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Africa

Parasite histones are toxic to brain endothelium and link blood barrier breakdown and thrombosis in cerebral malaria

July 15, 2020 - 14:22 -- Open Access
Author(s): 
Moxon CA, Alhamdi Y, Storm J, Toh CH, et al.
Reference: 
Blood Adv. 2020 Jul 14; 4(13):2851-2864

Microvascular thrombosis and blood-brain barrier (BBB) breakdown are key components of cerebral malaria (CM) pathogenesis in African children and are implicated in fatal brain swelling. How Plasmodium falciparum infection causes this endothelial disruption and why this occurs, particularly in the brain, is not fully understood. In this study, we have demonstrated that circulating extracellular histones, equally of host and parasite origin, are significantly elevated in CM patients. Higher histone levels are associated with brain swelling on magnetic resonance imaging.

Polymorphism analysis of propeller domain of k13 gene in Plasmodium ovale curtisi and Plasmodium ovale wallikeri isolates original infection from Myanmar and Africa in Yunnan Province, China

July 14, 2020 - 09:40 -- Open Access
Author(s): 
Mengni Chen, Ying Dong, Yan Deng, Yanchun Xu, Yan Liu, Canglin Zhang and Herong Huang
Reference: 
Malaria Journal 2020 19:246, 13 July 2020

Eighteen imported ovale malaria cases imported from Myanmar and various African countries have been reported in Yunnan Province, China from 2013 to 2018. All of them have been confirmed by morphological examination and 18S small subunit ribosomal RNA gene (18S rRNA) based PCR in YNRL. Nevertheless, the subtypes of Plasmodium ovale could not be identified based on 18S rRNA gene test, thus posing challenges on its accurate diagnosis. To help establish a more sensitive and specific method for the detection of P. ovale genes, this study performs sequence analysis on k13-propeller polymorphisms in P. ovale.

Mapping trends in insecticide resistance phenotypes in African malaria vectors

June 29, 2020 - 16:10 -- Open Access
Author(s): 
Hancock PA, Hendriks CJM, Tangena JA, Gibson H, Hemingway J, Coleman M, Gething PW, Cameron E, Bhatt S, Moyes CL
Reference: 
PLoS Biol. 2020 Jun 25; 18(6):e3000633

Mitigating the threat of insecticide resistance in African malaria vector populations requires comprehensive information about where resistance occurs, to what degree, and how this has changed over time. Estimating these trends is complicated by the sparse, heterogeneous distribution of observations of resistance phenotypes in field populations.

Low genetic diversity and strong immunogenicity within the apical membrane antigen-1 of Plasmodium ovale spp. imported from Africa to China

June 23, 2020 - 16:10 -- Open Access
Author(s): 
Lei Y, Shen F, Cheng Y, et al.
Reference: 
Acta Trop. 2020 Jun 17:105591

Malaria is still an important challenge for global public health because of its extensive mortality and morbidity. Plasmodium ovale is mainly distributed in tropical regions of Africa and Asia. it includes two distinct ovale malaria species, which are P. ovale curtisi and P. ovale wallikeri. Apical membrane antigen-1 (AMA-1) is an asexual blood-stage protein which is essential for Plasmodium. Thus far, no study on gene polymorphism and immunogenicity of P. ovale AMA-1 (PoAMA-1) has been conducted. Amplified poama1 gene products from 14 P ovale curtisi samples and 12 P ovale wallikeri samples imported from Africa to Jiangsu Province, China were sequenced and their polymorphisms were analyzed.

High-efficiency enrichment enables identification of aptamers to circulating Plasmodium falciparum-infected erythrocytes

June 17, 2020 - 13:06 -- Open Access
Author(s): 
Oteng EK, Gu W, McKeague M
Reference: 
Sci Rep. 2020 Jun 16; 10(1):9706

Plasmodium falciparum is the causative agent of the deadliest human malaria. New molecules are needed that can specifically bind to erythrocytes that are infected with P. falciparum for diagnostic purposes, to disrupt host-parasite interactions, or to deliver chemotherapeutics. Aptamer technology has the potential to revolutionize biological diagnostics and therapeutics; however, broad adoption is hindered by the high failure rate of the systematic evolution of ligands by exponential enrichment (SELEX). Here we performed parallel SELEX experiments to compare the impact of two different methods for single-strand recovery on the efficiency of aptamer enrichment.

