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Ivarsson AC, Fransén E, Broumou I, Färnert A, Persson KEM, Söbirk SK. Head-to-head comparison of two loop-mediated isothermal amplification (LAMP) kits for diagnosis of malaria in a non-endemic setting. Malar J 2023; 22:377. [PMID: 38093251 PMCID: PMC10717323 DOI: 10.1186/s12936-023-04809-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 11/28/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND Light microscopy and rapid diagnostic tests (RDT) have long been the recommended diagnostic methods for malaria. However, in recent years, loop-mediated isothermal amplification (LAMP) techniques have been shown to offer superior performance, in particular concerning low-grade parasitaemia, by delivering higher sensitivity and specificity with low laboratory capacity requirements in little more than an hour. In this study, the diagnostic performance of two LAMP kits were assessed head-to-head, compared to highly sensitive quantitative real time PCR (qPCR), in a non-endemic setting. METHODS In this retrospective validation study two LAMP kits; Alethia® Illumigene Malaria kit and HumaTurb Loopamp™ Malaria Pan Detection (PDT) kit, were evaluated head-to-head for detection of Plasmodium-DNA in 133 biobanked blood samples from suspected malaria cases at the Clinical Microbiology Laboratory of Region Skåne, Sweden to determine their diagnostic performance compared to qPCR. RESULTS Of the 133 samples tested, qPCR detected Plasmodium DNA in 41 samples (defined as true positives), and the two LAMP methods detected 41 and 37 of those, respectively. The results from the HumaTurb Loopamp™ Malaria PDT kit were in complete congruence with the qPCR, with a sensitivity of 100% (95% CI 91.40-100%) and specificity of 100% (95% CI 96.07-100%). The Alethia® Illumigene Malaria kit had a sensitivity of 90.24% (95% CI 76.87-97.28) and a specificity of 95.65% (95% CI 89.24-98.80) as compared to qPCR. CONCLUSIONS This head-to-head comparison showed higher performance indicators of the HumaTurb Loopamp™ Malaria PDT kit compared to the Alethia® illumigene Malaria kit for detection of malaria.
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Affiliation(s)
- Anna-Clara Ivarsson
- Clinical Microbiology, Infection Prevention and Control, Office for Medical Services, Region Skåne, Lund, Sweden.
| | - Elin Fransén
- Clinical Microbiology, Infection Prevention and Control, Office for Medical Services, Region Skåne, Lund, Sweden
| | - Ioanna Broumou
- Department of Medicine Solna, Karolinska Institute, Stockholm, Sweden
- Centre for Molecular Medicine, Stockholm, Sweden
| | - Anna Färnert
- Department of Medicine Solna, Karolinska Institute, Stockholm, Sweden
- Centre for Molecular Medicine, Stockholm, Sweden
- Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Kristina E M Persson
- Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lund University, Lund, Sweden
- Clinical Chemistry and Pharmacology, Laboratory Medicine, Office for Medical Services, Region Skåne, Lund, Sweden
| | - Sara Karlsson Söbirk
- Clinical Microbiology, Infection Prevention and Control, Office for Medical Services, Region Skåne, Lund, Sweden
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden
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2
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van Bergen KJM, Stuitje AR, Akkers RC, Vermeer HJ, Castel R, Mank TG. Performance of a novel melting curve-based qPCR assay for malaria parasites in routine clinical practice in non-endemic setting. Malar J 2023; 22:191. [PMID: 37349789 DOI: 10.1186/s12936-023-04617-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 06/06/2023] [Indexed: 06/24/2023] Open
Abstract
BACKGROUND High-quality malaria diagnosis is essential for effective treatment and clinical disease management. Microscopy and rapid diagnostic tests are the conventional methods performed as first-line malaria diagnostics in non-endemic countries. However, these methods lack the characteristic to detect very low parasitaemia, and accurate identification of the Plasmodium species can be difficult. This study evaluated the performance of the MC004 melting curve-based qPCR for the diagnosis of malaria in routine clinical practice in non-endemic setting. METHODS AND RESULTS Whole blood samples were collected from 304 patients with clinical suspicion of malaria and analysed by both the MC004 assay and conventional diagnostics. Two discrepancies were found between the MC004 assay and microscopy. Repeated microscopic analysis confirmed the qPCR results. Comparison of the parasitaemia of nineteen Plasmodium falciparum samples determined by both microscopy and qPCR showed the potential of the MC004 assay to estimate the parasite load of P. falciparum. Eight Plasmodium infected patients were followed after anti-malarial treatment by the MC004 assay and microscopy. The MC004 assay still detected Plasmodium DNA although no parasites were seen with microscopy in post-treatment samples. The rapid decline in Plasmodium DNA showed the potential for therapy-monitoring. CONCLUSION Implementation of the MC004 assay in non-endemic clinical setting improved the diagnosis of malaria. The MC004 assay demonstrated superior Plasmodium species identification, the ability to indicate the Plasmodium parasite load, and can potentially detect submicroscopic Plasmodium infections.
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Affiliation(s)
- Kim J M van Bergen
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands.
| | - Antoine R Stuitje
- MRC Holland, Willem Schoutenstraat 1, 1057 DL, Amsterdam, The Netherlands
| | - Robert C Akkers
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands
| | - Henricus J Vermeer
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands
| | - Rob Castel
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands
| | - Theo G Mank
- Regional Laboratory for Medical Microbiology and Public Health, Boerhaavelaan 26, 2035 RC, Haarlem, The Netherlands
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3
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Vincent JP, Existe AV, Komaki-Yasuda K, Boncy J, Kano S. Performance of the procedure for ultra-rapid extraction and loop-mediated isothermal amplification (PURE-LAMP) method to detect malaria in Haiti. Infect Dis Poverty 2023; 12:53. [PMID: 37217984 DOI: 10.1186/s40249-023-01097-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
BACKGROUND Malaria continues to cause burden in various parts of the world. Haiti, a Caribbean country, is among those aiming to eliminate malaria within a few years. Two surveys were conducted in Haiti during which we aimed to evaluate the performance of the simple and rapid procedure for ultra-rapid extraction-loop-mediated isothermal amplification (PURE-LAMP) method with dried blood spots as an alternative diagnostic method for malaria in the context of low to very low rates of transmission. METHODS Febrile and afebrile people were recruited from three administrative divisions within Haiti: Nippes, Sud and Grand'Anse, during the summers of 2017 (early August to early September) and 2018 (late July to late August). Their blood samples were tested by microscopy, rapid diagnostic tests (RDT), PURE-LAMP and nested PCR to detect Plasmodium infection. Sensitivity, specificity, positive and negative predictive values and kappa statistics were estimated with the nested PCR results as the gold standard. RESULTS Among 1074 samples analyzed, a positive rate of 8.3% was calculated based on the nested PCR results. Among febrile participants, the rates in 2017 and 2018 were 14.6% and 1.4%, respectively. Three positives were detected among 172 afebrile participants in 2018 by PURE-LAMP and nested PCR, and all three were from the same locality. There was no afebrile participants recruited in 2017. The PURE-LAMP, RDT and microscopy had respective sensitivities of 100%, 85.4% and 49.4%. All of the testing methods had specificities over 99%. CONCLUSIONS This study confirmed the high performance of the PURE-LAMP method to detect Plasmodium infection with dried blood spots and recommends its use in targeted mass screening and treatment activities in low endemic areas of malaria.
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Affiliation(s)
- Jeanne Perpétue Vincent
- Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, Tokyo, 162-8655, Japan
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, 305-8575, Japan
- Unité d'Épidémiologie des Maladies Émergentes, Institut Pasteur, Paris, France
| | | | - Kanako Komaki-Yasuda
- Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, Tokyo, 162-8655, Japan
| | - Jacques Boncy
- Laboratoire National de Santé Publique, 6120, Port-au-Prince, Haiti
| | - Shigeyuki Kano
- Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, Tokyo, 162-8655, Japan.
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, 305-8575, Japan.
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4
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van Dijk NJ, Menting S, Wentink-Bonnema EMS, Broekhuizen-van Haaften PE, Withycombe E, Schallig HDFH, Mens PF. Laboratory evaluation of the miniature direct-on-blood PCR nucleic acid lateral flow immunoassay (mini-dbPCR-NALFIA), a simplified molecular diagnostic test for Plasmodium. Malar J 2023; 22:98. [PMID: 36932372 PMCID: PMC10024383 DOI: 10.1186/s12936-023-04496-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 02/13/2023] [Indexed: 03/19/2023] Open
Abstract
BACKGROUND Point-of-care diagnosis of malaria is currently based on microscopy and rapid diagnostic tests. However, both techniques have their constraints, including poor sensitivity for low parasitaemias. Hence, more accurate diagnostic tests for field use and routine clinical settings are warranted. The miniature direct-on-blood PCR nucleic acid lateral flow immunoassay (mini-dbPCR-NALFIA) is an innovative, easy-to-use molecular assay for diagnosis of malaria in resource-limited settings. Unlike traditional molecular methods, mini-dbPCR-NALFIA does not require DNA extraction and makes use of a handheld, portable thermal cycler that can run on a solar-charged power pack. Result read-out is done using a rapid lateral flow strip enabling differentiation of Plasmodium falciparum and non-falciparum malaria infections. A laboratory evaluation was performed to assess the performance of the mini-dbPCR-NALFIA for diagnosis of pan-Plasmodium and P. falciparum infections in whole blood. METHODS Diagnostic accuracy of the mini-dbPCR-NALFIA was determined by testing a set of Plasmodium-positive blood samples from returned travellers (n = 29), and Plasmodium-negative blood samples from travellers with suspected malaria (n = 23), the Dutch Blood Bank (n = 19) and intensive care patients at the Amsterdam University Medical Centers (n = 16). Alethia Malaria (LAMP) with microscopy for species differentiation were used as reference. Limit of detection for P. falciparum was determined by 23 measurements of a dilution series of a P. falciparum culture. A fixed sample set was tested three times by the same operator to evaluate the repeatability, and once by five different operators to assess the reproducibility. RESULTS Overall sensitivity and specificity of the mini-dbPCR-NALFIA were 96.6% (95% CI, 82.2%-99.9%) and 98.3% (95% CI, 90.8%-100%). Limit of detection for P. falciparum was 10 parasites per microlitre of blood. The repeatability of the assay was 93.7% (95% CI, 89.5%-97.8%) and reproducibility was 84.6% (95% CI, 79.5%-89.6%). CONCLUSIONS Mini-dbPCR-NALFIA is a sensitive, specific and robust method for molecular diagnosis of Plasmodium infections in whole blood and differentiation of P. falciparum. Incorporation of a miniature thermal cycler makes the assay well-adapted to resource-limited settings. A phase-3 field trial is currently being conducted to evaluate the potential implementation of this tool in different malaria transmission areas.
