Monitoring of efficacy, tolerability and safety of artemether–lumefantrine and artesunate–amodiaquine for the treatment of uncomplicated Plasmodium falciparum malaria in Lambaréné, Gabon: an open-label clinical trial

Abstract Background Malaria remains a major public health problem, affecting mainly low-and middle-income countries. The management of this parasitic disease is challenged by ever increasing drug resistance. This study, investigated the therapeutic efficacy, tolerability and safety of artemether–lumefantrine (AL) and artesunate–amodiaquine (AS–AQ), used as first-line drugs to treat uncomplicated malaria in Lambaréné, Gabon. Methods A non-randomized clinical trial was conducted between October 2017 and March 2018 to assess safety, clinical and parasitological efficacy of fixed-doses of AL and AS–AQ administered to treat uncomplicated Plasmodium falciparum malaria in children aged from 6 months to 12 years. After 50 children were treated with AL, another 50 children received ASAQ. The 2009 World Health Organization protocol for monitoring of the efficacy of anti‑malarial drugs was followed. Molecular markers msp1 and msp2 were used to differentiate recrudescence and reinfection. For the investigation of artemisinin resistant markers, gene mutations in Pfk13 were screened. Results Per-protocol analysis on day 28 showed a PCR corrected cure rate of 97% (95% CI 86–100) and 95% (95% CI 84–99) for AL and AS–AQ, respectively. The most frequent adverse event in both groups was asthenia. No mutations in the kelch-13 gene associated with artemisinin resistance were identified. All participants had completed microscopic parasite clearance by day 3 post-treatment. Conclusion This study showed that AL and AS–AQ remain efficacious, well-tolerated, and are safe to treat uncomplicated malaria in children from Lambaréné. However, a regular monitoring of efficacy and a study of molecular markers of drug resistance to artemisinin in field isolates is essential. Trial registration ANZCTR, ACTRN12616001600437. Registered 18 November, http://www.anzctr.org.au/TrialSearch.aspx?searchTxt=ACTRN12616001600437p&isBasic=True

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Efficacy and safety of artesunate-amodiaquine and artemether-lumefantrine and prevalence of molecular markers associated with resistance, Guinea: an open-label two-arm randomized controlled trial

10.21203/rs.2.21808/v2 ◽

2020 ◽

Author(s):

Abdoul Habib Beavogui ◽

Alioune Camara ◽

Alexandre Delamou ◽

Abdoulaye Doumbouya ◽

Karifa Kourouma ◽

...

Keyword(s):

Randomized Controlled Trial ◽

Molecular Markers ◽

Treatment Failure ◽

Uncomplicated Malaria ◽

Controlled Trial ◽

Artemisinin Resistance ◽

Efficacy And Safety ◽

Open Label ◽

Randomized Controlled ◽

Kaplan Meier

Abstract Background: Antimalarial resistance is a threat to recent gains in malaria control. This study aimed to assess the efficacy and safety of artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) in the management of uncomplicated malaria and to measure the prevalence of molecular markers of resistance of Plasmodium falciparum in sentinel sites in Maferinyah and Labé Health Districts in Guinea in 2016. Methods: This was a two-arm randomized controlled trial of the efficacy of AL and ASAQ among children aged 6-59 months with uncomplicated P. falciparum malaria in two sites. Children were followed for 28 days to assess clinical and parasitological response. The primary outcome was the Kaplan-Meier estimate of Day 28 (D28) efficacy after correction by microsatellite-genotyping. Pre-treatment (D0) and day of failure samples were assayed for molecular markers of resistance in the pfk13 and pfmdr1 genes. Results: A total of 421 participants were included with 211 participants in the Maferinyah site and 210 in Labé. No early treatment failure was observed in any study arms. However, 22 (5.3%) participants developed a late treatment failure (8 in the ASAQ arm and 14 in the AL arm), which were further classified as 2 recrudescences and 20 reinfections. The Kaplan-Meier estimate of the corrected efficacy at D28 was 100% for both AL and ASAQ in Maferinyah site and 99% (95% Confidence Interval: 97.2-100%) for ASAQ and 99% (97.1-100%) for AL in Labé. The majority of successfully analyzed D0 (98%, 380/389) and all day of failure (100%, 22/22) samples were wild type for pfk13 . All 9 observed pfk13 mutations were polymorphisms not associated with artemisinin resistance. The NFD haplotype was the predominant haplotype in both D0 (197/362, 54%) and day of failure samples (11/18, 61%) successfully analyzed for pfmdr1 . Vomiting was the most common observed side effect (14%) across all arms. Conclusions: This study observed high efficacy and safety of both ASAQ and AL in Guinea, providing evidence for their continued use to treat uncomplicated malaria. Continued monitoring of ACT efficacy and safety and molecular makers of resistance in Guinea is important to detect emergence of parasite resistance and to inform evidence-based malaria treatment policies.

