Update on Malaria Diagnostics and Test Utilization

Mathison, Blaine A.; Pritt, Bobbi S.

doi:10.1128/jcm.02562-16

Cited by 164 publications

(153 citation statements)

References 13 publications

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“…The stability of the impregnated anti-bodies, product design and quality, transport, storage and handling conditions as well as the evolving HRP2 gene deletions as being continually reported [20,21] could explain the apparent difference in the performance of the HRP2-based RDTs. Many studies have also reported inherent inability of the RDTs to detect malaria positive cases at low parasite densities [1,22].…”

Section: Discussionmentioning

confidence: 99%

Diagnostic Performance of Blood Film Microscopy and PfHRP2-based RDT in a Routine Clinical Setting of a Secondary Health Facility in Ghana

Agyapong

Ansong

Owusu-Ofori

et al. 2019

JAMMR

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Background: Malaria remains a major public health threat claiming many lives particularly in Sub-Saharan Africa. Light microscopy and RDT are the mainstay tests in the clinical settings for malaria diagnosis. Many studies report varying levels of validity of these tests compared to molecular methods like PCR. Documentation on such comparative study involving the use of molecular techniques as reference test is scanty in Ghana. This study therefore assesses the diagnostic performance of these tests compared to PCR. Agyapong et al.; JAMMR, 31(4): 1-9, 2019; Article no.JAMMR.50357 Methods: Blood film microscopy (thin and thick), RDT and nested PCR were run on blood samples from a total of 188 malaria suspected patients. The accuracy indices of the microscopy and RDT were calculated using the results of the PCR as the reference test. Results: A total of 188 patients were recruited with females constituting the majority 128 (68%). The paediatric age group 1-10 years carried the largest burden of malaria by means of all the 3 tests. A sensitivity of 47.37% (95% ci, 37.03 -57.88%) was shown by both the microscopy and RDT with specificity of 93.55% (95% ci, 86.48 -97.60) and 100% (95% ci, 96.11 -100.00%) and kappa co -efficient of 0.41 and 0.47 respectively. Conclusion: Both microscopy and RDT exhibited high level of specificity but low sensitivity. Significant number of malaria parasitaemic patients as revealed by the PCR was missed by both the RDT and blood film microscopy and thus went undiagnosed. Short Research Article

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Section: Discussionmentioning

confidence: 99%

Diagnostic Performance of Blood Film Microscopy and PfHRP2-based RDT in a Routine Clinical Setting of a Secondary Health Facility in Ghana

Agyapong

Ansong

Owusu-Ofori

et al. 2019

JAMMR

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“…DNA-based diagnostics, also referred to as Nucleic Acid Amplification Tests (NAATs), such as DNA/RNA hybridization, conventional and real-time PCR, loopmediated isothermal amplification (LAMP), nucleic acid sequence-based amplification (NASBA) and others can potentially fill this gap by providing a sensitive and accurate identification of multiple Plasmodium species [10,13]. DNA-based malaria assays in general, and PCR in particular, are significantly more sensitive than microscopy and RDTs.…”

Section: Introductionmentioning

confidence: 99%

“…DNA-based malaria assays in general, and PCR in particular, are significantly more sensitive than microscopy and RDTs. Limit of detection (LOD) for PCR is typically 1-5 parasites/µL [13][14][15][16][17] compared to 50-500 parasites/µL for microscopy [13,14,18] and more than 100 parasites/µL for RDT's [14,19]. Depending on the assay, PCR can be used for accurate species identification, detection of mixed infections, and parasite density estimation [20].…”

Section: Introductionmentioning

confidence: 99%

Use of real-time multiplex PCR, malaria rapid diagnostic test and microscopy to investigate the prevalence of Plasmodium species among febrile hospital patients in Sierra Leone

