Clinical and molecular surveillance of artemisinin resistant falciparum malaria in Myanmar (2009–2013)

Nyunt, Myat Htut; Soe, Myat Thu; Myint, Hla Win; Oo, Htet Wai; Aye, Moe Moe; Han, Soe Soe; Zaw, Ni Ni; Cho, Cho; Aung, Phyo Zaw; Kyaw, Khin Thiri; Aye, Tin Tin; San, Naychi Aung; Ortega, Leonard; Thimasarn, Krongthong; Bustos, Maria Dorina; Galit, Sherwin; Hoque, Mohammad Rafiul; Ringwald, Pascal; Han, Eun‐Taek; Kyaw, Myat Phone

doi:10.1186/s12936-017-1983-9

Cited by 20 publications

(21 citation statements)

References 28 publications

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“…The N458Y mutation was also identified in Thailand and Cambodia and showed a significant association with prolonged parasite clearance half-lives in clinical studies and elevated in vitro RSA values (42,43,49,50). We identified one field isolate from the China-Myanmar border area with the C469Y mutation showing high in vitro RSA values (43,51). It is noteworthy that this mutation was also reported recently from Uganda (11,(52)(53)(54).…”

supporting

confidence: 54%

Role of Plasmodium falciparum Kelch 13 Protein Mutations in P. falciparum Populations from Northeastern Myanmar in Mediating Artemisinin Resistance

Siddiqui

Boonhok

Cabrera

et al. 2020

mBio

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Mutations in the Plasmodium falciparum Kelch 13 (PfK13) protein are associated with artemisinin resistance. PfK13 is essential for asexual erythrocytic development, but its function is not known. We tagged the PfK13 protein with green fluorescent protein in P. falciparum to study its expression and localization in asexual and sexual stages. We used a new antibody against PfK13 to show that the PfK13 protein is expressed ubiquitously in both asexual erythrocytic stages and gametocytes and is localized in punctate structures, partially overlapping an endoplasmic reticulum marker. We introduced into the 3D7 strain four PfK13 mutations (F446I, N458Y, C469Y, and F495L) identified in parasites from the China-Myanmar border area and characterized the in vitro artemisinin response phenotypes of the mutants. We found that all the parasites with the introduced PfK13 mutations showed higher survival rates in the ring-stage survival assay (RSA) than the wild-type (WT) control, but only parasites with N458Y displayed a significantly higher RSA value (26.3%) than the WT control. After these PfK13 mutations were reverted back to the WT in field parasite isolates, all revertant parasites except those with the C469Y mutation showed significantly lower RSA values than their respective parental isolates. Although the 3D7 parasites with introduced F446I, the predominant PfK13 mutation in northern Myanmar, did not show significantly higher RSA values than the WT, they had prolonged ring-stage development and showed very little fitness cost in in vitro culture competition assays. In comparison, parasites with the N458Y mutations also had a prolonged ring stage and showed upregulated resistance pathways in response to artemisinin, but this mutation produced a significant fitness cost, potentially leading to their lower prevalence in the Greater Mekong subregion. IMPORTANCE Artemisinin resistance has emerged in Southeast Asia, endangering the substantial progress in malaria elimination worldwide. It is associated with mutations in the PfK13 protein, but how PfK13 mediates artemisinin resistance is not completely understood. Here we used a new antibody against PfK13 to show that the PfK13 protein is expressed in all stages of the asexual intraerythrocytic cycle as well as in gametocytes and is partially localized in the endoplasmic reticulum. By introducing four PfK13 mutations into the 3D7 strain and reverting these mutations in field parasite isolates, we determined the impacts of these mutations identified in the parasite populations from northern Myanmar on the ring stage using the in vitro ring survival assay. The introduction of the N458Y mutation into the 3D7 background significantly increased the survival rates of the ring-stage parasites but at the cost of the reduced fitness of the parasites. Introduction of the F446I mutation, the most prevalent PfK13 mutation in northern Myanmar, did not result in a significant increase in ring-stage survival after exposure to dihydroartemisinin (DHA), but these parasites showed extended ring-stage development. Further, parasites with the F446I mutation showed only a marginal loss of fitness, partially explaining its high frequency in northern Myanmar. Conversely, reverting all these mutations, except for the C469Y mutation, back to their respective wild types reduced the ring-stage survival of these isolates in response to in vitro DHA treatment.

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supporting

confidence: 54%

Role of Plasmodium falciparum Kelch 13 Protein Mutations in P. falciparum Populations from Northeastern Myanmar in Mediating Artemisinin Resistance

Siddiqui

Boonhok

Cabrera

et al. 2020

mBio

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“…Of these mutations only one SNP at codon position E556K of pfkelch13 gene persisted even after introduction of ART use in malaria treatment [ 27 , 31 ]. A different allele at the same codon position 556 (E556D) was reported in SEA [ 29 , 35 – 37 ].…”

Section: Resultsmentioning

confidence: 99%

“… Q613E 01 Dakar, Senegal [ 22 ] 11. P553L 07 Southeast Asia [ 12 , 14 , 17 , 26 , 29 , 53 , 54 , 57 ] 12. P667T 05 Myanmar [ 28 ] 13.…”

Section: Resultsmentioning

confidence: 99%

K13-propeller gene polymorphisms in Plasmodium falciparum parasite population in malaria affected countries: a systematic review of prevalence and risk factors

