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Massamba JE, Djontu JC, Vouvoungui CJ, Kobawila C, Ntoumi F. Plasmodium falciparum multiplicity of infection and pregnancy outcomes in Congolese women from southern Brazzaville, Republic of Congo. Malar J 2022; 21:114. [PMID: 35366882 PMCID: PMC8976437 DOI: 10.1186/s12936-022-04105-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/24/2022] [Indexed: 11/30/2022] Open
Abstract
Background Investigating whether the multiplicity of Plasmodium falciparum infection (MOI) is related to pregnancy outcomes, is of interest in sub-Saharan area where malaria is highly endemic. The present study aimed to characterize the genetic diversity of P. falciparum in women at delivery from Southern Brazzaville, and investigate whether the MOI is associated with maternal anaemia, preterm delivery, or low birth weight. Methods This was a cross sectional study carried out with samples collected between March 2014 and April 2015 from 371 women recruited at delivery at a Health Centre in southern Brazzaville, Republic of Congo. Matched peripheral, placental, and cord blood collected from each of the women at delivery were used for the detection of P. falciparum microscopic and submicroscopic parasitaemia, and parasite DNA genotyping by nested PCR. Results From 371 recruited women, 27 were positive to microscopic malaria parasitaemia while 223 women harboured submicroscopic parasitaemia. All msp-1 block 2 family allelic types (K1, MAD20 and RO33) were observed in all the three compartments of blood, with K1 being most abundant. K1 (with 12, 10, and 08 alleles in the peripheral, placental, and cord blood respectively) and MAD20 (with 10, 09, and 06 alleles in the respective blood compartments) were more diverse compared to RO33 (with 06, 06, and 05 alleles in the respective blood compartments). From the 250 women with microscopic and/or submicroscopic parasitaemia, 38.5%, 30.5%, and 18.4% of peripheral, placental and cord blood sample, respectively, harboured more than one parasite clone, and polyclonal infection was more prevalent in the peripheral blood of women with microscopic parasitaemia (54.5%) compared to those with submicroscopic parasitaemia (36.7%) (p = 0.02). The mean multiplicity of genotypes per microscopic and submicroscopic infection in peripheral blood was higher in anemic women (2.00 ± 0.23 and 1.66 ± 0.11, respectively) than in non-anaemic women (1.36 ± 0.15 and 1.45 ± 0.06, respectively) (p = 0.03 and 0.06). In logistic regression, women infected with four or more clones of the parasite were 9.4 times more likely to be anaemic than women harbouring one clone. This association, however, was only observed with the peripheral blood infection. No significant association was found between the MOI and low birth weight or preterm delivery. Conclusions These results indicate that the genetic diversity of P. falciparum is high in pregnant women from southern Brazzaville in the Republic of Congo, and the multiplicity of the infection might represent a risk for maternal anaemia.
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Kilonzi M, Minzi O, Mutagonda R, Baraka V, Sasi P, Aklillu E, Kamuhabwa A. Usefulness of day 7 lumefantrine plasma concentration as a predictor of malaria treatment outcome in under-fives children treated with artemether-lumefantrine in Tanzania. Malar J 2020; 19:66. [PMID: 32046718 PMCID: PMC7014606 DOI: 10.1186/s12936-020-3150-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 02/04/2020] [Indexed: 12/18/2022] Open
Abstract
Background Day 7 plasma lumefantrine concentration is suggested as a predictor for malaria treatment outcomes and a cut-off of ≥ 200 ng/ml is associated with day 28 cure rate in the general population. However, day 7 lumefantrine plasma concentration can be affected by age, the extent of fever, baseline parasitaemia, and bodyweight. Therefore, this study assessed the usefulness of day 7 lumefantrine plasma concentration as a predictor of malaria treatment outcome in under-fives children treated with generic or innovator drug-containing artemether-lumefantrine (ALu) in Tanzania. Methods This study was nested in an equivalence prospective study that aimed at determining the effectiveness of a generic ALu (Artefan®) in comparison with the innovator’s product (Coartem®). Children with uncomplicated malaria aged 6–59 months were recruited and randomized to receive either generic or innovator’s product. Children were treated with ALu as per World Health Organization recommendations. The clinical and parasitological outcomes were assessed after 28 days of follow up. PCR was performed to distinguish recrudescence and re-infections among children with recurrent malaria. Analysis of day 7 lumefantrine plasma concentration was carried out using a high-performance liquid chromatographic method with UV detection. Results The PCR corrected cure rates were 98.7% for children treated with generic and 98.6% for those treated with the innovator product (p = 1.00). The geometric mean (± SD) of day 7 plasma lumefantrine concentration was 159.3 (± 2.4) ng/ml for the generic and 164 (± 2.5) ng/ml for the innovator groups, p = 0.87. Geometric mean (± SD) day 7 lumefantrine plasma concentration between cured and recurrent malaria was not statistically different in both treatment arms [158.5 (± 2.4) vs 100.0 (± 1.5) ng/ml, (p = 0.28) for generic arm and 158.5 (± 2.3) vs 251.2 (± 4.2) ng/ml, (p = 0.24) for innovator arm]. Nutritional status was found to be a determinant of recurrent malaria (adjusted hazardous ratio (95% confidence interval) = 3(1.1–8.2), p = 0.029. Conclusion Using the recommended cut-off point of ≥ 200 ng/ml, day 7 plasma lumefantrine concentration failed to predict malaria treatment outcome in children treated with ALu in Tanzania. Further studies are recommended to establish the day 7 plasma lumefantrine concentration cut-off point to predict malaria treatment outcome in children.
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Affiliation(s)
- Manase Kilonzi
- Department of Clinical Pharmacy and Pharmacology, School of Pharmacy, Muhimbili University of Health and Allied Sciences, P. O. BOX 65013, Dar es Salaam, Tanzania.
| | - Omary Minzi
- Department of Clinical Pharmacy and Pharmacology, School of Pharmacy, Muhimbili University of Health and Allied Sciences, P. O. BOX 65013, Dar es Salaam, Tanzania
| | - Ritah Mutagonda
- Department of Clinical Pharmacy and Pharmacology, School of Pharmacy, Muhimbili University of Health and Allied Sciences, P. O. BOX 65013, Dar es Salaam, Tanzania
| | - Vito Baraka
- Department of Research, National Institute of Medical Research, Tanga Centre, P O Box 5004, Tanga, Tanzania
| | - Philip Sasi
- Department of Clinical Pharmacology, School of Medicine, Muhimbili University of Health and Allied Sciences, P. O. BOX 6515, Dar es Salaam, Tanzania
| | - Eleni Aklillu
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital-Huddinge, C1:68, SE-141 86, Stockholm, Sweden
| | - Appolinary Kamuhabwa
- Department of Clinical Pharmacy and Pharmacology, School of Pharmacy, Muhimbili University of Health and Allied Sciences, P. O. BOX 65013, Dar es Salaam, Tanzania
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Aniweh Y, Suurbaar J, Morang'a CM, Nyarko PB, Wright KE, Kusi KA, Ansah F, Kyei-Baafour E, Quansah E, Asante J, Thiam LG, Higgins MK, Awandare GA. Analysis of Plasmodium falciparum Rh2b deletion polymorphism across different transmission areas. Sci Rep 2020; 10:1498. [PMID: 32001728 PMCID: PMC6992740 DOI: 10.1038/s41598-020-58300-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 01/14/2020] [Indexed: 11/12/2022] Open
Abstract
Despite significant progress in controlling malaria, the disease remains a global health burden. The intricate interactions the parasite Plasmodium falciparum has with its host allows it to grow and multiply in human erythrocytes. The mechanism by which P. falciparum merozoites invade human erythrocytes is complex, involving merozoite proteins as well as erythrocyte surface proteins. Members of the P. falciparum reticulocyte binding-like protein homolog (PfRh) family of proteins play a pivotal role in merozoite invasion and hence are important targets of immune responses. Domains within the PfRh2b protein have been implicated in its ability to stimulate natural protective antibodies in patients. More specifically, a 0.58 kbp deletion, at the C-terminus has been reported in high frequencies in Senegalese and Southeast Asian parasite populations, suggesting a possible role in immune evasion. We analysed 1218 P. falciparum clinical isolates, and the results show that this deletion is present in Ghanaian parasite populations (48.5% of all isolates), with Kintampo (hyper-endemic, 53.2%), followed by Accra (Hypo-endemic, 50.3%), Cape Coast (meso-endemic, 47.9%) and Sogakope (meso-endemic, 43.15%). Further analysis of parasite genomes stored in the MalariaGEN database revealed that the deletion variant was common across transmission areas globally, with an overall frequency of about 27.1%. Interestingly, some parasite isolates possessed mixed PfRh2b deletion and full-length alleles. We further showed that levels of antibodies to the domain of PfRh2 protein were similar to antibody levels of PfRh5, indicating it is less recognized by the immune system.
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Affiliation(s)
- Yaw Aniweh
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana. .,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.
| | - Jonathan Suurbaar
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Collins M Morang'a
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Prince B Nyarko
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Katherine E Wright
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.,Department of Life Sciences, Imperial College London, London, UK
| | - Kwadwo A Kusi
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Felix Ansah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Eric Kyei-Baafour
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Evelyn Quansah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Jessica Asante
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Laty G Thiam
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana. .,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, P.O. Box LG54, Legon, Accra, Ghana.
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Saito M, Mansoor R, Wiladphaingern J, Paw MK, Pimanpanarak M, Proux S, Guérin PJ, White NJ, Nosten F, McGready R. Optimal Duration of Follow-up for Assessing Antimalarial Efficacy in Pregnancy: A Retrospective Analysis of a Cohort Followed Up Until Delivery on the Thailand-Myanmar Border. Open Forum Infect Dis 2019; 6:ofz264. [PMID: 31281861 PMCID: PMC6602886 DOI: 10.1093/ofid/ofz264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/04/2019] [Indexed: 11/21/2022] Open
Abstract
Background Follow-up for 28–42 days is recommended by the World Health Organization to assess antimalarial drug efficacy for nonpregnant populations. This study aimed to determine the optimal duration for pregnant women, as no specific guidance currently exists. Methods The distributions of time to recrudescence (treatment failure), confirmed by polymerase chain reaction genotyping for different antimalarial drugs in pregnancy, were analyzed by accelerated failure time models using secondary data on microscopically confirmed recurrent falciparum malaria collected in prospective studies on the Thailand–Myanmar border between 1994 and 2010. Results Of 946 paired isolates from 703 women, the median duration of follow-up for each genotyped recurrence (interquartile range) was 129 (83–174) days, with 429 polymerase chain reaction–confirmed recrudescent. Five different treatments were evaluated, and 382 Plasmodium falciparum recrudescences were identified as eligible. With log-logistic models adjusted for baseline parasitemia, the predicted cumulative proportions of all the recrudescences that were detected by 28 days were 70% (95% confidence interval [CI], 65%–74%) for quinine monotherapy (n = 295), 66% (95% CI, 53%–76%) for artesunate monotherapy (n = 43), 62% (95% CI, 42%–79%) for artemether–lumefantrine (AL; n = 19), 46% (95% CI, 26%–67%) for artesunate with clindamycin (n = 19), and 34% (95% CI, 11%–67%) for dihydroartemisinin–piperaquine (DP; n = 6). Corresponding figures by day 42 were 89% (95% CI, 77%–95%) for AL and 71% (95% CI, 38%–91%) for DP. Follow-up for 63 days was predicted to detect ≥95% of all recrudescence, except for DP. Conclusions In low-transmission settings, antimalarial drug efficacy assessments in pregnancy require longer follow-up than for nonpregnant populations.
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Affiliation(s)
- Makoto Saito
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,WorldWide Antimalarial Resistance Network (WWARN)
| | - Rashid Mansoor
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,WorldWide Antimalarial Resistance Network (WWARN)
| | - Jacher Wiladphaingern
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Moo Kho Paw
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Mupawjay Pimanpanarak
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Stephane Proux
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Philippe J Guérin
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,WorldWide Antimalarial Resistance Network (WWARN)
| | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - François Nosten
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Rose McGready
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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5
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Tun KM, Jeeyapant A, Myint AH, Kyaw ZT, Dhorda M, Mukaka M, Cheah PY, Imwong M, Hlaing T, Kyaw TH, Ashley EA, Dondorp A, White NJ, Day NPJ, Smithuis F. Effectiveness and safety of 3 and 5 day courses of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in an area of emerging artemisinin resistance in Myanmar. Malar J 2018; 17:258. [PMID: 29996844 PMCID: PMC6042398 DOI: 10.1186/s12936-018-2404-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 07/03/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Artemisinin resistance in Plasmodium falciparum has emerged and spread in Southeast Asia. In areas where resistance is established longer courses of artemisinin-based combination therapy have improved cure rates. METHODS The standard 3-day course of artemether-lumefantrine (AL) was compared with an extended 5-day regimen for the treatment of uncomplicated falciparum malaria in Kayin state in South-East Myanmar, an area of emerging artemisinin resistance. Late parasite clearance dynamics were described by microscopy and quantitative ultra-sensitive PCR. Patients were followed up for 42 days. RESULTS Of 154 patients recruited (105 adults and 49 children < 14 years) 78 were randomized to 3 days and 76 to 5 days AL. Mutations in the P. falciparum kelch13 propeller gene (k13) were found in 46% (70/152) of infections, with F446I the most prevalent propeller mutation (29%; 20/70). Both regimens were well-tolerated. Parasite clearance profiles were biphasic with a slower submicroscopic phase which was similar in k13 wild-type and mutant infections. The cure rates were 100% (70/70) and 97% (68/70) in the 3- and 5-day arms respectively. Genotyping of the two recurrences was unsuccessful. CONCLUSION Despite a high prevalence of k13 mutations, the current first-line treatment, AL, was still highly effective in this area of South-East Myanmar. The extended 5 day regimen was very well tolerated, and would be an option to prolong the useful therapeutic life of AL. Trial registration NCT02020330. Registered 24 December 2013, https://clinicaltrials.gov/NCT02020330.
