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A Variant PfCRT Isoform Can Contribute to Plasmodium falciparum Resistance to the First-Line Partner Drug Piperaquine. mBio 2017; 8:mBio.00303-17. [PMID: 28487425 PMCID: PMC5424201 DOI: 10.1128/mbio.00303-17] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Current efforts to reduce the global burden of malaria are threatened by the rapid spread throughout Asia of Plasmodium falciparum resistance to artemisinin-based combination therapies, which includes increasing rates of clinical failure with dihydroartemisinin plus piperaquine (PPQ) in Cambodia. Using zinc finger nuclease-based gene editing, we report that addition of the C101F mutation to the chloroquine (CQ) resistance-conferring PfCRT Dd2 isoform common to Asia can confer PPQ resistance to cultured parasites. Resistance was demonstrated as significantly higher PPQ concentrations causing 90% inhibition of parasite growth (IC90) or 50% parasite killing (50% lethal dose [LD50]). This mutation also reversed Dd2-mediated CQ resistance, sensitized parasites to amodiaquine, quinine, and artemisinin, and conferred amantadine and blasticidin resistance. Using heme fractionation assays, we demonstrate that PPQ causes a buildup of reactive free heme and inhibits the formation of chemically inert hemozoin crystals. Our data evoke inhibition of heme detoxification in the parasite’s acidic digestive vacuole as the primary mode of both the bis-aminoquinoline PPQ and the related 4-aminoquinoline CQ. Both drugs also inhibit hemoglobin proteolysis at elevated concentrations, suggesting an additional mode of action. Isogenic lines differing in their pfmdr1 copy number showed equivalent PPQ susceptibilities. We propose that mutations in PfCRT could contribute to a multifactorial basis of PPQ resistance in field isolates. The global agenda to eliminate malaria depends on the continued success of artemisinin-based combination therapies (ACTs), which target the asexual blood stages of the intracellular parasite Plasmodium. Partial resistance to artemisinin, however, is now established in Southeast Asia, exposing the partner drugs to increased selective pressure. Plasmodium falciparum resistance to the first-line partner piperaquine (PPQ) is now spreading rapidly in Cambodia, resulting in clinical treatment failures. Here, we report that a variant form of the Plasmodium falciparum chloroquine resistance transporter, harboring a C101F mutation edited into the chloroquine (CQ)-resistant Dd2 isoform prevalent in Asia, can confer PPQ resistance in cultured parasites. This was accompanied by a loss of CQ resistance. Biochemical assays showed that PPQ, like CQ, inhibits the detoxification of reactive heme that is formed by parasite-mediated catabolism of host hemoglobin. We propose that novel PfCRT variants emerging in the field could contribute to a multigenic basis of PPQ resistance.
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Pholwat S, Liu J, Stroup S, Jacob ST, Banura P, Moore CC, Huang F, Laufer MK, Houpt E, Guler JL. The Malaria TaqMan Array Card Includes 87 Assays for Plasmodium falciparum Drug Resistance, Identification of Species, and Genotyping in a Single Reaction. Antimicrob Agents Chemother 2017; 61:e00110-17. [PMID: 28264857 PMCID: PMC5404514 DOI: 10.1128/aac.00110-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/02/2017] [Indexed: 11/20/2022] Open
Abstract
Antimalarial drug resistance exacerbates the global disease burden and complicates eradication efforts. To facilitate the surveillance of resistance markers in countries of malaria endemicity, we developed a suite of TaqMan assays for known resistance markers and compartmentalized them into a single array card (TaqMan array card, TAC). We included 87 assays for species identification, for the detection of Plasmodium falciparum mutations associated with chloroquine, atovaquone, pyrimethamine, sulfadoxine, and artemisinin resistance, and for neutral single nucleotide polymorphism (SNP) genotyping. Assay performance was first optimized using DNA from common laboratory parasite lines and plasmid controls. The limit of detection was 0.1 to 10 pg of DNA and yielded 100% accuracy compared to sequencing. The tool was then evaluated on 87 clinical blood samples from around the world, and the malaria TAC once again achieved 100% accuracy compared to sequencing and in addition detected the presence of mixed infections in clinical samples. With its streamlined protocol and high accuracy, this malaria TAC should be a useful tool for large-scale antimalarial resistance surveillance.
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Affiliation(s)
- Suporn Pholwat
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Jie Liu
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Suzanne Stroup
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Shevin T Jacob
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Patrick Banura
- Department of Community Health, Masaka Regional Referral Hospital, Masaka, Uganda
| | - Christopher C Moore
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Fang Huang
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - Miriam K Laufer
- Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Eric Houpt
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Jennifer L Guler
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
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Zhang HW, Li SJ, Hu T, Yu YM, Yang CY, Zhou RM, Liu Y, Tang J, Wang JJ, Wang XY, Sun YX, Feng ZC, Xu BL. Prolonged parasite clearance in a Chinese splenectomized patient with falciparum malaria imported from Nigeria. Infect Dis Poverty 2017; 6:44. [PMID: 28372588 PMCID: PMC5379605 DOI: 10.1186/s40249-017-0259-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 02/15/2017] [Indexed: 11/23/2022] Open
Abstract
Background The spleen plays a pivotal role in the rapid clearance of parasitized red blood cells in patients with falciparum malaria after artemisinin treatment. Prolonged parasite clearance can be found in patients who have had a splenectomy, or those with hemoglobin abnormalities and/or reduced immunity, which are all distinguishable from artemisinin resistance. This paper reports on a case of prolonged parasite clearance in a Chinese splenectomized patient with falciparum malaria imported from Nigeria. Case presentation A 35-year-old Chinese male suffered 2 days of febrile illness after returning to Zhumadian city of Henan province from Nigeria on October 1, 2014. The main symptoms were febrile, including the highest axillary temperature of 40 °C, headache, and chills. A peripheral blood smear showed parasitemia (53 913 asexual parasites/μl) of Plasmodium falciparum. The patient had not used any chemoprophylaxis against malaria in Nigeria when he worked there as a construction worker between 2009 and 2014. The patient had three episodes of malaria in Nigeria and had a splenectomy due to a traffic accident 8 years ago from the time he was admitted to hospital. The patient was orally administrated a total of 320 mg/2.56 g dihydroartemisinin-piperaquine for 2 days and intravenously administrated a total of 3 000 mg artesunate for 18 days. The axillary temperature of the patient ranged between 37.0 and 37.7 °C from Day 0 to Day 3, and blood microscopy revealed falciparum malaria parasitemia (26 674 asexual parasites/μl) on Day 3. The patient was afebrile on Day 4, falciparum malaria parasitemia was continuously present and then gradually decreased on the next days, and was negative on Day 21. The patient was cured and left hospital on Day 24 after no plasmodium falciparum was found in the blood on Day 21 to Day 23. No mutation was found in the K13 propeller gene when compared with the PF3D7_1343700 K13 propeller gene reference sequence. Conclusions This is the first reported case in China of prolonged parasite clearance in a splenectomized patient with imported falciparum malaria. Artemisinin resistance should be distinguished when prolonged parasite clearance is found in a malaria patient who has had splenectomy. Electronic supplementary material The online version of this article (doi:10.1186/s40249-017-0259-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hong-Wei Zhang
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China.
| | - San-Jin Li
- Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China
| | - Tao Hu
- School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China
| | - Yong-Min Yu
- Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China
| | - Cheng-Yun Yang
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China
| | - Rui-Min Zhou
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China
| | - Ying Liu
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China
| | - Jing Tang
- Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China
| | - Jing-Jing Wang
- Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China
| | - Xiu-Yun Wang
- Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China
| | - Yong-Xiang Sun
- Department of Infectious Diseases, the 6th People's Hospital of Zhengzhou, Zhengzhou, 450016, People's Republic of China
| | - Zhan-Chun Feng
- School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China
| | - Bian-Li Xu
- Department of Parasite Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, People's Republic of China.
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K13 Propeller Mutations in Plasmodium falciparum Populations in Regions of Malaria Endemicity in Vietnam from 2009 to 2016. Antimicrob Agents Chemother 2017; 61:AAC.01578-16. [PMID: 28137815 PMCID: PMC5365681 DOI: 10.1128/aac.01578-16] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 01/22/2017] [Indexed: 12/12/2022] Open
Abstract
The spread of artemisinin-resistant Plasmodium falciparum compromises the therapeutic efficacy of artemisinin combination therapies (ACTs) and is considered the greatest threat to current global initiatives to control and eliminate malaria. This is particularly relevant in Vietnam, where dihydroartemisinin-piperaquine (DP) is the recommended ACT for P. falciparum infection. The propeller domain gene of K13, a molecular marker of artemisinin resistance, was successfully sequenced in 1,060 P. falciparum isolates collected at 3 malaria hot spots in Vietnam between 2009 and 2016. Eight K13 propeller mutations (Thr474Ile, Tyr493His, Arg539Thr, Ile543Thr, Pro553Leu, Val568Gly, Pro574Leu, and Cys580Tyr), including several that have been validated to be artemisinin resistance markers, were found. The prevalences of K13 mutations were 29% (222/767), 6% (11/188), and 43% (45/105) in the Binh Phuoc, Ninh Thuan, and Gia Lai Provinces of Vietnam, respectively. Cys580Tyr became the dominant genotype in recent years, with 79.1% (34/43) of isolates in Binh Phuoc Province and 63% (17/27) of isolates in Gia Lai Province carrying this mutation. K13 mutations were associated with reduced ring-stage susceptibility to dihydroartemisinin (DHA) in vitro and prolonged parasite clearance in vivo. An analysis of haplotypes flanking K13 suggested the presence of multiple strains with the Cys580Tyr mutation rather than a single strain expanding across the three sites.
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105
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Impact of Extended Duration of Artesunate Treatment on Parasitological Outcome in a Cytocidal Murine Malaria Model. Antimicrob Agents Chemother 2017; 61:AAC.02499-16. [PMID: 28096162 DOI: 10.1128/aac.02499-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/11/2017] [Indexed: 11/20/2022] Open
Abstract
Artemisinin-based combination therapies are a key pillar in global malaria control and are recommended as a first-line Plasmodium falciparum treatment. They rely upon a rapid 4-log-unit reduction in parasitemia by artemisinin compounds with a short half-life and the killing of remaining parasites by a partner compound with a longer half-life. Current treatment guidelines stipulate giving three 24-h-interval doses or six 12-h-interval doses over a 3-day period. Due to the short half-life of artesunate and artemether, almost all of the resulting cytocidal activity is confined within a single 48-h asexual P. falciparum cycle. Here, we utilized a luciferase reporter, Plasmodium berghei ANKA, in a cytocidal model in which treatment was initiated at high parasitemia, allowing us to monitor a greater than 3-log-unit reduction in parasite density, as well as 30-day survival. In this study, we demonstrated that increasing the artesunate duration from spanning one asexual cycle to spanning three asexual cycles while keeping the total dose constant results in enhanced cytocidal activity. Single daily artesunate doses at 50 mg/kg of body weight over 7 days were the minimum necessary for curative monotherapy. In combination with a single sub-human-equivalent dose of the partner drug amodiaquine or piperaquine, the three-asexual-cycle artesunate duration was able to cure 75% and 100% of mice, respectively, whereas 0% and 33% cures were achieved with the single-asexual-cycle artesunate duration. In summary, cytocidal activity of the artemisinin compounds, such as artesunate, can be improved solely by altering the dosing duration.
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106
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Host immunity to Plasmodium falciparum and the assessment of emerging artemisinin resistance in a multinational cohort. Proc Natl Acad Sci U S A 2017; 114:3515-3520. [PMID: 28289193 DOI: 10.1073/pnas.1615875114] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Artemisinin-resistant falciparum malaria, defined by a slow-clearance phenotype and the presence of kelch13 mutants, has emerged in the Greater Mekong Subregion. Naturally acquired immunity to malaria clears parasites independent of antimalarial drugs. We hypothesized that between- and within-population variations in host immunity influence parasite clearance after artemisinin treatment and the interpretation of emerging artemisinin resistance. Antibodies specific to 12 Plasmodium falciparum sporozoite and blood-stage antigens were determined in 959 patients (from 11 sites in Southeast Asia) participating in a multinational cohort study assessing parasite clearance half-life (PCt1/2) after artesunate treatment and kelch13 mutations. Linear mixed-effects modeling of pooled individual patient data assessed the association between antibody responses and PCt1/2.P. falciparum antibodies were lowest in areas where the prevalence of kelch13 mutations and slow PCt1/2 were highest [Spearman ρ = -0.90 (95% confidence interval, -0.97, -0.65), and Spearman ρ = -0.94 (95% confidence interval, -0.98, -0.77), respectively]. P. falciparum antibodies were associated with faster PCt1/2 (mean difference in PCt1/2 according to seropositivity, -0.16 to -0.65 h, depending on antigen); antibodies have a greater effect on the clearance of kelch13 mutant compared with wild-type parasites (mean difference in PCt1/2 according to seropositivity, -0.22 to -0.61 h faster in kelch13 mutants compared with wild-type parasites). Naturally acquired immunity accelerates the clearance of artemisinin-resistant parasites in patients with falciparum malaria and may confound the current working definition of artemisinin resistance. Immunity may also play an important role in the emergence and transmission potential of artemisinin-resistant parasites.
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107
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Jovel IT, Björkman A, Roper C, Mårtensson A, Ursing J. Unexpected selections of Plasmodium falciparum polymorphisms in previously treatment-naïve areas after monthly presumptive administration of three different anti-malarial drugs in Liberia 1976-78. Malar J 2017; 16:113. [PMID: 28288632 PMCID: PMC5347173 DOI: 10.1186/s12936-017-1747-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 02/21/2017] [Indexed: 01/08/2023] Open
Abstract
Background To assess the effect on malaria prevalence, village specific monthly administrations of pyrimethamine, chlorproguanil, chloroquine or placebo were given to children in four previously treatment-naïve Liberian villages, 1976–78. Plasmodium falciparum in vivo resistance developed to pyrimethamine only. Selection of molecular markers of P. falciparum resistance after 2 years of treatment are reported. Methods Blood samples were collected from 191 study children in a survey in 1978. Polymorphisms in pfcrt, pfmdr1, pfdhfr, pfdhps, pfmrp1 and pfnhe1 genes were determined using PCR-based methods. Results Pfcrt 72–76 CVIET was found in one chloroquine village sample, all remaining samples had pfcrt CVMNK. Pfmdr1 N86 prevalence was 100%. A pfmdr1 T1069ACT→ACG synonymous polymorphism was found in 30% of chloroquine village samples and 3% of other samples (P = 0.008). Variations in pfnhe1 block I were found in all except the chloroquine treated village (P < 0.001). Resistance associated pfdhfr 108N prevalence was 2% in the pyrimethamine village compared to 45–65% elsewhere, including the placebo village (P = 0.001). Conclusions Chloroquine treatment possibly resulted in the development of pfcrt 72–76 CVIET. Selection of pfmdr1 T1069ACG and a pfnhe1 block 1 genotypes indicates that chloroquine treatment exerted a selective pressure on P. falciparum. Pyrimethamine resistance associated pfdhfr 108N was present prior to the introduction of any drug. Decreased pfdhfr 108N frequency concurrent with development of pyrimethamine resistance suggests a non-pfdhfr polymorphisms mediated resistance mechanism. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1747-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Irina T Jovel
- Malaria Research, Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
| | - Anders Björkman
- Malaria Research, Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Cally Roper
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Andreas Mårtensson
- Department of Women's and Children's Health, International Maternal and Child Health Unit, Uppsala University, Uppsala, Sweden
| | - Johan Ursing
- Malaria Research, Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Danderyds Hospital, Stockholm, Sweden
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108
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Tarique M, Ahmad M, Chauhan M, Tuteja R. Genome Wide In silico Analysis of the Mismatch Repair Components of Plasmodium falciparum and Their Comparison with Human Host. Front Microbiol 2017; 8:130. [PMID: 28232818 PMCID: PMC5298969 DOI: 10.3389/fmicb.2017.00130] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 01/18/2017] [Indexed: 12/28/2022] Open
Abstract
Malaria a major parasitic infection globally particularly in tropical and sub-tropical regions of the world is responsible for about 198 million cases and estimated deaths due to this disease are about 0.6 million. The emergence of drug resistance in the malaria parasite is alarming and it is necessary to understand its underlying cause and molecular mechanisms. It has been established that drug resistant malaria parasites have defective mismatch repair (MMR) therefore it is essential to study this pathway and its components in detail. Recently a number of non-synonymous Single Nucleotide Polymorphisms have been reported in genes involved in MMR pathways. PfMLH is an endonuclease essential to restore the MMR in drug resistant strains of Plasmodium falciparum. Considering all these facts about the role of MMR in emergence of drug resistant parasite, in this manuscript we report a genome wide analysis of the components of the MMR pathway such as MLH, Pms1, MSH2-1, MSH2-2, MSH6, and UvrD using in silico bioinformatics based approaches. The phylogenetic analysis revealed evolutionary closeness with the MMR components of various organisms. It is noteworthy that P. falciparum contains two homologs of MSH2, which are located on different chromosomes. The structural modeling of these components showed their similarity with the human/yeast MMR components. The docking studies reveal that PfUvrD and PfMLH interact with each other. The in silico identification of interacting partners of the major MMR components identified numerous P. falciparum specific proteins. In line with our previous studies the present study will also contribute significantly to understand the MMR pathway of malaria parasite.
