https://orcid.org/0000-0001-9694-9293
Figures
Abstract
Background
Resistance to antimalarial drugs has posed a significant challenge to global efforts to control and eliminate malaria. Partial artemisinin resistance has been observed in East Africa, a region that has been a historical hotspot for antimalarial drug resistance across the continent. Consequently, this review assesses the extent of non-synonymous mutations mediating artemisinin resistance, the varieties of these mutations, and their effects on treatment outcomes in East Africa.
Methods
Studies reporting artemisinin resistance (samples collected between 2014 and 2024), particularly the Pf-Kelch13 mutation among malaria patients in East Africa, were searched through the Medline, Cochrane Central Register of Controlled Trials (CENTRAL), LILACS, and EMBASE online databases. The protocol for the review was registered at PROSPERO (Reference number: CRD42024602752). Two independent reviewers extracted data. Potential publication bias was assessed using a funnel plot. Pooled proportion estimates were calculated using a random-effects model, and heterogeneity was assessed using I2 statistics.
Results
Twenty-four (24) studies were deemed eligible for data extraction. The heterogeneity among the studies included in the meta-analysis was high (I2 > 95% and p < 0.01). The overall estimated pooled proportions of non-synonymous Pf-Kelch13 mutations, using the random effects model, were 5.0% (95% CI 3.0%–7.0%), with the pooled proportion estimates being higher in Rwanda and Uganda (10.0%, 95% CI 4.0%–16.0%) and (10.0%, 95% CI 6.0%–14.0%), respectively. Subgroup analysis (per mutation type) revealed that R561H and A675V were the most prevalent non-synonymous mutations (9.0%, 95% CI 5.0%–15.0% and 7.0%, 95% CI 4.0%–10.0%, respectively). Patients harbouring parasites with Pf-Kelch13 non-synonymous mutations were significantly more likely to experience treatment failure than those harbouring wild P. falciparum parasites (Log OR: −2.06, 95% CI, −2.71–1.41).
Conclusion
The prevalence of Pf-Kelch13 non-synonymous mutations known to be associated with artemisinin resistance was significant. The most common mutations identified were R561H and A675V. Continued molecular surveillance and coordinated efforts are essential to contain the partial artemisinin resistance in the East African region and prevent its spread across the continent.
Citation: Kapesa A, Baraka V, Mwaiswelo R, Zinga M, Marwa KJ, Kweka EJ, et al. (2026) Plasmodium falciparum non-synonymous Kelch13 mutations mediating artemisinin resistance in East Africa: A systematic review and meta-analysis: 2014–2024. PLoS One 21(7): e0354429. https://doi.org/10.1371/journal.pone.0354429
Editor: Myat Htut Nyunt, Department of Medical Research (Lower Myanmar) Advanced Molecular Research Center, MYANMAR
Received: June 17, 2025; Accepted: July 7, 2026; Published: July 28, 2026
Copyright: © 2026 Kapesa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the manuscript and its Supporting Information files.
Funding: The author(s) received no specific funding for this work.
Competing interests: The authors have declared that no competing interests exist.
Abbreviations: ACT, artemisinin-based combination therapy; AL, artemether-lumefantrine; CQ, chloroquine; NIH, National Institutes of Health; pfcrt, Plasmodium falciparum chloroquine transporter; PfK13, Plasmodium falciparum Kelch 13; pfpm2/3, Plasmodium falciparum plasmepsin 2/3; SEA, South East Asia; sSA, sub-Saharan Africa; SP, Sulfadoxine-Pyrimethamine; WHO, World Health Organisation
Background
Despite the substantial progress made in sub-Saharan Africa (sSA), particularly in East Africa, the reduction of malaria transmission has recently stagnated [1]. In general, the current malaria control and elimination efforts confront challenges due to insufficient funding, emerging vector resistance, and the looming threat of artemisinin resistance [2]. The recent emergence and spread of partial artemisinin resistance in the East African region is concerning [3], as it could further compromise the progress made in reducing the disease burden in the region and Africa at large.
Previous evidence showed that resistance to the primary antimalarials, chloroquine (CQ) and later sulfadoxine-pyrimethamine (SP), spread from SEA to the East African region and throughout Africa; thus, EA is a historical hotspot for antimalarial resistance in Africa [4,5]. However, recent evidence on artemisinin records a change in trend whereby the Pf-Kelch13 mutations identified in the East African region have been confirmed to be indigenous (do not relate to those reported in SEA [3,6]. Partial artemisinin resistance was first recorded in Rwanda, followed by other neighbouring countries (Uganda and Tanzania). The emergence of partial artemisinin resistance in the region is crucial because of its potential to spread to different parts of Africa, considering the Horn of Africa, which borders EA, has also recorded partial artemisinin resistance [7].
The official use of ACTs as a first-line treatment in the East African region began between 2004 and 2006 due to confirmed widespread resistance to CQ and SP [8–11] whereby Artemether-lumefantrine (AL) and artesunate-amodiaquine were adopted as the first-line treatments for uncomplicated P. falciparum malaria. Other ACTs, such as dihydroartemisinin-piperaquine, are recommended as alternative or second-line treatments [12].