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Affiliation(s)
- Kyaw Myo Tun
- Defence Services Medical Academy, Yangon, Myanmar.
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Atthanee Jeeyapant
- 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
| | - Aung Hpone Myint
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
- Medical Action Myanmar, Yangon, Myanmar
| | - Zwe Thiha Kyaw
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
- Medical Action Myanmar, Yangon, Myanmar
| | - Mehul Dhorda
- 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
- Worldwide Antimalarial Resistance Network (WWARN), Asia Regional Centre, Bangkok, Thailand
| | - Mavuto Mukaka
- 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
| | - Phaik Yeong Cheah
- 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
| | - Mallika Imwong
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thaung Hlaing
- Department of Health, Ministry of Health and Sports, Naypyidaw, Myanmar
| | - Thar Htun Kyaw
- Department of Health, Ministry of Health and Sports, Naypyidaw, Myanmar
| | - Elizabeth A Ashley
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Arjen Dondorp
- 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
| | - Nicholas J White
- 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
| | - Nicholas P J Day
- 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
| | - Frank Smithuis
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- Medical Action Myanmar, Yangon, Myanmar
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Poespoprodjo JR, Kenangalem E, Wafom J, Chandrawati F, Puspitasari AM, Ley B, Trianty L, Korten Z, Surya A, Syafruddin D, Anstey NM, Marfurt J, Noviyanti R, Price RN. Therapeutic Response to Dihydroartemisinin-Piperaquine for P. falciparum and P. vivax Nine Years after Its Introduction in Southern Papua, Indonesia. Am J Trop Med Hyg 2018; 98:677-682. [PMID: 29345221 PMCID: PMC5850981 DOI: 10.4269/ajtmh.17-0662] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Dihydroartemisinin-piperaquine (DHP) has been the first-line treatment of uncomplicated malaria due to both Plasmodium falciparum and Plasmodium vivax infections in Papua, Indonesia, since March 2006. The efficacy of DHP was reassessed to determine whether there had been any decline following almost a decade of its extensive use. An open-label drug efficacy study of DHP for uncomplicated P. falciparum and P. vivax malaria was carried out between March 2015 and April 2016 in Timika, Papua, Indonesia. Patients with uncomplicated malaria were administered supervised DHP tablets once daily for 3 days. Clinical and laboratory data were collected daily until parasite clearance and then weekly for 6 weeks. Molecular analysis was undertaken for all patients with recurrent parasitemia. A total of 129 study patients were enrolled in the study. At day 42, the polymerase chain reaction-adjusted efficacy was 97.7% (95% confidence intervals [CI]: 87.4-99.9) in the 61 patients with P. falciparum malaria, and 98.2% [95% CI: 90.3-100] in the 56 patients with P. vivax malaria. By day 2, 98% (56/57) of patients with P. falciparum and 96.9% (63/65) of those with P. vivax had cleared their peripheral parasitemia; none of the patients were still parasitaemic on day 3. Molecular analysis of P. falciparum parasites showed that none (0/61) had K13 mutations associated previously with artemisinin resistance or increased copy number of plasmepsin 2-3 (0/61). In the absence of artemisinin resistance, DHP has retained high efficacy for the treatment of uncomplicated malaria despite extensive drug pressure over a 9-year period.
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Affiliation(s)
- Jeanne Rini Poespoprodjo
- Mimika District Hospital, Timika, Indonesia;,Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Indonesia;,Paediatric Research Office, Department of Child Health, Faculty of Medicine, Universitas Gadjah Mada/Dr. Sardjito Hospital, Yogyakarta, Indonesia;,Address correspondence to Jeanne Rini Poespoprodjo, Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Indonesia. E-mail:
| | - Enny Kenangalem
- Mimika District Hospital, Timika, Indonesia;,Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Indonesia
| | - Johny Wafom
- Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Indonesia
| | - Freis Chandrawati
- Timika Malaria Research Programme, Papuan Health and Community Development Foundation, Timika, Indonesia
| | | | - Benedikt Ley
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Leily Trianty
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Zoé Korten
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Asik Surya
- Indonesian Ministry of Health, National Malaria Control Program, Jakarta, Indonesia
| | - Din Syafruddin
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Nicholas M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Jutta Marfurt
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | | | - 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
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7
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Pattaradilokrat S, Trakoolsoontorn C, Simpalipan P, Warrit N, Kaewthamasorn M, Harnyuttanakorn P. Size and sequence polymorphisms in the glutamate-rich protein gene of the human malaria parasite Plasmodium falciparum in Thailand. Parasit Vectors 2018; 11:49. [PMID: 29357909 PMCID: PMC5778735 DOI: 10.1186/s13071-018-2630-1] [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: 09/30/2017] [Accepted: 01/08/2018] [Indexed: 11/10/2022] Open
Abstract
Background The glutamate-rich protein (GLURP) of the malaria parasite Plasmodium falciparum is a key surface antigen that serves as a component of a clinical vaccine. Moreover, the GLURP gene is also employed routinely as a genetic marker for malarial genotyping in epidemiological studies. While extensive size polymorphisms in GLURP are well recorded, the extent of the sequence diversity of this gene is rarely investigated. The present study aimed to explore the genetic diversity of GLURP in natural populations of P. falciparum. Results The polymorphic C-terminal repetitive R2 region of GLURP sequences from 65 P. falciparum isolates in Thailand were generated and combined with the data from 103 worldwide isolates to generate a GLURP database. The collection was comprised of 168 alleles, encoding 105 unique GLURP subtypes, characterized by 18 types of amino acid repeat units (AAU). Of these, 28 GLURP subtypes, formed by 10 AAU types, were detected in P. falciparum in Thailand. Among them, 19 GLURP subtypes and 2 AAU types are described for the first time in the Thai parasite population. The AAU sequences were highly conserved, which is likely due to negative selection. Standard Fst analysis revealed the shared distributions of GLURP types among the P. falciparum populations, providing evidence of gene flow among the different demographic populations. Conclusions Sequence diversity causing size variations in GLURP in Thai P. falciparum populations were detected, and caused by non-synonymous substitutions in repeat units and some insertion/deletion of aspartic acid or glutamic acid codons between repeat units. The P. falciparum population structure based on GLURP showed promising implications for the development of GLURP-based vaccines and for monitoring vaccine efficacy. Electronic supplementary material The online version of this article (doi: 10.1186/s13071-018-2630-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sittiporn Pattaradilokrat
- Department of Biology, Faculty of Science, Chualongkorn University, 254 Phayathai Road, Bangkok, 10330, Thailand. .,Veterinary Parasitology Research Group, Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.
| | - Chawinya Trakoolsoontorn
- Department of Biology, Faculty of Science, Chualongkorn University, 254 Phayathai Road, Bangkok, 10330, Thailand
| | - Phumin Simpalipan
- Department of Biology, Faculty of Science, Chualongkorn University, 254 Phayathai Road, Bangkok, 10330, Thailand
| | - Natapot Warrit
- Department of Biology, Faculty of Science, Chualongkorn University, 254 Phayathai Road, Bangkok, 10330, Thailand
| | - Morakot Kaewthamasorn
- Veterinary Parasitology Research Group, Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Pongchai Harnyuttanakorn
- Department of Biology, Faculty of Science, Chualongkorn University, 254 Phayathai Road, Bangkok, 10330, Thailand
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8
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Ayanful-Torgby R, Oppong A, Abankwa J, Acquah F, Williamson KC, Amoah LE. Plasmodium falciparum genotype and gametocyte prevalence in children with uncomplicated malaria in coastal Ghana. Malar J 2016; 15:592. [PMID: 27938356 PMCID: PMC5148883 DOI: 10.1186/s12936-016-1640-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 11/25/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum gametocytes are vital to sustaining malaria transmission. Parasite densities, multiplicity of infection as well as asexual genotype are features that have been found to influence gametocyte production. Measurements of the prevalence of Plasmodium sp. gametocytes may serve as a tool to monitor the success of malaria eradication efforts. METHODS Whole blood was collected from 112 children aged between 6 months and 13 years with uncomplicated P. falciparum malaria attending three health facilities in southern Ghana from June to August, 2014 before (day 0) and 4 days after completion of anti-malaria drug treatment (day 7). Malaria parasites were observed by microscopy and polymerase chain reaction (PCR); submicroscopic gametocyte carriage was measured by a Pfs25 (PF3D7_1031000) mRNA real time reverse transcriptase polymerase chain reaction (RT-PCR). Parasite genotyping was performed on gDNA extracted from dried filter paper blood blots by amplification of the polymorphic regions of msp1 (PF3D7_0930300) and msp2 (PF3D7_0206800) using PCR. RESULTS Microscopy estimated 3.1% (3/96) of the total population to carry gametocytes on day 0, which decreased to 2.1% (2/96) on day 7. In contrast, reverse transcriptase-real time PCR (RT-PCR) analysis of a subset of 35 samples estimated submicroscopic gametocyte carriage to be as high as 77% (27/35) using primers specific for Pfs25 (CT < 35) on day 0 and by day 7 this only declined to 60% (21/35). Genotyping the msp2 gene identified higher levels of MOI than the msp1 gene. CONCLUSIONS Although below detection by microscopy, gametocyte prevalence at submicroscopic levels are high in this region and emphasize the need for more effective elimination approaches like the development of transmission-blocking vaccines and safer gametocytocidal drugs.
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Affiliation(s)
- Ruth Ayanful-Torgby
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Akua Oppong
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joana Abankwa
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Festus Acquah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | | | - Linda Eva Amoah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.
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9
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Maguire JD, Susanti AI, Krisin, Sismadi P, Fryauff DJ, Baird JK. The T76 mutation in thepfcrtgene ofPlasmodium falciparumand clinical chloroquine resistance phenotypes in Papua, Indonesia. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.2001.11813671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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10
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Prospective Study of Plasmodium vivax Malaria Recurrence after Radical Treatment with a Chloroquine-Primaquine Standard Regimen in Turbo, Colombia. Antimicrob Agents Chemother 2016; 60:4610-9. [PMID: 27185794 DOI: 10.1128/aac.00186-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/09/2016] [Indexed: 01/15/2023] Open
Abstract
Plasmodium vivax recurrences help maintain malaria transmission. They are caused by recrudescence, reinfection, or relapse, which are not easily differentiated. A longitudinal observational study took place in Turbo municipality, Colombia. Participants with uncomplicated P. vivax infection received supervised treatment concomitantly with 25 mg/kg chloroquine and 0.25 mg/kg/day primaquine for 14 days. Incidence of recurrence was assessed over 180 days. Samples were genotyped, and origins of recurrences were established. A total of 134 participants were enrolled between February 2012 and July 2013, and 87 were followed for 180 days, during which 29 recurrences were detected. The cumulative incidence of first recurrence was 24.1% (21/87) (95% confidence interval [CI], 14.6 to 33.7%), and 86% (18/21) of these events occurred between days 51 and 110. High genetic diversity of P. vivax strains was found, and 12.5% (16/128) of the infections were polyclonal. Among detected recurrences, 93.1% (27/29) of strains were genotyped as genetically identical to the strain from the previous infection episode, and 65.5% (19/29) of infections were classified as relapses. Our results indicate that there is a high incidence of P. vivax malaria recurrence after treatment in Turbo municipality, Colombia, and that a large majority of these episodes are likely relapses from the previous infection. We attribute this to the primaquine regimen currently used in Colombia, which may be insufficient to eliminate hypnozoites.
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11
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Phyo AP, Ashley EA, Anderson TJC, Bozdech Z, Carrara VI, Sriprawat K, Nair S, White MM, Dziekan J, Ling C, Proux S, Konghahong K, Jeeyapant A, Woodrow CJ, Imwong M, McGready R, Lwin KM, Day NPJ, White NJ, Nosten F. Declining Efficacy of Artemisinin Combination Therapy Against P. Falciparum Malaria on the Thai-Myanmar Border (2003-2013): The Role of Parasite Genetic Factors. Clin Infect Dis 2016; 63:784-791. [PMID: 27313266 PMCID: PMC4996140 DOI: 10.1093/cid/ciw388] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/05/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Deployment of mefloquine-artesunate (MAS3) on the Thailand-Myanmar border has led to a sustained reduction in falciparum malaria, although antimalarial efficacy has declined substantially in recent years. The role of Plasmodium falciparum K13 mutations (a marker of artemisinin resistance) in reducing treatment efficacy remains controversial. METHODS Between 2003 and 2013, we studied the efficacy of MAS3 in 1005 patients with uncomplicated P. falciparum malaria in relation to molecular markers of resistance. RESULTS Polymerase chain reaction (PCR)-adjusted cure rates declined from 100% in 2003 to 81.1% in 2013 as the proportions of isolates with multiple Pfmdr1 copies doubled from 32.4% to 64.7% and those with K13 mutations increased from 6.7% to 83.4%. K13 mutations conferring moderate artemisinin resistance (notably E252Q) predominated initially but were later overtaken by propeller mutations associated with slower parasite clearance (notably C580Y). Those infected with both multiple Pfmdr1 copy number and a K13 propeller mutation were 14 times more likely to fail treatment. The PCR-adjusted cure rate was 57.8% (95% confidence interval [CI], 45.4, 68.3) compared with 97.8% (95% CI, 93.3, 99.3) in patients with K13 wild type and Pfmdr1 single copy. K13 propeller mutation alone was a strong risk factor for recrudescence (P = .009). The combined population attributable fraction of recrudescence associated with K13 mutation and Pfmdr1 amplification was 82%. CONCLUSIONS The increasing prevalence of K13 mutations was the decisive factor for the recent and rapid decline in efficacy of artemisinin-based combination (MAS3) on the Thailand-Myanmar border.
