid, Spain
| | - Carlota Muñoz-García
- Malaria and Emerging Parasitic Diseases Laboratory, National Microbiology Centre, Instituto de Salud Carlos III, Madrid, Spain
| | - Shamilah R. Hisam
- Parasitology Unit, Infectious Disease Research Centre, Institute for Medical Research, National Institute of Health, Ministry of Health Malaysia, Setia Alam, Selangor, Malaysia
| | - Ana Perez-Ayala
- Department of Clinical Microbiology, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - José M. Rubio
- Malaria and Emerging Parasitic Diseases Laboratory, National Microbiology Centre, Instituto de Salud Carlos III, Madrid, Spain
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Barazorda KA, Salas CJ, Braga G, Ricopa L, Ampuero JS, Siles C, Sanchez JF, Montano S, Lizewski SE, Joya CA, Bishop DK, Valdivia HO. Validation study of Boil & Spin Malachite Green Loop Mediated Isothermal Amplification (B&S MG-LAMP) versus microscopy for malaria detection in the Peruvian Amazon. PLoS One 2021; 16:e0258722. [PMID: 34695122 PMCID: PMC8544869 DOI: 10.1371/journal.pone.0258722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 10/04/2021] [Indexed: 11/19/2022] Open
Abstract
Malaria elimination efforts in Peru have dramatically reduced the incidence of cases in the Amazon Basin. To achieve the elimination, the detection of asymptomatic and submicroscopic carriers becomes a priority. Therefore, efforts should focus on tests sensitive enough to detect low-density parasitemia, deployable to resource-limited areas and affordable for large screening purposes. In this study, we assessed the performance of the Malachite–Green LAMP (MG-LAMP) using heat-treated DNA extraction (Boil & Spin; B&S MG-LAMP) on 283 whole blood samples collected from 9 different sites in Loreto, Peru and compared its performance to expert and field microscopy. A real-time PCR assay was used to quantify the parasite density. In addition, we explored a modified version of the B&S MG-LAMP for detection of submicroscopic infection in 500 samples and compared the turnaround time and cost of the MG-LAMP with microscopy. Compared to expert microscopy, the genus B&S MG-LAMP had a sensitivity of 99.4% (95%CI: 96.9%– 100%) and specificity of 97.1% (95%CI: 91.9%– 99.4%). The P. vivax specific B&S MG-LAMP had a sensitivity of 99.4% (96.6%– 100%) and specificity of 99.2% (95.5%– 100%) and the P. falciparum assay had a sensitivity of 100% (95%CI: 78.2%– 100%) and specificity of 99.3% (95%CI: 97.3%– 99.8%). The modified genus B&S MG-LAMP assay detected eight submicroscopic malaria cases (1.6%) which the species-specific assays did not identify. The turnaround time of B&S MG-LAMP was faster than expert microscopy with as many as 60 samples being processed per day by field technicians with limited training and utilizing a simple heat-block. The modified B&S MG-LAMP offers a simple and sensitive molecular test of choice for the detection of submicroscopic infections that can be used for mass screening in resources limited facilities in endemic settings nearing elimination and where a deployable test is required.