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Affiliation(s)
- Norbert J van Dijk
- Department of Medical Microbiology and Infection Prevention, Experimental Parasitology. Meibergdreef 9, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands.
- Amsterdam Institute for Infection and Immunity, Infectious Diseases Programme, Amsterdam, The Netherlands.
| | - Sandra Menting
- Department of Medical Microbiology and Infection Prevention, Experimental Parasitology. Meibergdreef 9, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Ellen M S Wentink-Bonnema
- Department of Medical Microbiology and Infection Prevention, Clinical Parasitology. Meibergdreef 9, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Patricia E Broekhuizen-van Haaften
- Department of Medical Microbiology and Infection Prevention, Clinical Parasitology. Meibergdreef 9, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Elen Withycombe
- Abingdon Health. York Biotech Campus, Sand Hutton, York, YO41 1LZ, UK
| | - Henk D F H Schallig
- Department of Medical Microbiology and Infection Prevention, Experimental Parasitology. Meibergdreef 9, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
- Amsterdam Institute for Infection and Immunity, Infectious Diseases Programme, Amsterdam, The Netherlands
| | - Petra F Mens
- Department of Medical Microbiology and Infection Prevention, Experimental Parasitology. Meibergdreef 9, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
- Amsterdam Institute for Infection and Immunity, Infectious Diseases Programme, Amsterdam, The Netherlands
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5
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Dong L, Li W, Xu Q, Gu J, Kang Z, Chen J, Xu X, Zhang X, Zhang X, Jiang H, Guan M. A rapid multiplex assay of human malaria parasites by digital PCR. Clin Chim Acta 2023; 539:70-78. [PMID: 36495929 DOI: 10.1016/j.cca.2022.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 11/25/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND Blood smear examination through traditional optical microscopy is the gold standard for malaria diagnosis. However, it imposes strict requirements for operational staff and its sensitivity cannot perfectly satisfy the needs of clinical requirements. More sensitive and accurate modern technologies should be applied to this field. Digital PCR (dPCR), as an absolute quantification detection method, can serve as an effective tool to facilitate the diagnosis and classification of different malaria species. OBJECTIVE We aimed to establish a new multiplex dPCR detection system for four main Plasmodium species: P. vivax, P. falciparum, P. ovale and P. malariae, which can distinguish exact species of malaria by one PCR reaction. METHODS A total of 39 patients were identified as malaria-positive by microscopic examination in Huashan Hospital from 2016 to 2021; seventy blood samples from these patients were collected. Additionally, 20 healthy individuals, 20 patients with fever and 6 patients with other types of blood parasites infection were also included in this study. Each blood sample was subjected to examination by both blood smears and dPCR. By optimizing four different fluorescence-labeled probes in one reaction system, dPCR permitted the performance of accurate quantitation and working out the exact number of copies of malaria DNA per microliter in whole blood. Rapid diagnostic tests were also conducted to verify part of the results obtained by dPCR. RESULTS The dPCR system was able to make rapid diagnosis and quantification of malaria DNA samples. The analytical sensitivity of multiplex dPCR was as low as 0.557 copies/μL (95% CI 0.521 to 0.607), and it had a sensitivity of 98.0% and a specificity of 100% in clinical samples. Additionally, three multiple malaria co-infection samples have been detected by this dPCR system, including one triple malaria infection case. By testing consecutive daily blood samples of Patient 39, dPCR facilitated monitoring the efficacy of drug treatment. It showed that the DNA concentrations of P. falciparum ranged from 5474 copies/μL to 0 copies/μL, which can reflect the efficacy of antimalarials in real time. This study also found that haemocyte samples (plasma removed) rather than whole blood had higher malaria detection capability and an enhanced positive rate. CONCLUSION The multiplex dPCR system newly established here made a substantial contribution in detecting malaria infection at low concentrations. It is suitable for mixed-infection diagnosis and multi-sample continuous monitoring, and presents a promising candidate as an absolute quantitative tool in clinical practice.
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Affiliation(s)
- Liu Dong
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China
| | - Weijia Li
- Department of Equipment, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Qianqian Xu
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China
| | - Jianfei Gu
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China
| | - Zhihua Kang
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, USA
| | - Jian Chen
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China
| | - Xiao Xu
- Central Laboratory, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Xinju Zhang
- Central Laboratory, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Xiuming Zhang
- Medical Laboratory of Shenzhen Luohu Hospital Group, Shenzhen Luohu People's Hospital, Shenzhen, PR China.
| | - Haoqin Jiang
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China.
| | - Ming Guan
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China.
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Ahuja V, Watts MR, Lee R. Verification and implementation of a commercial loop-mediated isothermal amplification (LAMP) assay for malaria testing in a public laboratory in New South Wales, Australia. Pathology 2022; 55:581-583. [PMID: 36707320 DOI: 10.1016/j.pathol.2022.10.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/01/2022] [Accepted: 10/06/2022] [Indexed: 12/31/2022]
Affiliation(s)
- Vishal Ahuja
- Parasitology Unit, NSW Health Pathology - Institute of Clinical Pathology and Medical Research, Westmead, NSW, Australia; Public Health Pathology, NSW Health Pathology, Sydney, NSW, Australia.
| | - Matthew R Watts
- Parasitology Unit, NSW Health Pathology - Institute of Clinical Pathology and Medical Research, Westmead, NSW, Australia; Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney Westmead Hospital, Westmead, NSW, Australia
| | - Rogan Lee
- Parasitology Unit, NSW Health Pathology - Institute of Clinical Pathology and Medical Research, Westmead, NSW, Australia; Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney Westmead Hospital, Westmead, NSW, Australia
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7
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Puri M, Kaur Brar H, Madan E, Srinivasan R, Rawat K, Gorthi SS, Kumari G, Sah R, Ojha SB, Panigrahi S, Dhangadamajhi G, Muthuswami R, Singh S, Madhubala R. Rapid diagnosis of Plasmodium falciparum malaria using a point-of-care loop-mediated isothermal amplification device. Front Cell Infect Microbiol 2022; 12:961832. [PMID: 36061865 PMCID: PMC9437306 DOI: 10.3389/fcimb.2022.961832] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 08/02/2022] [Indexed: 11/13/2022] Open
Abstract
LAMP diagnosis of malaria is simple and cost-effective with acceptable sensitivity and specificity as compared to standard diagnostic modules such as microscopy, RDTs and nested PCR, and thus its deployment for onsite screening of malaria in resource-limited regions is under consideration. However, the requirement of an electricity-operated dry bath and bulky read-out unit is still a major concern. In an effort to simplify this limitation, we have developed a portable LAMP device and fluorescence readout unit which can be used in the rapid point-of-care diagnosis of malaria. We have developed a point-of-care diagnostic LAMP device that is easy to operate by a mobile application, and the results can be quantified with a fluorescent readout unit. The diagnostic performance of the device was evaluated in 90 P. falciparum-infected clinical isolates stored at 4°C for 6-7 years and 10 freshly collected isolates from healthy volunteers. The LOD and quantitative ability of LAMP in estimating parasitemia levels were revealed with laboratory-grown P. falciparum strain (3D7). The LAMP assay performed in our device was exclusive for P. falciparum detection with sensitivity and specificity determined to be 98.89% and 100%, respectively, in clinical isolates. The LOD was documented to be 1 parasite/µl at the cut-off ADC value of 20. Parasite density estimated from ADC values showed concordance with microscopically determined parasite density of the cultured P. falciparum 3D7 strain. The LAMP assay performed in our device provides a possible portable platform for its deployment in the point-of-care diagnosis of malaria. Further validation of the quantitative ability of the assay with freshly collected or properly stored clinical samples of known parasitemia is necessary for field applicability.