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Affiliation(s)
- Aung Pyae Phyo
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Elizabeth A Ashley
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Tim J C Anderson
- Department of Genetics, Texas Biomedical Research Institute, San Antonio; and
| | - Zbynek Bozdech
- Division of Molecular Genetics & Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Verena I Carrara
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kanlaya Sriprawat
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Shalini Nair
- Department of Genetics, Texas Biomedical Research Institute, San Antonio; and
| | - Marina McDew White
- Department of Genetics, Texas Biomedical Research Institute, San Antonio; and
| | - Jerzy Dziekan
- Division of Molecular Genetics & Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Clare Ling
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Stephane Proux
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Kamonchanok Konghahong
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Atthanee Jeeyapant
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Charles J Woodrow
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mallika Imwong
- Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rose McGready
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Khin Maung Lwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nicholas P J Day
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nicholas J White
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
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12
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Apinjoh TO, Tata RB, Anchang-Kimbi JK, Chi HF, Fon EM, Mugri RN, Tangoh DA, Nyingchu RV, Ghogomu SM, Nkuo-Akenji T, Achidi EA. Plasmodium falciparum merozoite surface protein 1 block 2 gene polymorphism in field isolates along the slope of mount Cameroon: a cross - sectional study. BMC Infect Dis 2015; 15:309. [PMID: 26242307 PMCID: PMC4526171 DOI: 10.1186/s12879-015-1066-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/28/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria remains a major global health burden despite the intensification of control efforts, due partly to the lack of an effective vaccine. Information on genetic diversity in natural parasite populations constitutes a major impediment to vaccine development efforts and is limited in some endemic settings. The present study characterized diversity by investigating msp1 block 2 polymorphisms and the relationship between the allele families with ethnodemographic indices and clinical phenotype. METHOD Individuals with asymptomatic parasitaemia (AP) or uncomplicated malaria (UM) were enrolled from rural, semi-rural and semi-urban localities at varying altitudes along the slope of mount Cameroon. P. falciparum malaria parasitaemic blood screened by light microscopy was depleted of leucocytes using CF11 cellulose columns and the parasite DNA genotyped by nested PCR. RESULTS Length polymorphism was assessed in 151 field isolates revealing 64 (5) and 274 (22) distinct recombinant and major msp1 allelic fragments (genotypes) respectively. All family specific allelic types (K1, MAD20 and RO33) as well as MR were observed in the different locations, with K1 being most abundant. Eighty seven (60 %) of individuals harbored more than one parasite clone, with a significant proportion (p = 0.009) in rural compared to other settings. AP individuals had higher (p = 0.007) K1 allele frequencies but lower (p = 0.003) mean multiplicity of genotypes per infection (2.00 ± 0.98 vs. 2.56 ± 1.17) compared to UM patients. CONCLUSIONS These results indicate enormous diversity of P. falciparum in the area and suggests that allele specificity and complexity may be relevant for the progression to symptomatic disease.
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Affiliation(s)
- Tobias O Apinjoh
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon.
| | - Rolland B Tata
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | | | - Hanesh F Chi
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Eleanor M Fon
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon.
| | - Regina N Mugri
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Delphine A Tangoh
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon. .,Department of Medical Laboratory Science, University of Buea, Buea, Cameroon.
| | - Robert V Nyingchu
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon. .,Department of Medical Laboratory Science, University of Buea, Buea, Cameroon.
| | - Stephen M Ghogomu
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon.
| | - Theresa Nkuo-Akenji
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
| | - Eric A Achidi
- Department of Biochemistry and Molecular Biology, University of Buea, Buea, Cameroon.
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13
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Laochan N, Zaloumis SG, Imwong M, Lek-Uthai U, Brockman A, Sriprawat K, Wiladphaingern J, White NJ, Nosten F, McGready R. Intervals to Plasmodium falciparum recurrence after anti-malarial treatment in pregnancy: a longitudinal prospective cohort. Malar J 2015; 14:221. [PMID: 26017553 PMCID: PMC4449611 DOI: 10.1186/s12936-015-0745-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/21/2015] [Indexed: 11/10/2022] Open
Abstract
Background Plasmodium falciparum infections adversely affect pregnancy. Anti-malarial treatment failure is common. The objective of this study was to examine the duration of persistent parasite carriage following anti-malarial treatment in pregnancy. Methods The data presented here are a collation from previous studies carried out since 1994 in the Shoklo Malaria Research Unit (SMRU) on the Thailand-Myanmar border and performed using the same unique methodology detailed in the Materials and Methods section. Screening for malaria by microscopy is a routine part of weekly antenatal care (ANC) visits and therapeutic responses to anti-malarials were assessed in P. falciparum malaria cases. Women with microscopy confirmed P. falciparum malaria had a PCR blood spot from a finger-prick sample collected. Parasite DNA was extracted from the blood-spot samples using saponin lysis/Chelex extraction method and genotyped using polymorphic segments of MSP1, MSP2 and GLURP. Recurrent infections were classified by genotyping as novel, recrudescent or indeterminate. Factors associated with time to microscopy-detected recrudescence were analysed using multivariable regression techniques. Results From December 1994 to November 2009, 700 women were treated for P. falciparum and there were 909 recurrent episodes (481 novel and 428 recrudescent) confirmed by PCR genotyping. Most of the recurrences, 85 % (770/909), occurred after treatment with quinine monotherapy, artesunate monotherapy or artesunate-clindamycin. The geometric mean number of days to recurrence was significantly shorter in women with recrudescent infection, 24.5 (95 %: 23.4-25.8), compared to re-infection, 49.7 (95 %: 46.9-52.7), P <0.001. The proportion of recrudescent P. falciparum infections that occurred after days 28, 42 and 63 from the start of treatment was 29.1 % (124/428), 13.3 % (57/428) and 5.6 % (24/428). Recrudescent infections ≥100 days after treatment occurred with quinine and mefloquine monotherapy, and quinine + clindamycin and artesunate + atovaquone-proguanil combination therapy. Treatments containing an artemisinin derivative or an intercalated Plasmodium vivax infection increased the geometric mean interval to recrudescence by 1.28-fold (95 % CI: 1.09-1.51) and 2.19-fold (1.77-2.72), respectively. Intervals to recrudescence were decreased 0.83-fold (0.73-0.95) if treatment was not fully supervised (suggesting incomplete adherence) and 0.98-fold (0.96-0.99) for each doubling in baseline parasitaemia. Conclusions Prolonged time to recrudescence may occur in pregnancy, regardless of anti-malarial treatment. Long intervals to recrudescence are more likely with the use of artemisinin-containing treatments and also observed with intercalated P. vivax infections treated with chloroquine. Accurate determination of drug efficacy in pregnancy requires longer duration of follow-up, preferably until delivery or day 63, whichever occurs last.
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Affiliation(s)
- Natthapon Laochan
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.
| | - Sophie G Zaloumis
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Health, University of Melbourne, Melbourne, Australia.
| | - Mallika Imwong
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Usa Lek-Uthai
- Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok, Thailand.
| | - Alan Brockman
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.
| | - Kanlaya Sriprawat
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.
| | - Jacher Wiladphaingern
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - François Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand. .,Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Rose McGready
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand. .,Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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14
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Abdul-Ghani R, Al-Maktari MT, Al-Shibani LA, Allam AF. A better resolution for integrating methods for monitoring Plasmodium falciparum resistance to antimalarial drugs. Acta Trop 2014; 137:44-57. [PMID: 24801884 DOI: 10.1016/j.actatropica.2014.04.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/25/2014] [Accepted: 04/27/2014] [Indexed: 12/16/2022]
Abstract
Effective chemotherapy is the mainstay of malaria control. However, resistance of falciparum malaria to antimalarial drugs compromised the efforts to eliminate the disease and led to the resurgence of malaria epidemics. Three main approaches are used to monitor antimalarial drug efficacy and drug resistance; namely, in vivo trials, in vitro/ex vivo assays and molecular markers of drug resistance. Each approach has its implications of use as well as its advantages and drawbacks. Therefore, there is a need to use an integrated approach that would give the utmost effect to detect resistance as early as its emergence and to track it once spread. Such integration becomes increasingly needed in the era of artemisinin-based combination therapy as a forward action to deter resistance. The existence of regional and global networks for the standardization of methodology, provision of high quality reagents for the assessment of antimalarial drug resistance and dissemination of open-access data would help in approaching an integrated resistance surveillance system on a global scale.
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15
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Mayxay M, Khanthavong M, Cox L, Sichanthongthip O, Imwong M, Pongvongsa T, Hongvanthong B, Phompida S, Vanisaveth V, White NJ, Newton PN. Thiamin supplementation does not reduce the frequency of adverse events after anti-malarial therapy among patients with falciparum malaria in southern Laos. Malar J 2014; 13:275. [PMID: 25027701 PMCID: PMC4105794 DOI: 10.1186/1475-2875-13-275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 07/09/2014] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND In a recent study one third of Lao patients presenting with uncomplicated Plasmodium falciparum malaria had biochemical evidence of thiamin deficiency, which was associated with a higher incidence of adverse events. Thiamin supplementation might, therefore, reduce adverse events in this population. METHODS An exploratory, double-blind, parallel group, placebo-controlled, superiority trial of thiamin supplementation in patients of all ages with uncomplicated and severe falciparum malaria was conducted in Xepon District, Savannakhet Province, southern Laos. Patients were randomly assigned to either oral thiamin 10 mg/day for 7 days immediately after standard anti-malarial treatment then 5 mg daily until day 42, or identical oral placebo. RESULTS After interim analyses when 630 patients (314 in thiamin and 316 in placebo groups) had been recruited, the trial was discontinued on the grounds of futility. On admission biochemical thiamin deficiency (alpha ≥ 25%) was present in 27% of patients and 9% had severe deficiency (alpha > 31%). After 42 days of treatment, the frequency of thiamin deficiency was lower in the thiamin (2%, 1% severe) compared to the placebo (11%, 3% severe) groups (p < 0.001 and p = 0.05), respectively. Except for diarrhoea, 7% in the placebo compared to 3% in the thiamin group (p = 0.04), and dizziness on day 1 (33% vs 25%, p = 0.045), all adverse events were not significantly different between the groups (p > 0.05). Clinical, haematological, and parasitological responses to treatment did not differ significantly between the two groups. CONCLUSION Thiamin supplementation reduced biochemical thiamin deficiency among Lao malaria patients following anti-malarial drug treatment, but it did not reduce the frequency of adverse events after anti-malarial therapy or have any detected clinical or parasitological impact. TRIAL REGISTRATION ISRCTN 85411059.
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Affiliation(s)
- Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
- Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Lao People’s Democratic Republic
- Centre for Clinical Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK
| | - Maniphone Khanthavong
- Centre of Malariology, Parasitology and Entomology, Vientiane, Lao People’s Democratic Republic
| | - Lorna Cox
- MRC Human Nutrition Research, Cambridge, UK
| | - Odai Sichanthongthip
- Centre of Malariology, Parasitology and Entomology, Vientiane, Lao People’s Democratic Republic
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Tiengkham Pongvongsa
- Savannakhet Provincial Malaria Station, Savannakhet Province, Lao People’s Democratic Republic
| | - Bouasy Hongvanthong
- Centre of Malariology, Parasitology and Entomology, Vientiane, Lao People’s Democratic Republic
| | - Samlane Phompida
- Centre of Malariology, Parasitology and Entomology, Vientiane, Lao People’s Democratic Republic
| | - Viengxay Vanisaveth
- Centre of Malariology, Parasitology and Entomology, Vientiane, Lao People’s Democratic Republic
| | - Nicholas J White
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
- Centre for Clinical Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
- Centre for Clinical Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK
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16
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McCollum AM, Soberon V, Salas CJ, Santolalla ML, Udhayakumar V, Escalante AA, Graf PCF, Durand S, Cabezas C, Bacon DJ. Genetic variation and recurrent parasitaemia in Peruvian Plasmodium vivax populations. Malar J 2014; 13:67. [PMID: 24568141 PMCID: PMC3941685 DOI: 10.1186/1475-2875-13-67] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 02/13/2014] [Indexed: 11/12/2022] Open
Abstract
Background Plasmodium vivax is a predominant species of malaria in parts of South America and there is increasing resistance to drugs to treat infections by P. vivax. The existence of latent hypnozoites further complicates the ability to classify recurrent infections as treatment failures due to relapse, recrudescence of hyponozoites or re-infections. Antigen loci are putatively under natural selection and may not be an optimal molecular marker to define parasite haplotypes in paired samples. Putatively neutral microsatellite loci, however, offer an assessment of neutral haplotypes. The objective here was to assess the utility of neutral microsatellite loci to reconcile cases of recurrent parasitaemia in Amazonian P. vivax populations in Peru. Methods Patient blood samples were collected from three locations in or around Iquitos in the Peruvian Amazon. Five putatively neutral microsatellite loci were characterized from 445 samples to ascertain the within and amongst population variation. A total of 30 day 0 and day of recurrent parasitaemia samples were characterized at microsatellite loci and five polymorphic antigen loci for haplotype classification. Results The genetic diversity at microsatellite loci was consistent with neutral levels of variation measured in other South American P. vivax populations. Results between antigen and microsatellite loci for the 30 day 0 and day of recurrent parasitaemia samples were the same for 80% of the pairs. The majority of non-concordant results were the result of differing alleles at microsatellite loci. This analysis estimates that 90% of the paired samples with the same microsatellite haplotype are unlikely to be due to a new infection. Conclusions A population-level approach was used to yield a better estimate of the probability of a new infection versus relapse or recrudescence of homologous hypnozoites; hypnozoite activation was common for this cohort. Population studies are critical with the evaluation of genetic markers to assess P. vivax biology and epidemiology. The additional demonstration of microsatellite loci as neutral markers capable of distinguishing the origin of the recurrent parasites (new infection or originating from the patient) lends support to their use in assessment of treatment outcomes.
