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Chloroquine (CQ) is officially used for the primary treatment of Plasmodium falciparum malaria in Honduras. In this study, the therapeutic efficacy of CQ for the treatment of uncomplicated P. falciparum malaria in the municipality of Puerto Lempira, Gracias a Dios, Honduras was evaluated using the Pan American Health Organization-World Health Organ...
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Cambodia's first-line artemisinin combination therapy, dihydroartemisinin-piperaquine (DHA-PPQ), is no longer sufficiently curative against multidrug-resistant Plasmodium falciparum malaria at some Thai-Cambodian border regions. We report recent (2008-2013) drug resistance trends in 753 isolates from northern, western, and southern Cambodia, by sur...
Western Cambodia is recognized as the epicentre of Plasmodium falciparum multidrug resistance. Recent reports of dihydroartemisinin-piperaquine efficacy, the latest generation of ACTs recommended by the WHO, prompted further investigations. Clinical efficacy of dihydroartemisinin-piperaquine in uncomplicated falciparum malaria was assessed in weste...
Cambodia stopped using co-blistered, non-fixed, artesunate-mefloquine (ASMQ) in 2008 when treatment failure rates approximated 20%. Fixed dose combination (FDC) ASMQ is efficacious against acute uncomplicated, drug resistant Plasmodium falciparum malaria in Southeast Asia but has not been tested in Cambodia.
A 42-day WHO therapeutic efficacy study...
A major constraint in the study of Plasmodium falciparum malaria, including vaccine development, lies on the parasite's strict human host specificity and therefore the shortage of animal experimental models able to harbor human plasmodia. The best experimental models are neo-tropical primates of the genus Saimiri and Aotus, but they require splenec...
Citations
... To conclude, and in line with the low genetic diversity of P. falciparum, the Pfcrt gene sequencing results confirmed that the strains of the parasite circulating in Honduras continue to be susceptible to treatment with chloroquine, as previous publications have evidenced (Jovel et al., 2011;Mejia Torres et al., 2013;Fontecha et al., 2014Fontecha et al., , 2021. This result is encouraging as it facilitates the strategies used to eliminate malaria in Honduras. ...
Malaria continues to be a major threat to public health in tropical regions, primarily affecting sub-Saharan Africa but also Asia, the Middle East, and Latin America. Malaria cases in Honduras have seen a significant decline and the country aims to eliminate the disease by 2030. This study examines the genetic diversity of Plasmodium falciparum and Plasmodium vivax in Honduras using four molecular markers (Pfama1, Pfglurp, Pvmsp3α, and Pvmsp3β), and the chloroquine resistance marker pfcrt in the context of the elimination phase. Our findings indicate that P. falciparum populations in Honduras are more homogeneous compared to P. vivax. The multilocus sequence typing (MLST) approach, using four loci from Pvmsp3α and Pvmsp3β, proved more effective in assessing the genetic diversity of P. vivax than individual marker analyses. No geographical clustering was observed for P. vivax haplotypes, either within Honduras or globally. In Honduras, P. falciparum appears to be under more effective control, while P. vivax presents a greater challenge due to its higher genetic diversity. This requires enhanced surveillance, targeted control strategies, and measures to prevent the reintroduction of variants. The isolates of P. falciparum also displayed a wild-type Pfcrt phenotype, suggesting susceptibility to chloroquine.
... The mechanism by which HCQ and chloroquine exert anti-malarial effects is still not fully understood. The mechanism is presumed to involve the detoxification of plasmodium [23]. Various mechanisms for the inhibition of ferriprotoporphyrin IX using chloroquine have been reported to date. ...
... The primers and PCR conditions used for Pfcrt, Pfmdr1 and Pfk13 amplification were adapted from previously published work [35][36][37] (see Additional file 2: Table S2). For Pfmdr1 gene, the first fragment, covering codons 86 and184, was amplified using the same primers as shown in the publication [36]. ...
