scholarly journals Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Brandyce St. Laurent ◽  
Becky Miller ◽  
Timothy A. Burton ◽  
Chanaki Amaratunga ◽  
Sary Men ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Southeast Asia ◽  
Artemisinin Resistance ◽  
Rapid Expansion ◽  
Clinical Isolates ◽  
Anopheles Coluzzii ◽  
Mosquito Vectors ◽  
Anopheles Dirus ◽  
Global Spread

Abstract Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread.

scholarly journals Plasmodium falciparum K13 mutations in Africa and Asia present varying degrees of artemisinin resistance and an elevated fitness cost in African parasites

2021 ◽  
Author(s):  
Barbara H. Stokes ◽  
Kelly Rubiano ◽  
Satish K. Dhingra ◽  
Sachel Mok ◽  
Judith Straimer ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Southeast Asia ◽  
Survival Rates ◽  
Point Mutations ◽  
Artemisinin Resistance ◽  
Parasite Clearance ◽  
Definitive Evidence ◽  
The Impact

AbstractThe emergence of artemisinin (ART) resistance in Plasmodium falciparum parasites has led to increasing rates of treatment failure with first-line ART-based combination therapies (ACTs) in Southeast Asia. In this region, select mutations in K13 can result in delayed parasite clearance rates in vivo and enhanced survival in the ring-stage survival assay (RSA) in vitro. Our genotyping of 3,299 P. falciparum isolates across 11 sub-Saharan countries reveals the continuing dominance of wild-type K13 and confirms the emergence of a K13 R561H variant in Rwanda. Using gene editing, we provide definitive evidence that this mutation, along with M579I and C580Y, can confer variable degrees of in vitro ART resistance in African P. falciparum strains. C580Y and M579I were both associated with substantial fitness costs in African parasites, which may counter-select against their dissemination in high-transmission settings. We also report the impact of multiple K13 mutations, including the predominant variant C580Y, on RSA survival rates and fitness in multiple Southeast Asian strains. No change in ART susceptibility was observed upon editing point mutations in ferrodoxin or mdr2, earlier associated with ART resistance in Southeast Asia. These data point to the lack of an evident biological barrier to mutant K13 mediating ART resistance in Africa, while identifying their detrimental impact on parasite growth.

scholarly journals Gametocytes from K13 Propeller Mutant Plasmodium falciparum Clinical Isolates Demonstrate Reduced Susceptibility to Dihydroartemisinin in the Male Gamete Exflagellation Inhibition Assay

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
Sonia Lozano ◽  
Pablo Gamallo ◽  
Carolina González-Cortés ◽  
Jesús-Luís Presa Matilla ◽  
Rick M. Fairhurst ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Southeast Asia ◽  
Male Gamete ◽  
Clinical Isolates ◽  
Inhibition Assay ◽  
Wild Type ◽  
Content Type ◽  
Gamete Formation

ABSTRACT Mutations in the kelch propeller domain (K13 propeller) of Plasmodium falciparum parasites from Southeast Asia are associated with reduced susceptibility to artemisinin. We exposed in vitro-cultured stage V gametocytes from Cambodian K13 propeller mutant parasites to dihydroartemisinin and evaluated the inhibition of male gamete formation in an in vitro exflagellation inhibition assay (EIA). Gametocytes with the R539T and C580Y K13 propeller alleles were less susceptible to dihydroartemisinin and had significantly higher 50% inhibitory concentrations (IC50s) than did gametocytes with wild-type alleles.

scholarly journals Molecular assessment of kelch13 non-synonymous mutations in Plasmodium falciparum isolates from Central African Republic (2017–2019)

2020 ◽  
Author(s):  
Romaric Nzoumbou-Boko ◽  
Chris-Boris Gildas Panté-Wockama ◽  
Carine Ngoagoni ◽  
Nathalie Petiot ◽  
Eric Legrand ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Southeast Asia ◽  
Central African Republic ◽  
Artemisinin Resistance ◽  
Plasmodium Species ◽  
Sub Saharan Africa ◽  
Artemisinin Derivatives ◽  
Synonymous Mutations

Abstract Background: Over the last decade, Artemisinin-based Combination Therapies (ACT) have contributed substantially to the decrease in malaria-related morbidity and mortality. The emergence of Plasmodium falciparum parasites resistant to artemisinin derivatives in Southeast Asia and the risk of their spread or of local emergence in sub-Saharan Africa are a major threat to public health. This study thus set out to estimate the proportion of P. falciparum isolates, with PfKelch13 gene mutations associated with artemisinin resistance previously detected in Southeast Asia. Methods: Blood samples were collected in two sites of Bangui, the capital of the Central African Republic form 2017 to 2019. DNA was extracted and nested PCR were carried out to detect Plasmodium species and mutations in the propeller domain of the PfKelch13 gene. Results: A total of 255 P. falciparum isolates were analyzed. Among them, P. ovale DNA was found in four samples (1.57%, 4/255). Of 187 samples with interpretable PfKelch13 sequences, four isolates presented a mutation in the PfKelch13 gene (2.1%, 4/187), including one non-synonymous mutation (Y653N) (0.5%, 1/187). This mutation has never been described as associated with artemisinin resistance in Southeast Asia and its in vitro phenotype is unknown. Conclusion: This preliminary study indicates the need for a larger study on samples collected across the whole country along with the evaluation of in vitro and in vivo phenotype profiles of PfKelch13 mutant parasites to estimate the risk of artemisinin resistance in the CAR.