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Affiliation(s)
- Mohammed Tarique
- Parasite Biology Group, International Centre for Genetic Engineering and Biotechnology New Delhi, India
| | - Moaz Ahmad
- Parasite Biology Group, International Centre for Genetic Engineering and Biotechnology New Delhi, India
| | - Manish Chauhan
- Parasite Biology Group, International Centre for Genetic Engineering and Biotechnology New Delhi, India
| | - Renu Tuteja
- Parasite Biology Group, International Centre for Genetic Engineering and Biotechnology New Delhi, India
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Munkongdee T, Tanakulmas J, Butthep P, Winichagoon P, Main B, Yiannakis M, George J, Devenish R, Fucharoen S, Svasti S. Molecular Epidemiology of Hemoglobinopathies in Cambodia. Hemoglobin 2017; 40:163-7. [PMID: 27117566 DOI: 10.3109/03630269.2016.1158723] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Determining the magnitude of the thalassemia problem in a country is important for implementing a national prevention and control program. In order to acquire accurate thalassemia prevalence data, the gene frequency of α- and β-thalassemia (α- and β-thal) in different regions of a country should be determined. The molecular basis of thalassemia in Cambodia was performed by polymerase chain reaction (PCR)-based techniques in a community-based cross-sectional survey of 1631 unrelated individuals from three regions, Battambang, Preah Vihear and Phnom Penh. Thalassemia mutations were detected in 62.7% of the three studied population of Cambodia. Hb E (HBB: c.79G > A) was the most common β-globin gene mutation with a frequency ranging from 0.139 to 0.331, while the most frequent α-globin gene mutation was the -α(3.7) (rightward) deletion (0.098-0.255). The other frequencies were 0.001-0.003 for β-thal, 0.008-0.011 for α-thal-1 (- -(SEA)), 0.003-0.008 for α-thal-2 [-α(4.2) (leftward deletion)], 0.021-0.044 for Hb Constant Spring (Hb CS, HBA2: c.427T > C) and 0.009-0.036 for Hb Paksé (HBA2: c.429A > T). A regional specific thalassemia gene frequency was observed. Preah Vihear had the highest prevalence of Hb E (55.9%), α-thal-2 (24.0%) and nondeletional α-thal (15.1%), whereas Phnom Penh had the lowest frequency of thalassemia genes. Interestingly, in Preah Vihear, the frequency of Hb Paksé was extremely high (0.036), almost equivalent to that of Hb CS (0.044). Our results indicate the importance of micromapping and epidemiology studies of thalassemia, which will assist in establishing the national prevention and control program in Cambodia.
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Affiliation(s)
- Thongperm Munkongdee
- a Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University , Nakhon Pathom , Thailand
| | - Jatuporn Tanakulmas
- a Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University , Nakhon Pathom , Thailand.,b Department of Pathology , Faculty of Medicine, Ramathibodi Hospital, Mahidol University , Bangkok , Thailand
| | - Punnee Butthep
- b Department of Pathology , Faculty of Medicine, Ramathibodi Hospital, Mahidol University , Bangkok , Thailand
| | - Pranee Winichagoon
- a Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University , Nakhon Pathom , Thailand
| | - Barbara Main
- c World Vision Canada , Mississauga , Ontario , Canada
| | | | - Joby George
- d World Vision Cambodia , Phnom Penh , Cambodia
| | | | - Suthat Fucharoen
- a Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University , Nakhon Pathom , Thailand
| | - Saovaros Svasti
- a Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University , Nakhon Pathom , Thailand.,f Department of Biochemistry , Faculty of Science, Mahidol University , Bangkok , Thailand
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Amato R, Lim P, Miotto O, Amaratunga C, Dek D, Pearson RD, Almagro-Garcia J, Neal AT, Sreng S, Suon S, Drury E, Jyothi D, Stalker J, Kwiatkowski DP, Fairhurst RM. Genetic markers associated with dihydroartemisinin-piperaquine failure in Plasmodium falciparum malaria in Cambodia: a genotype-phenotype association study. THE LANCET. INFECTIOUS DISEASES 2017; 17:164-173. [PMID: 27818095 PMCID: PMC5564489 DOI: 10.1016/s1473-3099(16)30409-1] [Citation(s) in RCA: 257] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND As the prevalence of artemisinin-resistant Plasmodium falciparum malaria increases in the Greater Mekong subregion, emerging resistance to partner drugs in artemisinin combination therapies seriously threatens global efforts to treat and eliminate this disease. Molecular markers that predict failure of artemisinin combination therapy are urgently needed to monitor the spread of partner drug resistance, and to recommend alternative treatments in southeast Asia and beyond. METHODS We did a genome-wide association study of 297 P falciparum isolates from Cambodia to investigate the relationship of 11 630 exonic single-nucleotide polymorphisms (SNPs) and 43 copy number variations (CNVs) with in-vitro piperaquine 50% inhibitory concentrations (IC50s), and tested whether these genetic variants are markers of treatment failure with dihydroartemisinin-piperaquine. We then did a survival analysis of 133 patients to determine whether candidate molecular markers predicted parasite recrudescence following dihydroartemisinin-piperaquine treatment. FINDINGS Piperaquine IC50s increased significantly from 2011 to 2013 in three Cambodian provinces (2011 vs 2013 median IC50s: 20·0 nmol/L [IQR 13·7-29·0] vs 39·2 nmol/L [32·8-48·1] for Ratanakiri, 19·3 nmol/L [15·1-26·2] vs 66·2 nmol/L [49·9-83·0] for Preah Vihear, and 19·6 nmol/L [11·9-33·9] vs 81·1 nmol/L [61·3-113·1] for Pursat; all p≤10-3; Kruskal-Wallis test). Genome-wide analysis of SNPs identified a chromosome 13 region that associates with raised piperaquine IC50s. A non-synonymous SNP (encoding a Glu415Gly substitution) in this region, within a gene encoding an exonuclease, associates with parasite recrudescence following dihydroartemisinin-piperaquine treatment. Genome-wide analysis of CNVs revealed that a single copy of the mdr1 gene on chromosome 5 and a novel amplification of the plasmepsin 2 and plasmepsin 3 genes on chromosome 14 also associate with raised piperaquine IC50s. After adjusting for covariates, both exo-E415G and plasmepsin 2-3 markers significantly associate (p=3·0 × 10-8 and p=1·7 × 10-7, respectively) with decreased treatment efficacy (survival rates 0·38 [95% CI 0·25-0·51] and 0·41 [0·28-0·53], respectively). INTERPRETATION The exo-E415G SNP and plasmepsin 2-3 amplification are markers of piperaquine resistance and dihydroartemisinin-piperaquine failures in Cambodia, and can help monitor the spread of these phenotypes into other countries of the Greater Mekong subregion, and elucidate the mechanism of piperaquine resistance. Since plasmepsins are involved in the parasite's haemoglobin-to-haemozoin conversion pathway, targeted by related antimalarials, plasmepsin 2-3 amplification probably mediates piperaquine resistance. FUNDING Intramural Research Program of the US National Institute of Allergy and Infectious Diseases, National Institutes of Health, Wellcome Trust, Bill & Melinda Gates Foundation, Medical Research Council, and UK Department for International Development.
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Affiliation(s)
- Roberto Amato
- Wellcome Trust Sanger Institute, Hinxton, UK; Centre for Genomics and Global Health, Wellcome Trust Centre for Human Genetics, Oxford, UK.
| | - Pharath Lim
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA; National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Olivo Miotto
- Wellcome Trust Sanger Institute, Hinxton, UK; Centre for Genomics and Global Health, Wellcome Trust Centre for Human Genetics, Oxford, UK; Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Chanaki Amaratunga
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Dalin Dek
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Richard D Pearson
- Wellcome Trust Sanger Institute, Hinxton, UK; Centre for Genomics and Global Health, Wellcome Trust Centre for Human Genetics, Oxford, UK
| | - Jacob Almagro-Garcia
- Wellcome Trust Sanger Institute, Hinxton, UK; Centre for Genomics and Global Health, Wellcome Trust Centre for Human Genetics, Oxford, UK
| | - Aaron T Neal
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Sokunthea Sreng
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | - Seila Suon
- National Center for Parasitology, Entomology, and Malaria Control, Phnom Penh, Cambodia
| | | | | | - Jim Stalker
- Wellcome Trust Sanger Institute, Hinxton, UK
| | - Dominic P Kwiatkowski
- Wellcome Trust Sanger Institute, Hinxton, UK; Centre for Genomics and Global Health, Wellcome Trust Centre for Human Genetics, Oxford, UK
| | - Rick M Fairhurst
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
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Tripura R, Peto TJ, Veugen CC, Nguon C, Davoeung C, James N, Dhorda M, Maude RJ, Duanguppama J, Patumrat K, Imwong M, von Seidlein L, Grobusch MP, White NJ, Dondorp AM. Submicroscopic Plasmodium prevalence in relation to malaria incidence in 20 villages in western Cambodia. Malar J 2017; 16:56. [PMID: 28143518 PMCID: PMC5282880 DOI: 10.1186/s12936-017-1703-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 01/19/2017] [Indexed: 11/10/2022] Open
Abstract
Background Cambodia has seen a marked reduction in the incidence of Plasmodium falciparum over the past decade without a corresponding decline in Plasmodium vivax incidence. It is unknown to what extent local transmission is sustained by a chain of clinical and sub-clinical infections or by continued re-introduction via migration. Using an ultrasensitive molecular technique, 20 villages in western Cambodia were surveyed to detect the low season prevalence of P. falciparum and P. vivax and local treatment records were reviewed. Methods During March to May 2015 cross-sectional surveys were conducted in 20 villages in Battambang, western Cambodia. Demographic and epidemiological data and venous blood samples were collected from 50 randomly selected adult volunteers in each village. Blood was tested for Plasmodium infections by rapid diagnostic test (RDT), microscopy and high volume (0.5 ml packed red blood cell) quantitative polymerase chain reaction (uPCR). Positive samples were analysed by nested PCR to determine the Plasmodium species. Malaria case records were collected from the Provincial Health Department and village malaria workers to determine incidence and migration status. Results Among the 1000 participants, 91 (9.1%) were positive for any Plasmodium infection by uPCR, seven (0.7%) by microscopy, and two (0.2%) by RDT. uPCR P. vivax prevalence was 6.6%, P. falciparum 0.7%, and undetermined Plasmodium species 1.8%. Being male (adjusted OR 2.0; 95% CI 1.2-3.4); being a young adult <30 years (aOR 2.1; 95% CI 1.3–3.4); recent forest travel (aOR 2.8; 95% CI 1.6–4.8); and, a history of malaria (aOR 5.2; 95% CI 2.5–10.7) were independent risk factors for parasitaemia. Of the clinical malaria cases diagnosed by village malaria workers, 43.9% (297/634) and 38.4% (201/523) were among migrants in 2013 and in 2014, respectively. Plasmodium vivax prevalence determined by uPCR significantly correlated with vivax malaria incidences in both 2014 and 2015 (p = 0.001 and 0.002, respectively), whereas no relationship was observed in falciparum malaria (p = 0.36 and p = 0.59, respectively). Discussion There was heterogeneity in the malaria parasite reservoir between villages, and Plasmodium prevalence correlated with subsequent malaria incidence. The association was attributable chiefly to P. vivax infections, which were nine-fold more prevalent than P. falciparum infections. In the absence of a radical cure with 8-aminoquinolines, P. vivax transmission will continue even as P. falciparum prevalence declines. Migration was associated with over a third of incident cases of clinical malaria. Trial registration clinicaltrials.gov (NCT01872702). Registered 4 June 2013 Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1703-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand. .,Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
| | - Thomas J Peto
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Christianne C Veugen
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Nicola James
- Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK
| | - Mehul Dhorda
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand.,World-Wide Antimalarial Resistance Network, Mahidol University, Bangkok, Thailand
| | - Richard J Maude
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.,Department of Epidemiology, Harvard T. H. Chan School of Public Health, Harvard University, Boston, USA
| | - Jureeporn Duanguppama
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand.,Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Krittaya Patumrat
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand.,Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mallika Imwong
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand.,Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Martin P Grobusch
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Rajthevee, Bangkok, 10400, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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Baumgärtner F, Jourdan J, Scheurer C, Blasco B, Campo B, Mäser P, Wittlin S. In vitro activity of anti-malarial ozonides against an artemisinin-resistant isolate. Malar J 2017; 16:45. [PMID: 28122617 PMCID: PMC5267415 DOI: 10.1186/s12936-017-1696-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 01/13/2017] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Recently published data suggest that artemisinin derivatives and synthetic peroxides, such as the ozonides OZ277 and OZ439, have a similar mode of action. Here the cross-resistance of OZ277 and OZ439 and four additional next-generation ozonides was probed against the artemisinin-resistant clinical isolate Plasmodium falciparum Cam3.I, which carries the K13-propeller mutation R539T (Cam3.IR539T). METHODS The previously described in vitro ring-stage survival assay (RSA0-3h) was employed and a simplified variation of the original protocol was developed. RESULTS At the pharmacologically relevant concentration of 700 nM, all six ozonides were highly effective against the dihydroartemisinin-resistant P. falciparum Cam3.IR539T parasites, showing a per cent survival ranging from <0.01 to 1.83%. A simplified version of the original RSA0-3h method was developed and gave similar results, thus providing a practical drug discovery tool for further optimization of next-generation anti-malarial peroxides. CONCLUSION The absence of in vitro cross-resistance against the artemisinin-resistant clinical isolate Cam3.IR539T suggests that ozonides could be effective against artemisinin-resistant P. falciparum. How this will translate to the human situation in clinical settings remains to be investigated.