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Affiliation(s)
- Madhu Puri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | - Evanka Madan
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Rajesh Srinivasan
- Department of Instrumentation and Applied Physics, Indian Institute of Science, Bengaluru, India
| | - Kapil Rawat
- Department of Instrumentation and Applied Physics, Indian Institute of Science, Bengaluru, India
| | - Sai Siva Gorthi
- Department of Instrumentation and Applied Physics, Indian Institute of Science, Bengaluru, India
| | - Geeta Kumari
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Raj Sah
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Sashi Bhusan Ojha
- Department of Biotechnology, Maharaja Sriram Chandra Bhanjadeo University, Baripada, India
| | - Subhendu Panigrahi
- Department of General Medicine, VSS Medical College and Hospital, Sambalpur, India
| | | | - Rohini Muthuswami
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- *Correspondence: Rentala Madhubala, ; Shailja Singh,
| | - Rentala Madhubala
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
- *Correspondence: Rentala Madhubala, ; Shailja Singh,
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8
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Martín-Ramírez A, Lanza M, Hisam S, Perez-Ayala A, Rubio JM. Usefulness of a commercial LAMP assay for detection of malaria infection, including Plasmodium knowlesi cases, in returning travelers in Spain. BMC Res Notes 2022; 15:147. [PMID: 35468833 PMCID: PMC9036737 DOI: 10.1186/s13104-022-06037-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 04/11/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Objective
Main malaria diagnosis is based on microscopic examination combined with rapid diagnostic tests. Both methods have low sensitivity and specificity. Loop-mediated isothermal amplification techniques have shown a sensitivity similar to PCR but with lower times of performance. This study aimed to assess a commercial LAMP for the diagnosis of malaria (Alethia® Malaria) against the Nested-Multiplex-Malaria PCR, including the analytical sensitivity and the operational characteristics.
Results
One hundred five samples out of 114 rendered valid results, obtaining 85 positive samples and 18 negative samples with an agreement of 98% compared to the reference method with a sensitivity, specificity and kappa coefficient of 98.84%, 94.74% and 0.94 respectively, with only two discrepant samples. The turnaround time was estimated in 1 h and 30 min, with a cost of 32.67€ per determination. The results showed several advantages of the Alethia® Malaria, as it was easy to perform, minimal training requirement and 40 min run. Moreover, it includes an internal control to avoid false negatives. However, it also showed some limitations such as the need for a specific amplification and detection device, the detection of only Plasmodium spp. and a very high price.
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Oyegoke OO, Maharaj L, Akoniyon OP, Kwoji I, Roux AT, Adewumi TS, Maharaj R, Oyebola BT, Adeleke MA, Okpeku M. Malaria diagnostic methods with the elimination goal in view. Parasitol Res 2022; 121:1867-1885. [PMID: 35460369 PMCID: PMC9033523 DOI: 10.1007/s00436-022-07512-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 04/01/2022] [Indexed: 01/08/2023]
Abstract
Malaria control measures have been in use for years but have not completely curbed the spread of infection. Ultimately, global elimination is the goal. A major playmaker in the various approaches to reaching the goal is the issue of proper diagnosis. Various diagnostic techniques were adopted in different regions and geographical locations over the decades, and these have invariably produced diverse outcomes. In this review, we looked at the various approaches used in malaria diagnostics with a focus on methods favorably used during pre-elimination and elimination phases as well as in endemic regions. Microscopy, rapid diagnostic testing (RDT), loop-mediated isothermal amplification (LAMP), and polymerase chain reaction (PCR) are common methods applied depending on prevailing factors, each with its strengths and limitations. As the drive toward the elimination goal intensifies, the search for ideal, simple, fast, and reliable point-of-care diagnostic tools is needed more than ever before to be used in conjunction with a functional surveillance system supported by the ideal vaccine.
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Affiliation(s)
- Olukunle O Oyegoke
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Leah Maharaj
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Oluwasegun P Akoniyon
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Illiya Kwoji
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Alexandra T Roux
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Taiye S Adewumi
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Rajendra Maharaj
- Office of Malaria Research, Medical Research Council, Durban, South Africa
| | | | - Matthew A Adeleke
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Moses Okpeku
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa.
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10
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Clinical accuracy of malaria loop-mediated isothermal amplification assay as a stand-alone screening tool at a non-endemic Northern California regional health system. Diagn Microbiol Infect Dis 2022; 103:115680. [DOI: 10.1016/j.diagmicrobio.2022.115680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 02/18/2022] [Accepted: 03/04/2022] [Indexed: 11/17/2022]
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11
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Antinori S, Ridolfo AL, Grande R, Galimberti L, Casalini G, Giacomelli A, Milazzo L. Loop-mediated isothermal amplification (LAMP) assay for the diagnosis of imported malaria: a narrative review. LE INFEZIONI IN MEDICINA 2022; 29:355-365. [PMID: 35146340 DOI: 10.53854/liim-2903-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/09/2021] [Indexed: 11/03/2022]
Abstract
Loop-mediated isothermal amplification (LAMP) is a molecular method to detect malaria recently introduced in the market. LAMP is simple to perform and does not require advanced equipment and training thus satisfying the qualification as a point-of-care diagnostic screening test. In this narrative review, we focus on the role of LAMP for malaria diagnosis in non-endemic settings. We searched PubMed, Embase, Scopus, and Google Scholar, using the following search terms: 'Malaria LAMP' in combination with 'imported malaria' or 'travellers' malaria' or 'non-endemic setting' or 'non-endemic region' or 'malaria screening' or 'malaria diagnosis'. References of each article were also reviewed for possible studies or reports not identified in our search. Overall, 18 studies encompassing 6289 tested samples with 1663 confirmed malaria diagnoses were retrieved. Most of these studies (13/18, 72.2%) were conducted in Europe, and almost half were retrospective. Fourteen studies (77.8%) employed real-time or nested-polymerase chain reaction as the reference method for confirming malaria diagnosis. Sensitivity of LAMP ranged from 93.9 to 100% and specificity from 93.8 to 100% with a negative predictive value of 99.6%-100%. The rate of reported invalid results requiring repeat of the test varied from 0.01% to 5.7%, but they were solved in the majority of cases with a secondary analysis. In non-endemic countries the adoption of LAMP malaria assay as the screening test for malaria diagnosis seems to perform better than conventional methods. However, blood microscopy remains essential to either identify Plasmodium species and quantify parasitaemia and adequately managing malaria cases.
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Affiliation(s)
- Spinello Antinori
- Department of Biomedical and Clinical Sciences "Luigi Sacco", Università degli Studi di Milano, Milano, Italy.,III Division of Infectious Diseases, ASST Fatebenefratelli Sacco, Luigi Sacco Hospital, Milano, Italy
| | - Anna Lisa Ridolfo
- III Division of Infectious Diseases, ASST Fatebenefratelli Sacco, Luigi Sacco Hospital, Milano, Italy
| | - Romualdo Grande
- Clinical Microbiology, Virology and Bioemergency, ASST Fatebenefratelli Sacco, Luigi Sacco Hospital, Milano, Italy
| | - Laura Galimberti
- III Division of Infectious Diseases, ASST Fatebenefratelli Sacco, Luigi Sacco Hospital, Milano, Italy
| | - Giacomo Casalini
- Department of Biomedical and Clinical Sciences "Luigi Sacco", Università degli Studi di Milano, Milano, Italy
| | - Andrea Giacomelli
- Department of Biomedical and Clinical Sciences "Luigi Sacco", Università degli Studi di Milano, Milano, Italy.,III Division of Infectious Diseases, ASST Fatebenefratelli Sacco, Luigi Sacco Hospital, Milano, Italy
| | - Laura Milazzo
- III Division of Infectious Diseases, ASST Fatebenefratelli Sacco, Luigi Sacco Hospital, Milano, Italy
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Giacomelli A, Monti ME, Grande R, Oreni L, Galimberti L, Ridolfo AL, Bonazzetti C, Sabaini F, Cordier L, Zambelli A, Rizzardini G, Galli M, Antinori S. The value of lamp to rule out imported malaria diagnosis: a retrospective observational study in Milan, Italy. Infect Dis (Lond) 2022; 54:410-417. [PMID: 34983306 DOI: 10.1080/23744235.2021.2023754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND The diagnosis of malaria in returning travellers could be a challenge in non-endemic settings. We aimed to assess the performance of LAMP in comparison with standard conventional diagnostic methods using real-time-polymerase chain reaction (PCR) in case of discordant results. METHODS All travellers returning from malaria-endemic areas who presented to our Emergency Department (ED) from January 2017 to December 2020 with signs and symptoms suggestive for malaria were included. Blood microscopy was the reference diagnostic method applied at our laboratory with LAMP implemented as an additional method to aid in malaria diagnosis. PCR was employed only in case of between test's discordant results. Sensitivity and specificity of microscopy compared to LAMP were calculated with the confidence interval of 95%. RESULTS Four-hundred and eight patients (55.6% male, median age 42 years) were screened for malaria. The diagnosis was confirmed in 49 cases (12%): 44 cases (90%) caused by Plasmodium falciparum. Peripheral blood smear missed to identify three malaria cases, which tested positive with LAMP and PCR. One case of malaria caused by P. malariae in a naive tourist, one case by P. falciparum in a semi-immune pregnant women and one case by P. falciparum in a previously treated semi-immune patient. All the discordant cases were characterized by a very low parasitaemia. Microscopy when compared to LAMP showed a sensitivity of 93.9% (95% confidence interval (CI) 83.1-98.7%) and a specificity of 100% (95% CI 98.9-100%). CONCLUSIONS In our non-endemic setting LAMP was able to identify malaria cases with low-level parasitaemia otherwise missed by blood microscopy.