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Efficacy and Safety of Artemether-Lumefantrine and Dihydroartemisinin-Piperaquine for The Treatment of Uncomplicated Plasmodium Falciparum Malaria and Prevalence of Molecular Markers Associated With Artemisinin and Partner Drug Resistance in Uganda

10.21203/rs.3.rs-738188/v1 ◽

2021 ◽

Author(s):

Chris Ebong ◽

Asadu Sserwanga ◽

Jane Frances Namuganga ◽

James Kapisi ◽

Arthur Mpimbaza ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Molecular Markers ◽

Falciparum Malaria ◽

Uncomplicated Malaria ◽

Plasmodium Falciparum Malaria ◽

Pharmacokinetic Studies ◽

Efficacy And Safety ◽

Open Label ◽

Serious Adverse Events ◽

Line Therapy

Abstract Background In Uganda, artemether-lumefantrine (AL) is the first-line therapy and dihydroartemisinin-piperaquine (DP) the second-line therapy for the treatment of uncomplicated malaria. We evaluated the efficacy and safety of AL and DP in the management of uncomplicated Plasmodium falciparum malaria and measured the prevalence of molecular markers of resistance in three sentinel sites from 2018–2019 in Uganda. Methods This was a randomized, open-label, phase IV clinical trial. Children aged 6 months to 10 years with uncomplicated falciparum malaria were randomly assigned to treatment with AL or DP and followed for 28 and 42 days, respectively. Genotyping was used to distinguish recrudescence from new infection, and a Bayesian algorithm was used to assign each treatment failure a posterior probability of recrudescence. For monitoring resistance, Pfk13 and Pfmdr1 genes were Sanger sequenced and plasmepsin-2 copy number was assessed by qPCR. Results There were no early treatment failures. The uncorrected 28-day cumulative efficacy of AL ranged from 41.2–71.2% and the PCR-corrected cumulative 28-day efficacy of AL ranged from 87.2–94.4%. The uncorrected 28-day cumulative efficacy of DP ranged from 95.8–97.9% and the PCR-corrected cumulative 28-day efficacy of DP ranged from 98.9–100%. The uncorrected 42-day efficacy of DP ranged from 73.5–87.4% and the PCR-corrected 42-day efficacy of DP ranged from 92.1–97.5%. There were no reported serious adverse events associated with any of the regimens. No resistance-associated mutations in the Pfk13 gene were found in the successfully sequenced samples. In the AL arm, the NFD haplotype (N86Y, Y184F, D1246Y) was the predominant Pfmdr1 haplotype, present in 78 of 127 (61%) and 76 of 110 (69%) of the day 0 and day of failure samples, respectively. All the day 0 samples in the DP arm had one copy of the plasmepsin-2 gene. Conclusions DP remains highly effective and safe for the treatment of uncomplicated malaria in Uganda. Recurrent infections with AL were common. In Busia and Arua, the 95% confidence interval for PCR-corrected AL efficacy fell below 90%. Further efficacy monitoring for AL, including pharmacokinetic studies, is recommended. Trial registration: The trail was also registered with the ISRCTN registry with study Trial no PACTR201811640750761.