Background
Over the last two decades, the scale-up of vector control and changes in the first-line anti-malarial, from chloroquine (CQ) to sulfadoxine-pyrimethamine (SP) and then to artemether-lumefantrine (AL), have resulted in significant decreases in malaria burden in western Kenya. This study evaluated the long-term effects of control interventions on molecular markers of Plasmodium falciparum drug resistance using parasites obtained from humans and mosquitoes at discrete time points.
Methods
Dried blood spot samples collected in 2012 and 2017 community surveys in Asembo, Kenya were genotyped by Sanger sequencing for markers associated with resistance to SP ( Pfdhfr, Pfdhps) , CQ, AQ, lumefantrine ( Pfcrt, Pfmdr1) and artemisinin ( Pfk13). Temporal trends in the prevalence of these markers, including data from 2012 to 2017 as well as published data from 1996, 2001, 2007 from same area, were analysed. The same markers from mosquito oocysts collected in 2012 were compared with results from human blood samples.
Results
The prevalence of SP dhfr/dhps quintuple mutant haplotype C 50 I 51 R 59 N 108 I 164 /S 436 G 437 E 540 A 581 A 613 increased from 19.7% in 1996 to 86.0% in 2012, while an increase in the sextuple mutant haplotype C 50 I 51 R 59 N 108 I 164 / H 436 G 437 E 540 A 581 A 613 containing Pfdhps -436H was found from 10.5% in 2012 to 34.6% in 2017. Resistant Pfcrt -76 T declined from 94.6% in 2007 to 18.3% in 2012 and 0.9% in 2017. Mutant Pfmdr1 -86Y decreased across years from 74.8% in 1996 to zero in 2017, mutant Pfmdr1 -184F and wild Pfmdr1 -D1246 increased from 17.9% to 58.9% in 2007 to 55.9% and 90.1% in 2017, respectively. Pfmdr1 haplotype N 86 F 184 S 1034 N 1042 D 1246 increased from 11.0% in 2007 to 49.6% in 2017. No resistant mutations in Pfk13 were found. Prevalence of Pfdhps -436H was lower while prevalence of Pfcrt- 76 T was higher in mosquitoes than in human blood samples.
Conclusion
This study showed an increased prevalence of dhfr/dhps resistant markers over 20 years with the emergence of Pfdhps -436H mutant a decade ago in Asembo. The reversal of Pfcrt from CQ-resistant to CQ-sensitive genotype occurred following 19 years of CQ withdrawal. No Pfk13 markers associated with artemisinin resistance were detected, but the increased haplotype of Pfmdr1 N 86 F 184 S 1034 N 1042 D 1246 was observed. The differences in prevalence of Pfdhps -436H and Pfcrt- 76 T SNPs between two hosts and the role of mosquitoes in the transmission of drug resistant parasites require further investigation.
... Mutations in codons 72-76 of pfcrt are responsible for the resistant phenotype (CQR), generating five haplotypes associated with resistance: CVIET, SVMNT, SVIET, CVMNT and CVTNT [9,10]. Despite the selective pressure exerted by the drug for decades, P. falciparum strains circulating in Central America have not developed resistance-associated mutations in the pfcrt gene [11][12][13][14] and they continue to hold the CVMNK susceptible wild genotype. ...
... A fragment of the pfcrt gene encompassing codons 72-76 was amplified by nested PCR. Briefly, for the first round of PCR, 10 µL of genomic DNA was used in a volume of 50 µL containing 25 µL of Taq Master Mix and 2 µL of each primer [13,20] (Table 1) at a concentration of 10 µM and a remaining volume of nuclease free water. The reaction was mixed and subjected to the following program: initial denaturation at 94 °C for 10 min, followed by 35 In addition, three regions of the pfmdr1 gene were amplified to identify five polymorphisms at codons 86 and 184 (first segment), 1034 and 1046 (second segment), and 1246 (third segment) (Additional file 1: Fig. S1). ...