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Affiliation(s)
- Andrea Giacomelli
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Maria Elena Monti
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Romualdo Grande
- Diagnostic Services, Clinical Microbiology, Virology and Bioemergence Diagnostics, ASST Fatebenefratelli-Sacco, Milan, Italy
| | - Letizia Oreni
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Laura Galimberti
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Anna Lisa Ridolfo
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Cecilia Bonazzetti
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy.,Luigi Sacco Department of Biomedical and Clinical Sciences DIBIC, Università degli Studi di Milano, Milan, Italy
| | - Federico Sabaini
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Laura Cordier
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Agostino Zambelli
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy
| | - Giuliano Rizzardini
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy.,School of Clinical Medicine, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Massimo Galli
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy.,Luigi Sacco Department of Biomedical and Clinical Sciences DIBIC, Università degli Studi di Milano, Milan, Italy
| | - Spinello Antinori
- Department of Infectious Diseases, ASST Fatebenefratelli-Sacco, Luigi Sacco University Hospital, Milan, Italy.,Luigi Sacco Department of Biomedical and Clinical Sciences DIBIC, Università degli Studi di Milano, Milan, Italy
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Automated parasitological diagnosis in clinical microbiology laboratories. Sci Rep 2021; 11:13105. [PMID: 34162917 PMCID: PMC8222325 DOI: 10.1038/s41598-021-92441-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/10/2021] [Indexed: 11/21/2022] Open
Abstract
Although there is a low prevalence of parasitological infections in Europe, the diagnosis of intestinal parasites is still difficult and laborious for microbiology laboratories. Currently, antigen detection assays and molecular biology allow a more accurate diagnosis, but these techniques have limitations as they cannot detect all the possible parasites present in the samples. The objective of the study was to evaluate the accuracy and the usefulness of automated microscopy SediMAX2 (77 Elektronika, Budapest, Hungary) in the detection of parasitic infections from feces. A total of 197 formol-fixed stool samples were processed in parallel by wet mount examination and by SediMAX2. Sensitivities, specificities and predictive values were analyzed, reaching a sensitivity of 89.51% and a specificity of 98.15% and a very good positive predictive value (99.22%). SediMAX2 is a good tool for a reliable diagnosis of intestinal parasitic infections. The rapid processing and the flexibilty of storage of images analyzed make its incorporation into the day to day laboratory routine recommendable.
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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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McGinnis E, Chan G, Hudoba M, Markin T, Yakimec J, Roland K. Malaria Screening Using Front-Line Loop-Mediated Isothermal Amplification. Am J Clin Pathol 2021; 155:690-697. [PMID: 33283225 DOI: 10.1093/ajcp/aqaa173] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES We implemented front-line loop-mediated isothermal amplification (LAMP)-based malaria screening in our nonendemic multicenter health region to reduce reliance on microscopy without sacrificing diagnostic efficiency. We aimed to evaluate changes in test volumes, positivity rates, turnaround times, and approximate labor time savings resulting from implementation of LAMP-based malaria testing to assess the efficacy of the novel testing algorithm in our regional hub-and-spoke testing model. METHODS We reviewed data generated from institutional malaria testing between 2016 and 2019, having implemented LAMP in October 2018 as a front-line screening test for all malaria investigations from our hub facility and investigations from satellite facilities with negative rapid diagnostic tests (RDTs) and microscopy. RESULTS Blood film microscopy and RDT workloads decreased substantially in the year following LAMP implementation (by 90% and 46%, respectively,) despite similar numbers of patients tested and positivity rates for malaria compared with historical data. LAMP turnaround times (TATs) were comparable to historical TATs for RDTs, and TATs for RDTs and thick films did not increase with the change in workflow. CONCLUSIONS LAMP was successfully implemented in our multicenter health region malaria diagnostic algorithm, significantly reducing reliance on microscopic evaluations and RDT and providing substantial labor time savings without compromising TATs.
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Affiliation(s)
- Eric McGinnis
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
| | - Geoffrey Chan
- Division of Hematopathology, Department of Pathology and Laboratory Medicine, Vancouver General Hospital, Vancouver, Canada
| | - Monika Hudoba
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
- Division of Hematopathology, Department of Pathology and Laboratory Medicine, Vancouver General Hospital, Vancouver, Canada
| | - Todd Markin
- Division of Hematopathology, Department of Pathology and Laboratory Medicine, Vancouver General Hospital, Vancouver, Canada
| | - Jim Yakimec
- Division of Hematopathology, Department of Pathology and Laboratory Medicine, Vancouver General Hospital, Vancouver, Canada
| | - Kristine Roland
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
- Division of Hematopathology, Department of Pathology and Laboratory Medicine, Vancouver General Hospital, Vancouver, Canada
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Ljolje D, Abdallah R, Lucchi NW. Detection of malaria parasites in samples from returning US travelers using the Alethia® Malaria Plus LAMP assay. BMC Res Notes 2021; 14:128. [PMID: 33827683 PMCID: PMC8028069 DOI: 10.1186/s13104-021-05542-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 03/24/2021] [Indexed: 12/02/2022] Open
Abstract
Objective In this study, the performance of a commercially available malaria LAMP assay (Alethia® Malaria Plus LAMP) was evaluated using retrospective clinical samples obtained from travelers returning to the United States of America (USA). Recently, several laboratories in non-malaria endemic countries evaluated the use of the loop mediated isothermal amplification (LAMP) assays for the diagnosis of imported malaria cases. These tests are simpler than polymerase-chain reaction (PCR)-based assays and were shown to have high sensitivity. Much of malaria diagnoses in the USA, is undertaken at the state level using mainly microscopy and rapid diagnostic tests (RDTs). However, molecular tools offer greater sensitivity over microscopy and RDTs. A reliable, easy to perform molecular assay can provide a test of choice for the accurate detection of malaria parasites in places where expert microscopy is lacking and/or for the detection of low-parasite density infections. Results The Alethia® Malaria Plus LAMP assay was easy to use, had similar test performances as the real-time PCR reference test and results were obtained faster (within 1 h) than the reference test. The sensitivity of the assay was 100% with a kappa score of 1 when compared to the reference PET-PCR assay.
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Affiliation(s)
- Dragan Ljolje
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Rispah Abdallah
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Naomi W Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Performance and Application of Commercially Available Loop-Mediated Isothermal Amplification (LAMP) Kits in Malaria Endemic and Non-Endemic Settings. Diagnostics (Basel) 2021; 11:diagnostics11020336. [PMID: 33670618 PMCID: PMC7922894 DOI: 10.3390/diagnostics11020336] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 01/04/2023] Open
Abstract
Loop-mediated isothermal amplification (LAMP) is a sensitive molecular tool suitable for use as a near point-of-care test for the diagnosis of malaria. Recent meta-analyses have detailed high sensitivity and specificity of malaria LAMP when compared to microscopy, rapid diagnostic tests, and polymerase chain reaction in both endemic and non-endemic settings. Despite this, the use of malaria LAMP has primarily been limited to research settings to date. In this review, we aim to assess to what extent commercially available malaria LAMP kits have been applied in different settings, and to identify possible obstacles that may have hindered their use from being adopted further. In order to address this, we conducted a literature search in PubMed.gov using the search terms (((LAMP) OR (Loop-mediated isothermal amplification)) AND ((Malaria) OR (Plasmodium))). Focusing primarily on studies employing one of the commercially available kits, we then selected three key areas of LAMP application for further review: the performance and application of LAMP in malaria endemic settings including low transmission areas; LAMP for malaria screening during pregnancy; and malaria LAMP in returning travelers in non-endemic settings.
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Salminen T, Mehdi F, Rohila D, Kumar M, Talha SM, Prakash JAJ, Khanna N, Pettersson K, Batra G. Ultrasensitive and Robust Point-of-Care Immunoassay for the Detection of Plasmodium falciparum Malaria. Anal Chem 2020; 92:15766-15772. [PMID: 33228352 DOI: 10.1021/acs.analchem.0c02748] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Plasmodium falciparum malaria is widespread in the tropical and subtropical regions of the world. There is ongoing effort to eliminate malaria from endemic regions, and sensitive point-of-care (POC) diagnostic tests are required to support this effort. However, current POC tests are not sufficiently sensitive to detect P. falciparum in asymptomatic individuals. After extensive optimization, we have developed a highly sensitive and robust POC test for the detection of P. falciparum infection. The test is based on upconverting nanophosphor-based lateral flow (UCNP-LF) immunoassay. The developed UCNP-LF test was validated using whole blood reference panels containing samples at different parasite densities covering eight strains of P. falciparum from different geographical areas. The limit of detection was compared to a WHO-prequalified rapid diagnostic test (RDT). The UCNP-LF achieved a detection limit of 0.2-2 parasites/μL, depending on the strain, which is 50- to 250-fold improvement in analytical sensitivity over the conventional RDTs. The developed UCNP-LF is highly stable even at 40 °C for at least 5 months. The extensively optimized UCNP-LF assay is as simple as the conventional malaria RDTs and requires 5 μL of whole blood as sample. Results can be read after 20 min from sample addition, with a simple photoluminescence reader. In the absence of a reader device at the testing site, the strips after running the test can be transported and read at a central location with access to a reader. We have found that the test and control line signals are stable for at least 10 months after running the test. The UCNP-LF has potential for diagnostic testing of both symptomatic and asymptomatic individuals.