ACTs were adopted in EA due to their high safety and efficacy against multidrug-resistant P. falciparum strains according to the World Health Organisation (WHO) recommendation [13], their capability for rapid reduction of parasite biomass, and the elimination of remnant parasites, thus lowering the risk of recrudescence [8–11,14]. Unfortunately, partial artemisinin resistance has been identified after a decade of ACT use in the region, particularly Rwanda, Tanzania and Uganda [3,6,15–18].
Ariey et al. [19] demonstrated the occurrence and role of key mutations in the Pf-Kelch13 propeller gene (Pf3D7_1343700) in mediating delayed parasite clearance following ACT treatment in SEA [20]. Since then, more than 200 non-synonymous Pf-Kelch13 mutations in the propeller domain have been documented worldwide; however, only a few are associated with artemisinin resistance [21]. The WHO classifies these mutations as validated (confirmed to delay parasite clearance in vivo and in vitro) and candidate (observed to cause delayed clearance in vivo but not in vitro) [22].
As stated earlier, the Pf-Kelch13 mutations identified in East Africa have been confirmed to be indigenous (do not relate to those reported in SEA) [3,6], increase at a high rate, and have a high spreading capacity [15–17], making antimalarial drug resistance in the region an urgent threat to the global fight against malaria. Worse still, the Horn of Africa, which is a neighbouring region to East Africa, has also confirmed partial artemisinin resistance [23]. Hence, there is a potential for the spread of artemisinin resistance to countries neighbouring or interacting with the East African region. If not contained, partial artemisinin resistance may be followed by partner drug resistance, resulting in clinical treatment failure and total ACT resistance, which could jeopardise the global efforts towards malaria elimination.
As countries in the East African region strive to reduce the burden and eliminate malaria, understanding the patterns and varieties of artemisinin resistance molecular markers, particularly Pf-Kelch13, is imperative as part of the WHO strategy to combat antimalarial drug resistance in Africa [1]. In this review, we examine studies that document Pf-Kelch13 mutations across East African countries to determine the magnitude of non-synonymous mutations mediating artemisinin resistance, their types, and the impact on treatment outcomes (day-3 parasitemia).
Methods
The protocol for developing this systematic review and meta-analysis was registered on PROSPERO (Reference number: CRD42024602752). To select studies for inclusion in this review, we employed the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2020 checklist [24]: PRISMA statement (prisma-statement.org).
Information source and search strategy
A literature search for published studies assessing artemisinin resistance, particularly the Pf-Kelch13 mutation among malaria patients in East Africa, was conducted using the Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, Google Scholar, Medline, and LILACS online databases. References were cited and managed using EndNote software version X8.
The measure of effect was the proportion of samples from malaria patients with non-synonymous Pf-Kelch13 mutations mediating artemisinin resistance, the type of non-synonymous mutations, and the proportion of patients with parasitemia after day-3 of treatment.
The primary searching keywords used were “magnitude”; “prevalence”; “proportion”; ‘burden”; “artemisinin resistance”; “Kelch13”; “K13”; “malaria patients”; Boolean operator terms were searched separately and together accordingly as “OR” or “AND” or AND NOT or AND, NOT. The search included all articles published until December 2025.
Data extraction
The results of the literature search were screened by two independent reviewers. Studies were selected by the reviewers according to the inclusion criteria. A third reviewer was consulted when there were differences in opinion between the two reviewers on the inclusion and methodological quality of the studies. Abstracted information /data was entered into the extraction sheet. The basic information extracted included the general information (author’s names, country in which the study was carried out, samples collection year and publication year), study characteristics (study design, sample size, study participants), the total number of samples genotyped, the proportion of samples with non-synonymous Pf- Kelch13 mutation mediating artemisinin resistance, type of non-synonymous mutation and the proportion of patients with parasitaemia after day-3 of treatment.
Study inclusion criteria
All published studies on Pf-Kelch13 resistance markers were screened. We included studies that collected samples between 2014 and 2024. The year 2014 was used as a reference since the Pf-Kelch13 mutation was first reported in East Africa, specifically in Rwanda, that year [3,25]. These studies consisted of original research articles published in peer-reviewed journals and were conducted exclusively in East Africa.
Study exclusion criteria
To be specific to Plasmodium non-synonymous Pf-Kelch13 mutations established to mediate artemisinin resistance, our review did not include studies reporting non-synonymous mutations not mediating artemisinin resistance, only synonymous Pf-Kelch13 mutations or those that describe other markers of antimalarial drug resistance (Pfcrt, Pfmdr1, Pf coronin, Pf-ATPase6, plasmepsin genes, cysteine desulfurase, Pf-Kelch12, and other P. falciparum resistance genes), as meta-analyses for these genes have been published elsewhere or fall outside the scope of this review. Studies detailing mutations in other Plasmodium species were also excluded. Additionally, studies reporting Pf-Kelch13 mutations before 2014 were excluded.