Ocan

Akena

Nsobya

et al. 2019

Malar J

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Background: Efficacy of artemisinin (ART) agents, a critical element of current malaria control efforts is threatened by emergence and spread of resistance. Mutations in pfkelch13 gene associated with ART-resistance evolved in Southeast Asia (SEA). k13 mutations whose role in ART-resistance remains unknown, have subsequently emerged independently across all malaria-affected regions. The aim of this systematic review was to determine the prevalence and identify risk factors of Plasmodium falciparum k13 mutations in malaria-endemic countries. Methods: An electronic search of studies from 2014 to date was done in MEDLINE via PubMED, SCOPUS, EMBASE and LILACS/VHL databases. Mesh terms and Boolean operators (AND, OR) were used. Two librarians independently conducted this search (RS and AK). The articles were screened for inclusion using a priori criteria set following PRISMA-P and STREGA guidelines. Three independent reviewers (NL, BB, and OM) extracted the data. Data analysis was performed in Open Meta Analyst software. Random effects analysis (DL) was used and heterogeneity established using I 2-statistic. Results: A total of 482 articles were retrieved from Pubmed = 302, Lilacs/Vhl = 50, Embase = 80, and Scopus = 37; Bibliography/other searches = 13, of which 374 did not meet the inclusion criteria. The aggregate prevalence of single nucleotide polymorphisms (SNPs) in pfkelch13 gene was 27.6% (3694/14,827) (95% CI 22.9%, 32.3%). Subgroup analysis showed that aggregate prevalence of non-synonymous SNPs in pfkelch13 gene was higher, 45.4% (95% CI 35.4%, 55.3%) in Southeast Asia as opposed to 7.6% (95% CI 5.6%, 9.5%) in the African region. A total of 165 independent k13 mutations were identified across malaria-affected regions globally. A total of 16 non-validated k13 mutations were associated with increased ART parasite clearance half-life (t 1/2 > 5 h). The majority, 45.5% (75/165), of the mutations were reported in single P. falciparum parasite infections. Of the 165 k13-mutations, over half were reported as new alleles. Twenty (20) non-propeller mutations in the pfkelch13 gene were identified. Conclusion: This review identified emergence of potential ART-resistance mediating k13 mutations in the African region. Diversity of mutations in pfkelch13 gene is highest in African region compared to SEA. Mutations outside the pfkelch13 propeller region associated with increased ART parasite clearance half-life occur in malaria-affected regions.

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“…artesunate is activated for the rest of intra-erythrocytic development, and thus, K13 variant parasites are fully susceptible to prolonged exposure to artemisinin, as clearly seen in vitro [2,4,5] and in vivo [3,22,23].…”

Section: Variants Of Pfk13 and The Parasite Cell Cycle In Vitromentioning

confidence: 99%

“…In fact, the best interpretation of this study is that it is falling partner drug efficacy that has led to the low ACPR in some sites [17]. Furthermore, in Myanmar, despite a prevalence rate of 25-65% of the C580Y variant pfk13 in 2012 and 2013 in Kawthaung and Myawaddy, 3 days of standard ACT delivered ≥96% ACPR [22].…”

Section: The Perceived Threat To Artemisinin-based Malaria Therapeuticsmentioning

confidence: 99%

Genetic markers of artemisinin resistance in Plasmodium spp. parasites

Sutherland

2017

Emerging Topics in Life Sciences

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The vast majority of malaria patients worldwide are currently treated with combination therapy comprising one of the artemisinin family of drugs, characterised by rapid action and short plasma half-life, co-formulated with a longer-lasting drug from the amino arylalcohol or quinoline families. There is now a widely perceived threat to treatment efficacy, as reduced susceptibility to rapid artemisinin clearance in vivo has become prevalent among populations of Plasmodium falciparum in the Greater Mekong subregion since 2008. In vitro and in vivo drug selection studies, heterologous cell expression experiments and genetic epidemiology have identified many candidate markers of reduced ring-stage susceptibility to artemisinin. Certain variants of the P. falciparum pfk13 gene, which encodes a kelch domain protein implicated in the unfolded protein response, are strongly associated with slow parasite clearance by artemisinin in the Mekong subregion. However, anomalies in the epidemiological association of pfk13 variants with true treatment failure in vivo and the curious cell-cycle stage specificity of this phenotype in vitro warrant exploration in some depth. Taken together, available data suggest that the emergence of P. falciparum expressing K13 variants has not yet precipitated a public health emergency. Alternative candidate markers of artemisinin susceptibility are also described, as K13-independent treatment failure has been observed in African P. falciparum and in the rodent malaria parasite Plasmodium chabaudi.

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Clinical and molecular surveillance of artemisinin resistant falciparum malaria in Myanmar (2009–2013)

Cited by 20 publications

References 28 publications

Role of Plasmodium falciparum Kelch 13 Protein Mutations in P. falciparum Populations from Northeastern Myanmar in Mediating Artemisinin Resistance

Role of Plasmodium falciparum Kelch 13 Protein Mutations in P. falciparum Populations from Northeastern Myanmar in Mediating Artemisinin Resistance

K13-propeller gene polymorphisms in Plasmodium falciparum parasite population in malaria affected countries: a systematic review of prevalence and risk factors

Genetic markers of artemisinin resistance in Plasmodium spp. parasites

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