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Affiliation(s)
- Fabian Baumgärtner
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Joëlle Jourdan
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Christian Scheurer
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Benjamin Blasco
- Medicines for Malaria Venture, ICC, 20 Route de Pré-Bois, PO Box 1826, 1215 Geneva, Switzerland
| | - Brice Campo
- Medicines for Malaria Venture, ICC, 20 Route de Pré-Bois, PO Box 1826, 1215 Geneva, Switzerland
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
| | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, Petersplatz 1, 4001 Basel, Switzerland
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Significant Divergence in Sensitivity to Antimalarial Drugs between Neighboring Plasmodium falciparum Populations along the Eastern Border of Myanmar. Antimicrob Agents Chemother 2017; 61:AAC.01689-16. [PMID: 27919892 DOI: 10.1128/aac.01689-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/18/2016] [Indexed: 12/29/2022] Open
Abstract
Malaria parasites in different areas where malaria is endemic display different levels of resistance to antimalarial drugs as the result of varied drug use histories. To provide updated knowledge of drug sensitivities during the malaria elimination phase in Southeast Asia, an epicenter of multidrug resistance, we determined in vitro susceptibilities of culture-adapted Plasmodium falciparum isolates from two eastern border regions (Wa and Kachin) of Myanmar to 10 drugs. Despite their close proximity, the Kachin parasites displayed higher 50% inhibitory concentrations than the Wa parasites to chloroquine, piperaquine, naphthoquine, mefloquine, quinine, pyrimethamine, pyronaridine, lumefantrine, and dihydroartemisinin. Genotyping of genes associated with drug resistance also showed significant differences in the prevalence rates of mutant alleles between the two regions. Particularly, major pfdhfr mutations mediating pyrimethamine resistance and the pfdhps A437G mutation had significantly higher frequencies in the Kachin parasites (P < 0.005). Moreover, when pfdhfr and pfdhps were considered together, the wild-type allele was found only in the Wa samples (22.6%). In addition, the pfmdr1 Y184F mutation reached 38.7% in the Kachin parasites, compared to 9.7% in the Wa parasites, whereas N86Y was only detected in the Wa parasites, at 22.6%. Furthermore, the F446I mutation and all mutations in the propeller domain of the PfK13 gene were significantly more frequent in the Kachin parasites. Collectively, this work demonstrates that even in spatially closely separated regions, parasites can exhibit drastic differences in drug sensitivities and genetic makeups underlying drug resistance, which may reflect regionally different drug histories and genetic drift of these isolated parasite populations.
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114
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Kajubi R, Huang L, Were M, Kiconco S, Li F, Marzan F, Gingrich D, Nyunt MM, Ssebuliba J, Mwebaza N, Aweeka FT, Parikh S. Parasite Clearance and Artemether Pharmacokinetics Parameters Over the Course of Artemether-Lumefantrine Treatment for Malaria in Human Immunodeficiency Virus (HIV)-Infected and HIV-Uninfected Ugandan Children. Open Forum Infect Dis 2016; 3:ofw217. [PMID: 28018925 PMCID: PMC5170492 DOI: 10.1093/ofid/ofw217] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/11/2016] [Indexed: 11/13/2022] Open
Abstract
Background. Artemisinins are primarily responsible for initial parasite clearance. Antimalarial pharmacokinetics (PK), human immunodeficiency virus (HIV) infection, and antiretroviral therapy have been shown to impact treatment outcomes, although their impact on early parasite clearance in children has not been well characterized. Methods. Parasite clearance parameters were generated from twice-daily blood smears in HIV-infected and HIV-uninfected Ugandan children treated with artemether-lumefantrine (AL). Artemether and dihydroartemisinin (DHA) area-under-the-curve from 0–8 hours (AUC0-8hr) after the 1st AL dose was compared with AUC0-8hr after the last (6th) dose in a concurrently enrolled cohort. The association between post-1st dose artemisinin AUC0-8hr and parasite clearance was assessed. Results. Parasite clearance was longer in HIV-infected versus HIV-uninfected children (median, 3.5 vs 2.8 hours; P = .003). Artemether AUC0-8hr was 3- to 4-fold lower after the 6th dose versus the 1st dose of AL in HIV-infected children on nevirapine- or lopinavir/ritionavir-based regimens and in HIV-uninfected children (P ≤ .002, 1st vs 6th-dose comparisons). Children on efavirenz exhibited combined post-1st dose artemether/DHA exposure that was significantly lower than those on lopinavir/ritonavir and HIV-uninfected children. Multiple regression analysis supported that the effect of artemether/DHA exposure on parasite clearance was significantly moderated by HIV status. Conclusions. Parasite clearance rates remain rapid in Uganda and were not found to associate with PK exposure. However, significant decreases in artemisinin PK with repeated dosing in nearly all children, coupled with small, but significant increase in parasite clearance half-life in those with HIV, may have important implications for AL efficacy, particularly because reports of artemisinin resistance are increasing.
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Affiliation(s)
- Richard Kajubi
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Liusheng Huang
- University of California-San Francisco, San Francisco General Hospital
| | - Moses Were
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Sylvia Kiconco
- University of California-San Francisco, San Francisco General Hospital
| | - Fangyong Li
- Yale University School of Public Health and Medicine , New Haven, Connecticut
| | - Florence Marzan
- University of California-San Francisco, San Francisco General Hospital
| | - David Gingrich
- University of California-San Francisco, San Francisco General Hospital
| | - Myaing M Nyunt
- Institute for Global Health, University of Maryland Baltimore School of Medicine
| | | | - Norah Mwebaza
- Infectious Disease Research Collaboration, Kampala, Uganda
| | | | - Sunil Parikh
- Yale University School of Public Health and Medicine , New Haven, Connecticut
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115
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The Effects of Transdermally Delivered Oleanolic Acid on Malaria Parasites and Blood Glucose Homeostasis in P. berghei-Infected Male Sprague-Dawley Rats. PLoS One 2016; 11:e0167132. [PMID: 27907019 PMCID: PMC5132303 DOI: 10.1371/journal.pone.0167132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 11/09/2016] [Indexed: 11/19/2022] Open
Abstract
The present study investigated the effects of transdermally delivered oleanolic acid (OA) monotherapy and in combination with chloroquine (CHQ) on malaria parasites and glucose homeostasis of P. berghei-infected male Sprague-Dawley rats. Oral glucose test (OGT) responses to OA-pectin patch and CHQ-OA combination matrix patch were monitored in non-infected and infected rats. To evaluate the short-term effects of treatment, percentage parasitaemia, blood glucose, glycogen and plasma insulin were monitored in separate groups of animals treated with either OA-patch monotherapy or CHQ-OA combination pectin patch over a 21-days period. Animals treated with drug-free pectin and CHQ acted as untreated and treated positive controls, respectively. Infected control rats exhibited significantly increased parasitaemia which was accompanied by hypoglycaemia. Both OA monotherapy and CHQ-OA combination therapy reduced and cleared the malaria parasites within a period of 4 and 3 days, respectively. Compared to respective controls groups, OGT responses of animals treated with OA monotherapy or CHQ-OA combination therapy exhibited lower blood glucose levels at all time points. A once-off transdermal application of OA-patch or CHQ-OA combination patch significantly improved blood glucose concentrations inducing any changes in insulin concentration. Transdermal OA used as a monotherapy or in combination with CHQ is able to clear and reduce the malaria parasites within a shorter period of time without eliciting any adverse effects on glucose homeostasis of P. berghei-infected rats.
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Menard S, Tchoufack JN, Maffo CN, Nsango SE, Iriart X, Abate L, Tsapi MT, Awono-Ambéné PH, Abega Mekongo FA, Morlais I, Berry A. Insight into k13-propeller gene polymorphism and ex vivo DHA-response profiles from Cameroonian isolates. Malar J 2016; 15:572. [PMID: 27887614 PMCID: PMC5124315 DOI: 10.1186/s12936-016-1622-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 11/17/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The spread of Plasmodium falciparum resistance to artemisinin derivatives in Southeast Asia is a major source of concern and the emergence of resistance in Africa would have dramatic consequences, by increasing malaria mortality and morbidity. It is therefore urgent to implement regular monitoring in sentinel sites in sub-Saharan Africa using robust and easy-to-implement tools. The prevalence of k13-propeller mutations and the phenotypic profiles are poorly known in sub-Saharan Africa. Here, the k13-propeller polymorphism was compared to both ex vivo susceptibility to DHA and early parasitological and clinical responses to artemisinin combination therapy (ACT). METHODS Plasmodium falciparum isolates were collected in 2015 in Yaoundé (Cameroon) from patients treated with dihydroartemisinin-piperaquine combination. Samples were analysed for their susceptibility to artemisinin using the k13-propeller sequencing, the ex vivo ring-stage survival assay, the in vivo parasite positive rate and the clinical statute at day 2. RESULTS None of the collected isolates revealed the presence of resistance mutations in the k13-propeller sequence. The median ring-stage survival rate for all the 64 interpretable isolates after a 6-hour pulse of 700 nM dihydroartemisinin was low, 0.49% (IQR: 0-1.3). Total parasite clearance was observed for 87.5% of patients and the remaining parasitaemic isolates (12.5%) showed a high reduction of parasite load, ranging from 97.5 to 99.9%. Clinical symptoms disappeared in 92.8% of cases. CONCLUSION This study demonstrated the absence of k13-resistant genotypes in P. falciparum isolates from Cameroon. Only synonymous mutations were found with a low prevalence (4.3%). A good association between k13 genotypes and the ex vivo ring-stage survival assay or parasitological and clinical data was obtained. These results give a baseline for the long-term monitoring of artemisinin derivative efficacy in Africa.
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Affiliation(s)
- Sandie Menard
- Centre de Physiopathologie de Toulouse Purpan, INSERM U1043, CNRS UMR5282, Université de Toulouse, Toulouse, France
| | - Joëlle Njila Tchoufack
- Laboratoire d'Entomologie Médicale, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon
| | - Christelle Ngou Maffo
- Laboratoire d'Entomologie Médicale, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon
| | - Sandrine E Nsango
- Laboratoire d'Entomologie Médicale, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon.,Faculté de Médecine et des Sciences Pharmaceutiques, Université de Douala, Douala, Cameroon
| | - Xavier Iriart
- Centre de Physiopathologie de Toulouse Purpan, INSERM U1043, CNRS UMR5282, Université de Toulouse, Toulouse, France.,Service de Parasitologie-Mycologie, CHU Toulouse, Toulouse, France
| | - Luc Abate
- UMR MIVEGEC, IRD 224-CNRS5290-UM, Institut de Recherche pour le développement, Montpellier, France
| | - Majoline Tchioffo Tsapi
- UMR MIVEGEC, IRD 224-CNRS5290-UM, Institut de Recherche pour le développement, Montpellier, France
| | - Parfait H Awono-Ambéné
- Laboratoire d'Entomologie Médicale, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon
| | | | - Isabelle Morlais
- UMR MIVEGEC, IRD 224-CNRS5290-UM, Institut de Recherche pour le développement, Montpellier, France
| | - Antoine Berry
- Centre de Physiopathologie de Toulouse Purpan, INSERM U1043, CNRS UMR5282, Université de Toulouse, Toulouse, France. .,Service de Parasitologie-Mycologie, CHU Toulouse, Toulouse, France.
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Galarneau JR, Meseck EK, Hall RL, Li W, Weaver ML. Naphthoquine-induced Central Nervous System and Hepatic Vasculocentric Toxicity in the Beagle Dog. Toxicol Pathol 2016; 44:1128-1136. [PMID: 27834287 DOI: 10.1177/0192623316676422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Naphthoquine phosphate (NP) was considered as a partner drug with a promising antimalarial drug candidate. Here we report unexpected adverse clinical signs and microscopic findings in a canine pilot toxicology study with NP. Male and female dogs were dosed daily by oral gavage with NP at 2, 10, or 50 mg/kg/day for a maximum of 14 days. NP was not tolerated at ≥10 mg/kg/day; several animals were sacrificed in moribund condition and marked neurological clinical signs were noted at 50 mg/kg/day. The main microscopic observation was central nervous system vasculocentric inflammation (mainly lymphocytes and macrophages) in the white and gray matter of various regions of the brain at ≥2 mg/kg/day and at lower incidence in the spinal cord at ≥10 mg/kg/day. Vasculocentric microscopic changes predominantly centered on the centrilobular vein were also observed in the liver at ≥2 mg/kg/day. Females were more sensitive than males with comparable NP plasma exposure. In conclusion, under the conditions of this study, the administration of NP to dogs via daily oral gavage for up to 2 weeks was not tolerated causing moribundity, marked neurological clinical signs, and vasculocentric microscopic changes in the central nervous system and the liver.
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Affiliation(s)
- Jean-Rene Galarneau
- 1 Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA
| | - Emily K Meseck
- 2 Covance Laboratories, Madison, Wisconsin, USA.,3 Novartis Institutes for BioMedical Research, East Hanover, New Jersey, USA
| | | | - Wenkui Li
- 3 Novartis Institutes for BioMedical Research, East Hanover, New Jersey, USA
| | - Margaret L Weaver
- 1 Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA
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Srimuang K, Miotto O, Lim P, Fairhurst RM, Kwiatkowski DP, Woodrow CJ, Imwong M. Analysis of anti-malarial resistance markers in pfmdr1 and pfcrt across Southeast Asia in the Tracking Resistance to Artemisinin Collaboration. Malar J 2016; 15:541. [PMID: 27825353 PMCID: PMC5101715 DOI: 10.1186/s12936-016-1598-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 10/31/2016] [Indexed: 01/07/2023] Open
Abstract
Background Declining anti-malarial efficacy of artemisinin-based combination therapy, and reduced Plasmodium falciparum susceptibility to individual anti-malarials are being documented across an expanding area of Southeast Asia (SEA). Genotypic markers complement phenotypic studies in assessing the efficacy of individual anti-malarials. Methods The markers pfmdr1 and pfcrt were genotyped in parasite samples obtained in 2011–2014 at 14 TRAC (Tracking Resistance to Artemisinin Collaboration) sites in mainland Southeast Asia using a combination of PCR and next-generation sequencing methods. Results Pfmdr1 amplification, a marker of mefloquine and lumefantrine resistance, was highly prevalent at Mae Sot on the Thailand–Myanmar border (59.8% of isolates) and common (more than 10%) at sites in central Myanmar, eastern Thailand and western Cambodia; however, its prevalence was lower than previously documented in Pailin, western Cambodia. The pfmdr1 Y184F mutation was common, particularly in and around Cambodia, and the F1226Y mutation was found in about half of samples in Mae Sot. The functional significance of these two mutations remains unclear. Other previously documented pfmdr1 mutations were absent or very rare in the region. The pfcrt mutation K76T associated with chloroquine resistance was found in 98.2% of isolates. The CVIET haplotype made up 95% or more of isolates in western SEA while the CVIDT haplotype was common (30–40% of isolates) in north and northeastern Cambodia, southern Laos, and southern Vietnam. Conclusions These findings generate cause for concern regarding the mid-term efficacy of artemether–lumefantrine in Myanmar, while the absence of resistance-conferring pfmdr1 mutations and SVMNT pfcrt haplotypes suggests that amodiaquine could be an efficacious component of anti-malarial regimens in SEA. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1598-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Krongkan Srimuang
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Olivo Miotto
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand.,Wellcome Trust Sanger Institute, Hinxton, UK.,Medical Research Council (MRC) Centre for Genomics and Global Health, University of Oxford, Oxford, UK
| | - Pharath Lim
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Dominic P Kwiatkowski
- Wellcome Trust Sanger Institute, Hinxton, UK.,Medical Research Council (MRC) Centre for Genomics and Global Health, University of Oxford, Oxford, UK
| | - Charles J Woodrow
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand.,Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand.
