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Rodolfo F. Marques

Bio: Rodolfo F. Marques is an academic researcher from University of São Paulo. The author has contributed to research in topics: Plasmodium vivax & Circumsporozoite protein. The author has an hindex of 2, co-authored 6 publications receiving 11 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a review of diagnostic methods for malaria non-falciparum differential detection and the possibilities of their application in different circumstances is presented, including the classical procedures and new perspectives.
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.

20 citations

Journal ArticleDOI
TL;DR: In this article, a portable microfluidic electrochemical immunosensor for Plasmodium vivax antibodies determination was developed, which used a gold microelectrode placed inside the central channel of the micro fluididic device was used as immobilization platform for a specific fragment (19-kDa) derived from the P. vivaax merozoite surface protein 1, known as PvMSP119.
Abstract: A portable microfluidic electrochemical immunosensor for Plasmodium vivax antibodies determination was developed. A gold microelectrode placed inside the central channel of the microfluidic device was used as immobilization platform for a specific fragment (19-kDa) derived from the P. vivax merozoite surface protein 1, known as PvMSP119. The gold microelectrode surface was modified by using a dynamic hydrogen bubble template (DHBT) method in the presence of multiwalled carbon nanotubes. The synthesized nanocomposite presented exceptional properties, like high specific surface area, remarkable biocompatibility, and excellent electrochemical activity. The material was characterized by scanning electron microscopy, energy dispersive spectrometry, x-ray diffraction, and cyclic voltammetry. The antibodies (anti-PvMSP119) present in the sample bind to the PvMSP119 immobilized on the microelectrode surface, which is then labeled with an anti-IgG antibody marked with horseradish peroxidase (HRP-anti-IgG). Finally, the substrate solution (H2O2 + catechol) is added, and the enzymatic product (quinone) is reduced on the NPAu electrode at +0.2 V (vs. Ag/AgCl). The current obtained is directly proportional to the anti-PvMSP119 concentration in the sample. The detection limit of the microfluidic electrochemical immunosensor was 0.6 ng mL−1, much lower compared to the ELISA detection limit of 15 ng mL−1. This is the first microfluidic electrochemical immunosensor device suitable for point-of-care determination of anti-PvMSP119 in human serum samples.

12 citations

Journal ArticleDOI
19 Apr 2020-Vaccine
TL;DR: A formulation containing the three allelic variants of the P. vivax circumsporozoite protein showed partial protection in mice after a challenge with the hybrid Plasmodium berghei (Pb) sporozoite, and has the potential to be a good candidate for the development of a universal vaccine against P.vivax malaria.

7 citations

Journal ArticleDOI
TL;DR: In this article, two recombinant proteins representing three allelic variants of PvCSP (VK210, VK247 and P. vivax-like) were fused to the mumps virus nucleocapsid protein to enhance immune responses against PvCSP.
Abstract: Malaria is a highly prevalent parasitic disease in regions with tropical and subtropical climates worldwide. Among the species of Plasmodium causing human malaria, P. vivax is the second most prevalent and the most geographically widespread species. A major target of a pre-erythrocytic vaccine is the P. vivax circumsporozoite protein (PvCSP). In previous studies, we fused two recombinant proteins representing three allelic variants of PvCSP (VK210, VK247 and P. vivax-like) to the mumps virus nucleocapsid protein to enhance immune responses against PvCSP. The objective of the present study was to evaluate the protective efficacy of these recombinants in mice challenged with transgenic P. berghei parasites expressing PvCSP allelic variants. Formulations containing Poly (I:C) or Montanide ISA720 as adjuvants elicited high and long-lasting IgG antibody titers specific to each PvCSP allelic variant. Immunized mice were challenged with two existing chimeric P. berghei parasite lines expressing PvCSP-VK210 and PvCSP-VK247. We also developed a novel chimeric line expressing the third allelic variant, PvCSP-P. vivax-like, as a new murine immunization-challenge model. Our formulations conferred partial protection (significant delay in the time to reach 1% parasitemia) against challenge with the three chimeric parasites. Our results provide insights into the development of a vaccine targeting multiple strains of P. vivax.

7 citations

Journal ArticleDOI
17 Jun 2020
TL;DR: The multistage vaccine formulation provided partial protection in mice challenged with a transgenic Plasmodium berghei sporozoite expressing the homologous PvCSP protein.
Abstract: Infections with Plasmodium vivax are predominant in the Americas, representing 75% of malaria cases. Previously perceived as benign, malaria vivax is, in fact, a highly debilitating and economically important disease. Considering the high complexity of the malaria parasite life cycle, it has been hypothesized that an effective vaccine formulation against Plasmodium should contain multiple antigens expressed in different parasite stages. Based on that, we analyzed a recombinant P. vivax vaccine formulation mixing the apical membrane antigen 1 ectodomain (PvAMA-1) and a full-length circumsporozoite protein (PvCSP-AllFL) previously studied by our group, which elicits a potent antibody response in mice. Genetically distinct strains of mice (C57BL/6 and BALB/c) were immunized with the proteins, alone or in combination, in the presence of poly(I:C) adjuvant, a TLR3 agonist. In C57BL/6, high-antibody titers were induced against PvAMA-1 and the three PvCSP variants (VK210, VK247, and P. vivax-like). Meanwhile, mixing PvAMA-1 with PvCSP-AllFL had no impact on total IgG antibody titers, which were long-lasting. Moreover, antibodies from immunized mice recognized VK210 sporozoites and blood-stage parasites by immunofluorescence assay. However, in the BALB/c model, the antibody response against PvCSP-AllFL was relatively low. PvAMA-1-specific CD3+CD4+ and CD3+CD8+ T-cell responses were observed in C57BL/6 mice, and the cellular response was impaired by PvCSP-AllFL combination. More relevant, the multistage vaccine formulation provided partial protection in mice challenged with a transgenic Plasmodium berghei sporozoite expressing the homologous PvCSP protein.

