Unclear association between levels of Plasmodium falciparum lactate dehydrogenase (PfLDH) in saliva of malaria patients and blood parasitaemia: diagnostic implications?

Nambati, Eva Aluvaala; Kiarie, William Chege; Kimani, Francis; Kimotho, James; Otinga, Maureen; Too, Edwin; Kaniaru, Stephen; Limson, Janice; Bulimo, Wallace

doi:10.1186/s12936-017-2151-y

Cited by 12 publications

(15 citation statements)

References 9 publications

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“…A study showed that stored blood can lose antigen activity, and early lysis and protein coagulation can inhibit ow, thus in uencing the results of RDT-based malaria diagnosis [16]. Although this study and many others [23,24] clearly show the potential to use saliva as a non-invasive body uid for rapid diagnosis of malaria, there are still many challenges in establishing it as a reference.…”

Section: Discussionmentioning

confidence: 83%

Evaluation of a homemade saliva kit for the stabilization of plasmodium dna at room temperature

Netongo¹,

Tchoupe²,

Kamdem³

et al. 2020

Preprint

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Objectives : Most malaria diagnostic methods are invasive whereas non-invasive alternatives like saliva could be used for molecular diagnosis. However, long-term storage of saliva also requires a cold chain, which is challenging in poor countries. Current tools to conserve saliva at room temperature are not affordable (~$16/kit) for malaria endemic countries. In this cross-sectional study including 83 febrile participants, we evaluated the effectiveness of a cheaper (~$2/kit) homemade kit (Formulation f1 ) to stabilize Plasmodium DNA in saliva stored at room temperature for 12 months. The OMNIgene ® ORAL (OM-501) kit served as standard (S0 ). Results : The frequency of malaria in this study was 78.31% (65/83) using microscopy. Saliva PCR-f1 and PCR-S0 detected 59 (71.08%) and 56 (67.47%) positive malaria samples respectively. Using microscopy as gold standard, the sensitivities of PCR-S0 and PCR-f1 were 100% while the specificities were 80%, and 85%, respectively. PCR-f1 had a “very good” agreement (kappa 0.81) with microscopy compared to PCR-S0 (kappa 0.64). We obtained similar results after 12 months storage of saliva samples at room temperature (RT). Homemade kit could be effective in transportation, preservation and diagnosis of malaria parasite in saliva. Key words: Non-invasive, Saliva, DNA, Plasmodium , Malaria, Homemade kit.

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Section: Discussionmentioning

confidence: 83%

Evaluation of a homemade saliva kit for the stabilization of plasmodium dna at room temperature

Netongo¹,

Tchoupe²,

Kamdem³

et al. 2020

Preprint

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“…However, the correlation co-efficient for the saliva supernatant pLDH results with respect to Microscopy results (ĸ = 0.21) was weaker than that reported by this study. In a similar study in Kenya [20], when the sensitivity of saliva pLDH was compared with blood film microscopy, saliva pLDH was found to be only 35% sensitive with weak positive correlation relative to the microscopy results.…”

Section: Discussionmentioning

confidence: 91%

Determining the Potential Value of Salivary Plasmodium Falciparum Hisditine-Rich Protein 2 and Lactate Dehydrogenase as a Non-Invasive Test for Malaria