... The first study carried out with 30 samples collected in five departments of Honduras between 2004 and 2009 showed 100% of isolates with wild genotype, except for two individuals whose infection had been contracted in Asia and Africa [14]. A study of the therapeutic efficacy of CQ included 68 samples collected in Puerto Lempira, in the Honduran Mosquitia, revealing only wild genotypes in the pfcrt gene [13]. Likewise, an efficacy trial conducted in the North Atlantic Region (RAAN) of Nicaragua during 2005 and with samples from a surveillance study from 2011 showed that 96 of 98 samples had the CVMNK phenotype, while two samples had the CVIET CQR phenotype. ...
Background
Central America and the island of Hispaniola have set out to eliminate malaria by 2030. However, since 2014 a notable upturn in the number of cases has been reported in the Mosquitia region shared by Nicaragua and Honduras. In addition, the proportion of Plasmodium falciparum malaria cases has increased significantly relative to vivax malaria. Chloroquine continues to be the first-line drug to treat uncomplicated malaria in the region. The objective of this study was to evaluate the emergence of chloroquine resistant strains of P. falciparum using a genetic approach. Plasmodium vivax populations are not analysed in this study.
Methods
205 blood samples from patients infected with P. falciparum between 2018 and 2021 were analysed. The pfcrt gene fragment encompassing codons 72–76 was analysed. Likewise, three fragments of the pfmdr1 gene were analysed in 51 samples by nested PCR and sequencing.
Results
All samples revealed the CVMNK wild phenotype for the pfcrt gene and the N86, Y184F, S1034C, N1042D, D1246 phenotype for the pfmdr1 gene.
Conclusions
The increase in falciparum malaria cases in Nicaragua and Honduras cannot be attributed to the emergence of chloroquine-resistant mutants. Other possibilities should be investigated further. This is the first study to report the genotype of pfmdr1 for five loci of interest in Central America.
... Mutations in codons 72 to 76 of pfcrt are responsible for the resistant phenotype (CQR), generating ve haplotypes associated with resistance: CVIET, SVMNT, SVIET, CVMNT and CVTNT [7,8]. Despite the selective pressure exerted by the drug for decades, P. falciparum strains circulating in Central America have not developed resistance-associated mutations in the pfcrt gene [9][10][11][12] and they continue to hold the CVMNK susceptible wild genotype. ...
... The rst study carried out with 30 samples collected in ve departments of Honduras between 2004 and 2009 showed 100% of isolates with wild genotype, except for two individuals whose infection had been contracted in Asia and Africa [12]. A study of the therapeutic e cacy of CQ included 68 samples collected in Puerto Lempira, in the Honduran Mosquitia, revealing only wild genotypes in the pfcrt gene [11]. Likewise, an e cacy trial conducted in the North Atlantic Region (RAAN) of Nicaragua during 2005 and with samples from a surveillance study from 2011 showed that 96 of 98 samples had the CVMNK phenotype, while two samples had the CVIET CQR phenotype. ...
Background: Central America and the island of Hispaniola have set out to eliminate malaria by 2030. However, since 2014 a notable upturn in the number of cases has been reported in La Mosquitia region shared by Nicaragua and Honduras. In addition, the proportion of Plasmodium falciparum malaria cases has increased significantly relative to vivax malaria. Chloroquine continues to be the first line drug to treat uncomplicated malaria in the region. The objective of this study was to evaluate the emergence of chloroquine resistant strains using a genetic approach.
Methods: 205 blood samples from patients infected with P. falciparum between 2018 and 2021 were analyzed. The pfcrt gene fragment encompassing codons 72-76 was analyzed. Likewise, three fragments of the pfmdr1 gene were analyzed in 51 samples by nested PCR and sequencing.
Results: All samples revealed the CVMNK wild phenotype for the pfcrt gene and the N86, Y184F, S1034C, N1042D, D1246 phenotype for the pfmdr1 gene.
Conclusions: The increase in falciparum malaria cases in Nicaragua and Honduras cannot be attributed to the emergence of chloroquine-resistant mutants. Other possibilities should be investigated further. This is the first study to report the genotype of pfmdr1 for five loci of interest in Central America.