Since the aim of this review was to establish the proportions of non-synonymous Pf-Kelch13 mutations mediating artemisinin resistance and their influence on treatment outcomes, particularly day-3 parasitaemia among malaria patients in East Africa, where partial artemisinin resistance has been identified, studies reporting treatment outcomes including day-3 parasitaemia among malaria patients without information on Pf-kelch13 mutation were excluded.
Literature reviews, non-primary research studies, and conference abstracts were considered to lack sufficient information or reliable sources and were thus excluded from the present review.
Methodological and data quality assessment
A methodological quality assessment was conducted employing the National Institutes of Health (NIH) study quality assessment tools for controlled intervention studies, observational cohorts, and cross-sectional studies [26]. The score range for the NIH tool was 0–14, with each criterion worth 1 point, for a total of 14 points. The scores were converted into percentages, which were categorised as 0–60% (Poor), 61–80% (Fair), and 81–100% (Good) [26]. All articles were of good quality. Two independent reviewers reached consensus on the extracted data and the methodological quality assessment. The scores of the included studies are presented in Table 1.
Data collection and analysis
The proportions of non-synonymous Pf-Kelch13 mutations mediating artemisinin resistance, along with the types and proportions of treated patients exhibiting day-3 parasitaemia among malaria patients, were recorded in an Excel sheet. The proportion of Pf-Kelch13 mutation is defined as the proportion (%) of patients with the mutation confirmed by molecular techniques. Meta-analyses were conducted using STATA 17 (Statistical Corporation, College Station, TX, US). A random effects model was employed to consolidate information from comparable studies. The potential for publication bias was evaluated by examining asymmetry on funnel plots. Heterogeneity across studies was assessed using Cochran’s Q and I2. Heterogeneity was deemed substantial when the p-value of Q was < 0.10, or I2 exceeded 50% [27]. A sensitivity analysis was performed to examine the influence of each study on the overall proportion estimation through leave-one-out meta-analysis [28]. Ineligible articles and duplicates were excluded from the analysis. The pooled proportions/estimates of samples from malaria patients with non-synonymous Pf-Kelch13 mutations and day-3 parasitaemia among those treated with ACTs were illustrated using forest plots. Subgroup analyses were conducted to present the aggregated proportions for the types of mutations, year of sample collection and within each country.
Results
Study attributes
The electronic database search identified 575 records reporting SNPs in the Pf-Kelch13 gene, as shown in the PRISMA flow chart (Fig 1). These articles were included for full-text review. A total of 24 studies were eligible for data extraction and were therefore included in the meta-analysis for the estimation of the pooled proportions of Pf-Kelch13 non-synonymous mutations. These studies were conducted in five East African countries (Uganda, Rwanda, the Democratic Republic of Congo, Tanzania, and Kenya). Two countries (Burundi and South Sudan had no eligible studies for data extraction. A total of 15,951 P. falciparum malaria patients provided isolates for this review. Studies included were published between 2016 and 2025, while samples for these studies were collected from 2010 to 2024. Most of the studies (60%) employed samples from dried blood spots (DBS). Details on the study characteristics are provided in Table 1.
Heterogeneity, publication bias, and sensitivity analysis
The heterogeneity among the studies included in this meta-analysis was substantial (I2 > 95% and p < 0.01). The funnel plot was symmetrical, indicating that the conducted meta-analysis was not influenced by publication bias, as illustrated in Fig 2. A sensitivity analysis demonstrated robustness of the aggregated estimates (S3 Fig).
The dashed lines represent the 95% confidence interval (CI). The X-axis represents the proportions, and the dots show the distribution of individual studies.
Discussion
This review evaluates various non-synonymous mutations of the Pf-Kelch13 gene in the East African region, where partial artemisinin resistance has been reported specifically in Uganda, Tanzania and Rwanda [3,15,18].
A substantial prevalence of Pf-Kelch13 non-synonymous mutations associated with artemisinin resistance reported in this review varies between countries. The highest prevalences (≥10%) of these mutations were observed in Uganda and Rwanda (Fig 3). The considerable prevalence of non-synonymous mutations confirmed to mediate artemisinin resistance poses a challenge to the efficacy of ACT and treatment outcomes in the region.
The Pf-Kelch13 non-synonymous mutations have been slightly increasing during the ten years of the study (Fig 4). This is supported by recent studies, which have suggested that the indigenous mutations in East Africa are spreading at a high capacity [15–17]. The prevalence of these mutations may differ (high) at present, considering we only report studies which involve samples collected up to 2024. This calls for enhanced efforts to mitigate the emergence and spread of resistance in the region.
In general, the pooled prevalence reported in the region is lower, contrary to findings from SEA, where the aggregated prevalence of 45.5% has been observed, but presents with less diversity compared to East Africa [20]. This discrepancy is not surprising, considering that the Pf-Kelch13 mutations reported in East Africa are indigenous and have been identified recently compared to SEA. The variations in the introduction time of artemisinin between SEA and East Africa (1970s vs 2000s) [8–11,47] could also explain the difference in the frequencies of non-synonymous mutations between the two regions, whereby the higher drug pressure is observed with SEA than in East Africa; thus, parasite selection is higher in SEA [48].