Agyapong

Ansong

Owusu-Ofori

et al. 2020

Preprint

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Background Malaria remains an important public health threat claiming many lives particularly in Sub-Saharan Africa. Light microscopy which is a blood-based test is the Gold standard for laboratory diagnosis of malaria in the clinical settings. The lack of sensitivity of Microscopy coupled with the challenges associated with blood sampling necessitates exploring alternative methods of identifying malaria cases. Aims and Objectives The aim of this study was to detect the presence of Plasmodium Lactate Dehydrogenase (pLDH) and Plasmodium falciparum Histidine-Rich Protein 2 (PfHRP2) in the saliva of suspected malaria patients and to compare the diagnostic accuracy of these saliva-borne biomarkers with the results of blood film microscopy using Nested PCR as the reference test. Methods The research was a comparative study. Matched saliva and blood samples of suspected malaria patients were collected. The blood samples were aliquoted into 2 smaller volumes and used to run blood film microscopy (thick and thin) and Nested PCR to detect DNA of the 5 Plasmodium species known to clinically infect man. Sand-wiched ELISA was separately run to qualitatively detect pLDH and PfHRP2 in the saliva samples. Accuracy indices of the saliva-based assays (saliva pLDH and PfHRP2) were compared with the conventional blood-based Microscopy. Results Of the participating 188 subjects, malaria prevalence rates of 51 (27.13%), 80(42.55%), 117 (62.23%) and 95 (50.53%) were detected by the Microscopy, saliva pLDH, saliva PfHRP2 and the PCR respectively. The sensitivity of the saliva PfHRP2 ELISA, 78.95% (95% CI, 69.38-86.64%) and saliva pLDH ELISA, 64.21% (95% CI 53.72 -73.79) were better than those obtained for the blood film Microscopy. Conclusions The saliva pLDH and the PfHRP2 ELISAs were found to be more sensitive (64.21% and 78.95% respectively) in defining malaria cases than the results obtained for the conventional blood film microscopy. Both the saliva pLDH and the PfHRP2 ELISAs showed moderate agreement with the results of the Nested PCR with Kappa co-efficient of 0.44 and 0.5 respectively.

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“…Furthermore, the functionalization procedure of PIT can be carried out by a simple UV lamp in a few minutes, thus we anticipate that such an approach can be carried out in low resource settings which would be critical for many malaria diagnostic applications. Therefore, we foresee that our approach may provide a solution to the cold transport challenges common to the presently used immunochromatographic lateral flow assays [45][46][47] .…”

Section: Discussionmentioning

confidence: 99%

“…The conventional serologic antibodybased rapid diagnostic tests rely upon the PfLDH detection in pretreated blood and offer rapid and cost-effective malaria diagnosis. However, the poor LOD as well as the transportation and storage difficulties of pre-functionalized devices in tropical environment make such tests unfit for early diagnosis and screening [45][46][47] . The ultrasensitive PEF-based device in combination with a unique functionalization procedure (PIT), which can be accomplished in a few minutes, results in an immunosensor suitable for detecting PfLDH at femtomolar level in the whole blood without any pretreatment and preconcentration steps.…”

mentioning

confidence: 99%

Ultrasensitive antibody-aptamer plasmonic biosensor for malaria biomarker detection in whole blood

et al. 2020

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Development of plasmonic biosensors combining reliability and ease of use is still a challenge. Gold nanoparticle arrays made by block copolymer micelle nanolithography (BCMN) stand out for their scalability, cost-effectiveness and tunable plasmonic properties, making them ideal substrates for fluorescence enhancement. Here, we describe a plasmon-enhanced fluorescence immunosensor for the specific and ultrasensitive detection of Plasmodium falciparum lactate dehydrogenase (PfLDH)—a malaria marker—in whole blood. Analyte recognition is realized by oriented antibodies immobilized in a close-packed configuration via the photochemical immobilization technique (PIT), with a top bioreceptor of nucleic acid aptamers recognizing a different surface of PfLDH in a sandwich conformation. The combination of BCMN and PIT enabled maximum control over the nanoparticle size and lattice constant as well as the distance of the fluorophore from the sensing surface. The device achieved a limit of detection smaller than 1 pg/mL (<30 fM) with very high specificity without any sample pretreatment. This limit of detection is several orders of magnitude lower than that found in malaria rapid diagnostic tests or even commercial ELISA kits. Thanks to its overall dimensions, ease of use and high-throughput analysis, the device can be used as a substrate in automated multi-well plate readers and improve the efficiency of conventional fluorescence immunoassays.

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Unclear association between levels of Plasmodium falciparum lactate dehydrogenase (PfLDH) in saliva of malaria patients and blood parasitaemia: diagnostic implications?

Cited by 12 publications

References 9 publications

Evaluation of a homemade saliva kit for the stabilization of plasmodium dna at room temperature

Evaluation of a homemade saliva kit for the stabilization of plasmodium dna at room temperature

Determining the Potential Value of Salivary Plasmodium Falciparum Hisditine-Rich Protein 2 and Lactate Dehydrogenase as a Non-Invasive Test for Malaria

Ultrasensitive antibody-aptamer plasmonic biosensor for malaria biomarker detection in whole blood

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