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Affiliation(s)
- Teppo Salminen
- Department of Biotechnology, University of Turku, Kiinamyllynkatu 10, Turku 20520, Finland
| | - Farha Mehdi
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, Haryana, India
| | - Deepak Rohila
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, Haryana, India
| | - Manjit Kumar
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, Haryana, India
| | - Sheikh M Talha
- Department of Biotechnology, University of Turku, Kiinamyllynkatu 10, Turku 20520, Finland
| | - John Antony Jude Prakash
- Department of Clinical Microbiology, Christian Medical College, Vellore 632004, Tamil Nadu, India
| | - Navin Khanna
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Kim Pettersson
- Department of Biotechnology, University of Turku, Kiinamyllynkatu 10, Turku 20520, Finland
| | - Gaurav Batra
- Translational Health Science and Technology Institute, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, Haryana, India
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Abstract
BACKGROUND Plasmodium vivax (P vivax) is a focus of malaria elimination. It is important because P vivax and Plasmodium falciparum infection are co-endemic in some areas. There are asymptomatic carriers of P vivax, and the treatment for P vivax and Plasmodium ovale malaria differs from that used in other types of malaria. Rapid diagnostic tests (RDTs) will help distinguish P vivax from other malaria species to help treatment and elimination. There are RDTs available that detect P vivax parasitaemia through the detection of P vivax-specific lactate dehydrogenase (LDH) antigens. OBJECTIVES To assess the diagnostic accuracy of RDTs for detecting P vivax malaria infection in people living in malaria-endemic areas who present to ambulatory healthcare facilities with symptoms suggestive of malaria; and to identify which types and brands of commercial tests best detect P vivax malaria. SEARCH METHODS We undertook a comprehensive search of the following databases up to 30 July 2019: Cochrane Infectious Diseases Group Specialized Register; Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE (PubMed); Embase (OVID); Science Citation Index Expanded (SCI-EXPANDED) and Conference Proceedings Citation Index-Science (CPCI-S), both in the Web of Science. SELECTION CRITERIA Studies comparing RDTs with a reference standard (microscopy or polymerase chain reaction (PCR)) in blood samples from patients attending ambulatory health facilities with symptoms suggestive of malaria in P vivax-endemic areas. DATA COLLECTION AND ANALYSIS For each included study, two review authors independently extracted data using a pre-piloted data extraction form. The methodological quality of the studies were assessed using a tailored Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. We grouped studies according to commercial brand of the RDT and performed meta-analysis when appropriate. The results given by the index tests were based on the antibody affinity (referred to as the strength of the bond between an antibody and an antigen) and avidity (referred to as the strength of the overall bond between a multivalent antibody and multiple antigens). All analyses were stratified by the type of reference standard. The bivariate model was used to estimate the pooled sensitivity and specificity with 95% confidence intervals (CIs), this model was simplified when studies were few. We assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS We included 10 studies that assessed the accuracy of six different RDT brands (CareStart Malaria Pf/Pv Combo test, Falcivax Device Rapid test, Immuno-Rapid Malaria Pf/Pv test, SD Bioline Malaria Ag Pf/Pv test, OnSite Pf/Pv test and Test Malaria Pf/Pv rapid test) for detecting P vivax malaria. One study directly compared the accuracy of two RDT brands. Of the 10 studies, six used microscopy, one used PCR, two used both microscopy and PCR separately and one used microscopy corrected by PCR as the reference standard. Four of the studies were conducted in Ethiopia, two in India, and one each in Bangladesh, Brazil, Colombia and Sudan. The studies often did not report how patients were selected. In the patient selection domain, we judged the risk of bias as unclear for nine studies. We judged all studies to be of unclear applicability concern. In the index test domain, we judged most studies to be at low risk of bias, but we judged nine studies to be of unclear applicability concern. There was poor reporting on lot testing, how the RDTs were stored, and background parasitaemia density (a key variable determining diagnostic accuracy of RDTs). Only half of the included studies were judged to be at low risk of bias in the reference standard domain, Studies often did not report whether the results of the reference standard could classify the target condition or whether investigators knew the results of the RDT when interpreting the results of the reference standard. All 10 studies were judged to be at low risk of bias in the flow and timing domain. Only two brands were evaluated by more than one study. Four studies evaluated the CareStart Malaria Pf/Pv Combo test against microscopy and two studies evaluated the Falcivax Device Rapid test against microscopy. The pooled sensitivity and specificity were 99% (95% CI 94% to 100%; 251 patients, moderate-certainty evidence) and 99% (95% CI 99% to 100%; 2147 patients, moderate-certainty evidence) for CareStart Malaria Pf/Pv Combo test. For a prevalence of 20%, about 206 people will have a positive CareStart Malaria Pf/Pv Combo test result and the remaining 794 people will have a negative result. Of the 206 people with positive results, eight will be incorrect (false positives), and of the 794 people with a negative result, two would be incorrect (false negative). For the Falcivax Device Rapid test, the pooled sensitivity was 77% (95% CI: 53% to 91%, 89 patients, low-certainty evidence) and the pooled specificity was 99% (95% CI: 98% to 100%, 621 patients, moderate-certainty evidence), respectively. For a prevalence of 20%, about 162 people will have a positive Falcivax Device Rapid test result and the remaining 838 people will have a negative result. Of the 162 people with positive results, eight will be incorrect (false positives), and of the 838 people with a negative result, 46 would be incorrect (false negative). AUTHORS' CONCLUSIONS The CareStart Malaria Pf/Pv Combo test was found to be highly sensitive and specific in comparison to microscopy for detecting P vivax in ambulatory healthcare in endemic settings, with moderate-certainty evidence. The number of studies included in this review was limited to 10 studies and we were able to estimate the accuracy of 2 out of 6 RDT brands included, the CareStart Malaria Pf/Pv Combo test and the Falcivax Device Rapid test. Thus, the differences in sensitivity and specificity between all the RDT brands could not be assessed. More high-quality studies in endemic field settings are needed to assess and compare the accuracy of RDTs designed to detect P vivax.
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Affiliation(s)
- Ridhi Agarwal
- Institute of Applied Health Research, University of Birmingham, Birmingham, UK
| | - Leslie Choi
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Samuel Johnson
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Yemisi Takwoingi
- Test Evaluation Research Group, Institute of Applied Health Research, University of Birmingham, Birmingham, UK
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Picot S, Cucherat M, Bienvenu AL. Systematic review and meta-analysis of diagnostic accuracy of loop-mediated isothermal amplification (LAMP) methods compared with microscopy, polymerase chain reaction and rapid diagnostic tests for malaria diagnosis. Int J Infect Dis 2020; 98:408-419. [PMID: 32659450 DOI: 10.1016/j.ijid.2020.07.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 07/01/2020] [Accepted: 07/05/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Diagnosis is a challenging issue for eliminating malaria. Loop-mediated isothermal amplification (LAMP) could be an alternative to conventional methods. This study aimed to evaluate the diagnostic accuracy of LAMP for malaria compared with microscopy, polymerase chain reaction (PCR) and rapid diagnostic tests (RDTs). METHODS AND DESIGN MEDLINE, Web of Science and Scopus were searched from inception to 1 July 2019. Prospective and retrospective, randomised and non-randomised, mono-center and multi-center studies, including symptomatic or asymptomatic patients, that reported one LAMP method and one comparator (microscopy, RDT or PCR) were included. PROSPERO registration number: CRD42017075186. RESULTS Sixty-six studies published between 2006 and 2019 were included, leading to the analysis of 30,641 LAMP tests. The pooled sensitivity of LAMP remained between 96% and 98%, whichever the comparator. The pooled specificity of LAMP was around 95%, but was a little higher if the best PCR studies were considered. The AUC was found to be >0.98, whichever the subgroup of studies was considered. Diagnostic odds ratio (DOR) was found to be around 1000 for all subgroups, except for Plasmodium vivax. CONCLUSION This meta-analysis confirmed that the LAMP method is robust for diagnosing malaria, both in symptomatic and asymptomatic people. Thus, the impact of LAMP for controlling malaria is expected to be important.
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Affiliation(s)
- Stephane Picot
- Malaria Research Unit, SMITh, ICBMS UMR 5246 CNRS-INSA-CPE-Université de Lyon, Campus Lyon-Tech La Doua, 69622 Villeurbanne Cedex, France; Institut de Parasitologie et Mycologie Médicale, Hôpital de La Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Michel Cucherat
- Service de Pharmacotoxicologie, Hospices Civils de Lyon, Laboratoire de Biométrie et Biologie Évolutive, CNRS, UMR5558, Université Lyon 1, Lyon, France
| | - Anne-Lise Bienvenu
- Malaria Research Unit, SMITh, ICBMS UMR 5246 CNRS-INSA-CPE-Université de Lyon, Campus Lyon-Tech La Doua, 69622 Villeurbanne Cedex, France; Service Pharmacie, Groupement Hospitalier Nord, Hospices Civils de Lyon, France; Service d'Hématologie, Groupement Hospitalier Nord, Hospices Civils de Lyon, France.