The most prevalent Pf-Kelch13 non-synonymous mutation mediating artemisinin resistance in East Africa was R561H (Fig 5). R561H was reported in Uganda, Kenya, Tanzania, Rwanda, and DR Congo (five countries). The mutation was high in the bordering regions between them, suggesting there is a spread of the Pf-Kelch13 mutant gene/SNPs as a result of population interaction/migration due to socio-economic reasons. This is echoed by the evidence from Uganda, which has shown that the selection of Pf-Kelch 13 is similar to that in SEA, hence a quick increase and high spreading potential to other parts [49].
Note: NA: Not applied (for those with zero non-synonymous mutations); Others: refers to non-synonymous mutations which had not yet been reported elsewhere.
The A675V was the next most prevalent Pf-Kelch13 non-synonymous mutation in the East African region, existing at higher frequencies in Uganda and Kenya. Other Pf-Kelch13 non-synonymous mediating artemisinin resistance mutations have been reported in East Africa, albeit at low frequencies. These include C469Y, which was prevalent in Uganda and DR Congo [50], while R622I was identified in Tanzania and Kenya. The P441L, which has only been reported in Africa, was identified in DR Congo [38]. A578S, which is most prevalent in Africa [51], though some studies report its lack of association with artemisinin resistance [51,52], was not common in East Africa. However, this mutation is reported to be associated with low parasitaemia in Uganda [53]. Hence, this study included this marker.
The emergence of the non-synonymous mutations and partial artemisininresistance in the East African region may be attributed to the improper or irrational use of antimalarials through self-medication and inappropriate prescriptions, lack of adherence to guidelines, and the circulation of counterfeit or poor-quality antimalarials in the community [38,54–56].
The use of monotherapy in the early 2000s across all countries [57], before the shift to ACTs, along with the continued use of these treatments for uncomplicated malaria (not outlined in the treatment policy or guidelines) in some countries, may have contributed to the selection of artemisinin resistance in the region [16,21]. Moreover, the use of parenteral artesunate and artemether (reserved for severe malaria) to treat uncomplicated cases may also facilitate the emergence of resistant parasites in the communities [58].
It is worth noting that the Denovo Pf-Kelch13 mutations have now spread to various countries in East Africa and could extend to other sub-Saharan nations. As stated earlier, the region is a historical hotspot for the spread of antimalarial resistance across the continent [4,5]; therefore, the emergence and propagation of partial artemisinin resistance [3,59] necessitate coordinated regional and global efforts to prevent the further spread of artemisinin resistance across the continent.
Recent findings suggest that the partial artemisinin resistance in most areas in East Africa has emerged in high transmission zones (where population immunity is high) [15], unlike the known trend for antimalarial resistance, where emergence is from low transmission zones, as seen in southern Africa [60,61], where low immunity in the population favours resistant parasites to survive. The reasons for this discrepancy are yet to be established.
In this study, we evaluated research reporting parasite clearance among malaria-infected individuals with Pf-Kelch13 non-synonymous mutations upon enrolment for treatment with ACTs. Patients harbouring Pf-Kelch13 non-synonymous mutations were more likely to have day-3 parasitaemia than those with wild parasites after treatment with ACTs (Fig 6). This further confirms the presence of partial artemisinin resistance in the region.
Despite the efficacy of ACTs in the treatment of uncomplicated malaria in East African countries over recent years remaining at more than 96% [62–65]. It is worth noting that some areas in Rwanda, DR Congo, Tanzania and Uganda have reported artemether-lumefantrine failure above the WHO threshold for treatment change (10%) [12].
The emergence of artemisinin partial resistance calls for coordinated efforts among East African countries to systematically implement surveillance of parasite population genetics to ascertain their genetic origin and spreading potential, enabling timely interventions to mitigate the spread, improve case management, optimise resource allocation, and promote malaria elimination. This implies a need to scale up therapeutic efficacy studies assessing molecular markers for artemisinin resistance across entire regions in countries, rather than relying on data from a few selected sentinel sites in each country. Partner drug resistance markers surveillance is also warranted to avoid the emergence of total ACT failure in the region, taking into account the trend observed in SEA [66,67].
The present review has limitations; the data for analysis represent five countries, while two countries (Burundi and South Sudan) are not represented due to a lack of adequate evidence. Molecular surveillance on Pf-Kelch13 is scanty in these countries. Moreover, some studies overlook key variables, including sample amplification rate, Pf-Kelch13 prevalence, day-3 parasitaemia, and other treatment outcome parameters among patients harbouring Pf-Kelch13 mutations (only a few studies have assessed the clinical impact of the recorded Kelch-13 mutations). Studies looking at ex vivo data were also not included. The high heterogeneity recorded in the meta-analysis could affect the pooled estimates. The high heterogeneity could be attributed to differences in study design (S1 Fig), variation in sample size (S2 Fig), and study participants. Despite these constraints, this review is the first to provide evidence on the magnitude of non-synonymous Pf-Kelch13 mutations mediating artemisinin resistance in the East African region.