Interferon-gamma polymorphisms and risk of iron deficiency and anaemia in Gambian children

June 12, 2020 - 13:58 -- Open Access
Author(s): 
Abuga KM, Rockett KA, Muriuki JM, Koch O, Nairz M, Sirugo G, Bejon P, Kwiatkowski DP, Prentice AM, Atkinson SH
Reference: 
Wellcome Open Res. 2020 Jun 2; 5:40

Anaemia is a major public health concern especially in African children living in malaria-endemic regions. Interferon-gamma (IFN-γ) is elevated during malaria infection and is thought to influence erythropoiesis and iron status. Genetic variants in the IFN-γ gene (IFNG) are associated with increased IFN-γ production. We investigated putative functional single nucleotide polymorphisms (SNPs) and haplotypes of IFNG in relation to nutritional iron status and anaemia in Gambian children over a malaria season.

Uncovering hidden pfhrp2/3 deletion Plasmodium falciparum

June 10, 2020 - 15:08 -- Open Access
Author(s): 
Kobayashi T
Reference: 
EBioMedicine. 2020 Jun 5;56:102781

Deaths and transmission from malaria have declined significantly in the past decade, although the progress has somewhat stalled in recent years. Accurate and timely diagnosis is essential to providing adequate treatment to malaria cases. Plasmodium falciparum histidine-rich protein 2 (PfHRP2) based rapid diagnostic test (RDT) is widely used especially in Africa, where P. Falciparum accounts for 98%of estimated malaria cases. Despite its importance, reports of parasites lackingpfhrp2gene emerging across the globe are threatening the importance of this malaria diagnostic tool.

Prevalence of mutations in the Plasmodium falciparum chloroquine resistance transporter, PfCRT, and association with ex vivo susceptibility to common anti-malarial drugs against African Plasmodium falciparum isolates

June 8, 2020 - 15:27 -- Open Access
Author(s): 
Francis Tsombeng Foguim, Hervé Bogreau, Mathieu Gendrot, Joel Mosnier, Isabelle Fonta, Nicolas Benoit, Rémy Amalvict, Marylin Madamet, Sharon Wein and Bruno Pradines
Reference: 
Malaria Journal 2020 19:201, 5 June 2020

The Plasmodium falciparum chloroquine transporter gene (pfcrt) is known to be involved in chloroquine and amodiaquine resistance, and more particularly the mutations on the loci 72 to 76 localized within the second exon. Additionally, new mutations (T93S, H97Y, C101F, F145I, M343L, C350R and G353V) were recently shown to be associated with in vitro reduced susceptibility to piperaquine in Asian or South American P. falciparum strains. However, very few data are available on the prevalence of these mutations and their effect on parasite susceptibility to anti-malarial drugs, and more particularly piperaquine in Africa.

An Africa-wide genomic evolution of insecticide resistance in the malaria vector Anopheles funestus involves selective sweeps, copy number variations, gene conversion and transposons

June 8, 2020 - 14:50 -- Open Access
Author(s): 
Weedall GD, Riveron JM, Hearn J, Irving H, Kamdem C, Fouet C, White BJ, Wondji CS
Reference: 
PLoS Genet 16(6): e1008822

Insecticide resistance in malaria vectors threatens to reverse recent gains in malaria control. Deciphering patterns of gene flow and resistance evolution in malaria vectors is crucial to improve control strategies and preventing malaria resurgence. A genome-wide survey of Anopheles funestus genetic diversity Africa-wide revealed evidences of a major division between southern Africa and elsewhere, associated with different population histories.

Malaria outbreak investigation in a rural area south of Zimbabwe: a case–control study

June 3, 2020 - 15:39 -- Open Access
Author(s): 
Paddington T. Mundagowa and Pugie T. Chimberengwa
Reference: 
Malaria Journal 2020 19:197, 1 June 2020

Ninety percent of the global annual malaria mortality cases emanate from the African region. About 80–90% of malaria transmissions in sub-Saharan Africa occur indoors during the night. In Zimbabwe, 79% of the population are at risk of contracting the disease. Although the country has made significant progress towards malaria elimination, isolated seasonal outbreaks persistently resurface. In 2017, Beitbridge District was experiencing a second malaria outbreak within 12 months prompting the need for investigating the outbreak.

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