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Clinical and in vitro resistance of Plasmodium falciparum to artesunate-amodiaquine in Cambodia

Clinical Infectious Diseases ◽

10.1093/cid/ciaa628 ◽

2020 ◽

Cited By ~ 4

Author(s):

Melissa Mairet-Khedim ◽

Rithea Leang ◽

Camille Marmai ◽

Nimol Khim ◽

Saorin Kim ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Molecular Markers ◽

Falciparum Malaria ◽

Artemisinin Resistance ◽

Plasmodium Falciparum Malaria ◽

Open Label ◽

Parasite Survival ◽

Adults And Children

Abstract Background Artesunate-amodiaquine is a potential therapy for uncomplicated malaria in Cambodia. Methods Between September 2016 and January 2017, artesunate-amodiaquine efficacy and safety were evaluated in a prospective, open-label, single-arm observational study at health centers in Mondulkiri, Pursat and Siem Reap Provinces, Cambodia. Adults and children with microscopically-confirmed Plasmodium falciparum malaria received oral artesunate-amodiaquine once daily for three days plus single-dose primaquine, with follow-up on Days 7, 14, 21 and 28. The primary outcome was Day-28 PCR-adjusted adequate clinical and parasitological response (ACPR). An amodiaquine parasite survival assay (AQSA) was developed and applied to whole genome sequencing results to evaluate potential amodiaquine resistance molecular markers. Results In 63 patients, Day-28 PCR-adjusted ACPR was 81.0% (95% confidence interval [CI], 68.9–88.7). Day 3 parasite positivity rate was 44.4% (28/63; 95%CI, 31.9–57.5). All 63 isolates had the K13(C580Y) marker for artemisinin resistance; 79.4% (50/63) had Pfpm2 amplification. The AQSA resistance phenotype (≥45% parasite survival) was expressed in 36.5% (23/63) of isolates and was significantly associated with treatment failure (P = 0.0020). Pfmdr1 mutant haplotypes were N86/184F/D1246 and Pfcrt was CVIET or CVIDT at positions 72–76. Additional Pfcrt mutations were not associated with amodiaquine resistance, but the G353V mutant allele was associated with ACPR compared to Pfmdr1 haplotypes harboring F1068L or S784L/R945P mutations (P = 0.030 and P = 0.0004, respectively). Conclusions For uncomplicated falciparum malaria in Cambodia, artesunate-amodiaquine had inadequate efficacy owing to amodiaquine-resistant P. falciparum. Amodiaquine resistance was not associated with previously identified molecular markers.

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Historical literature review and molecular analysis of malaria drug resistance markers of Plasmodium falciparum field-isolates from Sudan.

10.21203/rs.2.24565/v1 ◽

2020 ◽

Author(s):

Nouh S. Mohamed ◽

Hanadi Abdelbagi ◽

Hussam A. Osman ◽

Abdallah E. Ahmed ◽

Alaa M. Yousif ◽

...

Keyword(s):