Conclusion: Evidence provided by this review on the magnitude and types of Pf-Kelch13 non-synonymous mutations confirmed to be associated with delayed parasite clearance calls for coordinated efforts to contain the partial artemisinin resistance in the region and the continent at large.
Supporting information
S1 Fig. Pooled proportions for Pf-Kelch13 non-synonymous mutations mediating artemisinin resistance per type of study.
https://doi.org/10.1371/journal.pone.0354429.s001
(DOCX)
S2 Fig. Pooled proportions for Pf-Kelch13 non-synonymous mutations mediating artemisinin resistance per sample size.
https://doi.org/10.1371/journal.pone.0354429.s002
(DOCX)
S3 Fig. Sensitivity analysis for the prevalence of Pf-Kelch13 non-synonymous mutations mediating artemisinin resistance.
https://doi.org/10.1371/journal.pone.0354429.s003
(DOCX)
Acknowledgments
This work is dedicated to Professor Eliningaya J Kweka, who passed away while the manuscript was in process. His love, dedication and contribution to science will always be remembered.
References
- 1.
WHO. World malaria report 2024: addressing inequity in the global malaria response. Geneva: World Health Organization; 2024.
- 2. Dhiman S. Are malaria elimination efforts on right track? An analysis of gains achieved and challenges ahead. Infect Dis Poverty. 2019;8(1):14. pmid:30760324
- 3. Uwimana A, Legrand E, Stokes BH, Ndikumana J-LM, Warsame M, Umulisa N, et al. Emergence and clonal expansion of in vitro artemisinin-resistant Plasmodium falciparum kelch13 R561H mutant parasites in Rwanda. Nat Med. 2020;26(10):1602–8. pmid:32747827
- 4. Ariey F, Fandeur T, Durand R, Randrianarivelojosia M, Jambou R, Legrand E, et al. Invasion of Africa by a single pfcrt allele of South East Asian type. Malar J. 2006;5:34. pmid:16638153
- 5. Mita T, Venkatesan M, Ohashi J, Culleton R, Takahashi N, Tsukahara T, et al. Limited geographical origin and global spread of sulfadoxine-resistant dhps alleles in Plasmodium falciparum populations. J Infect Dis. 2011;204(12):1980–8. pmid:22021623
- 6. Awor P, Coppée R, Khim N, Rondepierre L, Roesch C, Khean C, et al. Indigenous emergence and spread of kelch13 C469Y artemisinin-resistant Plasmodium falciparum in Uganda. Antimicrob Agents Chemother. 2024;68(8):e01659-23. pmid:39028193
- 7. Fola AA, Feleke SM, Mohammed H, Brhane BG, Hennelly CM, Assefa A, et al. Plasmodium falciparum resistant to artemisinin and diagnostics have emerged in Ethiopia. Nat Microbiol. 2023;8(10):1911–9. pmid:37640962
- 8.
Ministry of Gender LaSD. National policy for malaria treatment. Kampala: Ministry of Gender, Labour and Social Development; 2005.
- 9.
Rwanda Ro. National guidelines for the treatment of malaria in Rwanda. Ministry of Health; 2006.
- 10.
Kenya M. National guidelines for the diagnosis, treatment and prevention of malaria for health workers in Kenya. Nairobi: Ministry of Health, Republic of Kenya; 2006.
- 11.
Welfare MoHaS. Malaria treatment guideline. Dar es salaam. Ministry of Health and Social Welfare; 2006.
- 12. van Wyk S, Seocharan I, Mlugu EM, Ayuen DS, Mategula D, Makhaza T. The MARC SE-Africa Dashboard: Joining forces to counteract emerging antimalarial resistance in south and east Africa. medRxiv. 2025;2025.01.07.25320158.
- 13. Falade C, Makanga M, Premji Z, Ortmann C-E, Stockmeyer M, de Palacios PI. Efficacy and safety of artemether-lumefantrine (Coartem) tablets (six-dose regimen) in African infants and children with acute, uncomplicated falciparum malaria. Trans R Soc Trop Med Hyg. 2005;99(6):459–67. pmid:15837358
- 14.
Organization WH. Guidelines for the treatment of malaria. World Health Organization; 2015.