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Leang R, Khu NH, Mukaka M, Debackere M, Tripura R, Kheang ST, Chy S, Kak N, Buchy P, Tarantola A, Menard D, Roca-Felterer A, Fairhurst RM, Kheng S, Muth S, Ngak S, Dondorp AM, White NJ, Taylor WRJ. An optimised age-based dosing regimen for single low-dose primaquine for blocking malaria transmission in Cambodia. BMC Med 2016; 14:171. [PMID: 27784313 PMCID: PMC5081959 DOI: 10.1186/s12916-016-0701-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 09/20/2016] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND In 2012, the World Health Organization recommended the addition of single low-dose primaquine (SLDPQ, 0.25 mg base/kg body weight) to artemisinin combination therapies to block the transmission of Plasmodium falciparum without testing for glucose-6-phosphate dehydrogenase deficiency. The targeted group was non-pregnant patients aged ≥ 1 year (later changed to ≥ 6 months) with acute uncomplicated falciparum malaria, primarily in countries with artemisinin-resistant P. falciparum (ARPf). No dosing regimen was suggested, leaving malaria control programmes and clinicians in limbo. Therefore, we designed a user-friendly, age-based SLDPQ regimen for Cambodia, the country most affected by ARPf. METHODS By reviewing primaquine's pharmacology, we defined a therapeutic dose range of 0.15-0.38 mg base/kg (9-22.5 mg in a 60-kg adult) for a therapeutic index of 2.5. Primaquine doses (1-20 mg) were tested using a modelled, anthropometric database of 28,138 Cambodian individuals (22,772 healthy, 4119 with malaria and 1247 with other infections); age distributions were: 0.5-4 years (20.0 %, n = 5640), 5-12 years (9.1 %, n = 2559), 13-17 years (9.1 %, n = 2550), and ≥ 18 years (61.8 %, n = 17,389). Optimal age-dosing groups were selected according to calculated mg base/kg doses and proportions of individuals receiving a therapeutic dose. RESULTS Four age-dosing bands were defined: (1) 0.5-4 years, (2) 5-9 years, (3) 10-14 years, and (4) ≥15 years to receive 2.5, 5, 7.5, and 15 mg of primaquine base, resulting in therapeutic doses in 97.4 % (5494/5640), 90.5 % (1511/1669), 97.7 % (1473/1508), and 95.7 % (18,489/19,321) of individuals, respectively. Corresponding median (1st-99th centiles) mg base/kg doses of primaquine were (1) 0.23 (0.15-0.38), (2) 0.29 (0.18-0.45), (3) 0.27 (0.15-0.39), and (4) 0.29 (0.20-0.42). CONCLUSIONS This age-based SLDPQ regimen could contribute substantially to malaria elimination and requires urgent evaluation in Cambodia and other countries with similar anthropometric characteristics. It guides primaquine manufacturers on suitable tablet strengths and doses for paediatric-friendly formulations. Development of similar age-based dosing recommendations for Africa is needed.
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Affiliation(s)
- Rithea Leang
- National Center for Parasitology, Entomology and Malaria Control, Corner St. 92, Trapeng Svay Village, Sangkat Phnom Penh, Thmei, Khan Sen Sok, Phnom Penh, Cambodia
| | - Naw Htee Khu
- Mahidol Oxford Tropical Medicine Research Unit (MORU), 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand
| | - Mavuto Mukaka
- Mahidol Oxford Tropical Medicine Research Unit (MORU), 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand.,Oxford Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford, OX3 7FZ, UK
| | - Mark Debackere
- MSF Belgium Cambodia Malaria Program, #19, Street 388, Sangkat Tuol Svay Prey, Khan Chamkarmon, PO Box 1933, Phnom Penh, Cambodia
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit (MORU), 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand
| | - Soy Ty Kheang
- University Research Co., LLC, MK Building, House #10 (2nd floor), St. 214, Chey Chumneas, Daun Penh, Phnom Penh, Cambodia
| | - Say Chy
- University Research Co., LLC, MK Building, House #10 (2nd floor), St. 214, Chey Chumneas, Daun Penh, Phnom Penh, Cambodia
| | - Neeraj Kak
- University Research Co., LLC Washington DC: 7200 Wisconsin Ave, Bethesda, MD, 20814, USA
| | - Philippe Buchy
- Institut Pasteur du Cambodge, 5 Monivong Boulevard, PO Box 983, Phnom Penh, 12201, Cambodia
| | - Arnaud Tarantola
- Institut Pasteur du Cambodge, 5 Monivong Boulevard, PO Box 983, Phnom Penh, 12201, Cambodia
| | - Didier Menard
- Institut Pasteur du Cambodge, 5 Monivong Boulevard, PO Box 983, Phnom Penh, 12201, Cambodia
| | - Arantxa Roca-Felterer
- Malaria Consortium, House #91 Street 95, Boeung Trabek, Chamkar Morn, Phnom Penh, Cambodia
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Sim Kheng
- National Center for Parasitology, Entomology and Malaria Control, Corner St. 92, Trapeng Svay Village, Sangkat Phnom Penh, Thmei, Khan Sen Sok, Phnom Penh, Cambodia
| | - Sinoun Muth
- National Center for Parasitology, Entomology and Malaria Control, Corner St. 92, Trapeng Svay Village, Sangkat Phnom Penh, Thmei, Khan Sen Sok, Phnom Penh, Cambodia
| | - Song Ngak
- FHI 360 Cambodia Office, #03, Street 330 Boeung Keng Kang III Khan Chamkamon, PO Box: 2586, Phnom Penh, Cambodia
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit (MORU), 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand.,Oxford Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford, OX3 7FZ, UK
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit (MORU), 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand.,Oxford Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford, OX3 7FZ, UK
| | - Walter Robert John Taylor
- Mahidol Oxford Tropical Medicine Research Unit (MORU), 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand. .,Oxford Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford, OX3 7FZ, UK. .,Centre de Médecine Humanitaire, Hôpitaux Universitaires de Genève, Genève, Switzerland.
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Endoperoxide Drug Cross-Resistance Patterns for Plasmodium falciparum Exhibiting an Artemisinin Delayed-Clearance Phenotype. Antimicrob Agents Chemother 2016; 60:6952-6956. [PMID: 27600038 DOI: 10.1128/aac.00857-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/28/2016] [Indexed: 11/20/2022] Open
Abstract
The ring-stage susceptibility assay was modified to quantify the susceptibilities of multiple strains of control and delayed-clearance phenotype (DCP) Plasmodium falciparum strains to seven endoperoxide antimalarial drugs. The susceptibility of all of the DCP lines to six of the drugs was lower than that of the controls. In contrast, DCP parasites did not show reduced susceptibility to the synthetic endoperoxide drug OZ439. These data show that it is possible to circumvent emerging artemisinin resistance with a modified endoperoxide drug.
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121
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Intermittent Preventive Treatment with Dihydroartemisinin-Piperaquine in Ugandan Schoolchildren Selects for Plasmodium falciparum Transporter Polymorphisms That Modify Drug Sensitivity. Antimicrob Agents Chemother 2016; 60:5649-54. [PMID: 27401569 DOI: 10.1128/aac.00920-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/02/2016] [Indexed: 01/12/2023] Open
Abstract
Dihydroartemisinin-piperaquine (DP) offers prolonged protection against malaria, but its impact on Plasmodium falciparum drug sensitivity is uncertain. In a trial of intermittent preventive treatment in schoolchildren in Tororo, Uganda, in 2011 to 2012, monthly DP for 1 year decreased the incidence of malaria by 96% compared to placebo; DP once per school term offered protection primarily during the first month after therapy. To assess the impact of DP on selection of drug resistance, we compared the prevalence of key polymorphisms in isolates that emerged at different intervals after treatment with DP. Blood obtained monthly and at each episode of fever was assessed for P. falciparum parasitemia by microscopy. Samples from 160 symptomatic and 650 asymptomatic episodes of parasitemia were assessed at 4 loci (N86Y, Y184F, and D1246Y in pfmdr1 and K76T in pfcrt) that modulate sensitivity to aminoquinoline antimalarials, utilizing a ligase detection reaction-fluorescent microsphere assay. For pfmdr1 N86Y and pfcrt K76T, but not the other studied polymorphisms, the prevalences of mutant genotypes were significantly greater in children who had received DP within the past 30 days than in those not treated within 60 days (86Y, 18.0% versus 8.3% [P = 0.03]; 76T, 96.0% versus 86.1% [P = 0.05]), suggesting selective pressure of DP. Full sequencing of pfcrt in a subset of samples did not identify additional polymorphisms selected by DP. In summary, parasites that emerged soon after treatment with DP were more likely than parasites not under drug pressure to harbor pfmdr1 and pfcrt polymorphisms associated with decreased sensitivity to aminoquinoline antimalarials. (This study has been registered at ClinicalTrials.gov under no. NCT01231880.).
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Woodrow CJ, White NJ. The clinical impact of artemisinin resistance in Southeast Asia and the potential for future spread. FEMS Microbiol Rev 2016; 41:34-48. [PMID: 27613271 PMCID: PMC5424521 DOI: 10.1093/femsre/fuw037] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/11/2016] [Accepted: 07/31/2016] [Indexed: 11/25/2022] Open
Abstract
Artemisinins are the most rapidly acting of currently available antimalarial drugs. Artesunate has become the treatment of choice for severe malaria, and artemisinin-based combination therapies (ACTs) are the foundation of modern falciparum malaria treatment globally. Their safety and tolerability profile is excellent. Unfortunately, Plasmodium falciparum infections with mutations in the ‘K13’ gene, with reduced ring-stage susceptibility to artemisinins, and slow parasite clearance in patients treated with ACTs, are now widespread in Southeast Asia. We review clinical efficacy data from the region (2000–2015) that provides strong evidence that the loss of first-line ACTs in western Cambodia, first artesunate-mefloquine and then DHA-piperaquine, can be attributed primarily to K13 mutated parasites. The ring-stage activity of artemisinins is therefore critical for the sustained efficacy of ACTs; once it is lost, rapid selection of partner drug resistance and ACT failure are inevitable consequences. Consensus methods for monitoring artemisinin resistance are now available. Despite increased investment in regional control activities, ACTs are failing across an expanding area of the Greater Mekong subregion. Although multiple K13 mutations have arisen independently, successful multidrug-resistant parasite genotypes are taking over and threaten to spread to India and Africa. Stronger containment efforts and new approaches to sustaining long-term efficacy of antimalarial regimens are needed to prevent a global malaria emergency. Artemisinin resistance in Plasmodium falciparum malaria is causing failure of artemisinin-based combination therapies across an expanding area of Southeast Asia, undermining control and elimination efforts. The potential global consequences can only be avoided by new approaches that ensure sustained efficacy for antimalarial regimens in malaria affected populations.
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Affiliation(s)
- Charles J Woodrow
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6, Rajvithi Road, Bangkok 10400, Thailand
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6, Rajvithi Road, Bangkok 10400, Thailand
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Falq G, Van Den Bergh R, De Smet M, Etienne W, Nguon C, Rekol H, Imwong M, Dondorp A, Kindermans JM. Assessing the asymptomatic reservoir and dihydroartemisinin-piperaquine effectiveness in a low transmission setting threatened by artemisinin resistant Plasmodium falciparum. Malar J 2016; 15:446. [PMID: 27585957 PMCID: PMC5009552 DOI: 10.1186/s12936-016-1487-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/11/2016] [Indexed: 11/10/2022] Open
Abstract
Background In Cambodia, elimination of artemisinin resistance through direct elimination of the Plasmodium falciparum parasite may be the only strategy. Prevalence and incidence at district and village levels were assessed in Chey Saen district, Preah Vihear province, North of Cambodia. Molecular and clinical indicators for artemisinin resistance were documented. Methods A cross sectional prevalence survey was conducted at village level in the district of Chey Saen from September to October 2014. Plasmodium spp. was assessed with high volume quantitative real-time polymerase chain reaction (qPCR). Plasmodium falciparum-positive samples were screened for mutations in the k13-propeller domain gene. Treatment effectiveness was established after 28 days (D28) using the same qPCR technique. Data from the provincial surveillance system targeting symptomatic cases, supported by Médecins Sans Frontières (MSF), were used to assess incidence. Results District P. falciparum prevalence was of 0.74 % [0.41; 1.21]; village prevalence ranged from 0 to 4.6 % [1.4; 10.5]. The annual incidence of P. falciparum was 16.8 cases per 1000 inhabitants in the district; village incidence ranged from 1.3 to 54.9 for 1000 inhabitants. Two geographical clusters with high number of cases were identified by both approaches. The marker for artemisinin resistance was found in six samples out of the 11 tested (55 %). 34.9 % of qPCR blood analysis of symptomatic patients were still positive at D28. Conclusions The overall low prevalence of P. falciparum was confirmed in Chey Saen district in Cambodia, while there were important variations between villages. Symptomatic cases had a different pattern and were likely acquired outside the villages. It illustrates the importance of prevalence surveys in targeting interventions for elimination. Mutations in the k13-propeller domain gene (C580Y), conferring artemisinin resistance, were highly prevalent in both symptomatic and asymptomatic cases (realizing the absolute figures remain low). Asymptomatic individuals could be an additional reservoir for artemisinin resistance. The low effectiveness of dihydroartemisinin–piperaquine (DHA–PPQ) for symptomatic cases indicates that PPQ is no longer able to complement the reduced potency of DHA to treat falciparum malaria and highlights the need for an alternative first-line treatment.
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Affiliation(s)
- Grégoire Falq
- Médecins Sans Frontières, 46, rue de l'Arbre Bénit, 1050, Brussels, Belgium
| | - Rafael Van Den Bergh
- Médecins Sans Frontières, 68, rue de Gasperich, 1617, Luxembourg City, Luxembourg
| | - Martin De Smet
- Médecins Sans Frontières, 46, rue de l'Arbre Bénit, 1050, Brussels, Belgium
| | - William Etienne
- Médecins Sans Frontières, 46, rue de l'Arbre Bénit, 1050, Brussels, Belgium
| | - Chea Nguon
- Centre for Parasitology, Entomology and Malaria Control, 477 Betong Street, Village Trapangsvay, Sanakat Phnom Penh Thmey, Khan Sen Sok, Phnom Penh, Cambodia
| | - Huy Rekol
- Centre for Parasitology, Entomology and Malaria Control, 477 Betong Street, Village Trapangsvay, Sanakat Phnom Penh Thmey, Khan Sen Sok, Phnom Penh, Cambodia
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, 3/F, 60th Anniversary Chalermprakiat Building, 420/6 Rajvithi Road, Bangkok, 10400, Thailand
| | - Arjen Dondorp
- Mahidol Oxford Tropical Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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124
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The Spiroindolone KAE609 Does Not Induce Dormant Ring Stages in Plasmodium falciparum Parasites. Antimicrob Agents Chemother 2016; 60:5167-74. [PMID: 27297484 DOI: 10.1128/aac.02838-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 06/02/2016] [Indexed: 01/12/2023] Open
Abstract
In vitro drug treatment with artemisinin derivatives, such as dihydroartemisinin (DHA), results in a temporary growth arrest (i.e., dormancy) at an early ring stage in Plasmodium falciparum This response has been proposed to play a role in the recrudescence of P. falciparum infections following monotherapy with artesunate and may contribute to the development of artemisinin resistance in P. falciparum malaria. We demonstrate here that artemether does induce dormant rings, a finding which further supports the class effect of artemisinin derivatives in inducing the temporary growth arrest of P. falciparum parasites. In contrast and similarly to lumefantrine, the novel and fast-acting spiroindolone compound KAE609 does not induce growth arrest at the early ring stage of P. falciparum and prevents the recrudescence of DHA-arrested rings at a low concentration (50 nM). Our findings, together with previous clinical data showing that KAE609 is active against artemisinin-resistant K13 mutant parasites, suggest that KAE609 could be an effective partner drug with a broad range of antimalarials, including artemisinin derivatives, in the treatment of multidrug-resistant P. falciparum malaria.
