Molecular markers for chloroquine-resistant Plasmodium falciparum malaria in Thailand and Laos

2001 ◽  
Vol 95 (8) ◽  
pp. 781-788 ◽  
Author(s):  
A. C. Labbé ◽  
P. Bualombai ◽  
D. R. Pillai ◽  
K. J. Y. Zhong ◽  
V. Vanisaveth ◽  
...  
2007 ◽  
Vol 52 (4) ◽  
Author(s):  
Przemysław Myjak ◽  
Wacław Nahorski ◽  
Beata Szostakowska ◽  
Hanna Żarnowska-Prymek ◽  
Halina Pietkiewicz

2021 ◽  
Author(s):  
Chris Ebong ◽  
Asadu Sserwanga ◽  
Jane Frances Namuganga ◽  
James Kapisi ◽  
Arthur Mpimbaza ◽  
...  

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.


Author(s):  
Melissa Mairet-Khedim ◽  
Rithea Leang ◽  
Camille Marmai ◽  
Nimol Khim ◽  
Saorin Kim ◽  
...  

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.


2013 ◽  
Vol 12 (1) ◽  
pp. 414 ◽  
Author(s):  
Tiphaine Gaillard ◽  
Sébastien Briolant ◽  
Sandrine Houzé ◽  
Meïli Baragatti ◽  
Nathalie Wurtz ◽  
...  

2021 ◽  
Vol 17 ◽  
pp. 117693432199964
Author(s):  
Kwesi Z Tandoh ◽  
Lucas Amenga-Etego ◽  
Neils B Quashie ◽  
Gordon Awandare ◽  
Michael Wilson ◽  
...  

Sub-Saharan Africa is courting the risk of artemisinin resistance (ARTr) emerging in Plasmodium falciparum malaria parasites. Current molecular surveillance efforts for ARTr have been built on the utility of P. falciparum kelch13 ( pfk13) validated molecular markers. However, whether these molecular markers will serve the purpose of early detection of artemisinin-resistant parasites in Ghana is hinged on a pfk13 dependent evolution. Here, we tested the hypothesis that the background pfk13 genome may be present before the pfk13 ARTr-conferring variant(s) is selected and that signatures of balancing selection on these genomic loci may serve as an early warning signal of ARTr. We analyzed 12 198 single nucleotide polymorphisms (SNPs) in Ghanaian clinical isolates in the Pf3K MalariaGEN dataset that passed a stringent filtering regimen. We identified signatures of balancing selection in 2 genes (phosphatidylinositol 4-kinase and chloroquine resistance transporter) previously reported as background loci for ARTr. These genes showed statistically significant and high positive values for Tajima’s D, Fu and Li’s F, and Fu and Li’s D. This indicates that the biodiversity required to establish a pfk13 background genome may have been primed in clinical isolates of P. falciparum from Ghana as of 2010. Despite the absence of ARTr in Ghana to date, our finding supports the current use of pfk13 for molecular surveillance of ARTr in Ghana and highlights the potential utility of monitoring malaria parasite populations for balancing selection in ARTr precursor background genes as early warning molecular signatures for the emergence of ARTr.


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