- 15. Balikagala B, Fukuda N, Ikeda M, Katuro OT, Tachibana S-I, Yamauchi M, et al. Evidence of Artemisinin-Resistant Malaria in Africa. N Engl J Med. 2021;385(13):1163–71. pmid:34551228
- 16. Conrad MD, Asua V, Garg S, Giesbrecht D, Niaré K, Smith S, et al. Evolution of Partial Resistance to Artemisinins in Malaria Parasites in Uganda. N Engl J Med. 2023;389(8):722–32. pmid:37611122
- 17. Uwimana A, Umulisa N, Venkatesan M, Svigel SS, Zhou Z, Munyaneza T, et al. Association of Plasmodium falciparum kelch13 R561H genotypes with delayed parasite clearance in Rwanda: an open-label, single-arm, multicentre, therapeutic efficacy study. Lancet Infect Dis. 2021;21(8):1120–8. pmid:33864801
- 18. Ishengoma DS, Mandara CI, Bakari C, Fola AA, Madebe RA, Seth MD, et al. Evidence of artemisinin partial resistance in northwestern Tanzania: clinical and molecular markers of resistance. Lancet Infect Dis. 2024;24(11):1225–33. pmid:39159633
- 19. Ariey F, Witkowski B, Amaratunga C, Beghain J, Langlois A-C, Khim N, et al. A molecular marker of artemisinin-resistant Plasmodium falciparum malaria. Nature. 2014;505(7481):50–5. pmid:24352242
- 20. Ocan M, Akena D, Nsobya S, Kamya MR, Senono R, Kinengyere AA, et al. K13-propeller gene polymorphisms in Plasmodium falciparum parasite population in malaria affected countries: a systematic review of prevalence and risk factors. Malar J. 2019;18(1):60. pmid:30846002
- 21. Rosenthal PJ, Asua V, Bailey JA, Conrad MD, Ishengoma DS, Kamya MR. The emergence of artemisinin partial resistance in Africa: how do we respond? Lancet Infect Dis. 2024.
- 22.
Organization WH. Artemisinin resistance and artemisinin-based combination therapy efficacy: status report. World Health Organization; 2018.
- 23. Assefa A, Fola AA, Tasew G. Emergence of Plasmodium falciparum strains with artemisinin partial resistance in East Africa and the Horn of Africa: is there a need to panic? Malar J. 2024;23(1):34. pmid:38273360
- 24. Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. Int J Surg. 2021;88:105906. pmid:33789826
- 25.
Kirby R, Giesbrecht D, Karema C, Watson O, Lewis S, Munyaneza T, et al. Examining the early distribution of the artemisinin-resistant Plasmodium falciparum kelch13 R561H mutation in areas of higher transmission in Rwanda. In: Kirby R, Giesbrecht D, Karema C, Watson O, Lewis S, Munyaneza T, editors. Open Forum Infectious Diseases. Oxford University Press US; 2023.
- 26.
Health NIo. National Heart Lung, and Blood Institute. Study quality assessment tools. Bethesda (MD): National Institutes of Health; 2018.
- 27. Sedgwick P. Meta-analyses: heterogeneity and subgroup analysis. BMJ. 2013;346(jun24 2):f4040.
- 28.
Sadeghi M. Publication bias and funnel plot. Systematic Review and Meta-Analysis. Elsevier; 2025. p. 157–68.
- 29. Tacoli C, Gai PP, Bayingana C, Sifft K, Geus D, Ndoli J. Artemisinin resistance–associated K13 polymorphisms of Plasmodium falciparum in Southern Rwanda, 2010–2015. Am J Trop Med Hyg. 2016;95(5):1090.
- 30. Asua V, Vinden J, Conrad MD, Legac J, Kigozi SP, Kamya MR, et al. Changing Molecular Markers of Antimalarial Drug Sensitivity across Uganda. Antimicrob Agents Chemother. 2019;63(3):e01818-18. pmid:30559133
- 31. Ikeda M, Kaneko M, Tachibana S-I, Balikagala B, Sakurai-Yatsushiro M, Yatsushiro S, et al. Artemisinin-Resistant Plasmodium falciparum with High Survival Rates, Uganda, 2014-2016. Emerg Infect Dis. 2018;24(4):718–26. pmid:29553316
- 32. Straimer J, Gandhi P, Renner KC, Schmitt EK. High Prevalence of Plasmodium falciparum K13 Mutations in Rwanda Is Associated With Slow Parasite Clearance After Treatment With Artemether-Lumefantrine. J Infect Dis. 2022;225(8):1411–4. pmid:34216470
- 33. Ishengoma DS, Mandara CI, Francis F, Talundzic E, Lucchi NW, Ngasala B, et al. Efficacy and safety of artemether-lumefantrine for the treatment of uncomplicated malaria and prevalence of Pfk13 and Pfmdr1 polymorphisms after a decade of using artemisinin-based combination therapy in mainland Tanzania. Malar J. 2019;18(1):1–13. pmid:30898164
- 34. Angwe MK, Mwebaza N, Nsobya SL, Vudriko P, Dralabu S, Omali D, et al. Day 3 parasitemia and Plasmodium falciparum Kelch 13 mutations among uncomplicated malaria patients treated with artemether-lumefantrine in Adjumani district, Uganda. PLoS One. 2024;19(6):e0305064. pmid:38837973
- 35. Maniga JN, Samuel M, John O, Rael M, Muchiri JN, Bwogo P, et al. Novel Plasmodium falciparum k13 gene polymorphisms from Kisii County, Kenya during an era of artemisinin-based combination therapy deployment. Malar J. 2023;22(1):87. pmid:36894982
- 36. Bergmann C, van Loon W, Habarugira F, Tacoli C, Jäger JC, Savelsberg D, et al. Increase in Kelch 13 Polymorphisms in Plasmodium falciparum, Southern Rwanda. Emerg Infect Dis. 2021;27(1):294–6. pmid:33350925
- 37. Yobi DM, Kayiba NK, Mvumbi DM, Boreux R, Kabututu PZ, Situakibanza HNT, et al. Assessment of Plasmodium falciparum anti-malarial drug resistance markers in pfk13-propeller, pfcrt and pfmdr1 genes in isolates from treatment failure patients in Democratic Republic of Congo, 2018-2019. Malar J. 2021;20(1):144. pmid:33706773
- 38. Mesia Kahunu G, Wellmann Thomsen S, Wellmann Thomsen L, Muhindo Mavoko H, Mitashi Mulopo P, Filtenborg Hocke E, et al. Identification of the PfK13 mutations R561H and P441L in the Democratic Republic of Congo. Int J Infect Dis. 2024;139:41–9. pmid:38016502
- 39. Jeang B, Zhong D, Lee M-C, Atieli H, Yewhalaw D, Yan G. Molecular surveillance of Kelch 13 polymorphisms in Plasmodium falciparum isolates from Kenya and Ethiopia. Malar J. 2024;23(1):36. pmid:38287365
- 40.