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Lufungulo Bahati Y, Delanghe J, Bisimwa Balaluka G, Sadiki Kishabongo A, Philippé J. Asymptomatic Submicroscopic Plasmodium Infection Is Highly Prevalent and Is Associated with Anemia in Children Younger than 5 Years in South Kivu/Democratic Republic of Congo. Am J Trop Med Hyg 2020; 102:1048-1055. [PMID: 32124722 DOI: 10.4269/ajtmh.19-0878] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
One of the most important problems in controlling malaria is the limited access to effective and accurate diagnosis of malaria parasitemia. In the Democratic Republic of Congo (DRC), malaria is one of the leading causes of morbidity and mortality. The purpose of this study was to assess the prevalence of anemia and the relationship with asymptomatic submicroscopic Plasmodium infection. A cross-sectional study was carried out among 1,088 apparently healthy children aged between 6 and 59 months selected at random in the health zone of Miti Murhesa in South Kivu/DRC. Capillary blood was obtained for hemoglobin (Hb) concentration measurement by Hemocue® Hb 301. Malaria detection was performed by microscopy and the loop-mediated isothermal amplification (LAMP) assay. Anemia was defined as Hb < 11g/dL. We applied the chi-square test for comparisons, and multiple logistic regression was used to identify the risk factors for anemia and submicroscopic Plasmodium infection. The prevalence of anemia was 39.6%, and the prevalence of parasitemia was 15.9% and 34.0% using microscopy and LAMP test, respectively. Submicroscopic Plasmodium infection was found in 22.3% of the children. The independent risk factors for anemia are Plasmodium infection, children younger than 24 months, low middle-upper arm circumference, and history of illness two weeks before. Otherwise, children with submicroscopic malaria infection have a significantly increased risk for anemia, with a need of transfusion. The prevalence of malaria infection was underestimated, when microscopy was used to diagnose malaria. Children with low parasitemia detected by LAMP but not by microscopy showed a significantly increased prevalence of anemia.
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Affiliation(s)
- Yvette Lufungulo Bahati
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.,Department of Pediatrics, Catholic University of Bukavu, Bukavu, Democratic Republic of Congo
| | - Joris Delanghe
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | | | | | - Jan Philippé
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
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Pomari E, Silva R, Moro L, La Marca G, Perandin F, Verra F, Bisoffi Z, Piubelli C. Droplet Digital PCR for the Detection of Plasmodium falciparum DNA in Whole Blood and Serum: A Comparative Analysis with Other Molecular Methods. Pathogens 2020; 9:pathogens9060478. [PMID: 32560386 PMCID: PMC7350319 DOI: 10.3390/pathogens9060478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/08/2020] [Accepted: 06/15/2020] [Indexed: 12/24/2022] Open
Abstract
Background: The estimation of Plasmodium falciparum parasitaemia can vary according to the method used. Recently, droplet digital PCR (ddPCR) has been proposed as a promising approach in the molecular quantitation of Plasmodium, but its ability to predict the actual parasitaemia on clinical samples has not been largely investigated. Moreover, the possibility of applying the ddPCR-sensitive method to serum samples has never been explored. Methods: We used, for the first time, ddPCR on both blood and serum to detect the DNA of P. falciparum in 52 paired samples from 26 patients. ddPCR was compared with loop-mediated isothermal amplification (LAMP) and rtPCR. The correlation between the ddPCR results, microscopy, and clinical parameters was examined. Results: ddPCR and microscopy were found to be strongly correlated (ρ(26) = 0.83111, p < 0.0001) in blood. Samples deviating from the correlation were partially explained by clinical parameters. In serum samples, ddPCR revealed the best performance in detecting P. falciparum DNA, with 77% positive samples among malaria subjects. Conclusion: Absolute quantitation by ddPCR can be a flexible technique for Plasmodium detection, with potential application in the diagnosis of malaria. In particular, ddPCR is a powerful approach for Plasmodium DNA analysis on serum when blood samples are unavailable.
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Affiliation(s)
- Elena Pomari
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
- Correspondence: (E.P.); (C.P.)
| | - Ronaldo Silva
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Lucia Moro
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Giulia La Marca
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Francesca Perandin
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Federica Verra
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Zeno Bisoffi
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
- Department of Diagnostics and Public Health, University of Verona, 37134 Verona, Italy
| | - Chiara Piubelli
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
- Correspondence: (E.P.); (C.P.)
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23
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Tan Y, Dong G, Xu H, Niu J, Lu W, Wang K, Dong H, Zhang S, Huang H, Hu G. Development of a cross-priming isothermal amplification assay based on the glycoprotein B gene for instant and rapid detection of feline herpesvirus type 1. Arch Virol 2020; 165:743-747. [PMID: 31980939 DOI: 10.1007/s00705-020-04526-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 12/12/2019] [Indexed: 10/25/2022]
Abstract
A cross-priming isothermal amplification (CPA) assay was developed for detection of feline herpesvirus type 1 (FHV-1). In this assay, the target fragment of the FHV-1 glycoprotein B gene is amplified rapidly by Bst DNA polymerase at a constant temperature (63 °C, 45 min), using a simple thermostat. The assay had no cross-reactions with four types of feline viruses, and the detection limit was 100 copies/μl. The positive rate of clinical samples from CPA was 100% consistent with qPCR but higher than ordinary PCR, indicating its superiority to ordinary PCR. Visualization was achieved using SYBR Green I dye.
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Affiliation(s)
- Yuxin Tan
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Guoying Dong
- College of global change and Earth System Science, Beijing Normal University, Beijing, 100875, China
| | - Hefeng Xu
- China Medical University-The Queen's University of Belfast Joint College, Shenyang, 110122, China
| | - Jiangting Niu
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Wei Lu
- Animal Disease Prevention and Control Center, Changchun, 130012, China
| | - Kai Wang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Hao Dong
- College of Life Sciences, Jilin Agricultural University, Changchun, 130118, China
| | - Shuang Zhang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Hailong Huang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China
| | - Guixue Hu
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China.
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24
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Hartmeyer GN, Hoegh SV, Skov MN, Kemp M. Use of Loop-Mediated Isothermal Amplification in a Resource-Saving Strategy for Primary Malaria Screening in a Non-Endemic Setting. Am J Trop Med Hyg 2020; 100:566-571. [PMID: 30675835 PMCID: PMC6402892 DOI: 10.4269/ajtmh.18-0496] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Malaria is traditionally diagnosed by blood smear microscopy, which requires continuous resource-demanding training. In areas with only a few cases of malaria, a simple and rapid test that can reliably exclude malaria could significantly reduce the need for microscopy and training. We evaluated whether loop-mediated isothermal amplification (LAMP) for screening malaria parasites could reduce the workload in the diagnosis of malaria. Loop-mediated isothermal amplification was used to analyze 38 ethylene-diamine-tetraacetic acid (EDTA) blood samples from 23 patients who had previously been tested for malaria by microscopy, antigen-based rapid diagnostic test (antigen-RDT), and in-house real-time polymerase chain reaction (RT-PCR). The samples included blood with low-level parasitaemia and samples with discrepancies between the results of the different methods. Loop-mediated isothermal amplification detected malaria parasites in 27 of 28 samples that were positive according to in-house RT-PCR. There were negative microscopy results in 10 of these and negative antigen-RDT results in 11. The sample with a negative LAMP result and positive in-house RT-PCR result was from a patient who had recently been treated for low-level Plasmodium falciparum malaria parasitaemia. We found LAMP to be reliable for malaria screening and suitable for replacing microscopy without loss of performance. The low number of LAMP-positive samples needing microscopy can be handled by a limited number of trained microscopists. The time saved on training and documentation was estimated to be 520 working hours yearly in our laboratory. Using LAMP for primary screening of patient samples, we have made a diagnostic workflow that ensures more reliable, faster, and less resource-demanding diagnosis of malaria.
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Affiliation(s)
- Gitte N Hartmeyer
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark.,Research Unit of Clinical Microbiology, Department of Clinical Research, Faculty of Health Science, University of Southern Denmark, Odense, Denmark
| | - Silje V Hoegh
- Research Unit of Clinical Microbiology, Department of Clinical Research, Faculty of Health Science, University of Southern Denmark, Odense, Denmark
| | - Marianne N Skov
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark.,Research Unit of Clinical Microbiology, Department of Clinical Research, Faculty of Health Science, University of Southern Denmark, Odense, Denmark
| | - Michael Kemp
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark.,Research Unit of Clinical Microbiology, Department of Clinical Research, Faculty of Health Science, University of Southern Denmark, Odense, Denmark
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25
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Haeseleer C, Martiny D, Van Laethem Y, Cantinieaux B, Martin C. Reactivation of Plasmodium infection during a treatment with infliximab: A case report. Int J Infect Dis 2019; 91:101-103. [PMID: 31759170 DOI: 10.1016/j.ijid.2019.11.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/15/2019] [Accepted: 11/15/2019] [Indexed: 11/29/2022] Open
Abstract
We describe a symptomatic Plasmodium falciparum infection in a 29-year-old Guinean man receiving Infliximab for one year and without recent travel. The reactivation of submicroscopic malaria following the inhibition of TNF-alpha by infliximab is suspected.