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Affiliation(s)
| | - Carola J. Salas
- Department of Parasitology, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Greys Braga
- Department of Parasitology, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Leonila Ricopa
- Department of Parasitology, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Julia S. Ampuero
- Department of Virology and Emerging infections, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Crystyan Siles
- Department of Virology and Emerging infections, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Juan F. Sanchez
- Department of Parasitology, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Silvia Montano
- Department of Parasitology, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Stephen E. Lizewski
- Department of Parasitology, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Christie A. Joya
- Department of Parasitology, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Danett K. Bishop
- Department of Parasitology, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
| | - Hugo O. Valdivia
- Department of Parasitology, U.S. Naval Medical Research Unit N°6 (NAMRU-6), Lima, Peru
- * E-mail:
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7
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Field validation of a magneto-optical detection device (Gazelle) for portable point-of-care Plasmodium vivax diagnosis. PLoS One 2021; 16:e0253232. [PMID: 34157032 PMCID: PMC8219132 DOI: 10.1371/journal.pone.0253232] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 05/31/2021] [Indexed: 12/17/2022] Open
Abstract
A major challenge for malaria is the lack of tools for accurate and timely diagnosis in the field which are critical for case management and surveillance. Microscopy along with rapid diagnostic tests are the current mainstay for malaria diagnosis in most endemic regions. However, these methods present several limitations. This study assessed the accuracy of Gazelle, a novel rapid malaria diagnostic device, from samples collected from the Peruvian Amazon between 2019 and 2020. Diagnostic accuracy was compared against microscopy and two rapid diagnostic tests (SD Bioline and BinaxNOW) using 18ssr nested-PCR as reference test. In addition, a real-time PCR assay (PET-PCR) was used for parasite quantification. Out of 217 febrile patients enrolled and tested, 180 specimens (85 P. vivax and 95 negatives) were included in the final analysis. Using nested-PCR as the gold standard, the sensitivity and specificity of Gazelle was 88.2% and 97.9%, respectively. Using a cutoff of 200 parasites/μl, Gazelle’s sensitivity for samples with more than 200 p/uL was 98.67% (95%CI: 92.79% to 99.97%) whereas the sensitivity for samples lower than 200 p/uL (n = 10) was 12.5% (95%CI: 0.32% to 52.65%). Gazelle’s sensitivity and specificity were statistically similar to microscopy (sensitivity = 91.8, specificity = 100%, p = 0.983) and higher than both SD Bioline (sensitivity = 82.4, specificity = 100%, p = 0.016) and BinaxNOW (sensitivity = 71.8%, specificity = 97.9%, p = 0.002). The diagnostic accuracy of Gazelle for malaria detection in P. vivax infections was comparable to light microscopy and superior to both RDTs even in the presence of low parasitemia infections. The performance of Gazelle makes it a valuable tool for malaria diagnosis and active case detection that can be utilized in different malaria-endemic regions.
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Gimenez AM, Marques RF, Regiart M, Bargieri DY. Diagnostic Methods for Non-Falciparum Malaria. Front Cell Infect Microbiol 2021; 11:681063. [PMID: 34222049 PMCID: PMC8248680 DOI: 10.3389/fcimb.2021.681063] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/31/2021] [Indexed: 11/13/2022] Open
Abstract
Malaria is a serious public health problem that affects mostly the poorest countries in the world, killing more than 400,000 people per year, mainly children under 5 years old. Among the control and prevention strategies, the differential diagnosis of the Plasmodium-infecting species is an important factor for selecting a treatment and, consequently, for preventing the spread of the disease. One of the main difficulties for the detection of a specific Plasmodium sp is that most of the existing methods for malaria diagnosis focus on detecting P. falciparum. Thus, in many cases, the diagnostic methods neglect the other non-falciparum species and underestimate their prevalence and severity. Traditional methods for diagnosing malaria may present low specificity or sensitivity to non-falciparum spp. Therefore, there is high demand for new alternative methods able to differentiate Plasmodium species in a faster, cheaper and easier manner to execute. This review details the classical procedures and new perspectives of diagnostic methods for malaria non-falciparum differential detection and the possibilities of their application in different circumstances.
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Affiliation(s)
- Alba Marina Gimenez
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Rodolfo F. Marques
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Matías Regiart
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Daniel Youssef Bargieri
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Avila HG, Risso MG, Ruybal P, Repetto SA, Butti MJ, Trangoni MD, Grune Löffler S, Pérez VM, Periago MV. Development of a low-cost copro-LAMP assay for simultaneous copro-detection of Toxocara canis and Toxocara cati. Parasitology 2021; 148:819-826. [PMID: 33593468 PMCID: PMC11010131 DOI: 10.1017/s0031182021000342] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/02/2021] [Accepted: 02/13/2021] [Indexed: 11/06/2022]
Abstract
Toxocariasis is a zoonotic disease caused mainly by Toxocara canis and Toxocara cati and diagnosis in dogs and cats is an important tool for its control. For this reason, a new coprological loop-mediated isothermal amplification (LAMP) assay was developed for the simultaneous detection of these species. The primer set was designed on a region of the mitochondrial cox-1 gene. Amplification conditions were evaluated using a temperature gradient (52°C to 68°C), different incubation times (15–120 min), and different concentrations of malachite green dye (0.004–0.4% w/v). The analytical sensitivity was evaluated with serial dilutions of genomic DNA from T. canis and T. cati adult worms, and with serial dilutions of DNA extracted from feces using a low-cost in-house method. The specificity was evaluated using genomic DNA from Canis lupus familiaris, Felis catus, Escherichia coli, Toxascaris leonina, Ancylostoma caninum, Echinococcus granulosus sensu stricto and Taenia hydatigena. The LAMP assay applied to environmental fecal samples from an endemic area showed an analytical sensitivity of 10–100 fg of genomic DNA and 10−5 serial dilutions of DNA extracted from feces using the low-cost in-house method; with a specificity of 100%. Additionally, the total development of the assay was carried out in a basic laboratory and per-reaction reagent cost decreased by ~80%. This new, low-cost tool can help identify the most common agents of toxocariasis in endemic areas in order to manage prevention strategies without having to rely on a laboratory with sophisticated equipment.