Akala H, Opot B, Juma DW, Okoth RO, Mwalo M, Salim FA, et al. Detection of twenty-four Plasmodium falciparum kelch 13 mutations including C469Y, P553L, R561H, and A675V across Kenya.
- 41. Moriarty LF, Nkoli PM, Likwela JL, Mulopo PM, Sompwe EM, Rika JM, et al. Therapeutic Efficacy of Artemisinin-Based Combination Therapies in Democratic Republic of the Congo and Investigation of Molecular Markers of Antimalarial Resistance. Am J Trop Med Hyg. 2021;105(4):1067–75. pmid:34491220
- 42. Mhamilawa LE, Ngasala B, Morris U, Kitabi EN, Barnes R, Soe AP, et al. Parasite clearance, cure rate, post-treatment prophylaxis and safety of standard 3-day versus an extended 6-day treatment of artemether-lumefantrine and a single low-dose primaquine for uncomplicated Plasmodium falciparum malaria in Bagamoyo district, Tanzania: a randomized controlled trial. Malar J. 2020;19(1):216. pmid:32576258
- 43. Laury JE, Mugittu K, Kajeguka DC, Kamugisha E, Ishengoma DS, Mandara CI, et al. Efficacy and safety of artemether-lumefantrine against uncomplicated falciparum malaria infection in Tanzania, 2022: a single-arm clinical trial. J Infect Dis. 2025;231(1):251–9.
- 44. Msellem M, Morris U, Soe A, Abbas FB, Ali A-W, Barnes R, et al. Increased Sensitivity of Plasmodium falciparum to Artesunate/Amodiaquine Despite 14 Years as First-Line Malaria Treatment, Zanzibar. Emerg Infect Dis. 2020;26(8):1767–77. pmid:32687050
- 45. Bakari C, Mandara CI, Madebe RA, Seth MD, Ngasala B, Kamugisha E, et al. Trends of Plasmodium falciparum molecular markers associated with resistance to artemisinins and reduced susceptibility to lumefantrine in Mainland Tanzania from 2016 to 2021. Malar J. 2024;23(1):71. pmid:38461239
- 46. Asua V, Conrad MD, Aydemir O, Duvalsaint M, Legac J, Duarte E, et al. Changing Prevalence of Potential Mediators of Aminoquinoline, Antifolate, and Artemisinin Resistance Across Uganda. J Infect Dis. 2021;223(6):985–94. pmid:33146722
- 47.
Organization WH. Antimalarial drug combination therapy. Report of a WHO technical consultation. Geneva: World Health Organization; 2001. 33 p.
- 48. Amato R, Miotto O, Woodrow CJ, Almagro-Garcia J, Sinha I, Campino S, et al. Genomic epidemiology of artemisinin resistant malaria. Elife. 2016;48(8):959–64.
- 49. Meier-Scherling CPG, Watson OJ, Asua V, Ghinai I, Katairo T, Garg S, et al. Selection of Plasmodium falciparum kelch13 mutations in Uganda in comparison with southeast Asia: a modelling study. Lancet Microbe. 2025;6(5):101027. pmid:40112841
- 50. van Loon W, Bisimwa BC, Byela V, Kirby R, Bugeme PM, Balagizi A, et al. Detection of artemisinin resistance marker Kelch-13 469Y in Plasmodium falciparum, South Kivu, Democratic Republic of the Congo, 2022. Am J Trop Med Hyg. 2024;110(4):653–5.