... CQ/HCQ have been shown to have antiviral effects against several viruses (Tsai et al., 1990;Pardridge et al., 1998;Savarino et al., 2001). CQ and HCQ are affordable drugs, with known efficacy and safety profiles for the authorized indications (Mejia Torres et al., 2013;Schrezenmeier and Dörner, 2020), and are on the list of essential medications published by the World Health organization (WHO) (World Health Organization, 2019). The 2020 American College of Rheumatology Guideline for the Management of Reproductive Health in Rheumatic and Musculoskeletal Diseases recommends the continued use of CQ/ HCQ during pregnancy for women with SLE and RA (Sammaritano et al., 2020). ...
... for a daily dose of <400 mg. Given data supporting the benefits of CQ/HCQ during pregnancy for malarial prophylaxis (Mejia Torres et al., 2013), and lupus pregnancy outcome (Leroux et al., 2015), CQ/ HCQ should be given and available primarily to those with malaria (prevention and treatment), and rheumatic diseases. ...
Introduction: Chloroquine (CQ) and hydroxychloroquine (HCQ) are currently used for the prevention/treatment of malaria, and treatment of systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA). Although present data do not show their efficacy to treat COVID-19, they have been used as potential treatments for COVID-19. Given that pregnant women are excluded from randomized controlled trials, and present evidence are inconsistent and inconclusive, we aimed to investigate the safety of CQ or HCQ use in a large pregnancy cohort using real-world evidence.
Methods: Using Quebec Pregnancy Cohort, we identified women who delivered a singleton liveborn, 1998–2015, (n = 233,748). The exposure time window for analyses on prematurity and low birth weight (LBW) was the second/third trimesters; was any time during pregnancy; only first trimester exposure was considered for analyses on major congenital malformations (MCM). The risk of prematurity, LBW, and MCM (overall and organ-specific) were quantified using generalized estimation equations.
Results: We identified 288 pregnancies (0.12%) exposed to CQ (183, 63.5%) or HCQ (105, 36.5%) that resulted in liveborn singletons; CQ/HCQ was used for RA (17.4%), SLE (16.3%) or malaria (0.7%). CQ/HCQ was used for 71.8 days on average [standard-deviation (SD) 70.5], at a dose of 204.3 mg/d (SD, 155.6). We did not observe any increased risk related to CQ/HCQ exposure for prematurity (adjusted odds ratio [aOR] 1.39, 95%CI 0.84–2.30), LBW (aOR 1.11, 95%CI 0.59–2.06), or MCM (aOR 1.01, 95%CI 0.67–1.52).
Conclusion: in this large CQ/HCQ exposed pregnancy cohort, we saw no clear increased risk of prematurity, LBW, or MCM, although number of exposed cases remained low.
... Chloroquine is an easily-synthesized, affordable 4-aminoquinoline antimalarial that was highly efficacious until the emergence of resistance in the late 1950s. 1 Worldwide spread of resistance has restricted its use to areas of low resistance in Central America for the treatment of uncomplicated Plasmodium falciparum malaria. 2 Resistance to chloroquine is mediated by point mutations in pfcrt (notably K76T), a transporter that induces an efflux of chloroquine outside of the digestive vacuole, where it exerts its action. 3 To overcome and prevent the spread of resistance to single antimalarials, the current recommendation for the treatment of uncomplicated malaria is the use of artemisinin-based combination therapies (ACTs) that combine a fast-acting artemisinin derivative with a long-lasting partner drug. ...
Background:
Expanding resistance to multiple antimalarials, including chloroquine, in South-East Asia (SEA) urges the development of new therapies. AQ-13, a chloroquine derivative, is a new drug candidate for treating malaria caused by Plasmodium falciparum.
Objectives:
Possible cross-resistance between the 4-aminoquinolines amodiaquine, piperaquine and AQ-13 has not been assessed. In vitro parasite growth assays were used to characterize the susceptibility of multidrug-resistant and susceptible P. falciparum patient isolates to AQ-13.
Methods:
A [3H]hypoxanthine uptake assay and a 384-well high content imaging assay were used to assess efficacy of AQ-13 and desethyl-amodiaquine against 38 P. falciparum isolates.