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125
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Mechanism of artemisinin resistance for malaria PfATP6 L263 mutations and discovering potential antimalarials: An integrated computational approach. Sci Rep 2016; 6:30106. [PMID: 27471101 PMCID: PMC4965867 DOI: 10.1038/srep30106] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 06/27/2016] [Indexed: 11/08/2022] Open
Abstract
Artemisinin resistance in Plasmodium falciparum threatens global efforts in the elimination or eradication of malaria. Several studies have associated mutations in the PfATP6 gene in conjunction with artemisinin resistance, but the underlying molecular mechanism of the resistance remains unexplored. Associated mutations act as a biomarker to measure the artemisinin efficacy. In the proposed work, we have analyzed the binding affinity and efficacy between PfATP6 and artemisinin in the presence of L263D, L263E and L263K mutations. Furthermore, we performed virtual screening to identify potential compounds to inhibit the PfATP6 mutant proteins. In this study, we observed that artemisinin binding affinity with PfATP6 gets affected by L263D, L263E and L263K mutations. This in silico elucidation of artemisinin resistance enhanced the identification of novel compounds (CID: 10595058 and 10625452) which showed good binding affinity and efficacy with L263D, L263E and L263K mutant proteins in molecular docking and molecular dynamics simulations studies. Owing to the high propensity of the parasite to drug resistance the need for new antimalarial drugs will persist until the malarial parasites are eventually eradicated. The two compounds identified in this study can be tested in in vitro and in vivo experiments as possible candidates for the designing of new potential antimalarial drugs.
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126
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Okami S, Kohtake N. Fine-Scale Mapping by Spatial Risk Distribution Modeling for Regional Malaria Endemicity and Its Implications under the Low-to-Moderate Transmission Setting in Western Cambodia. PLoS One 2016; 11:e0158737. [PMID: 27415623 PMCID: PMC4944927 DOI: 10.1371/journal.pone.0158737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 06/21/2016] [Indexed: 11/18/2022] Open
Abstract
The disease burden of malaria has decreased as malaria elimination efforts progress. The mapping approach that uses spatial risk distribution modeling needs some adjustment and reinvestigation in accordance with situational changes. Here we applied a mathematical modeling approach for standardized morbidity ratio (SMR) calculated by annual parasite incidence using routinely aggregated surveillance reports, environmental data such as remote sensing data, and non-environmental anthropogenic data to create fine-scale spatial risk distribution maps of western Cambodia. Furthermore, we incorporated a combination of containment status indicators into the model to demonstrate spatial heterogeneities of the relationship between containment status and risks. The explanatory model was fitted to estimate the SMR of each area (adjusted Pearson correlation coefficient R2 = 0.774; Akaike information criterion AIC = 149.423). A Bayesian modeling framework was applied to estimate the uncertainty of the model and cross-scale predictions. Fine-scale maps were created by the spatial interpolation of estimated SMRs at each village. Compared with geocoded case data, corresponding predicted values showed conformity [Spearman’s rank correlation r = 0.662 in the inverse distance weighed interpolation and 0.645 in ordinal kriging (95% confidence intervals of 0.414–0.827 and 0.368–0.813, respectively), Welch’s t-test; Not significant]. The proposed approach successfully explained regional malaria risks and fine-scale risk maps were created under low-to-moderate malaria transmission settings where reinvestigations of existing risk modeling approaches were needed. Moreover, different representations of simulated outcomes of containment status indicators for respective areas provided useful insights for tailored interventional planning, considering regional malaria endemicity.
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Affiliation(s)
- Suguru Okami
- Graduate School of System Design and Management, Keio University, Kanagawa, Japan
- * E-mail:
| | - Naohiko Kohtake
- Graduate School of System Design and Management, Keio University, Kanagawa, Japan
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127
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Derek Charlwood J, Nenhep S, Sovannaroth S, Morgan JC, Hemingway J, Chitnis N, Briët OJT. 'Nature or nurture': survival rate, oviposition interval, and possible gonotrophic discordance among South East Asian anophelines. Malar J 2016; 15:356. [PMID: 27405767 PMCID: PMC4942970 DOI: 10.1186/s12936-016-1389-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 06/15/2016] [Indexed: 12/04/2022] Open
Abstract
Background Mosquito survival, oviposition interval and gonotrophic concordance are important determinants of vectorial capacity. These may vary between species or within a single species depending on the environment. They may be estimated by examination of the ovaries of host-seeking mosquitoes. Methods Landing collections, Furvela tent-trap and CDC light-trap collections were undertaken sequentially in four locations in Cambodia between February 2012 and December 2013 and samples from the collected mosquitoes were dissected to determine parity, sac stage (indicative of time spent prior to returning to feed) and egg stage. Results A total of 27,876 Anopheles from 15 species or species groups were collected in the four locations and 2883 specimens were dissected. Both the density and predominant species collected varied according to location and trapping method. Five species were dissected in sufficient numbers to allow comparisons between locations. Estimated oviposition interval differed markedly between species but less within species among different locations. Anopheles aconitus had the shortest cycle, which was 3.17 days (95 % CI 3–3.64), and Anopheles barbirostris had the longest cycle, which took four days (95 % CI 3.29–4). Anopheles minimus had a higher sac rate in weeks leading up to a full moon but there was apparently little effect of moon phase on Anopheles dirus. Despite the fact that many of the species occurred at very low densities, there was no evidence of gonotrophic dissociation in any of them, even during sustained hot, dry periods. The principal Cambodian malaria vector, An. dirus, was only common in one location where it was collected in miniature light-traps inside houses. It did not appear to have an exceptional survival rate (as judged by the low average parous rate) or oviposition cycle. Conclusions Differences in the oviposition interval were more pronounced among species within locations than within species among ecologically diverse locations. A nationwide survey using CDC light-traps for the collection of An. dirus inside houses may help in determining patterns of malaria transmission in Cambodia. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1389-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- J Derek Charlwood
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK. .,PAMVERC, P.O. Box 10, Muleba, Tanzania.
| | | | | | - John C Morgan
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Janet Hemingway
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Nakul Chitnis
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, 4003, Basel, Switzerland
| | - Olivier J T Briët
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland. .,University of Basel, 4003, Basel, Switzerland.
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Muangphrom P, Seki H, Fukushima EO, Muranaka T. Artemisinin-based antimalarial research: application of biotechnology to the production of artemisinin, its mode of action, and the mechanism of resistance of Plasmodium parasites. J Nat Med 2016; 70:318-34. [PMID: 27250562 PMCID: PMC4935751 DOI: 10.1007/s11418-016-1008-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/03/2016] [Indexed: 12/27/2022]
Abstract
Malaria is a worldwide disease caused by Plasmodium parasites. A sesquiterpene endoperoxide artemisinin isolated from Artemisia annua was discovered and has been accepted for its use in artemisinin-based combinatorial therapies, as the most effective current antimalarial treatment. However, the quantity of this compound produced from the A. annua plant is very low, and the availability of artemisinin is insufficient to treat all infected patients. In addition, the emergence of artemisinin-resistant Plasmodium has been reported recently. Several techniques have been applied to enhance artemisinin availability, and studies related to its mode of action and the mechanism of resistance of malaria-causing parasites are ongoing. In this review, we summarize the application of modern technologies to improve the production of artemisinin, including our ongoing research on artemisinin biosynthetic genes in other Artemisia species. The current understanding of the mode of action of artemisinin as well as the mechanism of resistance against this compound in Plasmodium parasites is also presented. Finally, the current situation of malaria infection and the future direction of antimalarial drug development are discussed.
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Affiliation(s)
- Paskorn Muangphrom
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hikaru Seki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ery Odette Fukushima
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Continuing Professional Development Center, Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Toshiya Muranaka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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Abstract
Eukaryotic microbial pathogens are major contributors to illness and death globally. Although much of their impact can be controlled by drug therapy as with prokaryotic microorganisms, the emergence of drug resistance has threatened these treatment efforts. Here, we discuss the challenges posed by eukaryotic microbial pathogens and how these are similar to, or differ from, the challenges of prokaryotic antibiotic resistance. The therapies used for several major eukaryotic microorganisms are then detailed, and the mechanisms that they have evolved to overcome these therapies are described. The rapid emergence of resistance and the restricted pipeline of new drug therapies pose considerable risks to global health and are particularly acute in the developing world. Nonetheless, we detail how the integration of new technology, biological understanding, epidemiology and evolutionary analysis can help sustain existing therapies, anticipate the emergence of resistance or optimize the deployment of new therapies.
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Affiliation(s)
- Alan H. Fairlamb
- Dundee Drug Discovery Unit, Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Neil A. R. Gow
- Aberdeen Fungal Group, Wellcome Trust Strategic Award in Medical Mycology and Fungal Immunology, School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Keith R. Matthews
- Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Andrew P. Waters
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical and Veterinary Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
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Ménard D, Khim N, Beghain J, Adegnika AA, Shafiul-Alam M, Amodu O, Rahim-Awab G, Barnadas C, Berry A, Boum Y, Bustos MD, Cao J, Chen JH, Collet L, Cui L, Thakur GD, Dieye A, Djallé D, Dorkenoo MA, Eboumbou-Moukoko CE, Espino FECJ, Fandeur T, Ferreira-da-Cruz MF, Fola AA, Fuehrer HP, Hassan AM, Herrera S, Hongvanthong B, Houzé S, Ibrahim ML, Jahirul-Karim M, Jiang L, Kano S, Ali-Khan W, Khanthavong M, Kremsner PG, Lacerda M, Leang R, Leelawong M, Li M, Lin K, Mazarati JB, Ménard S, Morlais I, Muhindo-Mavoko H, Musset L, Na-Bangchang K, Nambozi M, Niaré K, Noedl H, Ouédraogo JB, Pillai DR, Pradines B, Quang-Phuc B, Ramharter M, Randrianarivelojosia M, Sattabongkot J, Sheikh-Omar A, Silué KD, Sirima SB, Sutherland C, Syafruddin D, Tahar R, Tang LH, Touré OA, Tshibangu-wa-Tshibangu P, Vigan-Womas I, Warsame M, Wini L, Zakeri S, Kim S, Eam R, Berne L, Khean C, Chy S, Ken M, Loch K, Canier L, Duru V, Legrand E, Barale JC, Stokes B, Straimer J, Witkowski B, Fidock DA, Rogier C, Ringwald P, Ariey F, Mercereau-Puijalon O. A Worldwide Map of Plasmodium falciparum K13-Propeller Polymorphisms. N Engl J Med 2016; 374:2453-64. [PMID: 27332904 PMCID: PMC4955562 DOI: 10.1056/nejmoa1513137] [Citation(s) in RCA: 396] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Recent gains in reducing the global burden of malaria are threatened by the emergence of Plasmodium falciparum resistance to artemisinins. The discovery that mutations in portions of a P. falciparum gene encoding kelch (K13)-propeller domains are the major determinant of resistance has provided opportunities for monitoring such resistance on a global scale. METHODS We analyzed the K13-propeller sequence polymorphism in 14,037 samples collected in 59 countries in which malaria is endemic. Most of the samples (84.5%) were obtained from patients who were treated at sentinel sites used for nationwide surveillance of antimalarial resistance. We evaluated the emergence and dissemination of mutations by haplotyping neighboring loci. RESULTS We identified 108 nonsynonymous K13 mutations, which showed marked geographic disparity in their frequency and distribution. In Asia, 36.5% of the K13 mutations were distributed within two areas--one in Cambodia, Vietnam, and Laos and the other in western Thailand, Myanmar, and China--with no overlap. In Africa, we observed a broad array of rare nonsynonymous mutations that were not associated with delayed parasite clearance. The gene-edited Dd2 transgenic line with the A578S mutation, which expresses the most frequently observed African allele, was found to be susceptible to artemisinin in vitro on a ring-stage survival assay. CONCLUSIONS No evidence of artemisinin resistance was found outside Southeast Asia and China, where resistance-associated K13 mutations were confined. The common African A578S allele was not associated with clinical or in vitro resistance to artemisinin, and many African mutations appear to be neutral. (Funded by Institut Pasteur Paris and others.).
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Affiliation(s)
- Didier Ménard
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Nimol Khim
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Johann Beghain
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Ayola A Adegnika
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Mohammad Shafiul-Alam
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Olukemi Amodu
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Ghulam Rahim-Awab
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Céline Barnadas
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Antoine Berry
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Yap Boum
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Maria D Bustos
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Jun Cao
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Jun-Hu Chen
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Louis Collet
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Liwang Cui
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Garib-Das Thakur
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Alioune Dieye
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Djibrine Djallé
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Monique A Dorkenoo
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | | | | | - Thierry Fandeur
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | | | - Abebe A Fola
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Hans-Peter Fuehrer
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Abdillahi M Hassan
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Socrates Herrera
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Bouasy Hongvanthong
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Sandrine Houzé
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Maman L Ibrahim
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Mohammad Jahirul-Karim
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Lubin Jiang
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Shigeyuki Kano
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Wasif Ali-Khan
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Maniphone Khanthavong
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Peter G Kremsner
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Marcus Lacerda
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Rithea Leang
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Mindy Leelawong
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Mei Li
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Khin Lin
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Jean-Baptiste Mazarati
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Sandie Ménard
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Isabelle Morlais
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | | | - Lise Musset
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Kesara Na-Bangchang
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Michael Nambozi
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Karamoko Niaré
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Harald Noedl
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Jean-Bosco Ouédraogo
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Dylan R Pillai
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Bruno Pradines
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Bui Quang-Phuc
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Michael Ramharter
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | | | - Jetsumon Sattabongkot
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Abdiqani Sheikh-Omar
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Kigbafori D Silué
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Sodiomon B Sirima
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Colin Sutherland
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Din Syafruddin
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Rachida Tahar
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Lin-Hua Tang
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Offianan A Touré
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | | | - Inès Vigan-Womas
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Marian Warsame
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Lyndes Wini
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Sedigheh Zakeri
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Saorin Kim
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Rotha Eam
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Laura Berne
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Chanra Khean
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Sophy Chy
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Malen Ken
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Kaknika Loch
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Lydie Canier
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Valentine Duru
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Eric Legrand
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Jean-Christophe Barale
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Barbara Stokes
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Judith Straimer
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Benoit Witkowski
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - David A Fidock
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Christophe Rogier
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Pascal Ringwald
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
| | - Frederic Ariey
- The authors' affiliations are listed in the Supplementary Appendix , available at NEJM.org
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Efficacy and Safety of Pyronaridine-Artesunate for Treatment of Uncomplicated Plasmodium falciparum Malaria in Western Cambodia. Antimicrob Agents Chemother 2016; 60:3884-90. [PMID: 26926629 DOI: 10.1128/aac.00039-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/25/2016] [Indexed: 01/28/2023] Open
Abstract
Pyronaridine-artesunate efficacy for the treatment of uncomplicated Plasmodium falciparum malaria was assessed in an area of artemisinin resistance in western Cambodia. This nonrandomized, single-arm, observational study was conducted between 2014 and 2015. Eligible patients were adults or children with microscopically confirmed P. falciparum infection and fever. Patients received pyronaridine-artesunate once daily for 3 days, dosed according to body weight. The primary outcome was an adequate clinical and parasitological response (ACPR) on day 42, estimated by using Kaplan-Meier analysis, PCR adjusted to exclude reinfection. One hundred twenty-three patients were enrolled. Day 42 PCR-crude ACPRs were 87.2% (95% confidence interval [CI], 79.7 to 92.6%) for the overall study, 89.8% (95% CI, 78.8 to 95.3%) for Pursat, and 82.1% (95% CI, 68.4 to 90.2%) for Pailin. Day 42 PCR-adjusted ACPRs were 87.9% (95% CI, 80.6 to 93.2%) for the overall study, 89.8% (95% CI, 78.8 to 95.3%) for Pursat, and 84.0% (95% CI, 70.6 to 91.7%) for Pailin (P = 0.353 by a log rank test). Day 28 PCR-crude and -adjusted ACPRs were 93.2% (95% CI, 82.9 to 97.4%) and 88.1% (95% CI, 75.3 to 94.5%) for Pursat and Pailin, respectively. A significantly lower proportion of patients achieved day 3 parasite clearance in Pailin (56.4% [95% CI, 43.9 to 69.6%]) than in Pursat (86.7% [95% CI, 76.8 to 93.8%]; P = 0.0019). Fever clearance was also extended at Pailin versus Pursat (P < 0.0001). Most patients (95.9% [116/121]) harbored P. falciparum kelch13 C580Y mutant parasites. Pyronaridine-artesunate was well tolerated; mild increases in hepatic transaminase levels were consistent with data from previous reports. Pyronaridine-artesunate efficacy was below the World Health Organization-recommended threshold at day 42 for medicines with a long half-life (90%) for first-line treatment of P. falciparum malaria in western Cambodia despite high efficacy elsewhere in Asia and Africa. (This study has been registered at ClinicalTrials.gov under registration number NCT02389439.).