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Affiliation(s)
- Héctor Gabriel Avila
- Laboratorio Provincial de Zoonosis de San Juan, Facultad de Ciencias Veterinarias, Facultad de Ciencias Químicas y Tecnológicas, Universidad Católica de Cuyo, San Luis, San Juan, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina
| | - Marikena Guadalupe Risso
- Instituto de Investigaciones en Microbiología y Parasitología Médica, IMPAM-UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, CABA, Argentina
| | - Paula Ruybal
- Instituto de Investigaciones en Microbiología y Parasitología Médica, IMPAM-UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, CABA, Argentina
| | - Silvia Analía Repetto
- Instituto de Investigaciones en Microbiología y Parasitología Médica, IMPAM-UBA-CONICET, Facultad de Medicina, Universidad de Buenos Aires, CABA, Argentina
| | - Marcos Javier Butti
- Laboratorio de Parasitosis Humanas y Zoonosis Parasitarias, Cátedra de Parasitología Comparada, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Buenos Aires, Argentina
| | - Marcos David Trangoni
- Laboratorio de Brucella, Campylobacter y Microbiota del rumen, Instituto de Biotecnología/Instituto de Agrobiotecnología y Biología Molecular (IB/IABIMO), UEDD INTA-CONICET, CICVyA, CNIA, INTA Castelar, Hurlingham, Buenos Aires, Argentina
| | - Sylvia Grune Löffler
- Laboratorio de Leptospirosis, Instituto de Patobiología, Centro de Investigación en Ciencias Veterinarias y Agronómicas, Instituto Nacional de Tecnología Agropecuaria Castelar, Buenos Aires, Argentina
| | - Verónica Mirtha Pérez
- Sección de Rabia y Zoonosis, Dirección de Epidemiología, Ministerio de Salud Pública de San Juan, San Juan, Argentina
| | - María Victoria Periago
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina
- Fundación Mundo Sano, Buenos Aires, Argentina
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Nolasco O, Montoya J, Rosales Rosas AL, Barrientos S, Rosanas-Urgell A, Gamboa D. Multicopy targets for Plasmodium vivax and Plasmodium falciparum detection by colorimetric LAMP. Malar J 2021; 20:225. [PMID: 34011373 PMCID: PMC8135177 DOI: 10.1186/s12936-021-03753-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/07/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Loop-mediated isothermal amplification (LAMP) for malaria diagnosis at the point of care (POC) depends on the detection capacity of synthesized nucleic acids and the specificity of the amplification target. To improve malaria diagnosis, new colorimetric LAMP tests were developed using multicopy targets for Plasmodium vivax and Plasmodium falciparum detection. METHODS The cytochrome oxidase I (COX1) mitochondrial gene and the non-coding sequence Pvr47 for P. vivax, and the sub-telomeric sequence of erythrocyte membrane protein 1 (EMP1) and the non-coding sequence Pfr364 for P. falciparum were targeted to design new LAMP primers. The limit of detection (LOD) of each colorimetric LAMP was established and assessed with DNA extracted by mini spin column kit and the Boil & Spin method from 28 microscopy infections, 101 malaria submicroscopic infections detected by real-time PCR only, and 183 negatives infections by both microscopy and PCR. RESULTS The LODs for the colorimetric LAMPs were estimated between 2.4 to 3.7 parasites/µL of whole blood. For P. vivax detection, the colorimetric LAMP using the COX1 target showed a better performance than the Pvr47 target, whereas the Pfr364 target was the most specific for P. falciparum detection. All microscopic infections of P. vivax were detected by PvCOX1-LAMP using the mini spin column kit DNA extraction method and 81% (17/21) were detected using Boil & Spin sample preparation. Moreover, all microscopic infections of P. falciparum were detected by Pfr364-LAMP using both sample preparation methods. In total, PvCOX1-LAMP and Pfr364-LAMP detected 80.2% (81 samples) of the submicroscopic infections using the DNA extraction method by mini spin column kit, while 36.6% (37 samples) were detected using the Boil & Spin sample preparation method. CONCLUSION The colorimetric LAMPs with multicopy targets using the COX1 target for P. vivax and the Pfr364 for P. falciparum have a high potential to improve POC malaria diagnosis detecting a greater number of submicroscopic Plasmodium infections.