Results:
We observed a strong cross-resistance between the chloroquine derivative amodiaquine and AQ-13 in Cambodian P. falciparum isolates (Pearson correlation coefficient of 0.8621, P < 0.0001).
Conclusions:
In light of the poor efficacy of amodiaquine that we described recently in Cambodia, and its cross resistance with AQ-13, there is a significant risk that similar clinical efficacy of AQ-13-based combinations should be anticipated in areas of amodiaquine resistance.
... The Asia Pacific region has more instances of CRC, and the mortality rates were seen to have increased in regions of Japan and Singapore. CRC accounts for 10 to 15% of all cancers and is the second leading cause of cancer-related death in industrialized countries (Torres et al. 2013); 8-10% of global population is affected by common digestive system diseases which are known as intestine ulcers or gastric ulcers which represents up to 500,000 individuals every year in US (de Lira Mota et al. 2009). ...
... Downregulation of RhoA was documented in this study, a crucial regulator of cytoskeleton modulation. Its effects on multiple key signaling pathways, implicated in the malignant progression of numerous cancer types, make QC an exciting candidate as a chemotherapeutic agent in new types of combination treatments (Torres et al. 2013). Most importantly, cells were led to apoptosis, which was associated with caspase 3, caspase 8, and caspase 9. QC is an attractive chemotherapeutic agent having a 'shotgun' nature inducing different pathways leading to cell death, which opens a path to essential and interesting study in the future. ...
Quinacrine (QC), an FDA-approved anti-malarial drug, has shown to have anticancer activities. Due to its ‘shotgun’ nature, QC has become an inevitable candidate for combination chemotherapy. There is lack of study of the molecular interplay between colorectal cancer (CRC) microenvironment and its metastasis. In this study, we focused on the differential anti-cancerous effect of QC on two different human cancer cell lines, HCT 116 and INT 407. Results suggest that cytotoxicity increased in both the cell lines with an increase in QC concentration. The expression patterns of small-GTPases and caspases were altered significantly in QC-treated cells compared to non-treated cells. HSP70 and p53 showed comparable differences in the expression pattern. The wound-healing assay showed an increase in the denuded zone, with an increase in the concentration of QC. The formation of apoptotic nuclei increased with a rise in the concentration of QC in both the cell lines. The decrease and increase in caspase 9 and caspase 3 expression respectively were studied, confirming apoptosis by the extrinsic pathway.
... Chloroquine is a medication primarily used to prevent and treat malaria in areas where malaria remains sensitive to its effects [30]. Chloroquine was discovered in 1934 by Hans Andersag [31,32]. ...
... Resistance to chloroquine in Plasmodium falciparum has led to adopt artemisinin combination therapy (ACT) as the firstline drug for the treatment of malaria in most endemic countries. 3 However, P. falciparum resistant to artemisinin has been reported in the several endemic countries. 4 Therefore, discover new chemical compounds with antimalarial activities is urgently needed. ...
Harmsiopanax aculeatus leaf, locally name kapur, has been use traditionally to treat malaria in Maluku, Indonesia. However, the scientific evidences that support its use are still limited. This study aimed to investigate antiplasmodial activity of H. aculeatus leaf extract and its cytotoxicity on cancer cells line. Three extracts i.e. methanolic, n-hexanic and ethyl acetate extracts were evaluated for their in vitro activity against Plasmodium falciparum FCR3 strain using microscopic method. Cytotoxicity of the extracts on T47D, HeLa and Vero cells lines were determined using MTT assay method. The inhibitory concentration 50% (IC50) against P. falciparum or the cells lines growth was determined using probit analysis. Furthermore, their selectivity index (SI) were determined. The results showed that the methanolic extract was the most active extract with an IC50value of 13.82 μg/mL and the most selective with a SI value of 172.84. The three extracts tested exhibited weak or no cytotoxicity against the cells lines used with IC50 values ranged 101-2388.69 μg/mL. Further study will be conducted to isolate active antiplasmodial compounds from the methanol extract.