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Wamae KK, Ochola-Oyier LI. Implications from predicted B-cell and T-cell epitopes of Plasmodium falciparum merozoite proteins EBA175-RII and Rh5. Bioinformation 2016; 12:82-91. [PMID: 28149040 PMCID: PMC5267949 DOI: 10.6026/97320630012082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/21/2016] [Accepted: 03/25/2016] [Indexed: 11/23/2022] Open
Abstract
The leading circumsporozoite protein (CSP) based malaria vaccine, RTS,S, though promising, has shown limited efficacy in field studies. There is therefore, still a need to identify other malaria vaccine targets. Merozoite antigens are potential vaccine candidates, since naturally acquired antibodies generated against them inhibit erythrocyte invasion and in some cases result in the clinical protection from disease. We thus used in silico tools (BCPreds, NetMHCcons and NetMHCIIpan 3.0) to predict B-cell epitopes (BCEs) and T-cell epitopes (TCEs) in two merozoite invasion proteins, EBA175-RII and Rh5. Initially, we validated these tools using CSP to determine whether the algorithms could predict the epitopes in the RTS,S vaccine. In EBA175-RII, we prioritised three BCEs 15REKRKGMKWDCKKKNDRSNY34, 420SNRKLVGKINTNSNYVHRNKQ440 and 528WISKKKEEYNKQAKQYQEYQ547, a CD8+ epitope 553KMYSEFKSI561 and a CD4+ epitope 440QNDKLFRDEWWK VIKKD456. Three Rh5 epitopes were prioritised, a BCE 344SCYNNNFCNTNGIRYHYDEY363, a CD8+ epitope 198STYGKCIAV206 and a Rh5 CD4+ epitope 180TFLDYYKHLSYNSIYHKSSTY200. All these epitopes are in the region involved in the proteins' interaction with their erythrocyte receptors, thus enabling erythrocyte invasion. Therefore, upon validation of their immunogenicity, by ELISA using serum from a malaria endemic population, antibodies to these epitopes may inhibit erythrocyte invasion. All the epitopes we predicted in EBA175-RII and Rh5 are novel. We also identified polymorphic epitopes that may escape host immunity, as some variants were not predicted as epitopes, suggesting that they may not be immunogenic regions. We present a set of epitopes that following in vitro validation provide a set of molecules to screen as potential vaccine candidates.
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Affiliation(s)
- Kevin Kariuki Wamae
- Centre for Biotechnology and Bioinformatics, University of Nairobi, Kenya
- KEMRI-Wellcome Trust Collaborative Programme,Kilifi, Kenya; P.O. Box 230, Kilifi – 80108, Kenya
| | - Lynette Isabella Ochola-Oyier
- Centre for Biotechnology and Bioinformatics, University of Nairobi, Kenya
- KEMRI-Wellcome Trust Collaborative Programme,Kilifi, Kenya; P.O. Box 230, Kilifi – 80108, Kenya
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Tilley L, Straimer J, Gnädig NF, Ralph SA, Fidock DA. Artemisinin Action and Resistance in Plasmodium falciparum. Trends Parasitol 2016; 32:682-696. [PMID: 27289273 DOI: 10.1016/j.pt.2016.05.010] [Citation(s) in RCA: 206] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/10/2016] [Accepted: 05/13/2016] [Indexed: 12/16/2022]
Abstract
The worldwide use of artemisinin-based combination therapies (ACTs) has contributed in recent years to a substantial reduction in deaths resulting from Plasmodium falciparum malaria. Resistance to artemisinins, however, has emerged in Southeast Asia. Clinically, resistance is defined as a slower rate of parasite clearance in patients treated with an artemisinin derivative or an ACT. These slow clearance rates associate with enhanced survival rates of ring-stage parasites briefly exposed in vitro to dihydroartemisinin. We describe recent progress made in defining the molecular basis of artemisinin resistance, which has identified a primary role for the P. falciparum K13 protein. Using K13 mutations as molecular markers, epidemiological studies are now tracking the emergence and spread of artemisinin resistance. Mechanistic studies suggest potential ways to overcome resistance.
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Affiliation(s)
- Leann Tilley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Australia.
| | - Judith Straimer
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Nina F Gnädig
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Australia
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY, USA; Division of Infectious Diseases, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA.
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134
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Fairhurst RM, Dondorp AM. Artemisinin-Resistant Plasmodium falciparum Malaria. Microbiol Spectr 2016; 4:10.1128/microbiolspec.EI10-0013-2016. [PMID: 27337450 PMCID: PMC4992992 DOI: 10.1128/microbiolspec.ei10-0013-2016] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Indexed: 01/05/2023] Open
Abstract
For more than five decades, Southeast Asia (SEA) has been fertile ground for the emergence of drug-resistant Plasmodium falciparum malaria. After generating parasites resistant to chloroquine, sulfadoxine, pyrimethamine, quinine, and mefloquine, this region has now spawned parasites resistant to artemisinins, the world's most potent antimalarial drugs. In areas where artemisinin resistance is prevalent, artemisinin combination therapies (ACTs)-the first-line treatments for malaria-are failing fast. This worrisome development threatens to make malaria practically untreatable in SEA, and threatens to compromise global endeavors to eliminate this disease. A recent series of clinical, in vitro, genomics, and transcriptomics studies in SEA have defined in vivo and in vitro phenotypes of artemisinin resistance, identified its causal genetic determinant, explored its molecular mechanism, and assessed its clinical impact. Specifically, these studies have established that artemisinin resistance manifests as slow parasite clearance in patients and increased survival of early-ring-stage parasites in vitro; is caused by single nucleotide polymorphisms in the parasite's K13 gene, is associated with an upregulated "unfolded protein response" pathway that may antagonize the pro-oxidant activity of artemisinins, and selects for partner drug resistance that rapidly leads to ACT failures. In SEA, clinical studies are urgently needed to monitor ACT efficacy where K13 mutations are prevalent, test whether new combinations of currently available drugs cure ACT failures, and advance new antimalarial compounds through preclinical pipelines and into clinical trials. Intensifying these efforts should help to forestall the spread of artemisinin and partner drug resistance from SEA to sub-Saharan Africa, where the world's malaria transmission, morbidity, and mortality rates are highest.
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Affiliation(s)
- Rick M. Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, United States of America
| | - Arjen M. Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, United Kingdom
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Charlwood JD, Nenhep S, Protopopoff N, Sovannaroth S, Morgan JC, Hemingway J. Effects of the spatial repellent metofluthrin on landing rates of outdoor biting anophelines in Cambodia, Southeast Asia. MEDICAL AND VETERINARY ENTOMOLOGY 2016; 30:229-34. [PMID: 26991881 DOI: 10.1111/mve.12168] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/03/2015] [Accepted: 01/15/2016] [Indexed: 05/16/2023]
Abstract
The emergence of artemisinin-resistant malaria in Southeast Asia is a major problem. The fact that many people become infected with malaria when they are outside has prompted the development of 'spatial' rather than topical repellents. The respective effects of one or four slow-release emanators of metofluthrin, a pyrethroid, were tested in Pailin, Pursat and Koh Kong, Cambodia. Numbers of mosquitoes counted in outdoor landing catches when one or four emanators were suspended close to the collector were compared with control collections. In Pailin, the effects of emanators on catches in Furvela tent traps and Centers for Disease Control (CDC) light traps suspended underneath houses were also investigated. Rate ratios were used to determine differences. A total of 29 255 mosquitoes were collected over 2934 h of landing collections, 87 nights of tent trapping and 81 nights of light trap capture. In Pailin, landing rates were reduced by 48% by a single emanator and by 67% by four emanators (P < 0.001). Similar reductions were observed in the number of mosquitoes collected in tent traps and the number of anophelines only collected in light traps. Results were similar in Pursat, but, for unknown reasons, those in Koh Kong showed no difference between control and metofluthrin collections (P > 0.05). These findings suggest that although the product can produce a significant effect, it requires further improvement.
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Affiliation(s)
- J D Charlwood
- Department of Entomology, Liverpool School of Tropical Medicine, Liverpool, U.K
- SOREMA, IRD, Phnom Penh, Cambodia
| | - S Nenhep
- Centro Nacional de Malaria (CNM), Phnom Penh, Cambodia
| | - N Protopopoff
- PAMVERC Project, London School of Hygiene and Tropical Medicine, Moshi, Tanzania
| | - S Sovannaroth
- Centro Nacional de Malaria (CNM), Phnom Penh, Cambodia
| | - J C Morgan
- Department of Entomology, Liverpool School of Tropical Medicine, Liverpool, U.K
| | - J Hemingway
- Department of Entomology, Liverpool School of Tropical Medicine, Liverpool, U.K
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136
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Abstract
For more than five decades, Southeast Asia (SEA) has been fertile ground for the emergence of drug-resistant Plasmodium falciparum malaria. After generating parasites resistant to chloroquine, sulfadoxine, pyrimethamine, quinine, and mefloquine, this region has now spawned parasites resistant to artemisinins, the world's most potent antimalarial drugs. In areas where artemisinin resistance is prevalent, artemisinin combination therapies (ACTs)-the first-line treatments for malaria-are failing fast. This worrisome development threatens to make malaria practically untreatable in SEA, and threatens to compromise global endeavors to eliminate this disease. A recent series of clinical, in vitro, genomics, and transcriptomics studies in SEA have defined in vivo and in vitro phenotypes of artemisinin resistance, identified its causal genetic determinant, explored its molecular mechanism, and assessed its clinical impact. Specifically, these studies have established that artemisinin resistance manifests as slow parasite clearance in patients and increased survival of early-ring-stage parasites in vitro; is caused by single nucleotide polymorphisms in the parasite's K13 gene, is associated with an upregulated "unfolded protein response" pathway that may antagonize the pro-oxidant activity of artemisinins, and selects for partner drug resistance that rapidly leads to ACT failures. In SEA, clinical studies are urgently needed to monitor ACT efficacy where K13 mutations are prevalent, test whether new combinations of currently available drugs cure ACT failures, and advance new antimalarial compounds through preclinical pipelines and into clinical trials. Intensifying these efforts should help to forestall the spread of artemisinin and partner drug resistance from SEA to sub-Saharan Africa, where the world's malaria transmission, morbidity, and mortality rates are highest.
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137
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Khin HSS, Aung T, Thi A, White C. Oral artemisinin monotherapy removal from the private sector in Eastern Myanmar between 2012 and 2014. Malar J 2016; 15:286. [PMID: 27216408 PMCID: PMC4877749 DOI: 10.1186/s12936-016-1292-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 04/13/2016] [Indexed: 11/19/2022] Open
Abstract
Background In 2012 the Artemisinin Monotherapy Therapy Replacement (AMTR) project was implemented in Eastern Myanmar to increase access to subsidized, quality-assured artemisinin combination therapy (ACT) and to remove oral artemisinin monotherapy (AMT) from the private sector. The aim of this paper is to examine changes over time in the private sector anti-malarial landscape and to illustrate the value of complementary interventions in the context of a national ACT subsidy. Methods Three rounds of cross-sectional malaria medicine outlet surveys were conducted, in 2012, 2013 and 2014. Project intervention areas were selected from the Myanmar Artemisinin Resistance Containment (MARC) area. Provider detailing was implemented in these selected areas. Comparison areas were selected outside of this catchment area, from townships in close proximity to the MARC framework. Within each domain, multi-staged sampling was used to select areas for the survey. Outlets with the potential to sell or distribute anti-malarials in the private sector were screened for eligibility. Results The total number of outlets approached for an interview was as follows in the intervention and comparison areas, respectively: 2012, N = 2046 and 1612; 2013, N = 1636 and 1884; 2014, N = 2939 and 2941. The percentage of pharmacies, general retailers and mobile providers (classed as ‘priority outlets’) with oral AMT in stock on the day of the survey decreased over time in the intervention areas (2012 = 68 %; 2013 = 48 %; 2014 = 10 %). Conversely, quality-assured ACT availability increased among these outlets (2012 = 4 %; 2013 = 62 %; 2014 = 79 %). Relative oral AMT market share among priority outlets also decreased over time (2012 = 44 %; 2013 = 18 %; 2014 = 14 %), while market share of quality-assured ACT increased (2012 = 3 %; 2013 = 59 %; 2014 = 51 %). Among priority outlets in the comparison area, similar trends were observed, though changes over time were less substantial compared to the intervention area. Other outlet types (community health workers and health facilities) performed relatively well over time though modest improvements were also observed. Conclusion The findings point to the successful design and implementation of a strategy to rapidly remove oral AMT from pharmacies, general retailers and mobile providers and to replace its use with quality-assured ACT. The evidence also highlights the importance of supporting interventions in the context of a high-level subsidy. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1292-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hnin Su Su Khin
- Population Services International Myanmar, No. 16, Shwe Gon Taing Street 4, Yangon, Myanmar.