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Affiliation(s)
- Oscar Nolasco
- Instituto de Medicina Tropical "Alexander von Humboldt" Universidad Peruana Cayetano Heredia, Lima, Peru.
- Laboratorios de Investigación Y Desarrollo, Facultad de Ciencias Y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.
| | - Jhoel Montoya
- Unidad de Posgrado de la Facultad de Ciencias Biológicas Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Ana L Rosales Rosas
- Laboratorios de Investigación Y Desarrollo, Facultad de Ciencias Y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Scarlett Barrientos
- Laboratorios de Investigación Y Desarrollo, Facultad de Ciencias Y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Dionicia Gamboa
- Instituto de Medicina Tropical "Alexander von Humboldt" Universidad Peruana Cayetano Heredia, Lima, Peru
- Laboratorios de Investigación Y Desarrollo, Facultad de Ciencias Y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Celulares Y Moleculares, Facultad de Ciencias Y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
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Moehling TJ, Choi G, Dugan LC, Salit M, Meagher RJ. LAMP Diagnostics at the Point-of-Care: Emerging Trends and Perspectives for the Developer Community. Expert Rev Mol Diagn 2021; 21:43-61. [PMID: 33474990 DOI: 10.1080/14737159.2021.1873769] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Introduction: Over the past decade, loop-mediated isothermal amplification (LAMP) technology has played an important role in molecular diagnostics. Amongst numerous nucleic acid amplification assays, LAMP stands out in terms of sample-to-answer time, sensitivity, specificity, cost, robustness, and accessibility, making it ideal for field-deployable diagnostics in resource-limited regions.Areas covered: In this review, we outline the front-end LAMP design practices for point-of-care (POC) applications, including sample handling and various signal readout methodologies. Next, we explore existing LAMP technologies that have been validated with clinical samples in the field. We summarize recent work that utilizes reverse transcription (RT) LAMP to rapidly detect SARS-CoV-2 as an alternative to standard PCR protocols. Finally, we describe challenges in translating LAMP from the benchtop to the field and opportunities for future LAMP assay development and performance reporting.Expert opinion: Despite the popularity of LAMP in the academic research community and a recent surge in interest in LAMP due to the COVID-19 pandemic, there are numerous areas for improvement in the fundamental understanding of LAMP, which are needed to elevate the field of LAMP assay development and characterization.