Drug Resistance ◽

Plasmodium Falciparum ◽

Molecular Markers ◽

Frequency Distribution ◽

Malaria Infection ◽

Pearson Correlation ◽

Treatment Protocol ◽

Public Health Problem ◽

Historical Literature ◽

Resistance Markers

Abstract Background Malaria infection is still known to be a worldwide public health problem, especially in tropical and sub-tropical African countries like Sudan. The fight against malaria is still taking place due to many factors. One of these factors is the presence of Plasmodium falciparum drug resistant parasites. This study is aiming at studying the P. falciparum drug resistance markers and analyzing the historical literature on these markers in Sudan. Methods A descriptive cross-sectional healthcare-centers based study conducted in Khartoum state between December 2017 and July 2018. Febrile patients diagnosed with P. falciparum malaria infection were recruited. Two ml blood samples were collected prior to start treatment. Genotyping of the specific point mutations in the P. falciparum genome was done using Sanger sequencing method for the Pfcrt, Pfmdr-1, Pfdhfr, and Pfdhps genes. Data deposited by the worldwide antimalarial resistance network was consulted and the molecular markers previously reported from Sudan were identified, collected, and analyzed to compare between past and present frequency of malaria drug resistance mutations. One-way ANOVA test was used to calculate the least significance of frequency distribution in the molecular markers collected from the previous reports from Sudan in comparison to this study. Pearson correlation was used to investigate the association between the different drug resistance markers. Results Drug molecular markers analysis was successfully done on the 20 P. falciparum isolates. the Pfcrt K76 showed the highest frequency; 16 (80%). Pfcrt 76T was 4 (20%). For the Pfmdr-1 marker, 9 (45%) isolates were carrying the N86 allele and 11 (55%) were 86Y allele. While the Y184F of the Pfmdr-1 showed higher frequency of 184F compared to Y184; 16 (80%) and 4 (20%), respectively. Concerning the double Pfmdr-1 haplotype, NY haplotype was 2 (10%), NF was 7 (35%), YF was 9 (45%), and YY was 2 (10%). In the Pfdhfr , 51I allele showed higher frequency compared to N51; 18 (90%) and 2 (10%), respectively. Whereas for C59R, C59 was 18 (90%), and 59R was 2 (10%). For S108N, 18 (90%) for 108N and 2 (10%) for S108. The triplet haplotype ICN of the Pfdhfr ; was the most frequent haplotype; 16 (80%). Concerning the Pfdhps , all the 20 (100%) isolates were carrying the mutant alleles; 437G and 540E. the Pfdhps haplotype present was the double GE haplotype only. No statistically significant correlation was found for the Pfcrt , Pfmdr-1 , Pfdhfr , and Pfdhps . Historical reports on P. falciparum multidrug resistant collected from 1989 to 2016 showed extreme fluctuation. High prevalence of Pfcrt 76T allele was observed in Khartoum throughout all years of previous studies, while in Gedaref Pfcrt 76T showing increased prevalence each year. All studied genes were showing increase prevalence of the mutant alleles and reduction of the wildtype alleles. In this study, the GE mutant haplotype was prevalent in all the studied samples. Frequency distribution of the Pfcrt K76T and Pfmdr-1 N86Y alleles, Pfmdr-1 ; N86Y and Y184F, Pfdhfr ; N51I and S108N, and Pfdhps ; A437G and K540E double haplotypes was significantly different across the whole years in Sudan. Conclusion This study describes the distribution of P. falciparum multidrug resistance markers throughout Sudan providing a solid baseline data of the status of these markers which could be very useful for the malaria control program not only for establishing surveillance system that monitor the change in and/or the emergence of malaria drug resistance but it will also offer a guidance for the evidence-base decision-making regarding the treatment protocol national and regional wise.

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No evidence of amplified Plasmodium falciparum plasmepsin II gene copy number in an area with artemisinin-resistant malaria along the China–Myanmar border

Malaria Journal ◽

10.1186/s12936-020-03410-6 ◽

2020 ◽

Vol 19 (1) ◽

Author(s):

Fang Huang ◽

Biraj Shrestha ◽

Hui Liu ◽

Lin-Hua Tang ◽

Shui-Sen Zhou ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Molecular Markers ◽