Łęski

Taitt

Swaray

et al. 2020

Malar J

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Background: Malaria continues to affect over 200 million individuals every year, especially children in Africa. Rapid and sensitive detection and identification of Plasmodium parasites is crucial for treating patients and monitoring of control efforts. Compared to traditional diagnostic methods such as microscopy and rapid diagnostic tests (RDTs), DNA based methods, such as polymerase chain reaction (PCR) offer significantly higher sensitivity, definitive discrimination of Plasmodium species, and detection of mixed infections. While PCR is not currently optimized for routine diagnostics, its role in epidemiological studies is increasing as the world moves closer toward regional and eventually global malaria elimination. This study demonstrates the field use of a novel, ambient temperature-stabilized, multiplexed PCR assay in a small hospital setting in Sierra Leone.Methods: Blood samples from 534 febrile individuals reporting to a hospital in Bo, Sierra Leone, were tested using three methods: a commercial RDT, microscopy, and a Multiplex Malaria Sample Ready (MMSR) PCR designed to detect a universal malaria marker and species-specific markers for Plasmodium falciparum and Plasmodium vivax. A separate PCR assay was used to identify species of Plasmodium in samples in which MMSR detected malaria, but was unable to identify the species.Results: MMSR detected the presence of any malaria marker in 50.2% of all tested samples with P. falciparum identified in 48.7% of the samples. Plasmodium vivax was not detected. Testing of MMSR P. falciparum-negative/universal malaria-positive specimens with a panel of species-specific PCRs revealed the presence of Plasmodium malariae (n = 2) and Plasmodium ovale (n = 2). The commercial RDT detected P. falciparum in 24.6% of all samples while microscopy was able to detect malaria in 12.8% of tested specimens.

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“…Because of the versatility and wide adoption of manual microscopy [4] and its role in direct visual identification of parasites [5], it remains a WHO gold standard for numerous diseases [1]. Despite technological advancements in related fields, the practice of conventional manual microscopy has remained largely unchanged over the last half century and suffers from several drawbacks.…”

Section: Introductionmentioning

confidence: 99%

Octopi: Open configurable high-throughput imaging platform for infectious disease diagnosis in the field

Soto-Montoya

Voisin

et al. 2019

Preprint

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Access to quantitative, robust, yet affordable diagnostic tools is necessary to reduce global infectious disease burden. Manual microscopy has served as a bedrock for diagnostics with wide adaptability, although at a cost of tedious labor and human errors. Automated robotic microscopes are poised to enable a new era of smart field microscopy but current platforms remain cost prohibitive and largely inflexible, especially for resource poor and field settings. Here we present Octopi, a low-cost ($250-$500) and reconfigurable autonomous microscopy platform capable of automated slide scanning and correlated bright-field and fluorescence imaging. Being highly modular, it also provides a framework for new disease-specific modules to be developed.We demonstrate the power of the platform by applying it to automated detection of malaria parasites in blood smears. Specifically, we discovered a spectral shift on the order of 10 nm for DAPI-stained Plasmodium falciparum malaria parasites. This shift allowed us to detect the parasites with a low magnification (equivalent to 10x) large field of view (2.56 mm 2 ) module.Combined with automated slide scanning, real time computer vision and machine learningbased classification, Octopi is able to screen more than 1.5 million red blood cells per minute for parasitemia quantification, with estimated diagnostic sensitivity and specificity exceeding 90% at parasitemia of 50/ul and 100% for parasitemia higher than 150/l. With different modules, we further showed imaging of tissue slice and sputum sample on the platform. With roughly two orders of magnitude in cost reduction, Octopi opens up the possibility of a large robotic microscope network for improved disease diagnosis while providing an avenue for collective efforts for development of modular instruments.One sentence summary: We developed a low-cost ($250-$500) automated imaging platform that can quantify malaria parasitemia by scanning 1.5 million red blood cells per minute.Lack of cost-effective diagnostics is a major hurdle in global fight against infectious disease, 2 specially in resource poor settings [1]. This leaves our world in a highly vulnerable position 3 with therapeutic drugs being either overused, leading to drug resistant strains or not acces-4 sible to people who actually need these treatments [2]. Since health care is delivered around 5 the world in a tiered structure, local context such as high cost, lack of trained personal or 6 low throughput of many available diagnostics tests plays a large detrimental role on quality 7 of delivered health-care [3]. 8 Because of the versatility and wide adoption of manual microscopy [4] and its role in 9 direct visual identification of parasites [5], it remains a WHO gold standard for numerous 10 diseases [1]. Despite technological advancements in related fields, the practice of conventional 11 manual microscopy has remained largely unchanged over the last half century and suffers 12 from several drawbacks. With an average lab technician spending 6 to 8 hours imaging and 13 ...

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Update on Malaria Diagnostics and Test Utilization

Cited by 164 publications

References 13 publications

Diagnostic Performance of Blood Film Microscopy and PfHRP2-based RDT in a Routine Clinical Setting of a Secondary Health Facility in Ghana

Diagnostic Performance of Blood Film Microscopy and PfHRP2-based RDT in a Routine Clinical Setting of a Secondary Health Facility in Ghana

Use of real-time multiplex PCR, malaria rapid diagnostic test and microscopy to investigate the prevalence of Plasmodium species among febrile hospital patients in Sierra Leone

Octopi: Open configurable high-throughput imaging platform for infectious disease diagnosis in the field

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