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Affiliation(s)
- Taylor J Moehling
- Sandia National Laboratories, Biotechnology & Bioengineering Dept., Livermore, CA, USA
| | - Gihoon Choi
- Sandia National Laboratories, Biotechnology & Bioengineering Dept., Livermore, CA, USA
| | - Lawrence C Dugan
- Lawrence Livermore National Laboratory, Biosciences & Biotechnology Div., Livermore, CA, USA
| | - Marc Salit
- Joint Initiative for Metrology in Biology, SLAC National Accelerator Lab and Departments of Bioengineering and Pathology, Stanford University, Stanford, CA, USA
| | - Robert J Meagher
- Sandia National Laboratories, Biotechnology & Bioengineering Dept., Livermore, CA, USA
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12
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Bakari C, Jones S, Subramaniam G, Mandara CI, Chiduo MG, Rumisha S, Chacky F, Molteni F, Mandike R, Mkude S, Njau R, Herman C, Nace DP, Mohamed A, Udhayakumar V, Kibet CK, Nyanjom SG, Rogier E, Ishengoma DS. Community-based surveys for Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions in selected regions of mainland Tanzania. Malar J 2020; 19:391. [PMID: 33148255 PMCID: PMC7640459 DOI: 10.1186/s12936-020-03459-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 10/22/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Histidine-rich protein 2 (HRP2)-based malaria rapid diagnostic tests (RDTs) are effective and widely used for the detection of wild-type Plasmodium falciparum infections. Although recent studies have reported false negative HRP2 RDT results due to pfhrp2 and pfhrp3 gene deletions in different countries, there is a paucity of data on the deletions of these genes in Tanzania. METHODS A community-based cross-sectional survey was conducted between July and November 2017 in four regions: Geita, Kigoma, Mtwara and Ruvuma. All participants had microscopy and RDT performed in the field and provided a blood sample for laboratory multiplex antigen detection (for Plasmodium lactate dehydrogenase, aldolase, and P. falciparum HRP2). Samples showing RDT false negativity or aberrant relationship of HRP2 to pan-Plasmodium antigens were genotyped to detect the presence/absence of pfhrp2/3 genes. RESULTS Of all samples screened by the multiplex antigen assay (n = 7543), 2417 (32.0%) were positive for any Plasmodium antigens while 5126 (68.0%) were negative for all antigens. The vast majority of the antigen positive samples contained HRP2 (2411, 99.8%), but 6 (0.2%) had only pLDH and/or aldolase without HRP2. Overall, 13 samples had an atypical relationship between a pan-Plasmodium antigen and HRP2, but were positive by PCR. An additional 16 samples with negative HRP2 RDT results but P. falciparum positive by microscopy were also chosen for pfhrp2/3 genotyping. The summation of false negative RDT results and laboratory antigen results provided 35 total samples with confirmed P. falciparum DNA for pfhrp2/3 genotyping. Of the 35 samples, 4 (11.4%) failed to consistently amplify positive control genes; pfmsp1 and pfmsp2 and were excluded from the analysis. The pfhrp2 and pfhrp3 genes were successfully amplified in the remaining 31 (88.6%) samples, confirming an absence of deletions in these genes. CONCLUSIONS This study provides evidence that P. falciparum parasites in the study area have no deletions of both pfhrp2 and pfhrp3 genes. Although single gene deletions could have been missed by the multiplex antigen assay, the findings support the continued use of HRP2-based RDTs in Tanzania for routine malaria diagnosis. There is a need for the surveillance to monitor the status of pfhrp2 and/or pfhrp3 deletions in the future.
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Affiliation(s)
- Catherine Bakari
- Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
- National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | - Sophie Jones
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
- Williams Consulting, Baltimore, MD, USA
| | - Gireesh Subramaniam
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
- Oak Ridge Institute for Science and Education, Atlanta, GA, USA
| | - Celine I Mandara
- National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Mercy G Chiduo
- National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | - Susan Rumisha
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Frank Chacky
- National Malaria Control Programme (NMCP), Dodoma, Tanzania
| | | | - Renata Mandike
- National Malaria Control Programme (NMCP), Dodoma, Tanzania
| | - Sigsbert Mkude
- National Malaria Control Programme (NMCP), Dodoma, Tanzania
| | - Ritha Njau
- World Health Organization (WHO) Country Office, Dar es Salaam, Tanzania
| | - Camelia Herman
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
- CDC Foundation (CDCF), Atlanta, GA, USA
| | - Douglas P Nace
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ally Mohamed
- National Malaria Control Programme (NMCP), Dodoma, Tanzania
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Caleb K Kibet
- Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Steven G Nyanjom
- Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Eric Rogier
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Deus S Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania.
- Faculty of Pharmaceutical Sciences, Monash University, Melbourne, Australia.
- Harvard T.H Chan School of Public Health, Boston, MA, USA.
