scholarly journals Plasmodium vivax and Plasmodium ovale in the Malaria Elimination Agenda in Africa

Author(s):  
Isaac K. Quaye ◽  
Larysa Aleksenko

In recent times, several countries in sub-Saharan Africa have reported cases of Plasmodium vivax (Pv) with a considerable number being Duffy negative. Current efforts at malaria elimination are focused solely on Plasmodium falciparum (Pf) excluding non-falciparum malaria. Pv and Plasmodium ovale (Po) have hypnozoite forms that can serve as reservoirs of infection and sustain transmission. The burden of these parasites in Africa seems to be more than acknowledged, playing roles in migrant and autochthonous infections. Considering that elimination and eradication is a current aim for WHO and Roll Back Malaria (RBM), the inclusion of Pv and Po in the elimination agenda cannot be over-emphasized. The biology of Pv and Po are such that the same elimination strategies as are used for Pf cannot be applied so, going forward, new approaches will be required to attain elimination and eradication targets.

Author(s):  
Daniel Kepple ◽  
Alfred Hubbard ◽  
Musab M Ali ◽  
Beka R Abargero ◽  
Karen Lopez ◽  
...  

Abstract Plasmodium vivax malaria was thought to be rare in Africa, but an increasing number of P. vivax cases reported across Africa and in Duffy-negative individuals challenges this conventional dogma. The genetic characteristics of P. vivax in Duffy-negative infections, the transmission of P. vivax in East Africa, and the impact of environments on transmission remain largely unknown. This study examined genetic and transmission features of P. vivax from 107 Duffy-negative and 305 Duffy-positive individuals in Ethiopia and Sudan. No clear genetic differentiation was found in P. vivax between the two Duffy groups, indicating between-host transmission. P. vivax from Ethiopia and Sudan showed similar genetic clusters, except samples from Khartoum, possibly due to distance and road density that inhibited parasite gene flow. This study is the first to show that P. vivax can transmit to and from Duffy-negative individuals and provides critical insights into the spread of P. vivax in sub-Saharan Africa.


2020 ◽  
Vol 10 ◽  
pp. e00596
Author(s):  
Mary Aigbiremo Oboh ◽  
Kolapo Muyiwa Oyebola ◽  
Emmanuel Taiwo Idowu ◽  
Aida Sadikh Badiane ◽  
Olubunmi Adetoro Otubanjo ◽  
...  

2019 ◽  
Vol 220 (11) ◽  
pp. 1738-1749 ◽  
Author(s):  
Sarah Auburn ◽  
Sisay Getachew ◽  
Richard D Pearson ◽  
Roberto Amato ◽  
Olivo Miotto ◽  
...  

Abstract The Horn of Africa harbors the largest reservoir of Plasmodium vivax in the continent. Most of sub-Saharan Africa has remained relatively vivax-free due to a high prevalence of the human Duffy-negative trait, but the emergence of strains able to invade Duffy-negative reticulocytes poses a major public health threat. We undertook the first population genomic investigation of P. vivax from the region, comparing the genomes of 24 Ethiopian isolates against data from Southeast Asia to identify important local adaptions. The prevalence of the Duffy binding protein amplification in Ethiopia was 79%, potentially reflecting adaptation to Duffy negativity. There was also evidence of selection in a region upstream of the chloroquine resistance transporter, a putative chloroquine-resistance determinant. Strong signals of selection were observed in genes involved in immune evasion and regulation of gene expression, highlighting the need for a multifaceted intervention approach to combat P. vivax in the region.


2019 ◽  
Author(s):  
Mary Aigbiremo Oboh ◽  
Upasana Shyamsunder Singh ◽  
Daouda Nidaye ◽  
Aida S. Badiane ◽  
Anwar Ali ◽  
...  