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Affiliation(s)
- Andrea M McCollum
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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Jaki T, Parry A, Winter K, Hastings I. Analysing malaria drug trials on a per-individual or per-clone basis: a comparison of methods. Stat Med 2013; 32:3020-38. [PMID: 23258694 DOI: 10.1002/sim.5706] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 11/22/2012] [Indexed: 11/05/2022]
Abstract
There are a variety of methods used to estimate the effectiveness of antimalarial drugs in clinical trials, invariably on a per-person basis. A person, however, may have more than one malaria infection present at the time of treatment. We evaluate currently used methods for analysing malaria trials on a per-individual basis and introduce a novel method to estimate the cure rate on a per-infection (clone) basis. We used simulated and real data to highlight the differences of the various methods. We give special attention to classifying outcomes as cured, recrudescent (infections that never fully cleared) or ambiguous on the basis of genetic markers at three loci. To estimate cure rates on a per-clone basis, we used the genetic information within an individual before treatment to determine the number of clones present. We used the genetic information obtained at the time of treatment failure to classify clones as recrudescence or new infections. On the per-individual level, we find that the most accurate methods of classification label an individual as newly infected if all alleles are different at the beginning and at the time of failure and as a recrudescence if all or some alleles were the same. The most appropriate analysis method is survival analysis or alternatively for complete data/per-protocol analysis a proportion estimate that treats new infections as successes. We show that the analysis of drug effectiveness on a per-clone basis estimates the cure rate accurately and allows more detailed evaluation of the performance of the treatment.
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Affiliation(s)
- Thomas Jaki
- Medical and Pharmaceutical Research Unit, Department of Mathematics and Statistics, Lancaster University, Lancaster, UK
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Boel ME, Rijken MJ, Leenstra T, Phyo AP, Pimanpanarak M, Keereecharoen NL, Proux S, Laochan N, Imwong M, Singhasivanon P, White NJ, McGready R, Nosten FH. Malaria in the post-partum period; a prospective cohort study. PLoS One 2013; 8:e57890. [PMID: 23516418 PMCID: PMC3596341 DOI: 10.1371/journal.pone.0057890] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 01/28/2013] [Indexed: 01/14/2023] Open
Abstract
Background Several studies have shown a prolonged or increased susceptibility to malaria in the post-partum period. A matched cohort study was conducted to evaluate prospectively the susceptibility to malaria of post-partum women in an area where P.falciparum and P.vivax are prevalent. Methods In an area of low seasonal malaria transmission on the Thai-Myanmar border pregnant women attending antenatal clinics were matched to a non-pregnant, non-post-partum control and followed up prospectively until 12 weeks after delivery. Results Post-partum women (n = 744) experienced significantly less P.falciparum episodes than controls (hazard ratio (HR) 0.39 (95%CI 0.21–0.72) p = 0.003) but significantly more P.vivax (HR 1.34 (1.05–1.72) p = 0.018). The reduced risk of falciparum malaria was accounted for by reduced exposure, whereas a history of P.vivax infection during pregnancy was a strong risk factor for P.vivax in post-partum women (HR 13.98 (9.13–21.41), p<0.001). After controlling for effect modification by history of P.vivax, post-partum women were not more susceptible to P.vivax than controls (HR: 0.33 (0.21–0.51), p<0.001). Genotyping of pre-and post-partum infections (n⊕ = ⊕10) showed that each post-partum P.falciparum was a newly acquired infection. Conclusions In this area of low seasonal malaria transmission post-partum women were less likely to develop falciparum malaria but more likely to develop vivax malaria than controls. This was explained by reduced risk of exposure and increased risk of relapse, respectively. There was no evidence for altered susceptibility to malaria in the post-partum period. The treatment of vivax malaria during and immediately after pregnancy needs to be improved.
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Carrara VI, Lwin KM, Phyo AP, Ashley E, Wiladphaingern J, Sriprawat K, Rijken M, Boel M, McGready R, Proux S, Chu C, Singhasivanon P, White N, Nosten F. Malaria burden and artemisinin resistance in the mobile and migrant population on the Thai-Myanmar border, 1999-2011: an observational study. PLoS Med 2013; 10:e1001398. [PMID: 23472056 PMCID: PMC3589269 DOI: 10.1371/journal.pmed.1001398] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 01/24/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The Shoklo Malaria Research Unit has been working on the Thai-Myanmar border for 25 y providing early diagnosis and treatment (EDT) of malaria. Transmission of Plasmodium falciparum has declined, but resistance to artesunate has emerged. We expanded malaria activities through EDT and evaluated the impact over a 12-y period. METHODS AND FINDINGS Between 1 October 1999 and 30 September 2011, the Shoklo Malaria Research Unit increased the number of cross-border (Myanmar side) health facilities from two to 11 and recorded the number of malaria consultations. Changes in malaria incidence were estimated from a cohort of pregnant women, and prevalence from cross-sectional surveys. In vivo and in vitro antimalarial drug efficacy were monitored. Over this period, the number of malaria cases detected increased initially, but then declined rapidly. In children under 5 y, the percentage of consultations due to malaria declined from 78% (95% CI 76-80) (1,048/1,344 consultations) to 7% (95% CI 6.2-7.1) (767/11,542 consultations), p<0.001. The ratio of P. falciparum/P. vivax declined from 1.4 (95% CI 1.3-1.4) to 0.7 (95% CI 0.7-0.8). The case fatality rate was low (39/75,126; 0.05% [95% CI 0.04-0.07]). The incidence of malaria declined from 1.1 to 0.1 episodes per pregnant women-year. The cumulative proportion of P. falciparum decreased significantly from 24.3% (95% CI 21.0-28.0) (143/588 pregnant women) to 3.4% (95% CI 2.8-4.3) (76/2,207 pregnant women), p<0.001. The in vivo efficacy of mefloquine-artesunate declined steadily, with a sharp drop in 2011 (day-42 PCR-adjusted cure rate 42% [95% CI 20-62]). The proportion of patients still slide positive for malaria at day 3 rose from 0% in 2000 to reach 28% (95% CI 13-45) (8/29 patients) in 2011. CONCLUSIONS Despite the emergence of resistance to artesunate in P. falciparum, the strategy of EDT with artemisinin-based combination treatments has been associated with a reduction in malaria in the migrant population living on the Thai-Myanmar border. Although limited by its observational nature, this study provides useful data on malaria burden in a strategically crucial geographical area. Alternative fixed combination treatments are needed urgently to replace the failing first-line regimen of mefloquine and artesunate. Please see later in the article for the Editors' Summary.
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Affiliation(s)
- Verena I. Carrara
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Mahidol Oxford University Research Unit, Bangkok, Thailand
| | - Khin Maung Lwin
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Mahidol Oxford University Research Unit, Bangkok, Thailand
| | - Aung Pyae Phyo
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Mahidol Oxford University Research Unit, Bangkok, Thailand
| | - Elizabeth Ashley
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Mahidol Oxford University Research Unit, Bangkok, Thailand
- Centre for Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | | | | | - Marcus Rijken
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Department of Obstetrics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Machteld Boel
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Academic Medical Center, Amsterdam, The Netherlands
| | - Rose McGready
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Mahidol Oxford University Research Unit, Bangkok, Thailand
- Centre for Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Cindy Chu
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Mahidol Oxford University Research Unit, Bangkok, Thailand
- Centre for Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Nicholas White
- Mahidol Oxford University Research Unit, Bangkok, Thailand
- Centre for Tropical Medicine, University of Oxford, Oxford, United Kingdom
| | - François Nosten
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Mahidol Oxford University Research Unit, Bangkok, Thailand
- Centre for Tropical Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Akter J, Thriemer K, Khan WA, Sullivan DJ, Noedl H, Haque R. Genotyping of Plasmodium falciparum using antigenic polymorphic markers and to study anti-malarial drug resistance markers in malaria endemic areas of Bangladesh. Malar J 2012; 11:386. [PMID: 23173674 PMCID: PMC3519574 DOI: 10.1186/1475-2875-11-386] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 11/18/2012] [Indexed: 12/31/2022] Open
Abstract
Background In the past many regions of Bangladesh were hyperendemic for malaria. Malaria control in the 1960s to 1970s eliminated malaria from the plains but in the Chittagong Hill Tracts remained a difficult to control reservoir. The Chittagong Hill Tracts have areas with between 1 and 10% annual malaria rates, predominately 90-95% Plasmodium falciparum. In Southeast Asia, multiplicity of infection for hypo-endemic regions has been approximately 1.5. Few studies on the genetic diversity of P. falciparum have been performed in Bangladesh. Anderson et al. performed a study in Khagrachari, northern Chittagong Hill Tracts in 2002 on 203 patients and found that parasites had a multiplicity of infection of 1.3 by MSP-1, MSP-2 and GLURP genotyping. A total of 94% of the isolates had the K76T Pfcrt chloroquine resistant genotype, and 70% showed the N86Y Pfmdr1 genotype. Antifolate drug resistant genotypes were high with 99% and 73% of parasites having two or more mutations at the dhfr or dhps loci. Methods Nested and real-time polymerase chain reaction (PCR) methods were used to genotype P. falciparum using antigenic polymorphic markers and to study anti-malarial drug resistance markers in malaria endemic areas of Bangladesh. Results The analysis of polymorphic and drug resistant genotype on 33 paired recrudescent infections after drug treatment in the period 2004 to 2008 in the Chittagong Hill Tracts, which is just prior to countrywide provision of artemisinin combination therapy. Overall the multiplicity of infection for MSP-1 was 2.7 with a slightly smaller parasite diversity post-treatment. The 13 monoclonal infections by both GLURP and MSP-1 were evenly divided between pre- and post-treatment. The MSP-1 MAD block was most frequent in 66 of the samples. The prevalence of the K76T PfCRT chloroquine resistant allele was approximately 82% of the samples, while the resistant Pfmdr1 N86Y was present in 33% of the samples. Interestingly, the post-treatment samples had a small but significantly higher frequency of the sensitive PfCRT alleles by RT-PCR. Conclusion The parasite population retains high population diversity despite hypo-endemic transmission with retention, but decrease in the chloroquine-resistant allele and Pfmdr1 resistant alleles in the Chittagong Hill Tracts of Bangladesh.
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Gargano N, Ubben D, Tommasini S, Bacchieri A, Corsi M, Bhattacharyya PC, Rao BHK, Dubashi N, Dev V, Ghosh SK, Kumar A, Srivastava B, Valecha N. Therapeutic efficacy and safety of dihydroartemisinin-piperaquine versus artesunate-mefloquine in uncomplicated Plasmodium falciparum malaria in India. Malar J 2012; 11:233. [PMID: 22818552 PMCID: PMC3424202 DOI: 10.1186/1475-2875-11-233] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 07/05/2012] [Indexed: 03/19/2024] Open
Abstract
BACKGROUND Resistance in Plasmodium falciparum to commonly used anti-malarial drugs, especially chloroquine, is being increasingly documented in India. By 2007, the first-line treatment for uncomplicated malaria has been revised to recommend artemisinin-based combination therapy (ACT) for all confirmed P. falciparum cases. OBJECTIVE The objective of this study was to compare the efficacy, safety and tolerability between dihydroartemisinin-piperaquine (DP) and artesunate plus mefloquine (A + M) drug combinations in the treatment of uncomplicated P. falciparum malaria in India. METHODS Between 2006 and 2007, 150 patients with acute uncomplicated P. falciparum malaria were enrolled, randomized to DP (101) or A + M (49) and followed up for 63 days as part of an open-label, non-inferiority, randomized, phase III multicenter trial in Asia. RESULTS The heterogeneity analysis showed no statistically significant difference between India and the other countries involved in the phase III study, for both the PCR-corrected and uncorrected cure rates. As shown at the whole study level, both forms of ACT were highly efficacious in India. In fact, in the per protocol population, the 63-day cure rates were 100% for A + M and 98.8% for DP. The DP combination exerted a significant post-treatment prophylactic effect, and compared with A + M a significant reduction in the incidence of new infections for DP was observed (respectively 17.1% versus 7.5% of patients experienced new infection within follow up). Parasite and fever clearance was rapid in both treatment arms (median time to parasite clearance of one day for both groups). Both DP and A + M were well tolerated, with the majority of adverse events of mild or moderate severity. The frequencies of individual adverse events were generally similar between treatments, although the incidence of post treatment adverse events was slightly higher in patients who received A + M with respect to those treated with DP. CONCLUSION DP is a new ACT displaying high efficacy and safety in the treatment of uncomplicated P. falciparum malaria and could potentially be considered for the first-line treatment of uncomplicated falciparum malaria in India. TRIAL REGISTRATION Current Controlled Trials ISRCTN 81306618.