Therapeutic Efficacy ◽

Copy Number ◽

Copy Number Variants ◽

Gene Copy Number ◽

Artemisinin Resistance ◽

World Health ◽

Gene Copy ◽

Synonymous Mutations

Abstract Background The emergence and spread of artemisinin resistance in Plasmodium falciparum poses a threat to malaria eradication, including China’s plan to eliminate malaria by 2020. Piperaquine (PPQ) resistance has emerged in Cambodia, compromising an important partner drug that is widely used in China in the form of dihydroartemisinin (DHA)-PPQ. Several mutations in a P. falciparum gene encoding a kelch protein on chromosome 13 (k13) are associated with artemisinin resistance and have arisen spread in the Great Mekong subregion, including the China–Myanmar border. Multiple copies of the plasmepsin II/III (pm2/3) genes, located on chromosome 14, have been shown to be associated with PPQ resistance. Methods The therapeutic efficacy of DHA-PPQ for the treatment of uncomplicated P. falciparum was evaluated along the China–Myanmar border from 2010 to 2014. The dry blood spots samples collected in the efficacy study prior DHA-PPQ treatment and from the local hospital by passive detection were used to amplify k13 and pm2. Polymorphisms within k13 were genotyped by capillary sequencing and pm2 copy number was quantified by relative-quantitative real-time polymerase chain reaction. Treatment outcome was evaluated with the World Health Organization protocol. A linear regression model was used to estimate the association between the day 3 positive rate and k13 mutation and the relationship of the pm2 copy number variants and k13 mutations. Results DHA-PPQ was effective for uncomplicated P. falciparum infection in Yunnan Province with cure rates > 95%. Twelve non synonymous mutations in the k13 domain were observed among the 268 samples with the prevalence of 44.0% and the predominant mutation was F446I with a prevalence of 32.8%. Only one sample was observed with multi-copies of pm2, including parasites with and without k13 mutations. The therapeutic efficacy of DHA-PPQ was > 95% along the China–Myanmar border, consistent with the lack of amplification of pm2. Conclusion DHA-PPQ for uncomplicated P. falciparum infection still showed efficacy in an area with artemisinin-resistant malaria along the China–Myanmar border. There was no evidence to show PPQ resistance by clinical study and molecular markers survey. Continued monitoring of the parasite population using molecular markers will be important to track emergence and spread of resistance in this region.

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Therapeutic efficacy of artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in four malaria endemic states of India

Malaria Journal ◽

10.1186/s12936-021-03762-7 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Sri Krishna ◽

Sweta Mishra ◽

Prakash Tiwari ◽

Anup K. Vishwakarma ◽

Sushrikanta Khandai ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Treatment Failure ◽

Therapeutic Efficacy ◽

Public Health Problem ◽

World Health ◽

Fixed Dose ◽

Nucleotide Sequencing ◽

Major Public Health Problem ◽

Study Results ◽

Parasitological Response

Abstract Background Malaria is a major public health problem in India and accounts for about 88% of malaria burden in South-East Asia. India alone accounted for 2% of total malaria cases globally. Anti-malarial drug resistance is one of the major problems for malaria control and elimination programme. Artemether-lumefantrine (AL) is the first-line treatment of uncomplicated Plasmodium falciparum in north eastern states of India since 2013 after confirming the resistance against sulfadoxine-pyrimethamine. In the present study, therapeutic efficacy of artemether-lumefantrine and k13 polymorphism was assessed in uncomplicated P. falciparum malaria. Methods This study was conducted at four community health centres located in Koraput district of Odisha, Bastar district of Chhattisgarh, Balaghat district of Madhya Pradesh and Gondia district of Maharashtra state. Patients with uncomplicated P. falciparum malaria were administered with fixed dose combination (6 doses) of artemether-lumefantrine for 3 days and clinical and parasitological response was recorded up to 28 days as per World Health Organization protocol. Nucleotide sequencing of msp1 and msp2 gene was performed to differentiate between recrudescence and reinfection. Amplification and sequencing of k13 propeller gene region covering codon 450–680 was also carried out to identify the polymorphism. Results A total 376 malaria patients who fulfilled the enrolment criteria as well as consented for the study were enrolled. Total 356 patients were followed up successfully up to 28 days. Overall, the adequate clinical and parasitological response was 98.9% and 99.4% with and without PCR correction respectively. No case of early treatment failure was observed. However, four cases (1.1%) of late parasitological failure were found from the Bastar district of Chhattisgarh. Genotyping of msp1 and msp2 confirmed 2 cases each of recrudescence and reinfection, respectively. Mutation analysis of k13 propeller gene showed one non-synonymous mutation Q613H in one isolate from Bastar. Conclusions The study results showed that artemether-lumefantrine is highly effective in the treatment of uncomplicated P. falciparum malaria among all age groups. No functional mutation in k13 was found in the study area. The data from this study will be helpful in implementation of artemether-lumefantrine in case of treatment failure by artesunate plus sulfadoxine-pyrimethamine.