6 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a review of diagnostic methods for malaria non-falciparum differential detection and the possibilities of their application in different circumstances is presented, including the classical procedures and new perspectives.
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.

20 citations

Journal ArticleDOI
TL;DR: In this article , a review of recent advances in point-of-care (POC) bioanalysis on nano-sensor-based microfluidic platforms is presented.
Abstract: Microfluidic technology provides a portable, cost-effective, and versatile tool for point-of-care (POC) bioanalysis because of its associated advantages such as fast analysis, low volumes of reagent consumption, and high portability. Along with microfluidics, the application of nanomaterials in biosensing has attracted lots of attention due to their unique physical and chemical properties for enhanced signal modulation such as signal amplification and signal transduction for POC bioanalysis. Hence, an enormous number of microfluidic devices integrated with nano-sensors have been developed for POC bioanalysis targeting low-resource settings. Herein, we review recent advances in POC bioanalysis on nano-sensor-based microfluidic platforms. We first briefly summarized the different types of cost-effective microfluidic platforms, followed by a concise introduction to nanomaterial-based biosensors. Then, we highlighted the application of microfluidic platforms integrated with nano-sensors for POC bioanalysis. Finally, we discussed the current limitations and perspective trends of the nano-sensor-based microfluidic platforms for POC bioanalysis.

15 citations

Journal ArticleDOI
TL;DR: A vaccine to prevent disease is critical, considering the rapid spread of drug-resistant parasite strains, and the dev... as mentioned in this paper, which causes significant public health problems in endemic regions.
Abstract: Plasmodium vivax causes significant public health problems in endemic regions. A vaccine to prevent disease is critical, considering the rapid spread of drug-resistant parasite strains, and the dev...

14 citations

Journal ArticleDOI
TL;DR: In this paper , high selective measurements were achieved by covering with a perm-selective layer of electropolymerized m-phenylenediamine, deposition of a Nafion® film and by using a null sensor.

12 citations

Journal ArticleDOI
02 Aug 2022-JAMA
TL;DR: Prevention and treatment of malaria depend on the species and the drug sensitivity of parasites from the region of acquisition, and several options exist for chemoprophylaxis and selection should be based on patient characteristics and preferences.
Abstract: Importance Malaria is caused by protozoa parasites of the genus Plasmodium and is diagnosed in approximately 2000 people in the US each year who have returned from visiting regions with endemic malaria. The mortality rate from malaria is approximately 0.3% in the US and 0.26% worldwide. Observations In the US, most malaria is diagnosed in people who traveled to an endemic region. More than 80% of people diagnosed with malaria in the US acquired the infection in Africa. Of the approximately 2000 people diagnosed with malaria in the US in 2017, an estimated 82.4% were adults and about 78.6% were Black or African American. Among US residents diagnosed with malaria, 71.7% had not taken malaria chemoprophylaxis during travel. In 2017 in the US, P falciparum was the species diagnosed in approximately 79% of patients, whereas P vivax was diagnosed in an estimated 11.2% of patients. In 2017 in the US, severe malaria, defined as vital organ involvement including shock, pulmonary edema, significant bleeding, seizures, impaired consciousness, and laboratory abnormalities such as kidney impairment, acidosis, anemia, or high parasitemia, occurred in approximately 14% of patients, and an estimated 0.3% of those receiving a diagnosis of malaria in the US died. P falciparum has developed resistance to chloroquine in most regions of the world, including Africa. First-line therapy for P falciparum malaria in the US is combination therapy that includes artemisinin. If P falciparum was acquired in a known chloroquine-sensitive region such as Haiti, chloroquine remains an alternative option. When artemisinin-based combination therapies are not available, atovaquone-proguanil or quinine plus clindamycin is used for chloroquine-resistant malaria. P vivax, P ovale, P malariae, and P knowlesi are typically chloroquine sensitive, and treatment with either artemisinin-based combination therapy or chloroquine for regions with chloroquine-susceptible infections for uncomplicated malaria is recommended. For severe malaria, intravenous artesunate is first-line therapy. Treatment of mild malaria due to a chloroquine-resistant parasite consists of a combination therapy that includes artemisinin or chloroquine for chloroquine-sensitive malaria. P vivax and P ovale require additional therapy with an 8-aminoquinoline to eradicate the liver stage. Several options exist for chemoprophylaxis and selection should be based on patient characteristics and preferences. Conclusions and Relevance Approximately 2000 cases of malaria are diagnosed each year in the US, most commonly in travelers returning from visiting endemic areas. Prevention and treatment of malaria depend on the species and the drug sensitivity of parasites from the region of acquisition. Intravenous artesunate is first-line therapy for severe malaria.

9 citations