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Affiliation(s)
- Nicola Gargano
- Sigma-Tau Industrie Farmaceutiche Riunite, Pomezia, Italy
| | - David Ubben
- Medicines for Malaria Venture (MMV), Geneva, Switzerland
| | | | | | - Marco Corsi
- Sigma-Tau Industrie Farmaceutiche Riunite, Pomezia, Italy
| | | | - Bappanad HK Rao
- Wenlock District Government Hospital, Mangalore Karnataka, India
| | | | - Vas Dev
- National Institute of Malaria Research, Field Station, Guwahati, Assam, India
| | - Susanta K Ghosh
- National Institute of Malaria Research, Field Station, Bangalore Karnataka, India
| | - Ashwani Kumar
- National Institute of Malaria Research, Field Station, Goa, India
| | - Bina Srivastava
- National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, 110 077, India
| | - Neena Valecha
- National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, 110 077, India
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McGready R, Phyo AP, Rijken MJ, Tarning J, Lindegardh N, Hanpithakpon W, Than HH, Hlaing N, Zin NT, Singhasivanon P, White NJ, Nosten F. Artesunate/dihydroartemisinin pharmacokinetics in acute falciparum malaria in pregnancy: absorption, bioavailability, disposition and disease effects. Br J Clin Pharmacol 2012; 73:467-77. [PMID: 21950338 PMCID: PMC3370352 DOI: 10.1111/j.1365-2125.2011.04103.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To determine if reported lower plasma concentrations of artemisinin derivatives for malaria in pregnancy result from reduced oral bioavailability, expanded volume of distribution or increased clearance. METHODS In a sequentially assigned crossover treatment study, pregnant women with uncomplicated falciparum malaria received i.v. artesunate (i.v. ARS) (4 mg kg−1) on the first day and oral ARS (4 mg kg−1) on the second, or, oral on the first and i.v. on the second, in both groups followed by oral ARS (4 mg kg−1 day−1) for 5 days. Plasma concentrations of ARS and dihyroartemisinin (DHA) were measured by liquid chromatography-mass-spectrometry on days 0, 1, 2 and 6. Controls were the same women restudied when healthy (3 months post partum). RESULTS I.v. ARS administration resulted in similar ARS and DHA pharmacokinetics in pregnant women with malaria (n = 20) and in controls (n = 14). Oral administration resulted in higher total drug exposure in pregnancy [AUC (95% CI) in (ng ml−1 h)/(mg kg−1)] of 55.1 (30.1, 100.0) vs. 26.5 (12.2, 54.3) for ARS, P = 0.002 and 673 (386, 1130) vs. 523 (351, 724) for DHA, P = 0.007. The corresponding median absolute oral bioavailability (F%) was 21.7 (12.6, 75.1) vs. 9.9 (6.0, 36.81) for ARS (P = 0.046) and 77.0 (42.2, 129) vs. 72.7 (42.0, 87.7) for DHA, P = 0.033. Total DHA exposure was lower at day 6 in pregnant women with malaria (P < 0.001) compared with day 0 or 1, but not in the controls (P = 0.084). CONCLUSIONS This study demonstrates the effects of malaria on oral ARS drug disposition are greater than those of pregnancy. This probably results from a disease related reduction in first pass metabolism. The data are reassuring regarding current dosing recommendations.
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Affiliation(s)
- Rose McGready
- Shoklo Malaria Research Unit, PO Box 46, Mae Sot Tak 63110 Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
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Mayxay M, Khanthavong M, Chanthongthip O, Imwong M, Pongvongsa T, Hongvanthong B, Phompida S, Vanisaveth V, White NJ, Newton PN. Efficacy of artemether-lumefantrine, the nationally-recommended artemisinin combination for the treatment of uncomplicated falciparum malaria, in southern Laos. Malar J 2012; 11:184. [PMID: 22681769 PMCID: PMC3523969 DOI: 10.1186/1475-2875-11-184] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 05/24/2012] [Indexed: 11/13/2022] Open
Abstract
Background The Lao Government changed the national policy for uncomplicated Plasmodium falciparum malaria from chloroquine to artemether-lumefantrine (AL) in 2005. Since then, no information on AL efficacy has been reported. With evidence of resistance to artemisinin derivatives in adjacent Cambodia, there has been a concern as to AL efficacy. Monitoring of AL efficacy would help the Lao Government to make decisions on appropriate malaria treatment. Methods The efficacy of a three-day, twice daily oral artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Xepon District, Savannakhet Province, southern Laos was studied over 42 days follow-up. This was part of a trial of thiamin supplementation in falciparum malaria. Results Of 630 patients with P. falciparum enrolled in the trial of thiamin treatment, 549 (87%, 357 children ≤15 years and 192 adults) were included in this study. The per protocol 42-day cure rates were 97% (524/541) [96% (337/352) for children and 99% (187/189) for adults, p = 0.042]. By conventional intention-to-treat analysis, the 42-day cure rates adjusted for re-infection, were 97% (532/549) [96% (342/357) in children and 99% (190/192) in adults, p = 0.042]. The proportion of patients who remained parasitaemic at day 1 after treatment was significantly higher in children [33% (116/356)] compared to adults [15% (28/192)] (p < 0.001) and only one adult patient had detectable parasitaemia on day 2. There were no serious adverse events. Potential side effects after treatment were reported more commonly in adults (32%) compared to children (15%) (p < 0.001). Patients with recrudescent infections were significantly younger, had longer mean time to fever clearance, and had longer median time to parasite clearance compared to those who were cured. Conclusions The current nationally-recommended anti-malarial treatment (artemether-lumefantrine) remains highly efficacious for the treatment of uncomplicated falciparum malaria five years after introduction in Laos. Regular monitoring is required in case artemisinin-resistant P. falciparum parasites should appear. Trial registration ISRCTN85411059.
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Affiliation(s)
- Mayfong Mayxay
- Wellcome Trust-Mahosot Hospital-Oxford University Tropical Medicine Research Collaboration, Mahosot Hospital, Vientiane, Lao PDR.
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Nkhoma SC, Nair S, Cheeseman IH, Rohr-Allegrini C, Singlam S, Nosten F, Anderson TJC. Close kinship within multiple-genotype malaria parasite infections. Proc Biol Sci 2012; 279:2589-98. [PMID: 22398165 PMCID: PMC3350702 DOI: 10.1098/rspb.2012.0113] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Malaria infections containing multiple parasite genotypes are ubiquitous in nature, and play a central role in models of recombination, intra-host dynamics, virulence, sex ratio, immunity and drug resistance evolution in Plasmodium. While these multiple infections (MIs) are often assumed to result from superinfection (bites from multiple infected mosquitoes), we know remarkably little about their composition or generation. We isolated 336 parasite clones from eight patients from Malawi (high transmission) and six from Thailand (low transmission) by dilution cloning. These were genotyped using 384 single-nucleotide polymorphisms, revealing 22 independent haplotypes in Malawi (2–6 per MI) and 15 in Thailand (2–5 per MI). Surprisingly, all six patients from Thailand and six of eight from Malawi contained related haplotypes, and haplotypes were more similar within- than between-infections. These results argue against a simple superinfection model. Instead, the observed kinship patterns may be explained by inoculation of multiple related haploid sporozoites from single mosquito bites, by immune suppression of parasite subpopulations within infections, and serial transmission of related parasites between people. That relatedness is maintained in endemic areas in the face of repeated bites from infected mosquitoes has profound implications for understanding malaria transmission, immunity and intra-host dynamics of co-infecting parasite genotypes.
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Affiliation(s)
- Standwell C Nkhoma
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
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Kolaczinski K, Leslie T, Ali I, Durrani N, Lee S, Barends M, Beshir K, Ord R, Hallett R, Rowland M. Defining Plasmodium falciparum treatment in South West Asia: a randomized trial comparing artesunate or primaquine combined with chloroquine or SP. PLoS One 2012; 7:e28957. [PMID: 22303437 PMCID: PMC3269419 DOI: 10.1371/journal.pone.0028957] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 11/17/2011] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION Antimalarial resistance has led to a global policy of artemisinin-based combination therapy. Despite growing resistance chloroquine (CQ) remained until recently the official first-line treatment for falciparum malaria in Pakistan, with sulfadoxine-pyrimethamine (SP) second-line. Co-treatment with the gametocytocidal primaquine (PQ) is recommended for transmission control in South Asia. The relative effect of artesunate (AS) or primaquine, as partner drugs, on clinical outcomes and gametocyte carriage in this setting were unknown. METHODS A single-blinded, randomized trial among Afghan refugees in Pakistan compared six treatment arms: CQ; CQ+(single-dose)PQ; CQ+(3 d)AS; SP; SP+(single-dose)PQ, and SP+(3 d)AS. The objectives were to compare treatment failure rates and effect on gametocyte carriage, of CQ or SP monotherapy against the respective combinations (PQ or AS). Outcomes included trophozoite and gametocyte clearance (read by light microscopy), and clinical and parasitological failure. FINDINGS A total of 308 (87%) patients completed the trial. Failure rates by day 28 were: CQ 55/68 (81%); CQ+AS 19/67 (28%), SP 4/41 (9.8%), SP+AS 1/41 (2.4%). The addition of PQ to CQ or SP did not affect failure rates (CQ+PQ 49/67 (73%) failed; SP+PQ 5/33 (16%) failed). AS was superior to PQ at clearing gametocytes; gametocytes were seen on d7 in 85% of CQ, 40% of CQ+PQ, 21% of CQ+AS, 91% of SP, 76% of SP+PQ and 23% of SP+AS treated patients. PQ was more effective at clearing older gametocyte infections whereas AS was more effective at preventing emergence of mature gametocytes, except in cases that recrudesced. CONCLUSIONS CQ is no longer appropriate by itself or in combination. These findings influenced the replacement of CQ with SP+AS for first-line treatment of uncomplicated falciparum malaria in the WHO Eastern Mediterranean Region. The threat of SP resistance remains as SP monotherapy is still common. Three day AS was superior to single-dose PQ for reducing gametocyte carriage. TRIAL REGISTRATION ClinicalTrials.gov NCT00959517.
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Affiliation(s)
- Kate Kolaczinski
- London School of Hygiene and Tropical Medicine, London, United Kingdom.
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Population pharmacokinetics of dihydroartemisinin and piperaquine in pregnant and nonpregnant women with uncomplicated malaria. Antimicrob Agents Chemother 2012; 56:1997-2007. [PMID: 22252822 DOI: 10.1128/aac.05756-11] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pregnant women are particularly vulnerable to malaria. The pharmacokinetic properties of antimalarial drugs are often affected by pregnancy, resulting in lower drug concentrations and a consequently higher risk of treatment failure. The objective of this study was to evaluate the population pharmacokinetic properties of piperaquine and dihydroartemisinin in pregnant and nonpregnant women with uncomplicated malaria. Twenty-four pregnant and 24 matched nonpregnant women on the Thai-Myanmar boarder were treated with a standard fixed oral 3-day treatment, and venous plasma concentrations of both drugs were measured frequently for pharmacokinetic evaluation. Population pharmacokinetics were evaluated with nonlinear mixed-effects modeling. The main pharmacokinetic finding was an unaltered total exposure to piperaquine but reduced exposure to dihydroartemisinin in pregnant compared to nonpregnant women with uncomplicated malaria. Piperaquine was best described by a three-compartment disposition model with a 45% higher elimination clearance and a 47% increase in relative bioavailability in pregnant women compared with nonpregnant women. The resulting net effect of pregnancy was an unaltered total exposure to piperaquine but a shorter terminal elimination half-life. Dihydroartemisinin was best described by a one-compartment disposition model with a 38% lower relative bioavailability in pregnant women than nonpregnant women. The resulting net effect of pregnancy was a decreased total exposure to dihydroartemisinin. The shorter terminal elimination half-life of piperaquine and lower exposure to dihydroartemisinin will shorten the posttreatment prophylactic effect and might affect cure rates. The clinical impact of these pharmacokinetic findings in pregnant women with uncomplicated malaria needs to be evaluated in larger series.
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Song J, Socheat D, Tan B, Seila S, Xu Y, Ou F, Sokunthea S, Sophorn L, Zhou C, Deng C, Wang Q, Li G. Randomized trials of artemisinin-piperaquine, dihydroartemisinin-piperaquine phosphate and artemether-lumefantrine for the treatment of multi-drug resistant falciparum malaria in Cambodia-Thailand border area. Malar J 2011; 10:231. [PMID: 21827706 PMCID: PMC3169515 DOI: 10.1186/1475-2875-10-231] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 08/10/2011] [Indexed: 11/10/2022] Open
Abstract
Background Drug resistance of falciparum malaria is a global problem. Sulphadoxine/pyrimethamine-resistant and mefloquine-resistant strains of falciparum malaria have spread in Southeast Asia at lightning speed in 1980s-1990s, and the Cambodia-Thailand border is one of the malaria epidemic areas with the most severe forms of multi-drug resistant falciparum malaria. Methods Artemisinin-piperaquine (AP), dihydroartemisinin-piperaquine phosphate (DHP) and artemether-lumefantrine (AL) were used to treat 110, 55 and 55 uncomplicated malaria patients, respectively. The total dosage for adults is 1,750 mg (four tablets, twice over 24 hours) of AP, 2,880 mg (eight tablets, four times over two days) of DHP, and 3,360 mg (24 tablets, six times over three days) of AL. The 28-day cure rate, parasite clearance time, fever clearance time, and drug tolerance of patients to the three drugs were compared. All of the above methods were consistent with the current national guidelines. Results The mean parasite clearance time was similar in all three groups (66.7 ± 21.9 hrs, 65.6 ± 27.3 hrs, 65.3 ± 22.5 hrs in AP, DHP and AL groups, respectively), and there was no remarkable difference between them; the fever clearance time was also similar (31.6 ± 17.7 hrs, 34.6 ± 21.8 hrs and 36.9 ± 15.4 hrs, respectively). After following up for 28-days, the cure rate was 95.1%(97/102), 98.2%(54/55) and 82.4%(42/51); and the recrudescence cases was 4.9%(5/102), 1.8%(1/55) and 17.6%(9/51), respectively. Therefore, the statistical data showed that 28-day cure rate in AP and DHP groups was superior to AL group obviously. The patients had good tolerance to all the three drugs, and some side effects (anoxia, nausea, vomiting, headache and dizziness) could be found in every group and they were self-limited; patients in control groups also had good tolerance to DHP and AL, there was no remarkable difference in the three groups. Conclusions AP, DHP and AL all remained efficacious treatments for the treatment of falciparum malaria in Cambodia-Thailand border area. However, in this particular setting, the AP regimen turned out to be favourable in terms of efficacy and effectiveness, simplicity of administration, cost and compliance. Trial Registration The trial was registered at Chinese Clinical Trial Register under identifier 2005L01041.