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Efficacy and safety of artesunate-amodiaquine and artemether-lumefantrine and prevalence of molecular markers associated with resistance, Guinea: an open-label two-arm randomised controlled trial

10.21203/rs.2.21808/v3 ◽

2020 ◽

Author(s):

Abdoul Habib Beavogui ◽

Alioune Camara ◽

Alexandre Delamou ◽

Abdoulaye Doumbouya ◽

Karifa Kourouma ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Molecular Markers ◽

Randomised Controlled Trial ◽

Treatment Failure ◽

Uncomplicated Malaria ◽

Controlled Trial ◽

Artemisinin Resistance ◽

Efficacy And Safety ◽

Kaplan Meier ◽

Randomised Controlled

Abstract Background Anti-malarial resistance is a threat to recent gains in malaria control. This study aimed to assess the efficacy and safety of artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) in the management of uncomplicated malaria and to measure the prevalence of molecular markers of resistance of Plasmodium falciparum in sentinel sites in Maferinyah and Labé Health Districts in Guinea in 2016.Methods This was a two-arm randomised controlled trial of the efficacy of AL and ASAQ among children aged 6-59 months with uncomplicated Plasmodium falciparum malaria in two sites. Children were followed for 28 days to assess clinical and parasitological response. The primary outcome was the Kaplan-Meier estimate of Day 28 (D28) efficacy after correction by microsatellite-genotyping. Pre-treatment (D0) and day of failure samples were assayed for molecular markers of resistance in the pfk13 and pfmdr1 genes.Results A total of 421 participants were included with 211 participants in the Maferinyah site and 210 in Labé. No early treatment failure was observed in any study arms. However, 22 (5.3%) participants developed a late treatment failure (8 in the ASAQ arm and 14 in the AL arm), which were further classified as 2 recrudescences and 20 reinfections. The Kaplan-Meier estimate of the corrected efficacy at D28 was 100% for both AL and ASAQ in Maferinyah site and 99% (95% Confidence Interval: 97.2-100%) for ASAQ and 99% (97.1-100%) for AL in Labé. The majority of successfully analysed D0 (98%, 380/389) and all day of failure (100%, 22/22) samples were wild type for pfk13. All 9 observed pfk13 mutations were polymorphisms not associated with artemisinin resistance. The NFD haplotype was the predominant haplotype in both D0 (197/362, 54%) and day of failure samples (11/18, 61%) successfully analysed for pfmdr1. Conclusion This study observed high efficacy and safety of both ASAQ and AL in Guinea, providing evidence for their continued use to treat uncomplicated malaria. Continued monitoring of ACT efficacy and safety and molecular makers of resistance in Guinea is important to detect emergence of parasite resistance and to inform evidence-based malaria treatment policies.

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A comprehensive analysis of drug resistance molecular markers and Plasmodium falciparum genetic diversity in two malaria endemic sites in Mali

Malaria Journal ◽

10.1186/s12936-019-2986-5 ◽

2019 ◽

Vol 18 (1) ◽

Cited By ~ 4

Author(s):

Seidina A. S. Diakité ◽

Karim Traoré ◽

Ibrahim Sanogo ◽

Taane G. Clark ◽

Susana Campino ◽

...