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Affiliation(s)
- C Haeseleer
- Department of Hematology, Laboratoire Hospitalier Universitaire de Bruxelles - Universitair Laboratorium Brussel (LHUB-ULB), Brussels, Belgium; Université Libre de Bruxelles, Brussels, Belgium.
| | - D Martiny
- Department of Microbiology, Laboratoire Hospitalier Universitaire de Bruxelles - Universitair Laboratorium Brussel (LHUB-ULB), Brussels, Belgium; Faculté de Médecine et Pharmacie, Université de Mons (UMONS), Mons, Belgium
| | - Y Van Laethem
- Department of Infectious Diseases, Centre Hospitalier Universitaire Saint- Pierre, Université Libre de Bruxelles, Brussels, Belgium
| | - B Cantinieaux
- Department of Hematology, Laboratoire Hospitalier Universitaire de Bruxelles - Universitair Laboratorium Brussel (LHUB-ULB), Brussels, Belgium
| | - C Martin
- Department of Infectious Diseases, Centre Hospitalier Universitaire Saint- Pierre, Université Libre de Bruxelles, Brussels, Belgium
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26
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Burdino E, Calleri G, Ghisetti V. Added value of loop-mediated isothermal amplification technology (LAMP) in real life for the diagnosis of malaria in travellers. J Travel Med 2019; 26:5537692. [PMID: 31411701 DOI: 10.1093/jtm/taz052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/16/2019] [Accepted: 07/16/2019] [Indexed: 12/12/2022]
Abstract
Malaria diagnosis in non-endemic countries is questioned by lack of experience and low levels of parasite densities. Loop-mediated isothermal amplification (LAMP) is aimed at simplifying these challenges. In a prospective evaluation over a 2-year period, LAMP significantly simplified malaria identification in 478 febrile travellers and can be considered the primary diagnostic test in this setting.
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Affiliation(s)
- Elisa Burdino
- Laboratory of Microbiology and Virology, Amedeo di Savoia Hospital, ASL Città di Torino, Turin, Italy
| | - Guido Calleri
- Unit A of Infectious and Tropical Diseases, Amedeo di Savoia Hospital, ASL Città di Torino, Turin, Italy
| | - Valeria Ghisetti
- Laboratory of Microbiology and Virology, Amedeo di Savoia Hospital, ASL Città di Torino, Turin, Italy
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27
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Reuken PA, Baier M, Hagel S, Eisermann P, Stallmach A, Rödel J. Diagnosis of malaria in a traveler 9 months after returning from West Africa by illumigene® LAMP assay: A case report. Acta Microbiol Immunol Hung 2019; 66:301-306. [PMID: 31137943 DOI: 10.1556/030.66.2019.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Loop-mediated isothermal amplification (LAMP) is a rapid molecular technique that has been introduced into malaria diagnosis. The test is easy to perform and offers high sensitivity. We report a 53-year-old male patient who was hospitalized with fever attacks, chills, and headache caused 9 months after returning from Africa. During his stay in Africa, he used malaria chemoprophylaxis. Microscopy of thin and thick blood films and rapid diagnostic antigen testing remained negative for three times. The EDTA blood samples were tested using the Meridian illumigene® malaria LAMP assay that gave a positive result for Plasmodium spp. Diagnosis of malaria was subsequently specified as P. ovale infection by real-time PCR. Ovale malaria often manifests with delay and low parasitemia. The patient was treated with atovaquone-proguanil, followed by primaquine for prophylaxis of relapse. This case illustrates the usefulness of the illumigene® malaria LAMP assay for initial screening of malaria parasites.
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Affiliation(s)
- Philipp A. Reuken
- 1 Department of Internal Medicine IV (Gastroenterology, Hepatology, and Infectious Diseases), Jena University Hospital, Jena, Germany
| | - Michael Baier
- 2 Institute of Medical Microbiology, Jena University Hospital, Jena, Germany
| | - Stefan Hagel
- 3 Institute of Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany
| | - Philip Eisermann
- 4 National Reference Center for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Andreas Stallmach
- 1 Department of Internal Medicine IV (Gastroenterology, Hepatology, and Infectious Diseases), Jena University Hospital, Jena, Germany
| | - Jürgen Rödel
- 2 Institute of Medical Microbiology, Jena University Hospital, Jena, Germany
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28
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Frickmann H, Wegner C, Ruben S, Behrens C, Kollenda H, Hinz R, Rojak S, Schwarz NG, Hagen RM, Tannich E. Evaluation of the multiplex real-time PCR assays RealStar malaria S&T PCR kit 1.0 and FTD malaria differentiation for the differentiation of Plasmodium species in clinical samples. Travel Med Infect Dis 2019; 31:101442. [PMID: 31255712 DOI: 10.1016/j.tmaid.2019.06.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 06/20/2019] [Accepted: 06/26/2019] [Indexed: 12/28/2022]
Abstract
BACKGROUND Two commercial PCR assays were assessed in a retrospective study to determine their reliability as tools for the differentiation of Plasmodium species in human blood. METHODS A total of 1022 blood samples from 817 patients with suspected or confirmed malaria submitted to the German National Reference Centre for Tropical Pathogens were subjected to malaria microscopy using thick and thin blood films as well as to a genus-specific malaria real-time PCR. Parasite-positive samples were analysed by RealStar Malaria S&T PCR Kit 1.0 (altona Diagnostics) and FTD Malaria Differentiation (Fast Track Diagnostics) multiplex real-time PCR assays targeting species-specific Plasmodium DNA. RESULTS Out of the 1022 blood samples, 247 (24.2%) tested positive for Plasmodium spp. The two multiplex assays showed rather similar performance characteristics and provided concordant species information in 98.9% of samples positive by malaria microscopy and in 95.1% (RealStar) and 96.8% (FTD) of samples positive by genus-specific PCR. Compared to FTD, RealStar revealed slightly reduced sensitivity for submicroscopic, low-level P. falciparum infections, while FTD was unable to detect P. knowlesi. CONCLUSIONS The two commercial malaria PCR assays assessed are suitable for discriminating Plasmodium species in clinical samples, and can provide additional information in cases of microscopically uncertain findings.
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Affiliation(s)
- Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany; Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany.
| | - Christine Wegner
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Stefanie Ruben
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Christoph Behrens
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Hans Kollenda
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Rebecca Hinz
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Sandra Rojak
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany; Department of Infectious Diseases and Tropical Medicine, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Norbert G Schwarz
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ralf Matthias Hagen
- Department of Preventive Medicine, Bundeswehr Medical Academy, Munich, Germany
| | - Egbert Tannich
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Performance evaluation of different strategies based on microscopy techniques, rapid diagnostic test and molecular loop-mediated isothermal amplification assay for the diagnosis of imported malaria. Clin Microbiol Infect 2019; 26:115-121. [PMID: 31158521 DOI: 10.1016/j.cmi.2019.05.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 12/29/2022]
Abstract
OBJECTIVES Malaria is one of most common tropical diseases encountered in travellers and migrants. It requires an urgent and reliable diagnosis considering its potential severity. In this study, performance of five diagnostic assays were evaluated in a nonendemic region and compared prospectively to quantitative PCR (qPCR). METHODS A prospective study was conducted at Toulouse Hospital from August 2017 to January 2018 and included all patients with initial Plasmodium screening. Thin and thick blood smears (TnS, TkS), quantitative buffy coat (QBC), rapid diagnostic tests (RDTs) and commercial loop-mediated isothermal amplification (LAMP) were independently performed on each blood sample and compared to our qPCR reference standard. RESULTS The study encompassed 331 patients, mainly returning from Africa. qPCR detected 73 Plasmodium-positive samples (including 58 falciparum). Individually, LAMP had a 97.3% (71/73) sensitivity, far ahead of TnS (84.9%, 62/73), TkS (86.3%, 63/73), QBC (86.3%, 63/73) and RDT (86.3%, 63/73). RDT demonstrated a high sensitivity for falciparum (98.3%, 57/58) but missed all ovale, malariae and knowlesi infections. Specificity was excellent for all techniques (99.6-100%). The most sensitive diagnosis strategies were TnS + RDT (95.9%, 70/73), TnS + LAMP (97.3%, 71/73) and TnS + RDT + LAMP (100%, 73/73), about 10% higher than strategies using exclusively microscopy, TkS + TnS (87.7%, 64/73) or QBC + TnS (87.7%, 64/73). TnS remains necessary for Plasmodium species identification and quantification. Adding sequentially TnS only on LAMP-positive samples did not decrease TnS + LAMP strategy sensitivity. CONCLUSIONS In nonendemic countries, the currently recommended microscopy-based strategies seem unsatisfactory for malaria diagnosis considering RDT and LAMP performance, two rapid and sensitive assays that require limited training.
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Kollenda H, Hagen RM, Hanke M, Rojak S, Hinz R, Wassill L, Poppert S, Tannich E, Frickmann H. Poor Diagnostic Performance of a Species-Specific Loop-Mediated Isothermal Amplification (LAMP) Platform for Malaria. Eur J Microbiol Immunol (Bp) 2018; 8:112-118. [PMID: 30719327 PMCID: PMC6348705 DOI: 10.1556/1886.2018.00020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 08/19/2018] [Indexed: 12/31/2022] Open
Abstract
Background The objective of this study was to assess an in-house loop-mediated isothermal amplification (LAMP) platform for malaria parasite detection and identification on species level. Methods LAMP primers specific for the human Plasmodium spp., namely, P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi, as well as genus-specific primers, were tested against a composite gold standard comprising microscopy from thick and thin blood films, commercial genus-specific Meridian illumigene Malaria LAMP, in-house real-time polymerase chain reaction (PCR), and commercial fast-track diagnostics (FTD) Malaria differentiation PCR. Results Of the 523 blood samples analyzed, the composite gold standard indicated 243 Plasmodium-species-DNA-containing samples (46.5%). Sensitivity and specificity of the analyzed genus- and species-specific LAMP primers were 71.0%–100.0% and 90.8%–100.0%, respectively. The influence of parasitemia was best documented for P. falciparum-specific LAMP with sensitivity values of 35.5% (22/62) for microscopically negative samples containing P. falciparum DNA, 50% (19/38) for parasitemia ≤50/μL, 84% (21/25) for parasitemia ≤500/μL, and 100% (92/92) for parasitemia >500/μL. Conclusions In our hands, performance characteristics of species-specific in-house LAMP for malaria lack reliability required for diagnostic laboratories. The use of the easy-to-apply technique for surveillance purposes may be considered.