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Affiliation(s)
- Jianping Song
- Research Center for Qinghao (Artemisia annual L.), Guangzhou University of Chinese Medicine, Guangzhou, China.
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A small amount of fat does not affect piperaquine exposure in patients with malaria. Antimicrob Agents Chemother 2011; 55:3971-6. [PMID: 21709087 DOI: 10.1128/aac.00279-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dihydroartemisinin-piperaquine is a new, highly effective, and well-tolerated combination treatment for uncomplicated falciparum malaria. The lipophilic characteristic of piperaquine suggests that administration together with fat will increase the oral bioavailability of the drug, and this has been reported for healthy volunteers. This pharmacokinetic study monitored 30 adult patients with uncomplicated falciparum malaria for 4.5 months to evaluate the effects of the concomitant intake of fat on the total piperaquine exposure. The fixed-drug combination of dihydroartemisinin-piperaquine was given with water to fasting patients (n = 15) or was coadministered with 200 ml milk containing 6.4 g fat (n = 15). The drug combination was generally well tolerated, and there were no severe adverse effects reported for either group during the study. Total piperaquine exposure (area under the concentration-time curve from zero to infinity [AUC(0-∞)]; results are given as medians [ranges]) were not statistically different between fed (29.5 h · μg/ml [20.6 to 58.7 h · μg/ml]) and fasting (23.9 h · μg/ml [11.9 to 72.9 h · μg/ml]) patients, but the interindividual variation was reduced in the fed group. Overall, none of the pharmacokinetic parameters differed statistically between the groups. Total piperaquine exposure correlated well with the day 7 concentrations in the fasted group, but the fed group showed a poor correlation. In conclusion, the coadministration of 6.4 g fat did not have any significant effect on piperaquine pharmacokinetics in the treatment of uncomplicated malaria.
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McGready R, White NJ, Nosten F. Parasitological efficacy of antimalarials in the treatment and prevention of falciparum malaria in pregnancy 1998 to 2009: a systematic review. BJOG 2010; 118:123-35. [DOI: 10.1111/j.1471-0528.2010.02810.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mayxay M, Keomany S, Khanthavong M, Souvannasing P, Stepniewska K, Khomthilath T, Keola S, Pongvongsa T, Phompida S, Ubben D, Valecha N, White NJ, Newton PN. A phase III, randomized, non-inferiority trial to assess the efficacy and safety of dihydroartemisinin-piperaquine in comparison with artesunate-mefloquine in patients with uncomplicated Plasmodium falciparum malaria in southern Laos. Am J Trop Med Hyg 2010; 83:1221-9. [PMID: 21118925 PMCID: PMC2990035 DOI: 10.4269/ajtmh.2010.10-0276] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 08/23/2010] [Indexed: 01/30/2023] Open
Abstract
We conducted an open, randomized clinical trial of oral dihydroartemisinin-piperaquine (DP) versus artesunate-mefloquine (AM) in 300 patients in Laos with uncomplicated Plasmodium falciparum malaria as part of a multicentre study in Asia. Survival analysis and adjustment for re-infection showed that the 63-day cure rates (95% confidence interval [CI]) were 100% for AM and 99.5% (96.4-99.8%) for DP. The 63-day cure rates per protocol were 99% (97 of 98) for AM and 99.5% (196 of 197) for DP (P = 0.55). The difference (AM minus DP) in cure rates (95% CI) was -0.5% (-5.1 to 2.0%), which is within the 5% non-inferiority margin. The median fever and parasite clearance times were also similar for AM and DP. The proportion of patients with at least one recorded potential adverse event was significantly higher in the AM group (38 of 87, 44%) than in the DP group (57 of 182, 31%) (relative risk = 0.6, 95% CI = 0.4-0.9; P = 0.04). Dihydroartemisinin-piperaquine is not inferior to AM in the treatment of uncomplicated P. falciparum malaria in Laos and is associated with fewer adverse effects. The results of this study were similar to those of the larger multicentre study.
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Affiliation(s)
- Mayfong Mayxay
- Wellcome Trust, Mahosot Hospital, Oxford University Tropical Medicine Research Collaboration, Mahosot Hospital, Vientiane, Laos.
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Effectiveness of five artemisinin combination regimens with or without primaquine in uncomplicated falciparum malaria: an open-label randomised trial. THE LANCET. INFECTIOUS DISEASES 2010; 10:673-81. [PMID: 20832366 PMCID: PMC2947715 DOI: 10.1016/s1473-3099(10)70187-0] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Background Artemisinin-combination therapy (ACT) is recommended as first-line treatment of falciparum malaria throughout the world, and fixed-dose combinations are preferred by WHO; whether a single gametocytocidal dose of primaquine should be added is unknown. We aimed to compare effectiveness of four fixed-dose ACTs and a loose tablet combination of artesunate and mefloquine, and assess the addition of a single gametocytocidal dose of primaquine. Methods In an open-label randomised trial in clinics in Rakhine state, Kachin state, and Shan state in Myanmar (Burma) between Dec 30, 2008, and March 20, 2009, we compared the effectiveness of all four WHO-recommended fixed-dose ACTs (artesunate–mefloquine, artesunate–amodiaquine, dihydroartemisinin–piperaquine, artemether–lumefantrine) and loose artesunate–mefloquine in Burmese adults and children. Eligible patients were those who presented to the clinics with acute uncomplicated Plasmodium falciparum malaria or mixed infection, who were older than 6 months, and who weighed more than 5 kg. Treatments were randomised in equal numbers within blocks of 50 and allocation was in sealed envelopes. All patients were also randomly assigned to receive either a single dose of primaquine 0·75 mg base/kg or not. Patients were followed up for 63 days. Treatment groups were compared by analysis of variance and multiple logistic regression. The primary outcome was the 63 day recrudescence rate. This study is registered with clinicaltrials.gov, number NCT00902811. Findings 155 patients received artesunate–amodiaquine, 162 artemether–lumefantrine, 169 artesunate–mefloquine, 161 loose artesunate–mefloquine, and 161 dihydroartemisinin–piperaquine. By day 63 of follow-up, 14 patients (9·4%; 95% CI 5·7–15·3%) on artesunate–amodiaquine had recrudescent P falciparum infections, a rate significantly higher than for artemether–lumefantrine (two patients; 1·4%; 0·3–5·3; p=0·0013), fixed-dose artesunate–mefloquine (0 patients; 0–2·3; p<0·0001), loose artesunate–mefloquine (two patients; 1·3%; 0·3–5·3; p=0·0018), and dihydroartemisinin–piperaquine (two patients 1·3%; 0·3–5·2%; p=0·0012). Hazard ratios for re-infection (95% CI) after artesunate–amodiaquine were 3·2 (1·3–8·0) compared with the two artesunate–mefloquine groups (p=0·01), 2·6 (1·0–6–0) compared with artemether–lumefantrine (p=0·04), and 2·3 (0·9–6·0) compared with dihydroartemisinin–piperaquine (p=0·08). Mixed falciparum and vivax infections were common: 129 (16%) had a mixed infection at presentation and 330 (41%) patients had one or more episodes of Plasmodium vivax infection during follow-up. The addition of a single dose of primaquine (0·75 mg/kg) reduced P falciparum gametocyte carriage substantially: rate ratio 11·9 (95% CI 7·4–20·5). All regimens were well tolerated. Adverse events were reported by 599 patients, most commonly vomiting and dizziness. Other side-effects were less common and were not related to a specific treatment. Interpretation Artesunate–amodiaquine should not be used in Myanmar, because the other ACTs are substantially more effective. Artesunate–mefloquine provided the greatest post-treatment suppression of malaria. Adding a single dose of primaquine would substantially reduce transmission potential. Vivax malaria, not recurrent falciparum malaria, is the main complication after treatment of P falciparum infections in this region. Funding Médecins sans Frontières (Holland) and the Wellcome Trust Mahidol University Oxford Tropical Medicine Research Programme.
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Uncertain outcomes: adjusting for misclassification in antimalarial efficacy studies. Epidemiol Infect 2010; 139:544-51. [PMID: 20619072 DOI: 10.1017/s0950268810001652] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Evaluation of antimalarial efficacy is difficult because recurrent parasitaemia can be due to recrudescence or re-infection. PCR is used to differentiate between recrudescences and re-infections by comparing parasite allelic variants before and after treatment. However, PCR-corrected results are susceptible to misclassification: false positives, due to re-infection by the same variant present in the patient before treatment; and false negatives, due to variants that are present but too infrequent to be detected in the pre-treatment PCR, but are then detectable post-treatment. This paper aimed to explore factors affecting the probability of false positives and proposes a Monte Carlo uncertainty analysis to account for both types of misclassification. Higher levels of transmission intensity, increased multiplicity of infection, and limited allelic variation resulted in more false recrudescences. The uncertainty analysis exploits characteristics of study data to minimize bias in the estimate of efficacy and can be applied to areas of different transmission intensity.
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McGready R, Nosten F. Which drug is effective and safe for acute malaria in pregnancy? Reviewing the evidence. Drug Dev Res 2009. [DOI: 10.1002/ddr.20348] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Juliano JJ, Ariey F, Sem R, Tangpukdee N, Krudsood S, Olson C, Looareesuwan S, Rogers WO, Wongsrichanalai C, Meshnick SR. Misclassification of drug failure in Plasmodium falciparum clinical trials in southeast Asia. J Infect Dis 2009; 200:624-8. [PMID: 19591576 DOI: 10.1086/600892] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Most trials of antimalarials occur in areas in which reinfections are possible. For Plasmodium falciparum, reinfections are distinguished from recrudescences by polymerase chain reaction analysis of 3 polymorphic genes. However, the validity of this approach has never been rigorously tested. We tested for misclassification in 6 patients from clinical trials in Thailand and Cambodia who were classified as being reinfected by the standard polymerase chain reaction protocol. Using heteroduplex tracking assays and direct DNA sequencing, we found that 5 (83%) of 6 patients were misclassified. Misclassification in this manner overestimates the efficacy of antimalarials and delays the recognition of decreasing therapeutic efficacy, thus delaying potential changes in policy.
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Affiliation(s)
- Jonathan J Juliano
- Division of Infectious Diseases, School of Medicine, Department of Epidemiology, University of North Carolina, Chapel Hill, NC 27599, USA
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Zwang J, Olliaro P, Barennes H, Bonnet M, Brasseur P, Bukirwa H, Cohuet S, D'Alessandro U, Djimdé A, Karema C, Guthmann JP, Hamour S, Ndiaye JL, Mårtensson A, Rwagacondo C, Sagara I, Same-Ekobo A, Sirima SB, van den Broek I, Yeka A, Taylor WRJ, Dorsey G, Randrianarivelojosia M. Efficacy of artesunate-amodiaquine for treating uncomplicated falciparum malaria in sub-Saharan Africa: a multi-centre analysis. Malar J 2009; 8:203. [PMID: 19698172 PMCID: PMC2745424 DOI: 10.1186/1475-2875-8-203] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 08/23/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Artesunate and amodiaquine (AS&AQ) is at present the world's second most widely used artemisinin-based combination therapy (ACT). It was necessary to evaluate the efficacy of ACT, recently adopted by the World Health Organization (WHO) and deployed over 80 countries, in order to make an evidence-based drug policy. METHODS An individual patient data (IPD) analysis was conducted on efficacy outcomes in 26 clinical studies in sub-Saharan Africa using the WHO protocol with similar primary and secondary endpoints. RESULTS A total of 11,700 patients (75% under 5 years old), from 33 different sites in 16 countries were followed for 28 days. Loss to follow-up was 4.9% (575/11,700). AS&AQ was given to 5,897 patients. Of these, 82% (4,826/5,897) were included in randomized comparative trials with polymerase chain reaction (PCR) genotyping results and compared to 5,413 patients (half receiving an ACT). AS&AQ and other ACT comparators resulted in rapid clearance of fever and parasitaemia, superior to non-ACT. Using survival analysis on a modified intent-to-treat population, the Day 28 PCR-adjusted efficacy of AS&AQ was greater than 90% (the WHO cut-off) in 11/16 countries. In randomized comparative trials (n = 22), the crude efficacy of AS&AQ was 75.9% (95% CI 74.6-77.1) and the PCR-adjusted efficacy was 93.9% (95% CI 93.2-94.5). The risk (weighted by site) of failure PCR-adjusted of AS&AQ was significantly inferior to non-ACT, superior to dihydroartemisinin-piperaquine (DP, in one Ugandan site), and not different from AS+SP or AL (artemether-lumefantrine). The risk of gametocyte appearance and the carriage rate of AS&AQ was only greater in one Ugandan site compared to AL and DP, and lower compared to non-ACT (p = 0.001, for all comparisons). Anaemia recovery was not different than comparator groups, except in one site in Rwanda where the patients in the DP group had a slower recovery. CONCLUSION AS&AQ compares well to other treatments and meets the WHO efficacy criteria for use against falciparum malaria in many, but not all, the sub-Saharan African countries where it was studied. Efficacy varies between and within countries. An IPD analysis can inform general and local treatment policies. Ongoing monitoring evaluation is required.