Keyword(s):

Genetic Diversity ◽

Drug Resistance ◽

Plasmodium Falciparum ◽

Molecular Markers ◽

Malaria Transmission ◽

Resistance Gene ◽

Artemisinin Resistance ◽

Chloroquine Resistance ◽

Malaria Control Programme ◽

Codon Substitution

Abstract Background Drug resistance is one of the greatest challenges of malaria control programme in Mali. Recent advances in next-generation sequencing (NGS) technologies provide new and effective ways of tracking drug-resistant malaria parasites in Africa. The diversity and the prevalence of Plasmodium falciparum drug-resistance molecular markers were assessed in Dangassa and Nioro-du-Sahel in Mali, two sites with distinct malaria transmission patterns. Dangassa has an intense seasonal malaria transmission, whereas Nioro-du-Sahel has an unstable and short seasonal malaria transmission. Methods Up to 270 dried blood spot samples (214 in Dangassa and 56 in Nioro-du-Sahel) were collected from P. falciparum positive patients in 2016. Samples were analysed on the Agena MassARRAY® iPLEX platform. Specific codons were targeted in Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps, Pfarps10, Pfferredoxin, Pfexonuclease and Pfmdr2 genes. The Sanger’s 101-SNPs-barcode method was used to assess the genetic diversity of P. falciparum and to determine the parasite species. Results The Pfcrt_76T chloroquine-resistance genotype was found at a rate of 64.4% in Dangassa and 45.2% in Nioro-du-Sahel (p = 0.025). The Pfdhfr_51I-59R-108N pyrimethamine-resistance genotype was 14.1% and 19.6%, respectively in Dangassa and Nioro-du-Sahel. Mutations in the Pfdhps_S436-A437-K540-A581-613A sulfadoxine-resistance gene was significantly more prevalent in Dangassa as compared to Nioro-du-Sahel (p = 0.035). Up to 17.8% of the isolates from Dangassa vs 7% from Nioro-du-Sahel harboured at least two codon substitutions in this haplotype. The amodiaquine-resistance Pfmdr1_N86Y mutation was identified in only three samples (two in Dangassa and one in Nioro-du-Sahel). The lumefantrine-reduced susceptibility Pfmdr1_Y184F mutation was found in 39.9% and 48.2% of samples in Dangassa and Nioro-du-Sahel, respectively. One piperaquine-resistance Exo_E415G mutation was found in Dangassa, while no artemisinin resistance genetic-background were identified. A high P. falciparum diversity was observed, but no clear genetic aggregation was found at either study sites. Higher multiplicity of infection was observed in Dangassa with both COIL (p = 0.04) and Real McCOIL (p = 0.02) methods relative to Nioro-du-Sahel. Conclusions This study reveals high prevalence of chloroquine and pyrimethamine-resistance markers as well as high codon substitution rate in the sulfadoxine-resistance gene. High genetic diversity of P. falciparum was observed. These observations suggest that the use of artemisinins is relevant in both Dangassa and Nioro-du-Sahel.

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Molecular surveillance of drug resistance: Plasmodium falciparum artemisinin resistance single nucleotide polymorphisms in Kelch protein propeller (K13) domain from Southern Pakistan

Malaria Journal ◽

10.1186/s12936-021-03715-0 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Najia Karim Ghanchi ◽

Bushra Qurashi ◽

Hadiqa Raees ◽

Mohammad Asim Beg

Keyword(s):

Drug Resistance ◽

Plasmodium Falciparum ◽

Molecular Markers ◽

Single Nucleotide Polymorphisms ◽

Low Frequency ◽

Artemisinin Resistance ◽

University Hospital ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Low Frequencies