scholarly journals The Diversity of the Plasmodium falciparum K13 Propeller Domain Did Not Increase after Implementation of Artemisinin-Based Combination Therapy in Uganda

2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Melissa D. Conrad ◽  
Sam L. Nsobya ◽  
Philip J. Rosenthal
Keyword(s):  
Plasmodium Falciparum ◽  
Southeast Asia ◽  
Artemisinin Resistance ◽  
Standard Of Care ◽  
Parasite Clearance ◽  
Sub Saharan Africa ◽  
Clinical Isolates ◽  
Nucleotide Polymorphisms ◽  
Content Type ◽  
Sub Saharan

ABSTRACT Artemisinin-based combination therapies (ACTs) are the standard of care to treat uncomplicated falciparum malaria. However, resistance to artemisinins, defined as delayed parasite clearance after therapy, has emerged in Southeast Asia, and the spread of resistance to sub-Saharan Africa could have devastating consequences. Artemisinin resistance has been associated in Southeast Asia with multiple nonsynonymous single nucleotide polymorphisms (NS-SNPs) in the propeller domain of the gene encoding the Plasmodium falciparum K13 protein (K13PD). Some K13PD NS-SNPs have been seen in Africa, but the relevance of these mutations is unclear. To assess whether ACT use has selected for specific K13PD mutations, we compared the K13PD genetic diversity in clinical isolates collected before and after the implementation of ACT use from seven sites across Uganda. We detected K13PD NS-SNPs in 16 of 683 (2.3%) clinical isolates collected between 1999 and 2004 and in 26 of 716 (3.6%) isolates collected between 2012 and 2016 (P = 0.16), representing a total of 29 different polymorphisms at 27 codons. Individual NS-SNPs were usually detected only once, and none were found in more than 0.7% of the isolates. Three SNPs (C469F, P574L, and A675V) associated with delayed clearance in Southeast Asia were seen in samples collected between 2012 and 2016, each in a single isolate. No differences in diversity following implementation of ACT use were found at any of the seven sites, nor was there evidence of selective pressures acting on the locus. Our results suggest that selection by ACTs is not impacting on K13PD diversity in Uganda.

scholarly journals Local emergence in Amazonia of Plasmodium falciparum k13 C580Y mutants associated with in vitro artemisinin resistance

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Luana C Mathieu ◽  
Horace Cox ◽  
Angela M Early ◽  
Sachel Mok ◽  
Yassamine Lazrek ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
South America ◽  
Southeast Asia ◽  
De Novo ◽  
Artemisinin Resistance ◽  
Parasite Clearance ◽  
De Novo Mutations ◽  
Plasmodium Falciparum Parasite ◽  
Parasite Populations

Antimalarial drug resistance has historically arisen through convergent de novo mutations in Plasmodium falciparum parasite populations in Southeast Asia and South America. For the past decade in Southeast Asia, artemisinins, the core component of first-line antimalarial therapies, have experienced delayed parasite clearance associated with several pfk13 mutations, primarily C580Y. We report that mutant pfk13 has emerged independently in Guyana, with genome analysis indicating an evolutionary origin distinct from Southeast Asia. Pfk13 C580Y parasites were observed in 1.6% (14/854) of samples collected in Guyana in 2016–2017. Introducing pfk13 C580Y or R539T mutations by gene editing into local parasites conferred high levels of in vitro artemisinin resistance. In vitro growth competition assays revealed a fitness cost associated with these pfk13 variants, potentially explaining why these resistance alleles have not increased in frequency more quickly in South America. These data place local malaria control efforts at risk in the Guiana Shield.

scholarly journals Molecular assessment of kelch13 non-synonymous mutations in Plasmodium falciparum isolates from Central African Republic (2017–2019)

2020 ◽  
Author(s):  
Romaric Nzoumbou-Boko ◽  
Chris-Boris Gildas Panté-Wockama ◽  
Carine Ngoagoni ◽  
Nathalie Petiot ◽  
Eric Legrand ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Southeast Asia ◽  
Central African Republic ◽  
Artemisinin Resistance ◽  
Plasmodium Species ◽  
Sub Saharan Africa ◽  
Artemisinin Derivatives ◽  
Synonymous Mutations