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Affiliation(s)
- Julien Zwang
- Shoklo Malaria Research Unit (SMRU), Mae Sot, Thailand
| | - Piero Olliaro
- UNICEF/UNDP/WB/WHO Special Programme for Research and Training in Tropical Diseases, Geneva, Switzerland
| | - Hubert Barennes
- Institut de la Francophonie pour la Médecine Tropicale, BP 9519, Vientiane, Lao PDR
| | | | | | | | | | | | - Abdulaye Djimdé
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Pharmacy, University of Bamako, Bamako, Mali
| | | | | | | | - Jean-Louis Ndiaye
- Department of Parasitology, Faculty of Medicine, Cheikh Anta Diop University, Dakar, Senegal
| | - Andreas Mårtensson
- Infectious Diseases Unit, Department of Medicine, Karolinska University Hospital, Karolinska Institute, Stockholm, Sweden
| | | | - Issaka Sagara
- Malaria Research and Training Center, Department of Epidemiology of Parasitic Diseases, Faculty of Medicine and Pharmacy, University of Bamako, Bamako, Mali
| | - Albert Same-Ekobo
- Laboratoire de Parasitologie, Centre Hospitalier Universitaire, Yaoundé, Cameroun
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme, Ministère de la Santé, Ouagadougou, Burkina Faso
| | | | - Adoke Yeka
- Uganda Malaria Surveillance Project, Kampala, Uganda
| | - Walter RJ Taylor
- UNICEF/UNDP/WB/WHO Special Programme for Research and Training in Tropical Diseases, Geneva, Switzerland
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
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Stepniewska K, Taylor W, Sirima SB, Ouedraogo EB, Ouedraogo A, Gansané A, Simpson JA, Morgan CC, White NJ, Kiechel JR. Population pharmacokinetics of artesunate and amodiaquine in African children. Malar J 2009; 8:200. [PMID: 19691851 PMCID: PMC3224946 DOI: 10.1186/1475-2875-8-200] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2009] [Accepted: 08/20/2009] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Pharmacokinetic (PK) data on amodiaquine (AQ) and artesunate (AS) are limited in children, an important risk group for malaria. The aim of this study was to evaluate the PK properties of a newly developed and registered fixed dose combination (FDC) of artesunate and amodiaquine. METHODS A prospective population pharmacokinetic study of AS and AQ was conducted in children aged six months to five years. Participants were randomized to receive the new artesunate and amodiaquine FDC or the same drugs given in separate tablets. Children were divided into two groups of 70 (35 in each treatment arm) to evaluate the pharmacokinetic properties of AS and AQ, respectively. Population pharmacokinetic models for dihydroartemisinin (DHA) and desethylamodiaquine (DeAq), the principal pharmacologically active metabolites of AS and AQ, respectively, and total artemisinin anti-malarial activity, defined as the sum of the molar equivalent plasma concentrations of DHA and artesunate, were constructed using the non-linear mixed effects approach. Relative bioavailability between products was compared by estimating the ratios (and 95% CI) between the areas under the plasma concentration-time curves (AUC). RESULTS The two regimens had similar PK properties in young children with acute malaria. The ratio of loose formulation to fixed co-formulation AUCs, was estimated as 1.043 (95% CI: 0.956 to 1.138) for DeAq. For DHA and total anti-malarial activity AUCs were estimated to be the same. Artesunate was rapidly absorbed, hydrolysed to DHA, and eliminated. Plasma concentrations were significantly higher following the first dose, when patients were acutely ill, than after subsequent doses when patients were usually afebrile and clinically improved. Amodiaquine was converted rapidly to DeAq, which was then eliminated with an estimated median (range) elimination half-life of 9 (7 to 12) days. Efficacy was similar in the two treatments groups, with cure rates of 0.946 (95% CI: 0.840-0.982) in the AS+AQ group and 0.892 (95% CI: 0.787 - 0.947) in the AS/AQ group. Four out of five patients with PCR confirmed recrudescences received AQ doses < 10 mg/kg. Both regimens were well tolerated. No child developed severe, post treatment neutropaenia (<1,000/muL). There was no evidence of AQ dose related hepatotoxicity, but one patient developed an asymptomatic rise in liver enzymes that was resolving by Day-28. CONCLUSION The bioavailability of the co-formulated AS-AQ FDC was similar to that of the separate tablets for desethylamodiaquine, DHA and the total anti-malarial activity. These data support the use this new AS-AQ FDC in children with acute uncomplicated falciparum malaria.
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Affiliation(s)
- Kasia Stepniewska
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
| | - Walter Taylor
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
- Service de Médecine Internationale et Humanitaire, Hopitaux Universitaires de Genève, Switzerland
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Esperance B Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Alphonse Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Adama Gansané
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Julie A Simpson
- Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, The University of Melbourne, Melbourne, Australia
| | | | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK
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Bonnet M, Broek IVD, van Herp M, Urrutia PPP, van Overmeir C, Kyomuhendo J, Ndosimao CN, Ashley E, Guthmann JP. Varying efficacy of artesunate+amodiaquine and artesunate+sulphadoxine-pyrimethamine for the treatment of uncomplicated falciparum malaria in the Democratic Republic of Congo: a report of two in-vivo studies. Malar J 2009; 8:192. [PMID: 19664280 PMCID: PMC2734861 DOI: 10.1186/1475-2875-8-192] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 08/10/2009] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Very few data on anti-malarial efficacy are available from the Democratic Republic of Congo (DRC). DRC changed its anti-malarial treatment policy to amodiaquine (AQ) and artesunate (AS) in 2005. METHODS The results of two in vivo efficacy studies, which tested AQ and sulphadoxine-pyrimethamine (SP) monotherapies and AS+SP and AS+AQ combinations in Boende (Equatorial province), and AS+SP, AS+AQ and SP in Kabalo (Katanga province), between 2003 and 2004 are presented. The methodology followed the WHO 2003 protocol for assessing the efficacy of anti-malarials in areas of high transmission. RESULTS Out of 394 included patients in Boende, the failure rates on day 28 after PCR-genotyping adjustment of AS+SP and AS+AQ were estimated as 24.6% [95% CI: 16.6-35.5] and 15.1% [95% CI: 8.6-25.7], respectively. For the monotherapies, failure rates were 35.9% [95% CI: 27.0-46.7] for SP and 18.3% [95% CI: 11.6-28.1] for AQ. Out of 207 patients enrolled in Kabalo, the failure rate on day 28 after PCR-genotyping adjustment was 0 [1-sided 95% CI: 5.8] for AS+SP and AS+AQ [1-sided 95% CI: 6.2]. It was 19.6% [95% CI: 11.4-32.7] for SP monotherapy. CONCLUSION The finding of varying efficacy of the same combinations at two sites in one country highlights one difficulty of implementing a uniform national treatment policy in a large country. The poor efficacy of AS+AQ in Boende should alert the national programme to foci of resistance and emphasizes the need for systems for the prospective monitoring of treatment efficacy at sentinel sites in the country.
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Zwang J, Ashley EA, Karema C, D'Alessandro U, Smithuis F, Dorsey G, Janssens B, Mayxay M, Newton P, Singhasivanon P, Stepniewska K, White NJ, Nosten F. Safety and efficacy of dihydroartemisinin-piperaquine in falciparum malaria: a prospective multi-centre individual patient data analysis. PLoS One 2009; 4:e6358. [PMID: 19649267 PMCID: PMC2716525 DOI: 10.1371/journal.pone.0006358] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Accepted: 06/05/2009] [Indexed: 11/25/2022] Open
Abstract
Background The fixed dose antimalarial combination of dihydroartemisinin-piperaquine
(DP) is a promising new artemisinin-based combination therapy (ACT). We
present an individual patient data analysis of efficacy and tolerability in
acute uncomplicated falciparum malaria, from seven published randomized
clinical trials conducted in Africa and South East Asia using a predefined
in-vivo protocol. Comparator drugs were mefloquine-artesunate (MAS3) in
Thailand, Myanmar, Laos and Cambodia; artemether-lumefantrine in Uganda; and
amodiaquine+sulfadoxine-pyrimethamine and
artesunate+amodiaquine in Rwanda. Methods and Findings In total 3,547 patients were enrolled: 1,814 patients (32%
children under five years) received DP and 1,733 received a comparator
antimalarial at 12 different sites and were followed for 28–63
days. There was no significant heterogeneity between trials. DP was well
tolerated with 1.7% early vomiting. There were less adverse
events with DP in children and adults compared to MAS3 except for diarrhea;
ORs (95%CI) 2.74 (2.13 to 3.51) and 3.11 (2.31 to 4.18),
respectively. DP treatment resulted in a rapid clearance of fever and
parasitaemia. The PCR genotype corrected efficacy at Day 28 of DP assessed
by survival analysis was 98.7% (95%CI
97.6–99.8). DP was superior to the comparator drugs in protecting
against both P.falciparum recurrence and recrudescence
(P = 0.001, weighted by site). There was no
difference between DP and MAS3 in treating P. vivax co-infections and in
suppressing the first relapse (median interval to P. vivax recurrence: 6
weeks). Children under 5 y were at higher risk of recurrence for both
infections. The proportion of patients developing gametocytaemia
(P = 0.002, weighted by site) and the
subsequent gametocyte carriage rates were higher with DP (11/1000 person
gametocyte week, PGW) than MAS3 (6/1000 PGW,
P = 0.001, weighted by site). Conclusions DP proved a safe, well tolerated, and highly effective treatment of
P.falciparum malaria in Asia and Africa, but the effect on gametocyte
carriage was inferior to that of MAS3.
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Affiliation(s)
| | | | - Corine Karema
- National Malaria Control Programme, Kigali, Rwanda
- Institute of Tropical Medicine, Antwerp, Belgium
| | | | | | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San
Francisco, California, United States of America
| | - Bart Janssens
- Médecins Sans Frontières- Belgium, Phnom Penh,
Cambodia
| | - Mayfong Mayxay
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine,
University of Oxford, CCVTM, Oxford, United Kingdom
- Wellcome Trust – Mahosot Hospital – Oxford Tropical
Medicine Research Collaboration, Mahosot Hospital, Vientiane, Laos
- Department of Postgraduate Studies and Research, University of Health
Sciences, Vientiane, Laos
| | - Paul Newton
- Wellcome Trust – Mahosot Hospital – Oxford Tropical
Medicine Research Collaboration, Mahosot Hospital, Vientiane, Laos
| | | | - Kasia Stepniewska
- Faculty of Tropical Medicine, Mahidol University, Bangkok,
Thailand
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine,
University of Oxford, CCVTM, Oxford, United Kingdom
| | - Nicholas J. White
- Faculty of Tropical Medicine, Mahidol University, Bangkok,
Thailand
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine,
University of Oxford, CCVTM, Oxford, United Kingdom
| | - François Nosten
- Shoklo Malaria Research Unit, Mae Sot, Thailand
- Faculty of Tropical Medicine, Mahidol University, Bangkok,
Thailand
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine,
University of Oxford, CCVTM, Oxford, United Kingdom
- * E-mail:
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Verret WJ, Dorsey G, Nosten F, Price RN. The effect of varying analytical methods on estimates of anti-malarial clinical efficacy. Malar J 2009; 8:77. [PMID: 19386088 PMCID: PMC2679050 DOI: 10.1186/1475-2875-8-77] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 04/22/2009] [Indexed: 11/25/2022] Open
Abstract
Background Analytical approaches for the interpretation of anti-malarial clinical trials vary considerably. The aim of this study was to quantify the magnitude of the differences between efficacy estimates derived from these approaches and identify the factors underlying these differences. Methods Data from studies conducted in Africa and Thailand were compiled and the risk estimates of treatment failure, adjusted and unadjusted by genotyping, were derived by three methods (intention to treat (ITT), modified intention to treat (mITT) and per protocol (PP)) and then compared. Results 29 clinical trials (15 from Africa and 14 from Thailand) with a total of 65 treatment arms (38 from Africa and 27 from Thailand) were included in the analysis. Of the 15,409 patients enrolled, 2,637 (17.1%) had incomplete follow up for the unadjusted analysis and 4,489 (33.4%) for the adjusted analysis. Estimates of treatment failure were consistently higher when derived from the ITT or PP analyses compared to the mITT approach. In the unadjusted analyses the median difference between the ITT and mITT estimates was greater in Thai studies (11.4% [range 2.1–31.8]) compared to African Studies (1.8% [range 0–11.7]). In the adjusted analyses the median difference between PP and mITT estimates was 1.7%, but ranged from 0 to 30.9%. The discrepancy between estimates was correlated significantly with the proportion of patients with incomplete follow-up; p < 0.0001. The proportion of studies with a major difference (> 5%) between adjusted PP and mITT was 28% (16/57), with the risk difference greater in African (37% 14/38) compared to Thai studies (11% 2/19). In the African studies, a major difference in the adjusted estimates was significantly more likely in studies in high transmission sites (62% 8/13) compared to studies in moderate transmission sites (24% 6/25); p = 0.035. Conclusion Estimates of anti-malarial clinical efficacy vary significantly depending on the analytical methodology from which they are derived. In order to monitor temporal and spatial trends in anti-malarial efficacy, standardized analytical tools need to be applied in a transparent and systematic manner.
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Affiliation(s)
- Wendy J Verret
- Nuffield Department of Clinical Medicine, Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, UK.