- 51. Ménard D, Khim N, Beghain J, Adegnika AA, Shafiul-Alam M, Amodu O, et al. A Worldwide Map of Plasmodium falciparum K13-Propeller Polymorphisms. N Engl J Med. 2016;374(25):2453–64. pmid:27332904
- 52. Muwanguzi J, Henriques G, Sawa P, Bousema T, Sutherland CJ, Beshir KB. Lack of K13 mutations in Plasmodium falciparum persisting after artemisinin combination therapy treatment of Kenyan children. Malar J. 2016;15:36. pmid:26801909
- 53. Hawkes M, Conroy AL, Opoka RO, Namasopo S, Zhong K, Liles WC, et al. Slow Clearance of Plasmodium falciparum in Severe Pediatric Malaria, Uganda, 2011-2013. Emerg Infect Dis. 2015;21(7):1237–9. pmid:26079933
- 54. Akilimali A, Bisimwa C, Aborode AT, Biamba C, Sironge L, Balume A, et al. Self-medication and Anti-malarial Drug Resistance in the Democratic Republic of the Congo (DRC): A silent threat. Trop Med Health. 2022;50(1):73. pmid:36195896
- 55. Nayyar GM, Breman JG, Newton PN, Herrington J. Poor-quality antimalarial drugs in southeast Asia and sub-Saharan Africa. Lancet Infect Dis. 2012;12(6):488–96.
- 56.
Newton PN, Fernández FM, Green MD, Primo-Carpenter J, White NJ. Counterfeit and Substandard Anti-infectives in Developing Countries. Antimicrobial Resistance in Developing Countries. Springer New York; 2010. p. 413–43.
- 57. Bosman A, Mendis KN. A major transition in malaria treatment: the adoption and deployment of artemisinin-based combination therapies. Am J Trop Med Hyg. 2007;77(6).
- 58. Wang LT, Bwambale R, Keeler C, Reyes R, Muhindo R, Matte M, et al. Private sector drug shops frequently dispense parenteral anti-malarials in a rural region of Western Uganda. Malar J. 2018;17(1):305. pmid:30134987
- 59. Agaba BB, Travis J, Smith D, Rugera SP, Zalwango MG, Opigo J, et al. Emerging threat of artemisinin partial resistance markers (pfk13 mutations) in Plasmodium falciparum parasite populations in multiple geographical locations in high transmission regions of Uganda. Malar J. 2024;23(1):330. pmid:39501325
- 60. Casanova D, Baptista V, Costa M, Freitas B, Pereira M das NI, Calçada C, et al. Artemisinin resistance-associated gene mutations in Plasmodium falciparum: A case study of severe malaria from Mozambique. Travel Med Infect Dis. 2024;57:102684. pmid:38159875
- 61. Gupta H, Macete E, Bulo H, Salvador C, Warsame M, Carvalho E, et al. Drug-Resistant Polymorphisms and Copy Numbers in Plasmodium falciparum, Mozambique, 2015. Emerg Infect Dis. 2018;24(1):40–8. pmid:29260689
- 62. Kakolwa MA, Mahende MK, Ishengoma DS, Mandara CI, Ngasala B, Kamugisha E, et al. Efficacy and safety of artemisinin-based combination therapy, and molecular markers for artemisinin and piperaquine resistance in Mainland Tanzania. Malar J. 2018;17(1):369. pmid:30333022
- 63. Ishengoma DS, Mandara CI, Francis F, Talundzic E, Lucchi NW, Ngasala B, et al. Efficacy and safety of artemether-lumefantrine for the treatment of uncomplicated malaria and prevalence of Pfk13 and Pfmdr1 polymorphisms after a decade of using artemisinin-based combination therapy in mainland Tanzania. Malar J. 2019;18(1):88. pmid:30898164
- 64. Uwimana A, Penkunas MJ, Nisingizwe MP, Warsame M, Umulisa N, Uyizeye D, et al. Efficacy of artemether-lumefantrine versus dihydroartemisinin-piperaquine for the treatment of uncomplicated malaria among children in Rwanda: an open-label, randomized controlled trial. Trans R Soc Trop Med Hyg. 2019;113(6):312–9. pmid:30892640
- 65. Yeka A, Wallender E, Mulebeke R, Kibuuka A, Kigozi R, Bosco A, et al. Comparative Efficacy of Artemether-Lumefantrine and Dihydroartemisinin-Piperaquine for the Treatment of Uncomplicated Malaria in Ugandan Children. J Infect Dis. 2019;219(7):1112–20. pmid:30418593
- 66. Phyo AP, Ashley EA, Anderson TJ, Bozdech Z, Carrara VI, Sriprawat K, et al. Declining efficacy of artemisinin combination therapy against P. falciparum malaria on the Thai–Myanmar border (2003–2013): the role of parasite genetic factors. Clin Infect Dis. 2016;63(6):784–91.
- 67. Amaratunga C, Lim P, Suon S, Sreng S, Mao S, Sopha C, et al. Dihydroartemisinin-piperaquine resistance in Plasmodium falciparum malaria in Cambodia: a multisite prospective cohort study. Lancet Infect Dis. 2016;16(3):357–65. pmid:26774243