Abstract Background K13 propeller (k13) polymorphism are useful molecular markers for tracking the emergence and spread of artemisinin resistance in Plasmodium falciparum. Polymorphisms are reported from Cambodia with rapid invasion of the population and almost near fixation in south East Asia. The study describes single nucleotide polymorphisms in Kelch protein propeller domain of P. falciparum associated with artemisinin resistance from Southern Pakistan. Methods Two hundred and forty-nine samples were collected from patients with microscopy confirmed P. falciparum malaria attending Aga Khan University Hospital during September 2015-April 2018. DNA was isolated using the whole blood protocol for the QIAmp DNA Blood Kit. The k13 propeller gene (k13) was amplified using nested PCR. Double-strand sequencing of PCR products was performed using Sanger sequencing methodology. Sequences were analysed with MEGA 6 and Bio edit software to identify specific SNP combinations. Results All isolates analysed for k13 propeller allele were observed as wild-type in samples collected post implementation of ACT in Pakistan. C580Y, A675V, Y493H and R539T variants associated with reduced susceptibility to artemisinin-based combination therapy (ACT) were not found. Low frequency of M476I and C469Y polymorphisms was found, which is significantly associated with artemisinin resistance. Conclusion Low frequencies of both nonsynonymous and synonymous polymorphisms were observed in P. falciparum isolates circulating in Southern Pakistan. The absence of known molecular markers of artemisinin resistance in this region is favourable for anti-malarial efficacy of ACT. Surveillance of anti-malarial drug resistance to detect its emergence and spread need to be strengthened in Pakistan.

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Efficacy of Artesunate-Amodiaquine and Artemether-Lumefantrine for Uncomplicated Plasmodium Falciparum Malaria in Madagascar, 2018

10.21203/rs.3.rs-660636/v1 ◽

2021 ◽

Author(s):

Catherine M. Dentinger ◽

Tovonahary Angelo Rakotomanga ◽

Antsa Rakotondrandriana ◽

Arinomenjanahary Rakotoarisoa ◽

Marie Ange Rason ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Molecular Markers ◽

Artemisinin Resistance ◽

Plasmodium Falciparum Malaria ◽

Outcome Data ◽

World Health ◽

Antimalarial Resistance ◽

Health Organization ◽

Uncomplicated Plasmodium Falciparum Malaria

Abstract Background: Since 2005, artemisinin-based combination therapy (ACT) has been recommended to treat uncomplicated Plasmodium falciparum malaria in Madagascar. Artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) are the first- and second-line treatments, respectively. A therapeutic efficacy study was conducted to assess ACT efficacy and molecular markers of antimalarial resistance.Methods: Children aged six months through 14 years with uncomplicated P. falciparum malaria and a parasitemia of 1,000—100,000 parasites/µl determined by microscopy were enrolled from May—September 2018 in a 28-day in vivo trial using the 2009 World Health Organization protocol for monitoring antimalarial efficacy. Participants from two communes, Ankazomborona (tropical, northwest) and Matanga (equatorial, southeast), were randomly assigned to ASAQ or AL arms. PCR correction was achieved by genotyping seven neutral microsatellites in paired pre- and post-treatment samples. Genotyping assays for molecular markers of resistance in the pfk13, pfcrt, and pfmdr1 genes were conducted.Results: Of 344 patients enrolled, 164/170 (96%) receiving ASAQ and 170/174 (98%) receiving AL completed the study. For ASAQ, the day-28 cumulative PCR-uncorrected efficacy was 100% (95% CI 100–100) and 95% (95% CI 91–100) for Ankazomborona and Matanga, respectively; for AL, it was 99% (95% CI 97–100) in Ankazomborona and 84% (95% CI 76–92) in Matanga. The day-28 cumulative PCR-corrected efficacy for ASAQ was 100% (95% CI 100–100) and 97% (95% CI 94–100%) for Ankazomborona and Matanga, respectively; for AL, it was 100% (95% CI 99–100) in Ankazomborona and 96% (95% CI 91–100) in Matanga. Of 83 successfully sequenced samples for pfk13, no mutations associated with artemisinin resistance were observed. A majority of successfully sequenced samples for pfmdr1 carried either the NFD or NYD haplotypes corresponding to codons 86, 184, and 1246. Of 82 successfully sequenced samples for pfcrt, all were wild type at codons 72–76. Conclusion: PCR-corrected analysis indicated that ASAQ and AL have therapeutic efficacies above the 90% WHO acceptable cut-off. We did not observe any genetic evidence of resistance to artemisinin, consistent with the clinical outcome data. However, the most common pfmdr1 haplotypes were NYD and NFD, previously associated with tolerance to lumefantrine.

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