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Author: search.filters.author.Łęski, Tomasz A.Subject: search.filters.subject.Plasmodium

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    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
    (BioMed Central, 2020-02-21) Łęski, Tomasz A.
    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. CONCLUSIONS: Wider application of PCR for detection of malaria parasites may help to fill gaps existing as a result of use of microscopy and RDTs. Due to its high sensitivity and specificity, species coverage, room temperature stability and relative low complexity, the MMSR assay may be useful for detection of malaria and epidemiological studies especially in low-resource settings.
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    Comparison of capillary and venous blood for malaria detection using two PCR-based assays in febrile patients in Sierra Leone
    (BioMed Central, 2021-03-06) Łęski, Tomasz A.
    Background Malaria parasites infect over 200 million people and cause more than 400,000 deaths each year. Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally sensitive with both materials the published data on this subject are scarce are not conclusive. Methods Paired samples of venous and capillary blood from 103 febrile individuals in Bo, Sierra Leone, were obtained between January and May 2019 and tested for the presence of Plasmodium parasites using two multiplexed PCR assays: the FilmArray-based Global Fever Panel (GFP) and the TaqMan-based Malaria Multiplex Sample Ready (MMSR) assay. Results We observed no significant differences in Plasmodium parasite detection between capillary and venous blood when using the MMSR assay. In GFP assays, however, markers for Plasmodium spp. and P. falciparum were detected at significantly higher numbers of venous samples (p<0.002 and p<0.05, respectively). The GFP assay was more sensitive than MMSR for Plasmodium spp. in both types of samples and overall more sensitive (taking all detected malaria markers into account) in venous samples only. Conclusions Malaria detection sensitivity may be higher for venous blood compared to capillary blood in case of certain targets when using PCR-based detection methods. The overall sensitivity of GFP assay was generally higher than MMSR but depended on the target and clinical material used.