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Affiliation(s)
- Hans Kollenda
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Ralf Matthias Hagen
- Department of Preventive Medicine, Bundeswehr Medical Academy, Munich, Germany
| | - Miriam Hanke
- Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Sandra Rojak
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany.,Department of Infectious Diseases and Tropical Medicine, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Rebecca Hinz
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | | | - Sven Poppert
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,Faculty of Medicine, University Basel, Basel, Switzerland
| | - Egbert Tannich
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Hamburg, Germany.,Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
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31
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Nijhuis RHT, van Lieshout L, Verweij JJ, Claas ECJ, Wessels E. Multiplex real-time PCR for diagnosing malaria in a non-endemic setting: a prospective comparison to conventional methods. Eur J Clin Microbiol Infect Dis 2018; 37:2323-2329. [PMID: 30259214 DOI: 10.1007/s10096-018-3378-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 09/06/2018] [Indexed: 11/29/2022]
Abstract
Almost a decade ago our diagnostic laboratory implemented an in-house real-time PCR for the detection of Plasmodium DNA to diagnose malaria in parallel with conventional diagnostics, i.e., microscopy (thick and thin smears), quantitative buffy coat microscopy (QBC), and a rapid diagnostic test (RDT). Here we report our experiences and make a comparison between the different diagnostic procedures used in this non-endemic setting. All patients during the period February 2009-December 2017 suspected of malaria were prospectively tested at the moment of sample collection. Both PCR and conventional malaria diagnostics were carried out on a total of 839 specimens from 825 patients. In addition, three Plasmodium falciparum (Pf) patients were closely followed by real-time PCR and microscopy after treatment. Overall, 56 samples (55 patients) tested positive by real-time PCR, of which six were missed by microscopy and seven by QBC. RDT showed fairly good results in detecting Pf, whereas specificity was not optimal. RDT failed to detect 10 of 17 non-Pf PCR positive specimens. One Plasmodium malariae patient would have been missed if only conventional diagnostic tests had been used. The high sensitivity of the PCR was confirmed by the number of PCR positive, microscopy negative post-treatment samples. In conclusion, within our routine diagnostic setting, malaria real-time PCR not only showed a high level of agreement with the conventional methods used, but also showed higher sensitivity and better specificity. Still, for complete replacement of the conventional procedures in a non-endemic setting, the time-to-results of the real-time PCR is currently too long.
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Affiliation(s)
- R H T Nijhuis
- Department of Medical Microbiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
- Laboratory for Medical Microbiology and Immunology, Meander Medical Center, Amersfoort, The Netherlands
| | - L van Lieshout
- Department of Medical Microbiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - J J Verweij
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
- Laboratory for Medical Microbiology and Immunology, Elisabeth Hospital, Tilburg, The Netherlands
| | - E C J Claas
- Department of Medical Microbiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - E Wessels
- Department of Medical Microbiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
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Martín-Díaz A, Rubio JM, Herrero-Martínez JM, Lizasoain M, Ruiz-Giardin JM, Jaqueti J, Cuadros J, Rojo-Marcos G, Martín-Rabadán P, Calderón M, Campelo C, Velasco M, Pérez-Ayala A. Study of the diagnostic accuracy of microbiological techniques in the diagnosis of malaria in the immigrant population in Madrid. Malar J 2018; 17:314. [PMID: 30157862 PMCID: PMC6116490 DOI: 10.1186/s12936-018-2459-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 08/17/2018] [Indexed: 11/16/2022] Open
Abstract
Background Malaria is currently the most important human parasitic disease in the world responsible for high morbidity and mortality. Appropriate diagnostic methods are essential for early detection. Microscopy examination remains the gold standard, although molecular techniques have higher sensitivity and are very useful in cases of low parasitaemia and mixed infections. The objective of this study was to evaluate a new commercial molecular diagnostic technique. Methods A prospective, observational, multicentre study was performed between January 2015 and April 2017. All participants were immigrants from malaria-endemic areas, who were divided into two groups: asymptomatic group and symptomatic. Samples from both groups were evaluated by a rapid diagnostic test (ImmunoQuick® Malaria + 4 RDT), microscopy examination, and two commercial molecular malaria tests (FTD Malaria and FTD Malaria Differentiation), then compared against an in-house reference PCR technique. Results In all, 250 patients were included: 164 (65.6%) in the asymptomatic group, and 86 (34.4%) in the symptomatic group. There were seven cases of asymptomatic parasitaemia (prevalence = 2.8%) that were detected only by molecular methods. In the symptomatic group, there were seven cases of submicroscopic malaria. The main species detected was Plasmodium falciparum (96.6%). The commercial molecular technique had higher sensitivity than the other methods (S = 96%) and a high rate of concordance with the in-house reference PCR technique (Kappa score = 0.93). Conclusions The molecular techniques, although slower than microscopy, have adequate diagnostic accuracy and are very useful for the detection of P. falciparum in cases with low parasitaemia.
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Affiliation(s)
- Ariadna Martín-Díaz
- Department of Clinical Microbiology, Hospital Universitario 12 de Octubre, Avenida de Córdoba, s/n, 28041, Madrid, Spain
| | - José Miguel Rubio
- Malaria & Emerging Parasitic Diseases Laboratory, Parasitology Department, National Microbiology Centre, Instituto de Salud Carlos III, Madrid, Spain
| | | | - Manolo Lizasoain
- Internal Medicine and Infectious Diseases Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | | | | | - Juan Cuadros
- University Hospital Príncipe de Asturias, Alcalá de Henares, Madrid, Spain
| | | | | | | | | | - María Velasco
- University Hospital Fundación Alcorcón, Madrid, Spain
| | - Ana Pérez-Ayala
- Department of Clinical Microbiology, Hospital Universitario 12 de Octubre, Avenida de Córdoba, s/n, 28041, Madrid, Spain.
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Frickmann H, Hinz R, Rojak S, Bonow I, Ruben S, Wegner C, Zielke I, Hagen RM, Tannich E. Evaluation of automated loop-mediated amplification (LAMP) for routine malaria detection in blood samples of German travelers - A cross-sectional study. Travel Med Infect Dis 2018; 24:25-30. [PMID: 29763668 DOI: 10.1016/j.tmaid.2018.05.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 04/30/2018] [Accepted: 05/11/2018] [Indexed: 01/24/2023]
Abstract
BACKGROUND We assessed a commercial loop-mediated amplification (LAMP) platform for its reliability as a screening tool for malaria parasite detection. METHODS A total of 1000 blood samples from patients with suspected or confirmed malaria submitted to the German National Reference Center for Tropical Pathogens were subjected to LAMP using the Meridian illumigene Malaria platform. Results were compared with microscopy from thick and thin blood films in all cases. In case of discordant results between LAMP and microscopy (n = 60), confirmation testing was performed with real-time PCR. Persistence of circulating parasite DNA was analyzed by serial assessments of blood samples following malaria treatment. RESULTS Out of 1000 blood samples analyzed, 238 were positive for malaria parasites according to microscopy (n = 181/1000) or PCR (additional n = 57/60). LAMP demonstrated sensitivity of 98.7% (235/238), specificity of 99.6% (759/762), positive predictive value (PPV) of 98.7% (235/238) and negative predictive value (NPV) of 99.6% (759/762), respectively. For first slides of patients with malaria and for follow-up slides, sensitivity values were 99.1% (106/107) and 98.5% (129/131), respectively. CONCLUSIONS The performance of the Meridian illumigene Malaria platform is suitable for initial screening of patients suspected of clinical malaria.
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Affiliation(s)
- Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Bernhard Nocht Str. 74, 20359 Hamburg, Germany; Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Schillingallee 70, 18057 Rostock, Germany.
| | - Rebecca Hinz
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Bernhard Nocht Str. 74, 20359 Hamburg, Germany.
| | - Sandra Rojak
- Department of Microbiology and Hospital Hygiene, Tropical Microbiology and Entomology Unit, Bundeswehr Hospital Hamburg, Bernhard Nocht Str. 74, 20359 Hamburg, Germany; Department of Infectious Diseases and Tropical Medicine, Bundeswehr Hospital Hamburg, Bernhard Nocht Str. 74, 20359 Hamburg, Germany.
| | - Insa Bonow
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Bernhard Nocht Str. 74, 20359 Hamburg, Germany.
| | - Stefanie Ruben
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Bernhard Nocht Str. 74, 20359 Hamburg, Germany.
| | - Christine Wegner
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Bernhard Nocht Str. 74, 20359 Hamburg, Germany.
| | - Iris Zielke
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Bernhard Nocht Str. 74, 20359 Hamburg, Germany.
| | - Ralf Matthias Hagen
- Department of Preventive Medicine, Bundeswehr Medical Academy, Neuherbergstr. 11, 80937 Munich, Germany.
| | - Egbert Tannich
- National Reference Centre for Tropical Pathogens, Bernhard Nocht Institute for Tropical Medicine, Bernhard Nocht Str. 74, 20359 Hamburg, Germany.
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