AbstractMalaria in sub-Saharan Africa (sSA) is thought to be hugely caused by Plasmodium falciparum and very infrequently by P. ovale, P. malariae, with P. vivax not even being considered to be of any significant role. However, with the availability of very sensitive diagnostic tool, it has become more clear that, the percentage of non-falciparum malaria in this sub-region has been underestimated. P. vivax was historically thought to be absent in sSA due to the high prevalence of the Duffy null antigen in individuals residing here. Nevertheless, recent studies reporting the detection of vivax malaria in Duffy-negative individuals challenges this notion. Following our earlier report of P. vivax in Duffy-negative individuals, we have re-assessed all previous samples following the classical PCR method and sequencing to confirm both single/mixed infections as well as the Duffy status of the individuals.Interestingly, fifteen additional Plasmodium infections were detected, representing 5.9% in prevalence from our earlier work. In addition, P. vivax represents 26.7% (4/15) of the new isolates collected in Nigeria. Sequencing results confirmed, all vivax isolates as truly vivax malaria and their Duffy status to be that of the Duffy-negative genotype. The identification of more vivax isolates among these Duffy-negative individuals from Nigeria, substantiate the expanding body of evidence of the ability of P. vivax to infect RBCs that do not express the DARC gene. Hence, such geno-epidemiological study should be conducted at the national level in order to evaluate the actual burden of P. vivax in the country.


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Ommer Mohammed Dafalla ◽  
Mohammed Alzahrani ◽  
Ahmed Sahli ◽  
Mohammed Abdulla Al Helal ◽  
Mohammad Mohammad Alhazmi ◽  
...  

Abstract Background Artemisinin-based combination therapy (ACT) is recommended at the initial phase for treatment of Plasmodium falciparum, to reduce morbidity and mortality in all countries where malaria is endemic. Polymorphism in portions of P. falciparum gene encoding kelch (K13)-propeller domains is associated with delayed parasite clearance after ACT. Of about 124 different non-synonymous mutations, 46 have been identified in Southeast Asia (SEA), 62 in sub-Saharan Africa (SSA) and 16 in both the regions. This is the first study designed to analyse the prevalence of polymorphism in the P. falciparum k13-propeller domain in the Jazan region of southwest Saudi Arabia, where malaria is endemic. Methods One-hundred and forty P. falciparum samples were collected from Jazan region of southwest Saudi Arabia at three different times: 20 samples in 2011, 40 samples in 2016 and 80 samples in 2020 after the implementation of ACT. Plasmodium falciparum kelch13 (k13) gene DNA was extracted, amplified, sequenced, and analysed using a basic local alignment search tool (BLAST). Results This study obtained 51 non-synonymous (NS) mutations in three time groups, divided as follows: 6 single nucleotide polymorphisms (SNPs) ‘11.8%’ in samples collected in 2011 only, 3 (5.9%) in 2011and 2016, 5 (9.8%) in 2011 and 2020, 5 (9.8%) in 2016 only, 8 (15.7%) in 2016 and 2020, 14 (27.5%) in 2020 and 10 (19.6%) in all the groups. The BLAST revealed that the 2011 isolates were genetically closer to African isolates (53.3%) than Asian ones (46.7%). Interestingly, this proportion changed completely in 2020, to become closer to Asian isolates (81.6%) than to African ones (18.4%). Conclusions Despite the diversity of the identified mutations in the k13-propeller gene, these data did not report widespread artemisinin-resistant polymorphisms in the Jazan region where these samples were collected. Such a process would be expected to increase frequencies of mutations associated with the resistance of ACT.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ashley Osborne ◽  
Emilia Manko ◽  
Mika Takeda ◽  
Akira Kaneko ◽  
Wataru Kagaya ◽  
...  

AbstractCharacterising the genomic variation and population dynamics of Plasmodium falciparum parasites in high transmission regions of Sub-Saharan Africa is crucial to the long-term efficacy of regional malaria elimination campaigns and eradication. Whole-genome sequencing (WGS) technologies can contribute towards understanding the epidemiology and structural variation landscape of P. falciparum populations, including those within the Lake Victoria basin, a region of intense transmission. Here we provide a baseline assessment of the genomic diversity of P. falciparum isolates in the Lake region of Kenya, which has sparse genetic data. Lake region isolates are placed within the context of African-wide populations using Illumina WGS data and population genomic analyses. Our analysis revealed that P. falciparum isolates from Lake Victoria form a cluster within the East African parasite population. These isolates also appear to have distinct ancestral origins, containing genome-wide signatures from both Central and East African lineages. Known drug resistance biomarkers were observed at similar frequencies to those of East African parasite populations, including the S160N/T mutation in the pfap2mu gene, which has been associated with delayed clearance by artemisinin-based combination therapy. Overall, our work provides a first assessment of P. falciparum genetic diversity within the Lake Victoria basin, a region targeting malaria elimination.


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