Abstract Background: Over the last decade, Artemisinin-based Combination Therapies (ACT) have contributed substantially to the decrease in malaria-related morbidity and mortality. The emergence of Plasmodium falciparum parasites resistant to artemisinin derivatives in Southeast Asia and the risk of their spread or of local emergence in sub-Saharan Africa are a major threat to public health. This study thus set out to estimate the proportion of P. falciparum isolates, with PfKelch13 gene mutations associated with artemisinin resistance previously detected in Southeast Asia. Methods: Blood samples were collected in two sites of Bangui, the capital of the Central African Republic form 2017 to 2019. DNA was extracted and nested PCR were carried out to detect Plasmodium species and mutations in the propeller domain of the PfKelch13 gene. Results: A total of 255 P. falciparum isolates were analyzed. Among them, P. ovale DNA was found in four samples (1.57%, 4/255). Of 187 samples with interpretable PfKelch13 sequences, four isolates presented a mutation in the PfKelch13 gene (2.1%, 4/187), including one non-synonymous mutation (Y653N) (0.5%, 1/187). This mutation has never been described as associated with artemisinin resistance in Southeast Asia and its in vitro phenotype is unknown. Conclusion: This preliminary study indicates the need for a larger study on samples collected across the whole country along with the evaluation of in vitro and in vivo phenotype profiles of PfKelch13 mutant parasites to estimate the risk of artemisinin resistance in the CAR.

scholarly journals Correction: Corrigendum: Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Brandyce St. Laurent ◽  
Becky Miller ◽  
Timothy A. Burton ◽  
Chanaki Amaratunga ◽  
Sary Men ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Southeast Asia ◽  
Clinical Isolates ◽  
Mosquito Vectors

scholarly journals Effect of Fluorescent Dyes onIn Vitro-Differentiated, Late-Stage Plasmodium falciparum Gametocytes

2014 ◽  
Vol 58 (12) ◽  
pp. 7398-7404 ◽  
Author(s):  
Tamirat Gebru ◽  
Benjamin Mordmüller ◽  
Jana Held
Keyword(s):  
Plasmodium Falciparum ◽  
Late Stage ◽  
Fluorescent Dyes ◽  
Clinical Symptoms ◽  
Laboratory Strain ◽  
Clinical Isolates ◽  
Synthetic Dyes ◽  
Content Type ◽  
Highly Active

ABSTRACTPlasmodium falciparumgametocytes are not associated with clinical symptoms, but they are responsible for transmitting the pathogen to mosquitoes. Therefore, gametocytocidal interventions are important for malaria control and resistance containment. Currently available drugs and vaccines are not well suited for that purpose. Several dyes have potent antimicrobial activity, but their use against gametocytes has not been investigated systematically. The gametocytocidal activity of nine synthetic dyes and four control compounds was tested against stage V gametocytes of the laboratory strain 3D7 and three clinical isolates ofP. falciparumwith a bioluminescence assay. Five of the fluorescent dyes had submicromolar 50% inhibitory concentration (IC50) values against mature gametocytes. Three mitochondrial dyes, MitoRed, dihexyloxacarbocyanine iodide (DiOC6), and rhodamine B, were highly active (IC50s < 200 nM). MitoRed showed the highest activity against gametocytes, with IC50s of 70 nM against 3D7 and 120 to 210 nM against clinical isolates. All compounds were more active against the laboratory strain 3D7 than against clinical isolates. In particular, the endoperoxides artesunate and dihydroartemisinin showed a 10-fold higher activity against 3D7 than against clinical isolates. In contrast to all clinically used antimalarials, several fluorescent dyes had surprisingly highin vitroactivity against late-stage gametocytes. Since they also act against asexual blood stages, they shall be considered starting points for the development of new antimalarial lead compounds.

scholarly journals Mutation in Plasmodium falciparum BTB/POZ domain of K13 protein confers artemisinin resistance

2021 ◽  
Author(s):  
Lucie Paloque ◽  
Romain Coppée ◽  
Barbara H. Stokes ◽  
Nina F. Gnädig ◽  
Karamoko Niaré ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Artemisinin Resistance ◽  
Parasite Clearance ◽  
West African ◽  
Whole Genome Sequence ◽  
Drug Pressure ◽  
Synonymous Mutations ◽  
Survival Assay ◽  
One Year

Partial artemisinin resistance, defined in patients as a delayed parasite clearance following artemisinin-based treatment, is conferred by non-synonymous mutations in the Kelch beta-propeller domain of the Plasmodium falciparum k13 ( pfk13 ) gene. Here, we carried out in vitro selection over a one-year period on a West African P. falciparum strain isolated from Kolle (Mali) under a dose-escalating artemisinin regimen. After 18 cycles of sequential drug pressure, the selected parasites exhibited enhanced survival to dihydroartemisinin in the ring-stage survival assay (RSA 0-3h = 9.2%). Sanger and whole-genome sequence analyses identified the PfK13 P413A mutation, localized in the BTB/POZ domain, upstream of the propeller domain. This mutation was sufficient to confer in vitro artemisinin resistance when introduced into the PfK13 coding sequence of the parasite strain Dd2 by CRISPR/Cas9 gene editing. These results together with structural studies of the protein demonstrate that the propeller domain is not the sole in vitro mediator of PfK13-mediated artemisinin resistance, and highlight the importance of monitoring for mutations throughout PfK13.

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