| | - Tin Aung
- Population Services International Myanmar, No. 16, Shwe Gon Taing Street 4, Yangon, Myanmar
| | - Aung Thi
- National Malaria Control Program, Department of Public Health, Ministry of Health, Naypyidaw, Myanmar
| | - Chris White
- Division of Global Policy & Advocacy, Bill & Melinda Gates Foundation, Seattle, WA, USA
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Ley B, Alam MS, Thriemer K, Hossain MS, Kibria MG, Auburn S, Poirot E, Price RN, Khan WA. G6PD Deficiency and Antimalarial Efficacy for Uncomplicated Malaria in Bangladesh: A Prospective Observational Study. PLoS One 2016; 11:e0154015. [PMID: 27128675 PMCID: PMC4851315 DOI: 10.1371/journal.pone.0154015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/07/2016] [Indexed: 12/19/2022] Open
Abstract
Background The Bangladeshi national treatment guidelines for uncomplicated malaria follow WHO recommendations but without G6PD testing prior to primaquine administration. A prospective observational study was conducted to assess the efficacy of the current antimalarial policy. Methods Patients with uncomplicated malaria, confirmed by microscopy, attending a health care facility in the Chittagong Hill Tracts, Bangladesh, were treated with artemether-lumefantrine (days 0–2) plus single dose primaquine (0.75mg/kg on day2) for P. falciparum infections, or with chloroquine (days 0–2) plus 14 days primaquine (3.5mg/kg total over 14 days) for P. vivax infections. Hb was measured on days 0, 2 and 9 in all patients and also on days 16 and 30 in patients with P. vivax infection. Participants were followed for 30 days. The study was registered with the clinical trials website (NCT02389374). Results Between September 2014 and February 2015 a total of 181 patients were enrolled (64% P. falciparum, 30% P. vivax and 6% mixed infections). Median parasite clearance times were 22.0 (Interquartile Range, IQR: 15.2–27.3) hours for P. falciparum, 20.0 (IQR: 9.5–22.7) hours for P. vivax and 16.6 (IQR: 10.0–46.0) hours for mixed infections. All participants were afebrile within 48 hours, two patients with P. falciparum infection remained parasitemic at 48 hours. No patient had recurrent parasitaemia within 30 days. Adjusted male median G6PD activity was 7.82U/gHb. One male participant (1/174) had severe G6PD deficiency (<10% activity), five participants (5/174) had mild G6PD deficiency (10–60% activity). The Hb nadir occurred on day 2 prior to primaquine treatment in P. falciparum and P. vivax infected patients; mean fractional fall in Hb was -8.8% (95%CI -6.7% to -11.0%) and -7.4% (95%CI: -4.5 to -10.4%) respectively. Conclusion The current antimalarial policy remains effective. The prevalence of G6PD deficiency was low. Main contribution to haemolysis in G6PD normal individuals was attributable to acute malaria rather than primaquine administration. Trial Registration ClinicalTrials.gov NCT02389374
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Affiliation(s)
- Benedikt Ley
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | | | - Kamala Thriemer
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | | | | | - Sarah Auburn
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Eugenie Poirot
- Global Health Group, University of California San Francisco, San Francisco, California, United States of America
| | - Ric N. Price
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Wasif Ali Khan
- International Centre for Diarrheal Diseases and Research, Dhaka, Bangladesh
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Lee AH, Fidock DA. Evidence of a Mild Mutator Phenotype in Cambodian Plasmodium falciparum Malaria Parasites. PLoS One 2016; 11:e0154166. [PMID: 27100094 PMCID: PMC4839739 DOI: 10.1371/journal.pone.0154166] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 04/09/2016] [Indexed: 12/22/2022] Open
Abstract
Malaria control efforts have been continuously stymied by drug-resistant strains of Plasmodium falciparum, which typically originate in Southeast Asia prior to spreading into high-transmission settings in Africa. One earlier proposed explanation for Southeast Asia being a hotbed of resistance has been the hypermutability or "Accelerated Resistance to Multiple Drugs" (ARMD) phenotype, whereby multidrug-resistant Southeast Asian parasites were reported to exhibit 1,000-fold higher rates of resistance to unrelated antimalarial agents when compared to drug-sensitive parasites. However, three recent studies do not recapitulate this hypermutability phenotype. Intriguingly, genome sequencing of recently derived multidrug-resistant Cambodian isolates has identified a high proportion of DNA repair gene mutations in multidrug-resistant parasites, suggesting their potential role in shaping local parasite evolution. By adapting fluctuation assays for use in P. falciparum, we have examined the in vitro mutation rates of five recent Cambodian isolates and three reference laboratory strains. For these studies we also generated a knockout parasite line lacking the DNA repair factor Exonuclease I. In these assays, parasites were typed for their ability to acquire resistance to KAE609, currently in advanced clinical trials, yielding 13 novel mutations in the Na+/H+-ATPase PfATP4, the primary resistance determinant. We observed no evidence of hypermutability. Instead, we found evidence of a mild mutator (up to a 3.4-fold increase in mutation rate) phenotype in two artemisinin-resistant Cambodian isolates, which carry DNA repair gene mutations. We observed that one such mutation in the Mismatch Repair protein Mlh1 contributes to the mild mutator phenotype when modeled in yeast (scmlh1-P157S). Compared to basal rates of mutation, a mild mutator phenotype may provide a greater overall benefit for parasites in Southeast Asia in terms of generating drug resistance without incurring detrimental fitness costs.
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Affiliation(s)
- Andrew H. Lee
- Department of Microbiology and Immunology, Columbia University, New York, New York, United States of America
| | - David A. Fidock
- Department of Microbiology and Immunology, Columbia University, New York, New York, United States of America
- Division of Infectious Diseases, Department of Medicine, Columbia University, New York, New York, United States of America
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Lo E, Nguyen J, Oo W, Hemming-Schroeder E, Zhou G, Yang Z, Cui L, Yan G. Examining Plasmodium falciparum and P. vivax clearance subsequent to antimalarial drug treatment in the Myanmar-China border area based on quantitative real-time polymerase chain reaction. BMC Infect Dis 2016; 16:154. [PMID: 27084511 PMCID: PMC4833920 DOI: 10.1186/s12879-016-1482-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 03/25/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recent emergence of artemisinin-resistant P. falciparum has posed a serious hindrance to the elimination of malaria in the Greater Mekong Subregion. Parasite clearance time, a measure of change in peripheral parasitaemia in a sequence of samples taken after treatment, can be used to reflect the susceptibility of parasites or the efficiency of antimalarials. The association of genetic polymorphisms and artemisinin resistance has been documented. This study aims to examine clearance time of P. falciparum and P. vivax parasitemia as well as putative gene mutations associated with residual or recurred parasitemia in Myanmar. METHODS A total of 63 P. falciparum and 130 P. vivax samples collected from two internally-displaced populations and one surrounding village were examined for parasitemia changes. At least four samples were taken from each patient, at the first day of diagnosis up to 3 months following the initial treatment. The amount of parasite gene copy number was estimated using quantitative real-time PCR based on a species-specific region of the 18S rRNA gene. For samples that showed residual or recurred parasitemia after treatment, microsatellites were used to identify the 'post-treatment' parasite genotype and compared such with the 'pre-treatment' genotype. Mutations in genes pfcrt, pfmdr1, pfatp6, pfmrp1 and pfK13 that are potentially associated with ACT resistance were examined to identify if mutation is a factor for residual or persistent parasitemia. RESULTS Over 30% of the P. falciprium infections showed delayed clearance of parasitemia after 2-3 days of treatment and 9.5% showed recurred parasitemia. Mutations in codon 876 of the pfmrp1 corroborated significance association with slow clearance time. However, no association was observed in the variation in pfmdr1 gene copy number as well as mutations of various codonsinpfatp6, pfcrt, and pfK13 with clearance time. For P. vivax, over 95% of the infections indicated cleared parasitemia at days 2-3 of treatment. Four samples were found to be re-infected with new parasite strains based on microsatellite genotypes after initial treatment. CONCLUSION The appearance of P.falciparum infected samples showing delayed clearance or recurred parasitemia after treatment raises concerns on current treatment and ACT drug resistance.
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Affiliation(s)
- Eugenia Lo
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
| | - Jennifer Nguyen
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
| | - Winny Oo
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
| | | | - Guofa Zhou
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
| | - Zhaoqing Yang
- />Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Liwang Cui
- />Department of Entomology, Pennsylvania State University, University Park, PA USA
| | - Guiyun Yan
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
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Novotny J, Singh A, Dysoley L, Sovannaroth S, Rekol H. Evidence of successful malaria case management policy implementation in Cambodia: results from national ACTwatch outlet surveys. Malar J 2016; 15:194. [PMID: 27059952 PMCID: PMC4826540 DOI: 10.1186/s12936-016-1200-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 03/01/2016] [Indexed: 01/11/2023] Open
Abstract
Background For over a decade, Cambodia has implemented a number of policies and innovative strategies to increase access to quality malaria case management services and address the drivers of multi-drug resistance. This paper utilizes outlet survey trend data collected by the ACTwatch project to demonstrate how changes in Cambodian policy and strategies have led to shifts in anti-malarial markets. Methods Anti-malarial ACTwatch outlet surveys were conducted in Cambodia in 2009 (June–July), 2011 (June–August) and 2013 (September–October). A census of all outlets with the potential to sell or distribute anti-malarials was conducted within a nationally representative sample of communes. Drug information, sales/distribution in the previous week, and retail price were collected for each anti-malarial in stock. Information on availability of malaria blood testing was also collected. Results A total of 7833 outlets were enumerated in 2009, 18,584 in 2011, and 16,153 in 2013. The percentage of public health facilities with at least one anti-malarial in stock on the day of the survey increased between 2009 (65.8 %) and 2011 (90.0 %) and remained high in 2013 (82.0 %). Similar trends were found for village malaria workers (VMW). Overall, private sector availability of anti-malarials declined over time and varied by outlet type. By 2013 most anti-malarial stocking public health facilities (81.5 %), VMW (95.4 %), private for-profit health facilities (64.8 %), and pharmacies (71.9 %) had the countries first-line artemisinin-based combination therapy (ACT) treatment in stock. In 2013, 60 % of anti-malarials were delivered through the private sector, 40 % through the public sector, and the most common anti-malarial to be sold or distributed was the first-line ACT, comprising 62.8 % of the national market share. Oral artemisinin monotherapy, which had accounted for 6 % of total anti-malarial market share in 2009, was no longer reportedly sold/distributed in 2013. Malaria blood testing availability remained high over time among public facilities and VMW, with availability over 90 % in 2011 and 2013. Moderate availability was observed in the private sector. Conclusions Continued implementation of successful public and private sector strategies in support of evolving malaria drug treatment policies will be important to protect the efficacy of anti-malarial medicines and ultimately facilitate malaria elimination in Cambodia by 2025. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1200-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Joe Novotny
- Clinton Health Access Initiative, #7B, Str. 81 and corner Str. 109, Sangkat Boeung Raing, Khan Don Penh, Phnom Penh, Cambodia
| | - Amandeep Singh
- Clinton Health Access Initiative, #7B, Str. 81 and corner Str. 109, Sangkat Boeung Raing, Khan Don Penh, Phnom Penh, Cambodia
| | - Lek Dysoley
- Cambodia National Centre of Entomology, Parasitological and Malaria control, House 372, St Monivong Vong, Boeung Keng Kang I, Chamcar Mon, Phnom Penh, Cambodia.,School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Siv Sovannaroth
- Cambodia National Centre of Entomology, Parasitological and Malaria control, House 372, St Monivong Vong, Boeung Keng Kang I, Chamcar Mon, Phnom Penh, Cambodia
| | - Huy Rekol
- Cambodia National Centre of Entomology, Parasitological and Malaria control, House 372, St Monivong Vong, Boeung Keng Kang I, Chamcar Mon, Phnom Penh, Cambodia
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Li J, Chen J, Xie D, Eyi UM, Matesa RA, Ondo Obono MM, Ehapo CS, Yang L, Yang H, Lin M. Limited artemisinin resistance-associated polymorphisms in Plasmodium falciparum K13-propeller and PfATPase6 gene isolated from Bioko Island, Equatorial Guinea. Int J Parasitol Drugs Drug Resist 2016; 6:54-59. [PMID: 27054064 PMCID: PMC4805774 DOI: 10.1016/j.ijpddr.2015.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/03/2015] [Accepted: 11/25/2015] [Indexed: 02/05/2023]
Abstract
OBJECTIVE With emergence and geographically expanding of antimalarial resistance worldwide, molecular markers are essential tool for surveillance of resistant Plasmodium parasites. Recently, single-nucleotide polymorphisms (SNPs) in the PF3D7_1343700 kelch propeller (K13-propeller) domain are shown to be associated with artemisinin (ART) resistance in vivo and in vitro. This study aims to investigate the ART resistance-associated polymorphisms of K13-propeller and PfATPase6 genes in Plasmodium falciparum isolates from Bioko Island, Equatorial Guinea (EG). METHODS A total of 172 samples were collected from falciparum malaria patients on Bioko Island between 2013 and 2014. The polymorphisms of K13-propeller and PfATPase6 genes were analyzed by Nest-PCR and sequencing. RESULTS Sequences of K13-propeller and PfATPase6 were obtained from 90.74% (98/108) and 91.45% (139/152) samples, respectively. The 2.04% (2/98) cases had non-synonymous K13-propeller A578S mutation but no found the mutations associated with ART resistance in Southeast Asia. For PfATPase6, the mutations were found at positions N569K and A630S with the mutation prevalence of 7.91% (11/139) and 1.44% (2/139), respectively. In addition, a sample with the mixed type at position I723V was discovered (0.72%, 1/139). CONCLUSIONS This study initially offers an insight of K13-propeller and PfATPase6 polymorphisms on Bioko Island, EG. It suggests no widespread ART resistance or tolerance in the region, and might be helpful for developing and updating guidance for the use of ART-based combination therapies (ACTs).
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Affiliation(s)
- Jian Li
- Institute of Basic Medical Sciences, College of Basic Medicine, Department of Infectious Diseases, Renmin Hospital, Hubei University of Medicine, Shiyan 442000, People's Republic of China
| | - Jiangtao Chen
- Laboratory Medical Center, Huizhou Municipal Central Hospital, Huizhou 516001, People's Republic of China; The Chinese Medical Aid Team to the Republic of Equatorial Guinea, Guangzhou 510000, People's Republic of China
| | - Dongde Xie
- The Chinese Medical Aid Team to the Republic of Equatorial Guinea, Guangzhou 510000, People's Republic of China
| | - Urbano Monsuy Eyi
- Central Blood Transfusion Service, Department of Medical Laboratory Science, Malabo Regional Hospital, Malabo 999115, Equatorial Guinea
| | - Rocio Apicante Matesa
- Central Blood Transfusion Service, Department of Medical Laboratory Science, Malabo Regional Hospital, Malabo 999115, Equatorial Guinea
| | - Maximo Miko Ondo Obono
- Central Blood Transfusion Service, Department of Medical Laboratory Science, Malabo Regional Hospital, Malabo 999115, Equatorial Guinea
| | - Carlos Sala Ehapo
- Central Blood Transfusion Service, Department of Medical Laboratory Science, Malabo Regional Hospital, Malabo 999115, Equatorial Guinea
| | - Liye Yang
- Laboratory Medical Center, Chaozhou Central Hospital, Southern Medical University, Chaozhou 521021, People's Republic of China
| | - Huitian Yang
- Laboratory Medical Center, Chaozhou Central Hospital, Southern Medical University, Chaozhou 521021, People's Republic of China
| | - Min Lin
- Laboratory Medical Center, Chaozhou Central Hospital, Southern Medical University, Chaozhou 521021, People's Republic of China; Department of Histology and Embryology, Shantou University Medical College, Shantou 515000, Guangdong, People's Republic of China.
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143
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Tun KM, Jeeyapant A, Imwong M, Thein M, Aung SSM, Hlaing TM, Yuentrakul P, Promnarate C, Dhorda M, Woodrow CJ, Dondorp AM, Ashley EA, Smithuis FM, White NJ, Day NPJ. Parasite clearance rates in Upper Myanmar indicate a distinctive artemisinin resistance phenotype: a therapeutic efficacy study. Malar J 2016; 15:185. [PMID: 27036739 PMCID: PMC4815199 DOI: 10.1186/s12936-016-1240-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 03/16/2016] [Indexed: 01/23/2023] Open
Abstract
Background Artemisinin resistance in Plasmodium falciparum extends across Southeast Asia where it is associated with worsening partner drug resistance and a decline in the efficacy of frontline artemisinin-based combination therapy. Dihydroartemisinin-piperaquine (DP) is an essential component of preventive and curative treatment in the region, but its therapeutic efficacy has fallen in Cambodia. Methods A prospective clinical and parasitological evaluation of DP was conducted at two sites in Upper Myanmar between August 2013 and December 2014, enrolling 116 patients with acute uncomplicated falciparum malaria. Patients received DP orally for 3 days together with primaquine 0.25 mg/kg on admission. Parasite clearance half-lives based on 6 hourly blood smears, and day 42 therapeutic responses were assessed as well as parasite K13 genotypes. Results Median parasite clearance half-life was prolonged, and clearance half-life was greater than 5 h in 21 % of patients. Delayed parasite clearance was significantly associated with mutations in the propeller region of the parasite k13 gene. The k13 F446I mutation was found in 25.4 % of infections and was associated with a median clearance half-life of 4.7 h compared with 2.7 h for infections without k13 mutations (p < 0.001). There were no failures after 42 days of follow-up, although 18 % of patients had persistent parasitaemia on day 3. Conclusion The dominant k13 mutation observed in Upper Myanmar, F446I, appears to be associated with an intermediate rate of parasite clearance compared to other common mutations described elsewhere in the Greater Mekong Subregion. Discerning this phenotype requires relatively detailed clearance measurements, highlighting the importance of methodology in assessing artemisinin resistance. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1240-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kyaw Myo Tun
- Defence Services Medical Research Centre, Naypyitaw, Myanmar.,Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
| | - Atthanee Jeeyapant
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Rd., Ratchathewi District, Bangkok, 10400, Thailand
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Min Thein
- Defence Services Medical Research Centre, Naypyitaw, Myanmar
| | | | | | - Prayoon Yuentrakul
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Rd., Ratchathewi District, Bangkok, 10400, Thailand
| | | | - Mehul Dhorda
- Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.,Worldwide Antimalarial Resistance Network (WWARN), Bangkok, Thailand
| | - Charles J Woodrow
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Rd., Ratchathewi District, Bangkok, 10400, Thailand.,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Rd., Ratchathewi District, Bangkok, 10400, Thailand.,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Elizabeth A Ashley
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Rd., Ratchathewi District, Bangkok, 10400, Thailand
| | - Frank M Smithuis
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar.,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.,Medical Action Myanmar, Yangon, Myanmar
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Rd., Ratchathewi District, Bangkok, 10400, Thailand.,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Rd., Ratchathewi District, Bangkok, 10400, Thailand. .,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.