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Gachugia J, Chebore W, Otieno K, Ngugi CW, Godana A, Kariuki S. Evaluation of the colorimetric malachite green loop-mediated isothermal amplification (MG-LAMP) assay for the detection of malaria species at two different health facilities in a malaria endemic area of western Kenya. Malar J 2020; 19:329. [PMID: 32907582 PMCID: PMC7487890 DOI: 10.1186/s12936-020-03397-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 08/30/2020] [Indexed: 01/03/2023] Open
Abstract
Background Prompt diagnosis and effective malaria treatment is a key strategy in malaria control. However, the recommended diagnostic methods, microscopy and rapid diagnostic tests (RDTs), are not supported by robust quality assurance systems in endemic areas. This study compared the performance of routine RDTs and smear microscopy with a simple molecular-based colorimetric loop-mediated isothermal amplification (LAMP) at two different levels of the health care system in a malaria-endemic area of western Kenya. Methods Patients presenting with clinical symptoms of malaria at Rota Dispensary (level 2) and Siaya County Referral Hospital (level 4) were enrolled into the study after obtaining written informed consent. Capillary blood was collected to test for malaria by RDT and microscopy at the dispensary and county hospital, and for preparation of blood smears and dried blood spots (DBS) for expert microscopy and real-time polymerase chain reaction (RT-PCR). Results of the routine diagnostic tests were compared with those of malachite green loop-mediated isothermal amplification (MG-LAMP) performed at the two facilities. Results A total of 264 participants were enrolled into the study. At the dispensary level, the positivity rate by RDT, expert microscopy, MG-LAMP and RT-PCR was 37%, 30%, 44% and 42%, respectively, and 42%, 43%, 57% and 43% at the county hospital. Using RT-PCR as the reference test, the sensitivity of RDT and MG-LAMP was 78.1% (CI 67.5–86.4) and 82.9% (CI 73.0–90.3) at Rota dispensary. At Siaya hospital the sensitivity of routine microscopy and MG-LAMP was 83.3% (CI 65.3–94.4) and 93.3% (CI 77.9–99.2), respectively. Compared to MG-LAMP, there were 14 false positives and 29 false negatives by RDT at Rota dispensary and 3 false positives and 13 false negatives by routine microscopy at Siaya Hospital. Conclusion MG-LAMP is more sensitive than RDTs and microscopy in the detection of malaria parasites at public health facilities and might be a useful quality control tool in resource-limited settings.
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Affiliation(s)
- James Gachugia
- Department of Medical Microbiology, College of Health Sciences, Jomo Kenyatta University of Agriculture and Technology, P. O. Box 62000-00200, Nairobi, Kenya
| | - Winnie Chebore
- Kenya Medical Research Institute, Centre for Global Health Research, P. O. Box 1578-40100, Kisumu, Kenya
| | - Kephas Otieno
- Kenya Medical Research Institute, Centre for Global Health Research, P. O. Box 1578-40100, Kisumu, Kenya
| | - Caroline Wangari Ngugi
- Department of Medical Microbiology, College of Health Sciences, Jomo Kenyatta University of Agriculture and Technology, P. O. Box 62000-00200, Nairobi, Kenya
| | - Adano Godana
- National Malaria Control Programme, Ministry of Health, Kenyatta National Hospital, P. O. Box, Nairobi, 19982-00202, Kenya
| | - Simon Kariuki
- Kenya Medical Research Institute, Centre for Global Health Research, P. O. Box 1578-40100, Kisumu, Kenya.
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Selvarajah D, Naing C, Htet NH, Mak JW. Loop-mediated isothermal amplification (LAMP) test for diagnosis of uncomplicated malaria in endemic areas: a meta-analysis of diagnostic test accuracy. Malar J 2020; 19:211. [PMID: 32560728 PMCID: PMC7305603 DOI: 10.1186/s12936-020-03283-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 06/12/2020] [Indexed: 11/13/2022] Open
Abstract
Background The global malaria decline has stalled and only a few countries are pushing towards pre-elimination. The aim of the malaria elimination phase is interruption of local transmission of a specified malaria parasite in a defined geographical area. New and improved screening tools and strategies are required for detection and management of very low-density parasitaemia in the field. The objective of this study was to synthesize evidence on the diagnostic accuracy of loop-mediated isothermal amplification (LAMP) test for the detection of malaria parasites among people living in endemic areas. Methods This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis for Diagnostic Test Accuracy (PRISMA-DTA) guideline. Relevant studies in the health-related electronic databases were searched. According to the criteria set for this study, eligible studies were identified. The quality of included studies was evaluated with the use of a quality