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Scientific Articles

Immunogenicity of full-length P. vivax rPvs48/45 protein formulations in BALB/c mice

November 25, 2021 - 13:04 -- Open Access
Author(s): 
Arévalo-Herrera M, Miura K, Solano E, Sebastián Ramírez J, Long CA, Corradin G, Herrera S
Reference: 
Vaccine. 2021 Nov 18:S0264-410X(21)01481-X

Pvs48/45 is a Plasmodium vivax gametocyte surface protein involved in the parasite fertilization process. Previous studies showed that Pvs48/45 proteins expressed in Escherichia coli (E. coli) and Chinese hamster ovary (CHO) cells were highly immunoreactive with sera from malaria-endemic areas and highly immunogenic in animal models. Here the immunogenicity in mice of three different vaccine formulations was compared.

Safety, infectivity and immunogenicity of a genetically attenuated blood-stage malaria vaccine

November 25, 2021 - 13:03 -- Open Access
Author(s): 
Webster R, Sekuloski S, McCarthy JS, et al.
Reference: 
BMC Med. 2021 Nov 22;19(1):293

There is a clear need for novel approaches to malaria vaccine development. We aimed to develop a genetically attenuated blood-stage vaccine and test its safety, infectivity, and immunogenicity in healthy volunteers. Our approach was to target the gene encoding the knob-associated histidine-rich protein (KAHRP), which is responsible for the assembly of knob structures at the infected erythrocyte surface. Knobs are required for correct display of the polymorphic adhesion ligand P. falciparum erythrocyte membrane protein 1 (PfEMP1), a key virulence determinant encoded by a repertoire of var genes.

Cohort profile: the Mancio Lima cohort study of urban malaria in Amazonian Brazil

November 25, 2021 - 13:00 -- Open Access
Author(s): 
Johansen IC, Rodrigues PT, Tonini J, Vinetz J, Castro MC, Ferreira MU
Reference: 
BMJ Open. 2021 Nov 17;11(11):e048073

This population-based open cohort study aims to investigate biological and sociodemographic drivers of malaria transmission in the main urban hotspot of Amazonian Brazil.

Genetic diversity of plasmodium falciparum isolates in Minna, North Central Nigeria inferred by PCR genotyping of Merozoite surface protein 1 and 2

November 25, 2021 - 12:59 -- Open Access
Author(s): 
Hadijah UY, Innocent OCJ, Abdulkadir A, Abolarinwa SO, Samuel ES, Chidiebere OA
Reference: 
Infect Genet Evol. 2021 Nov 17:105143

North Central Nigeria is one region in Nigeria with a significant incidence of malaria caused majorly by Plasmodium falciparum. This study utilizes the msp1 and msp2 genes of P. falciparum to examine its diversity and multiplicity of infection (MOI). Blood samples were collected from 247 children across selected healthcare facilities in Minna, from infants and children aged 6 months to 17 years.

G-quadruplex RNA motifs influence gene expression in the malaria parasite Plasmodium falciparum

November 25, 2021 - 12:48 -- Open Access
Author(s): 
Dumetz F, Chow EY, Harris LM, Liew SW, Jensen A, Umar MI, Chung B, Chan TF, Merrick CJ, Kwok CK
Reference: 
Nucleic Acids Res. 2021 Nov 18:gkab1095

G-quadruplexes are non-helical secondary structures that can fold in vivo in both DNA and RNA. In human cells, they can influence replication, transcription and telomere maintenance in DNA, or translation, transcript processing and stability of RNA. We have previously showed that G-quadruplexes are detectable in the DNA of the malaria parasite Plasmodium falciparum, despite a very highly A/T-biased genome with unusually few guanine-rich sequences. Here, we show that RNA G-quadruplexes can also form in P. falciparum RNA, using rG4-seq for transcriptome-wide structure-specific RNA probing.

Not Open Access | Safety and efficacy of a three-dose regimen of Plasmodium falciparum sporozoite vaccine in adults during an intense malaria transmission season in Mali: a randomised, controlled phase 1 trial

November 25, 2021 - 12:35 -- NOT Open Access
Author(s): 
Sissoko MS, Healy SA, Duffy PE, et al.
Reference: 
Lancet Infect Dis. 2021 Nov 18:S1473-3099(21)00332-7

WHO recently approved a partially effective vaccine that reduces clinical malaria in children, but increased vaccine activity is required to pursue malaria elimination. A phase 1 clinical trial was done in Mali, west Africa, to assess the safety, immunogenicity, and protective efficacy of a three-dose regimen of Plasmodium falciparum sporozoite (PfSPZ) Vaccine (a metabolically active, non-replicating, whole malaria sporozoite vaccine) against homologous controlled human malaria infection (CHMI) and natural P falciparum infection.

NOT Open Access | Assessment of experimental malaria vaccine induced protection in pre-exposed populations

November 24, 2021 - 20:02 -- NOT Open Access
Author(s): 
Daubenberger C
Reference: 
Lancet Infect Dis. 2021 Nov 18:S1473-3099(21)00359-5

Efforts to control and further reduce morbidity and mortality caused by Plasmodium falciparum infections in all age groups will be substantially strengthened by development of efficacious malaria vaccines in malaria pre-exposed populations.

NOT Open Access | Cerebral malaria associated with mixed forms of acute macular neuroretinopathy and paracentral acute middle maculopathy

November 24, 2021 - 20:01 -- NOT Open Access
Author(s): 
Bradly K, Relvas LJM, Draganova D, Postelmans L
Reference: 
J Fr Ophtalmol. 2021 Nov 18:S0181-5512(21)00537-4

Acute macular neuroretinopathy (AMN) is a rare retinal disorder first described by Bos and Deutman in 1975. It usually presents as an acute onset of paracentral scotoma, with characteristic fundus findings of reddish-brown wedge-shaped or petaloid lesions located within the parafoveal area. With the recent advances of spectral domain optical coherence tomography (SD-OCT), Sarraf et al. initially categorized the lesions into two types according to the layer involved: either above or below the outer plexiform layer (OPL).

Extracellular vesicles in malaria: an agglomeration of two decades of research

November 23, 2021 - 10:00 -- Open Access
Author(s): 
Tosin Opadokun and Petra Rohrbach
Reference: 
Malaria Journal 2021 20:442, 20 November 2021

Malaria is a complex parasitic disease, caused by Plasmodium spp. More than a century after the discovery of malaria parasites, this disease continues to pose a global public health problem and the pathogenesis of the severe forms of malaria remains incompletely understood. Extracellular vesicles (EVs), including exosomes and microvesicles, have been increasingly researched in the field of malaria in a bid to fill these knowledge gaps.

Red blood cell blood group A antigen level affects the ability of heparin and PfEMP1 antibodies to disrupt Plasmodium falciparum rosettes

November 23, 2021 - 09:29 -- Open Access
Author(s): 
Pontus Hedberg, Madle Sirel, Kirsten Moll, Mpungu Steven Kiwuwa, Petter Höglund, Ulf Ribacke and Mats Wahlgren
Reference: 
Malaria Journal 2021 20:441, 18 November 2021

The histo-blood group ABO system has been associated with adverse outcomes in COVID-19, thromboembolic diseases and Plasmodium falciparum malaria. An integral part of the severe malaria pathogenesis is rosetting, the adherence of parasite infected red blood cells (RBCs) to uninfected RBCs. Rosetting is influenced by the host’s ABO blood group (Bg) and rosettes formed in BgA have previously been shown to be more resilient to disruption by heparin and shield the parasite derived surface antigens from antibodies. However, data on rosetting in weak BgA subgroups is scarce and based on investigations of relatively few donors.

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