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Pulice G, Pelaz S, Matías-Hernández L. Molecular Farming in Artemisia annua, a Promising Approach to Improve Anti-malarial Drug Production. FRONTIERS IN PLANT SCIENCE 2016; 7:329. [PMID: 27047510 PMCID: PMC4796020 DOI: 10.3389/fpls.2016.00329] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 03/03/2016] [Indexed: 05/03/2023]
Abstract
Malaria is a parasite infection affecting millions of people worldwide. Even though progress has been made in prevention and treatment of the disease; an estimated 214 million cases of malaria occurred in 2015, resulting in 438,000 estimated deaths; most of them occurring in Africa among children under the age of five. This article aims to review the epidemiology, future risk factors and current treatments of malaria, with particular focus on the promising potential of molecular farming that uses metabolic engineering in plants as an effective anti-malarial solution. Malaria represents an example of how a health problem may, on one hand, influence the proper development of a country, due to its burden of the disease. On the other hand, it constitutes an opportunity for lucrative business of diverse stakeholders. In contrast, plant biofarming is proposed here as a sustainable, promising, alternative for the production, not only of natural herbal repellents for malaria prevention but also for the production of sustainable anti-malarial drugs, like artemisinin (AN), used for primary parasite infection treatments. AN, a sesquiterpene lactone, is a natural anti-malarial compound that can be found in Artemisia annua. However, the low concentration of AN in the plant makes this molecule relatively expensive and difficult to produce in order to meet the current worldwide demand of Artemisinin Combination Therapies (ACTs), especially for economically disadvantaged people in developing countries. The biosynthetic pathway of AN, a process that takes place only in glandular secretory trichomes of A. annua, is relatively well elucidated. Significant efforts have been made using plant genetic engineering to increase production of this compound. These include diverse genetic manipulation approaches, such as studies on diverse transcription factors which have been shown to regulate the AN genetic pathway and other biological processes. Results look promising; however, further efforts should be addressed toward optimization of the most cost-effective biofarming approaches for synthesis and production of medicines against the malaria parasite.
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Affiliation(s)
- Giuseppe Pulice
- Sequentia Biotech, Parc Científic de BarcelonaBarcelona, Spain
| | - Soraya Pelaz
- Plant Development and Signal Transduction Department, Centre for Research in Agricultural GenomicsBarcelona, Spain
- Institució Catalana de Recerca i Estudis AvançatsBarcelona, Spain
| | - Luis Matías-Hernández
- Sequentia Biotech, Parc Científic de BarcelonaBarcelona, Spain
- Plant Development and Signal Transduction Department, Centre for Research in Agricultural GenomicsBarcelona, Spain
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Hawkes M, Conroy AL, Opoka RO, Namasopo S, Zhong K, Liles WC, John CC, Kain KC. Slow Clearance of Plasmodium falciparum in Severe Pediatric Malaria, Uganda, 2011-2013. Emerg Infect Dis 2016; 21:1237-9. [PMID: 26079933 PMCID: PMC4480400 DOI: 10.3201/eid2107.150213] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Plasmodium falciparum resistance to artemisinin derivatives is emerging in Asia. We examined molecular markers of resistance in 78 children in Uganda who had severe malaria and were treated with intravenous artesunate. We observed in the K13-propeller domain, A578S, a low-frequency (3/78), nonsynonymous, single-nucleotide polymorphism associated with prolonged parasite clearance.
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146
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Abstract
PURPOSE OF REVIEW The emergence of artemisinin resistance in Southeast Asia (SEA), where artemisinin combination therapies (ACTs) are beginning to fail, threatens global endeavors to control and eliminate Plasmodium falciparum malaria. Future efforts to prevent the spread of this calamity to Africa will benefit from last year's tremendous progress in understanding artemisinin resistance. RECENT FINDINGS Multiple international collaborations have established that artemisinin resistance is associated with slow parasite clearance in patients, increased survival of early-ring-stage parasites in vitro, single-nucleotide polymorphisms (SNPs) in the parasite's kelch protein gene (K13), parasite 'founder' populations sharing a genetic background of four additional SNPs, parasite transcriptional profiles reflecting an 'unfolded protein response' and decelerated parasite development, and elevated parasite phosphatidylinositol-3-kinase activity. In Western Cambodia, where the K13 C580Y mutation is approaching fixation, the frontline ACT is failing to cure nearly half of patients, likely due to partner drug resistance. In Africa, where dozens of K13 mutations have been detected at low frequency, there is no evidence yet of artemisinin resistance. SUMMARY In SEA, clinical and epidemiological investigations are urgently needed to stop the further spread of artemisinin resistance, monitor the efficacy of ACTs where K13 mutations are prevalent, identify currently-available drug regimens that cure ACT failures, and rapidly advance new antimalarial compounds through preclinical studies and clinical trials.
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147
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Gonçalves D, Hunziker P. Transmission-blocking strategies: the roadmap from laboratory bench to the community. Malar J 2016; 15:95. [PMID: 26888537 PMCID: PMC4758146 DOI: 10.1186/s12936-016-1163-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 02/11/2016] [Indexed: 11/10/2022] Open
Abstract
Malaria remains one of the most prevalent tropical and infectious diseases in the world, with an estimated more than 200 million clinical cases every year. In recent years, the mosquito stages of the parasite life cycle have received renewed attention with some progress being made in the development of transmission-blocking strategies. From gametocytes to late ookinetes, some attractive antigenic targets have been found and tested in order to develop a transmission blocking vaccine, and drugs are being currently screened for gametocytocidal activity, and also some new and less conventional approaches are drawing increased attention, such as genetically modified and fungus-infected mosquitoes that become refractory to Plasmodium infection. In this review some of those strategies focusing on the progress made so far will be summarized, but also, the challenges that come from the translation of early promising benchwork resulting in successful applications in the field. To do this, the available literature will be screened and all the pieces of the puzzle must be combined: from molecular biology to epidemiologic and clinical data.
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Affiliation(s)
- Daniel Gonçalves
- CLINAM Foundation for Nanomedicine, University of Basel, Basel, Switzerland.
| | - Patrick Hunziker
- CLINAM Foundation for Nanomedicine, University of Basel, Basel, Switzerland.
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148
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Kite WA, Melendez-Muniz VA, Moraes Barros RR, Wellems TE, Sá JM. Alternative methods for the Plasmodium falciparum artemisinin ring-stage survival assay with increased simplicity and parasite stage-specificity. Malar J 2016; 15:94. [PMID: 26888201 PMCID: PMC4756417 DOI: 10.1186/s12936-016-1148-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/04/2016] [Indexed: 11/16/2022] Open
Abstract
Background Artemisinin-based combination therapy is recommended to treat Plasmodium falciparum worldwide, but observations of longer artemisinin (ART) parasite clearance times (PCTs) in Southeast Asia are widely interpreted as a sign of potential ART resistance. In search of an in vitro correlate of in vivo PCT after ART treatment, a ring-stage survival assay (RSA) of 0–3 h parasites was developed and linked to polymorphisms in the Kelch propeller protein (K13). However, RSA remains a laborious process, involving heparin, Percoll gradient, and sorbitol treatments to obtain rings in the 0–3 h window. Here two alternative RSA protocols are presented and compared to the standard Percoll-based method, one highly stage-specific and one streamlined for laboratory application. Methods For all protocols, P. falciparum cultures were synchronized with 5 % sorbitol treatment twice over two intra-erythrocytic cycles. For a filtration-based RSA, late-stage schizonts were passed through a 1.2 μm filter to isolate merozoites, which were incubated with uninfected erythrocytes for 45 min. The erythrocytes were then washed to remove lysis products and further incubated until 3 h post-filtration. Parasites were pulsed with either 0.1 % dimethyl sulfoxide (DMSO) or 700 nM dihydroartemisinin in 0.1 % DMSO for 6 h, washed twice in drug-free media, and incubated for 66–90 h, when survival was assessed by microscopy. For a sorbitol-only RSA, synchronized young (0–3 h) rings were treated with 5 % sorbitol once more prior to the assay and adjusted to 1 % parasitaemia. The drug pulse, incubation, and survival assessment were as described above. Results Ring-stage survival of P. falciparum parasites containing either the K13 C580 or C580Y polymorphism (associated with low and high RSA survival, respectively) were assessed by the described filtration and sorbitol-only methods and produced comparable results to the reported Percoll gradient RSA. Advantages of both new methods include: fewer reagents, decreased time investment, and fewer procedural steps, with enhanced stage-specificity conferred by the filtration method. Conclusions Assessing P. falciparum ART sensitivity in vitro via RSA can be streamlined and accurately evaluated in the laboratory by filtration or sorbitol synchronization methods, thus increasing the accessibility of the assay to research groups. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1148-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Whitney A Kite
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Room 3E - 10, Rockville, MD, 20852, USA.
| | - Viviana A Melendez-Muniz
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Room 3E - 10, Rockville, MD, 20852, USA. .,Universidad Central del Caribe School of Medicine, Bayamon, PR, 00960, USA.
| | - Roberto R Moraes Barros
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Room 3E - 10, Rockville, MD, 20852, USA.
| | - Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Room 3E - 10, Rockville, MD, 20852, USA.
| | - Juliana M Sá
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Room 3E - 10, Rockville, MD, 20852, USA.
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149
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Birgersson S, Van Toi P, Truong NT, Dung NT, Ashton M, Hien TT, Abelö A, Tarning J. Population pharmacokinetic properties of artemisinin in healthy male Vietnamese volunteers. Malar J 2016; 15:90. [PMID: 26879816 PMCID: PMC4754918 DOI: 10.1186/s12936-016-1134-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/27/2016] [Indexed: 11/17/2022] Open
Abstract
Background
Artemisinin-based combination therapy is recommended as first-line anti-malarial treatment worldwide. A combination of artemisinin with the long acting drug piperaquine has shown high efficacy and tolerability in patients with uncomplicated Plasmodium falciparum infections. The aim of this study was to characterize the population pharmacokinetic properties of artemisinin in healthy male Vietnamese volunteers after two different dose sizes, formulations and in a combination with piperaquine. A secondary aim was to compare two different methods for the evaluation of bioequivalence of the formulations. Methods Fifteen subjects received four different dose regimens of a single dose of artemisinin as a conventional formulation (160 and 500 mg) and as a micronized test formulation (160 mg alone and in combination with piperaquine phosphate, 360 mg) with a washout period of 3 weeks between each period (i.e. four-way cross-over). Venous plasma samples were collected frequently up to 12 h after dose in each period. Artemisinin was quantified in plasma using liquid chromatography coupled with tandem mass spectrometry. A nonlinear mixed-effects modelling approach was utilized to evaluate the population pharmacokinetic properties of the drug and to investigate the clinical impact of different formulations. Results The plasma concentration–time profiles for artemisinin were adequately described by a transit-absorption model with a one-compartment disposition, in all four sequences simultaneously. The mean oral clearance, volume of distribution and terminal elimination half-life was 417 L/h, 1210 L and 1.93 h, respectively. Influence of formulation, dose and possible interaction of piperaquine was evaluated as categorical covariates in full covariate approaches. No clinically significant differences between formulations were shown which was in accordance with the previous results using a non-compartmental bioequivalence approach. Conclusions This is the first population pharmacokinetic characterization of artemisinin in healthy volunteers. Increasing the dose resulted in a significant increase in the mean transit-time but the micronized formulation or concomitant piperaquine administration did not affect the pharmacokinetic properties of artemisinin. The results from the traditional bioequivalence evaluation were comparable with results obtained from mixed-effects modelling.
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Affiliation(s)
- Sofia Birgersson
- Unit for Pharmacokinetics and Drug Metabolism, Department of Pharmacology, University of Gothenburg, Gothenburg, Sweden.
| | - Pham Van Toi
- Oxford University Clinical Research Unit, South East Asia Infectious Disease Clinical Research Network, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.
| | | | | | - Michael Ashton
- Unit for Pharmacokinetics and Drug Metabolism, Department of Pharmacology, University of Gothenburg, Gothenburg, Sweden.
| | - Tran Tinh Hien
- Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.
| | - Angela Abelö
- Unit for Pharmacokinetics and Drug Metabolism, Department of Pharmacology, University of Gothenburg, Gothenburg, Sweden.
| | - Joel Tarning
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK. .,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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150
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Ye R, Hu D, Zhang Y, Huang Y, Sun X, Wang J, Chen X, Zhou H, Zhang D, Mungthin M, Pan W. Distinctive origin of artemisinin-resistant Plasmodium falciparum on the China-Myanmar border. Sci Rep 2016; 6:20100. [PMID: 26831371 PMCID: PMC4735722 DOI: 10.1038/srep20100] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/22/2015] [Indexed: 02/06/2023] Open
Abstract
The artemisinin (ART), discovered in China, has been widely used against malaria in China over the last 30 years. Understanding the emergence and origin of ART resistance in China is therefore of great interest. We analyzed 111 culture-adapted isolates of P. falciparum from China-Myanmar (CM) border for their susceptibility to dihydroartemisinin using the ring stage survival assay (RSA0−3h) and genotyped their K13 genes. Of the isolates, 59 had a wild type of the K13 marker and a median ring survival rate of 0.26% (P95 = 1.005%). Among the remaining isolates harboring single mutations in the K13 marker, 26 survived at >P95(median survival rate = 2.95%). Further, we genotyped the K13 gene of 693 isolates collected from different regions in China and China-Myanmar/Thai-Cambodia/Thai-Myanmar (CM/TC/TM) borders, 308 (44.4%) had K13 mutations and marked differences in the patterns of K13 mutations were observed between the CM and the TC/TM borders. A network diagram showed that majority of the K13 mutant alleles from the CM border clustered together including those harboring the high resistant-associated R539T mutations. The resistant parasites carrying distinct halplotypes suggested the multiple indigenous origins of the resistant alleles, which highlight the importance of surveillance of resistance in all malaria endemic areas where ART has been introduced.
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Affiliation(s)
- Run Ye
- Department of Tropical Infectious Diseases, Second Military Medical University, Shanghai 200433, China
| | - Dongwei Hu
- Department of Tropical Infectious Diseases, Second Military Medical University, Shanghai 200433, China
| | - Yilong Zhang
- Department of Tropical Infectious Diseases, Second Military Medical University, Shanghai 200433, China
| | - Yufu Huang
- Department of Tropical Infectious Diseases, Second Military Medical University, Shanghai 200433, China
| | - Xiaodong Sun
- Yunnan Institute of Parasitic Diseases, Puer 665000, China
| | - Jian Wang
- Yunnan Institute of Parasitic Diseases, Puer 665000, China
| | - Xuedi Chen
- Department of Tropical Infectious Diseases, Second Military Medical University, Shanghai 200433, China
| | - Hongning Zhou
- Yunnan Institute of Parasitic Diseases, Puer 665000, China
| | - Dongmei Zhang
- Department of Tropical Infectious Diseases, Second Military Medical University, Shanghai 200433, China
| | - Mathirut Mungthin
- Department of Parasitology, Phramongkutklao College of Medicine, Bangkok 10400, Thailand
| | - Weiqing Pan
- Department of Tropical Infectious Diseases, Second Military Medical University, Shanghai 200433, China
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