assessment checklist. A summary performance estimates such as pooled sensitivity and specificity were stratified by type of LAMP. Bivariate model for data analyses was applied. Summary receiver operating characteristics plots were created to display the results of individual studies in a receiver operating characteristics space. Meta-regression analysis was performed to investigate the sources of heterogeneity among individual studies. Results Twenty-seven studies across 17 endemic countries were identified. The vast majority of studies were with unclear risk of bias in the selection of index test. Overall, the pooled test performances were high for Pan LAMP (sensitivity: 0.95, 95% CI 0.91 to 0.97; specificity: 0.98, 95% CI 0.95 to 0.99), Plasmodium falciparum (Pf) LAMP (sensitivity: 0.96, 95% CI 0.94 to 0.98; specificity: 0.99, 95% CI 0.96 to 1.00) or for Plasmodium vivax (Pv) LAMP from 6 studies (sensitivity: 0.98, 95% CI 0.92 to 0.99; specificity: 0.99, 95% CI 0.72 to 1.00). The area under the curve for Pan LAMP (0.99, 95% CI 0.98–1.00), Pf LAMP (0.99, 95% CI 0.97–0.99) and Pv LAMP was (1.00, 95% CI 0.98–1.00) indicated that the diagnostic performance of these tests were within the excellent accuracy range. Meta-regression analysis showed that sample size had the greatest impact on test performance, among other factors. Conclusions The current findings suggest that LAMP-based assays are appropriate for detecting low-level malaria parasite infections in the field and would become valuable tools for malaria control and elimination programmes. Future well-designed larger sample studies on LAMP assessment in passive and active malaria surveillances that use PCR as the reference standard and provide sufficient data to construct 2 × 2 diagnostic table are needed.
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Affiliation(s)
- Denesh Selvarajah
- School of Medicine, International Medical University, Kuala Lumpur, 5700, Malaysia
| | - Cho Naing
- Institute for Research, Development and Innovation (IRDI), International Medical University, Kuala Lumpur, Malaysia. .,Faculty of Tropical Heath and Medicine, James Cook University, Queensland, Australia.
| | - Norah Htet Htet
- School of Medicine, International Medical University, Kuala Lumpur, 5700, Malaysia
| | - Joon Wah Mak
- Institute for Research, Development and Innovation (IRDI), International Medical University, Kuala Lumpur, Malaysia
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Comparison of real time and malachite-green based loop-mediated isothermal amplification assays for the detection of Plasmodium vivax and P. falciparum. PLoS One 2020; 15:e0234263. [PMID: 32525900 PMCID: PMC7289405 DOI: 10.1371/journal.pone.0234263] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/21/2020] [Indexed: 11/26/2022] Open
Abstract
The current context of malaria elimination requires urgent development and implementation of highly sensitive and specific methods for prompt detection and treatment of malaria parasites. Such methods should overcome current delays in diagnosis, allow the detection of low-density infections and address the difficulties in accessing remote endemic communities. In this study, we assessed the performance of the RealAmp and malachite-green loop mediated isothermal amplification (MG-LAMP) methodologies, using microscopy and conventional nested-PCR as reference techniques. Both LAMP techniques were performed for Plasmodium genus, P. falciparum, and P. vivax identification using 136 whole blood samples collected from three communities located in the Peruvian Amazon basin. Turnaround time and costs of performing the LAMP assays were estimated and compared to that of microscopy and nested-PCR. Using nested-PCR as reference standard, we calculated the sensitivity, specificity and 95% confidence interval (CI) for all methods. RealAmp had a sensitivity of 92% (95% CI: 85–96.5%) and specificity of 100% (95% CI: 89.1–100%) for species detection; sensitivity and specificity of MG-LAMP were 94% (95% CI: 87.5–97.8%) and 100% (89.1–100%), respectively. Whereas microscopy showed 88.1% sensitivity (95% CI: 80.2–93.7%) and 100% specificity (95%: 89.1–100%). The turnaround time and costs of performing the LAMP assays were lower compared to those associated with nested-PCR but higher than those associated with microscopy. The two LAMP assays were shown to be more sensitive and simple to implement than microscopy. Both LAMP methodologies could be used as large-scale screening tests, but the MG-LAMP assay uses a simple, portable heat-block while the RealAmp requires a RealAmp machine or a real-time PCR machine. This makes the MG-LAMP an appropriate choice for malaria surveillance studies in endemic sites. Use of LAMP tests in active case detection of Plasmodium parasites could help to detect positive malaria cases early.
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