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Carrara VI, Zwang J, Ashley EA, Price RN, Stepniewska K, Barends M, Brockman A, Anderson T, McGready R, Phaiphun L, Proux S, van Vugt M, Hutagalung R, Lwin KM, Phyo AP, Preechapornkul P, Imwong M, Pukrittayakamee S, Singhasivanon P, White NJ, Nosten F. Changes in the treatment responses to artesunate-mefloquine on the northwestern border of Thailand during 13 years of continuous deployment. PLoS One 2009; 4:e4551. [PMID: 19234601 PMCID: PMC2641001 DOI: 10.1371/journal.pone.0004551] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 01/19/2009] [Indexed: 11/25/2022] Open
Abstract
Background Artemisinin combination treatments (ACT) are recommended as first line treatment for falciparum malaria throughout the malaria affected world. We reviewed the efficacy of a 3-day regimen of mefloquine and artesunate regimen (MAS3), over a 13 year period of continuous deployment as first-line treatment in camps for displaced persons and in clinics for migrant population along the Thai-Myanmar border. Methods and Findings 3,264 patients were enrolled in prospective treatment trials between 1995 and 2007 and treated with MAS3. The proportion of patients with parasitaemia persisting on day-2 increased significantly from 4.5% before 2001 to 21.9% since 2002 (p<0.001). Delayed parasite clearance was associated with increased risk of developing gametocytaemia (AOR = 2.29; 95% CI, 2.00–2.69, p = 0.002). Gametocytaemia on admission and carriage also increased over the years (p = 0.001, test for trend, for both). MAS3 efficacy has declined slightly but significantly (Hazards ratio 1.13; 95% CI, 1.07–1.19, p<0.001), although efficacy in 2007 remained well within acceptable limits: 96.5% (95% CI, 91.0–98.7). The in vitro susceptibility of P. falciparum to artesunate increased significantly until 2002, but thereafter declined to levels close to those of 13 years ago (geometric mean in 2007: 4.2 nM/l; 95% CI, 3.2–5.5). The proportion of infections caused by parasites with increased pfmdr1 copy number rose from 30% (12/40) in 1996 to 53% (24/45) in 2006 (p = 0.012, test for trend). Conclusion Artesunate-mefloquine remains a highly efficacious antimalarial treatment in this area despite 13 years of widespread intense deployment, but there is evidence of a modest increase in resistance. Of particular concern is the slowing of parasitological response to artesunate and the associated increase in gametocyte carriage.
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Affiliation(s)
| | | | - Elizabeth A. Ashley
- Shoklo Malaria Research Unit, Tak, Thailand
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine Churchill Hospital, Headington, Oxford, United Kingdom
| | - Ric N. Price
- Centre for Clinical Vaccinology and Tropical Medicine Churchill Hospital, Headington, Oxford, United Kingdom
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Kasia Stepniewska
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine Churchill Hospital, Headington, Oxford, United Kingdom
| | | | - Alan Brockman
- Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Tim Anderson
- Southwest Foundation for Biomedical Research, San Antonio, Texas, United States of America
| | - Rose McGready
- Shoklo Malaria Research Unit, Tak, Thailand
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine Churchill Hospital, Headington, Oxford, United Kingdom
| | | | | | | | | | | | | | | | - Mallika Imwong
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Nicholas J. White
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine Churchill Hospital, Headington, Oxford, United Kingdom
| | - François Nosten
- Shoklo Malaria Research Unit, Tak, Thailand
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine Churchill Hospital, Headington, Oxford, United Kingdom
- * E-mail:
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Plasmodium falciparum pfmdr1 amplification, mefloquine resistance, and parasite fitness. Antimicrob Agents Chemother 2009; 53:1509-15. [PMID: 19164150 DOI: 10.1128/aac.00241-08] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mefloquine is widely used in combination with artemisinin derivatives for the treatment of falciparum malaria. Mefloquine resistance in Plasmodium falciparum has been related to increased copy numbers of multidrug-resistant gene 1 (pfmdr1). We studied the ex vivo dynamics of pfmdr1 gene amplification in culture-adapted P. falciparum in relation to mefloquine resistance and parasite fitness. A Thai P. falciparum isolate (isolate TM036) was assessed by the use of multiple genetic markers as a single genotype. Resistance was selected by exposure to stepwise increasing concentrations of mefloquine up to 30 ng/ml in continuous culture. The pfmdr1 gene copy numbers increased as susceptibility to mefloquine declined (P = 0.03). No codon mutations at positions 86, 184, 1034, 1042, and 1246 in the pfmdr1 gene were detected. Two subclones of selected parasites (average copy numbers, 2.3 and 3.1, respectively) showed a fitness disadvantage when they were grown together with the original parasites containing a single pfmdr1 gene copy in the absence of mefloquine; the multiplication rates were 6.3% and 8.7% lower, respectively (P < 0.01). Modeling of the dynamics of the pfmdr1 copy numbers over time in relation to the relative fitness of the parasites suggested that net pfmdr1 gene amplification from one to two copies occurs once in every 10(8) parasites and that amplification from two to three copies occurs once in every 10(3) parasites. pfmdr1 gene amplification in P. falciparum is a frequent event and confers mefloquine resistance. Parasites with multiple copies of the pfmdr1 gene have decreased survival fitness in the absence of drug pressure.
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Mayor A, Serra-Casas E, Bardají A, Sanz S, Puyol L, Cisteró P, Sigauque B, Mandomando I, Aponte JJ, Alonso PL, Menéndez C. Sub-microscopic infections and long-term recrudescence of Plasmodium falciparum in Mozambican pregnant women. Malar J 2009; 8:9. [PMID: 19134201 PMCID: PMC2633011 DOI: 10.1186/1475-2875-8-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 01/09/2009] [Indexed: 11/20/2022] Open
Abstract
Background Control of malaria in pregnancy remains a public health challenge. Improvements in its correct diagnosis and the adequacy of protocols to evaluate anti-malarial drug efficacy in pregnancy, are essential to achieve this goal. Methods The presence of Plasmodium falciparum was assessed by real-time (RT) PCR in 284 blood samples from pregnant women with clinical complaints suggestive of malaria, attending the maternity clinic of a Mozambican rural hospital. Parasite recrudescences in 33 consecutive paired episodes during the same pregnancy were identified by msp1 and msp2 genotyping. Results Prevalence of parasitaemia by microscopy was 5.3% (15/284) and 23.2% (66/284) by RT-PCR. Sensitivity of microscopy, compared to RT-PCR detection, was 22.7%. Risk of maternal anaemia was higher in PCR-positive women than in PCR-negative women (odds ratio [OR] = 1.92, 95% confidence interval [CI] 1.09–3.36). Genotyping confirmed that recrudescence after malaria treatment occurred in 7 (21%) out of 33 pregnant women with consecutive episodes during the same pregnancy (time range between recrudescent episodes: 14 to 187 days). Conclusion More accurate and sensitive diagnostic indicators of malaria infection in pregnancy are needed to improve malaria control. Longer follow-up periods than the standard in vivo drug efficacy protocol should be used to assess anti-malarial drug efficacy in pregnancy.
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Affiliation(s)
- Alfredo Mayor
- Centre de Recerca en Salut Internacional de Barcelona, Hospital Clínic/Institut d'Investigacions Biomèdiques August Pi i Sunyer, Universitat de Barcelona, Rosselló 132, E-08036 Barcelona, Spain.
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McGready R, Tan SO, Ashley EA, Pimanpanarak M, Viladpai-nguen J, Phaiphun L, Wüstefeld K, Barends M, Laochan N, Keereecharoen L, Lindegardh N, Singhasivanon P, White NJ, Nosten F. A randomised controlled trial of artemether-lumefantrine versus artesunate for uncomplicated plasmodium falciparum treatment in pregnancy. PLoS Med 2008; 5:e253. [PMID: 19265453 PMCID: PMC2605900 DOI: 10.1371/journal.pmed.0050253] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Accepted: 11/12/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND To date no comparative trials have been done, to our knowledge, of fixed-dose artemisinin combination therapies (ACTs) for the treatment of Plasmodium falciparum malaria in pregnancy. Evidence on the safety and efficacy of ACTs in pregnancy is needed as these drugs are being used increasingly throughout the malaria-affected world. The objective of this study was to compare the efficacy, tolerability, and safety of artemether-lumefantrine, the most widely used fixed ACT, with 7 d artesunate monotherapy in the second and third trimesters of pregnancy. METHODS AND FINDINGS An open-label randomised controlled trial comparing directly observed treatment with artemether-lumefantrine 3 d (AL) or artesunate monotherapy 7 d (AS7) was conducted in Karen women in the border area of northwestern Thailand who had uncomplicated P. falciparum malaria in the second and third trimesters of pregnancy. The primary endpoint was efficacy defined as the P. falciparum PCR-adjusted cure rates assessed at delivery or by day 42 if this occurred later than delivery, as estimated by Kaplan-Meier survival analysis. Infants were assessed at birth and followed until 1 y of life. Blood sampling was performed to characterise the pharmacokinetics of lumefantrine in pregnancy. Both regimens were very well tolerated. The cure rates (95% confidence interval) for the intention to treat (ITT) population were: AS7 89.2% (82.3%-96.1%) and AL 82.0% (74.8%-89.3%), p = 0.054 (ITT); and AS7 89.7% (82.6%-96.8%) and AL 81.2% (73.6%-88.8%), p = 0.031 (per-protocol population). One-third of the PCR-confirmed recrudescent cases occurred after 42 d of follow-up. Birth outcomes and infant (up to age 1 y) outcomes did not differ significantly between the two groups. The pharmacokinetic study indicated that low concentrations of artemether and lumefantrine were the main contributors to the poor efficacy of AL. CONCLUSION The current standard six-dose artemether-lumefantrine regimen was well tolerated and safe in pregnant Karen women with uncomplicated falciparum malaria, but efficacy was inferior to 7 d artesunate monotherapy and was unsatisfactory for general deployment in this geographic area. Reduced efficacy probably results from low drug concentrations in later pregnancy. A longer or more frequent AL dose regimen may be needed to treat pregnant women effectively and should now be evaluated. Parasitological endpoints in clinical trials of any antimalarial drug treatment in pregnancy should be extended to delivery or day 42 if it comes later. TRIAL REGISTRATION Current Controlled Trials ISRCTN86353884.
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Affiliation(s)
- Rose McGready
- Shoklo Malaria Research Unit (SMRU), Mae Sot, Tak, Thailand
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, United Kingdom
- * To whom correspondence should be addressed. E-mail:
| | - Saw Oo Tan
- Shoklo Malaria Research Unit (SMRU), Mae Sot, Tak, Thailand
| | - Elizabeth A Ashley
- Shoklo Malaria Research Unit (SMRU), Mae Sot, Tak, Thailand
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, United Kingdom
| | | | | | - Lucy Phaiphun
- Shoklo Malaria Research Unit (SMRU), Mae Sot, Tak, Thailand
| | | | - Marion Barends
- Shoklo Malaria Research Unit (SMRU), Mae Sot, Tak, Thailand
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Niklas Lindegardh
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, United Kingdom
| | | | - Nicholas J White
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, United Kingdom
| | - François Nosten
- Shoklo Malaria Research Unit (SMRU), Mae Sot, Tak, Thailand
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, Oxford, United Kingdom
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Dolmazon V, Matsika-Claquin MD, Manirakiza A, Yapou F, Nambot M, Menard D. Genetic diversity and genotype multiplicity of Plasmodium falciparum infections in symptomatic individuals living in Bangui (CAR). Acta Trop 2008; 107:37-42. [PMID: 18501320 DOI: 10.1016/j.actatropica.2008.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 04/10/2008] [Accepted: 04/10/2008] [Indexed: 10/22/2022]
Abstract
This study provides the first estimate of the genetic diversity and genotype multiplicity of Plasmodium falciparum infections in symptomatic individuals living in Bangui (Central African Republic, CAR). Three hundred thirty six clinical isolates were used for analysis of parasite population polymorphism and genotyped by nested-PCR of msp-1 block 2, and msp-2 block 3. We found a very high level of polymorphism, with, respectively, 17 and 25 different alleles at the msp-1 and msp-2 loci and a high percentage of multiclonal infections (42.7% with msp-1 and 76.7% with msp-2), with a mean of 1.7 genotype with msp-1 and 2.8 with msp-2. We observed that (i) multiclonal infections and allelic polymorphism of msp-2 were significantly more frequent in Southern districts than in Northern districts of Bangui suggesting that the epidemiological features of P. falciparum may vary within Bangui and (ii) showed that immunocompromised HIV-positive patients tend to have a lower average number of msp-2 allele per isolate than immunocompetent patients.
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Population pharmacokinetics of piperaquine after two different treatment regimens with dihydroartemisinin-piperaquine in patients with Plasmodium falciparum malaria in Thailand. Antimicrob Agents Chemother 2008; 52:1052-61. [PMID: 18180343 PMCID: PMC2258541 DOI: 10.1128/aac.00955-07] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The population pharmacokinetics of piperaquine in adults and children with uncomplicated Plasmodium falciparum malaria treated with two different dosage regimens of dihydroartemisinin-piperaquine were characterized. Piperaquine pharmacokinetics in 98 Burmese and Karen patients aged 3 to 55 years were described by a two-compartment disposition model with first-order absorption and interindividual random variability on all parameters and were similar with the three- and four-dose regimens. Children had a lower body weight-normalized oral clearance than adults, resulting in longer terminal elimination half-lives and higher total exposure to piperaquine (area under the concentration-time curve from 0 to 63 days [AUC day 0-63]). However, children had lower plasma concentrations in the therapeutically relevant posttreatment prophylactic period (AUC day 3-20) because of smaller body weight-normalized central volumes of distribution and shorter distribution half-lives. Our data lend further support to a simplified once-daily treatment regimen to improve treatment adherence and efficacy and indicate that weight-adjusted piperaquine doses in children may need to be higher than in adults.
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46
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Can estimates of antimalarial efficacy from field studies be improved? Trends Parasitol 2008; 24:68-73. [PMID: 18182325 DOI: 10.1016/j.pt.2007.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 10/30/2007] [Accepted: 11/01/2007] [Indexed: 11/23/2022]
Abstract
Monitoring therapeutic efficacy of antimalarial drugs is important because treatment failure rates are the primary basis for changing antimalarial treatment policy. An important aspect of efficacy studies is the use of PCR genotyping to distinguish recrudescent from new infections. The conclusions reached using this technique might be misleading if there is insufficient parasite diversity or a non-uniform haplotype frequency distribution in the study area. Statistical techniques can be used to overcome this problem, but only when data describing the haplotype frequency distribution are available. Therefore, assessing haplotype frequency and distribution should form an integral part of all studies investigating the therapeutic efficacy of antimalarial treatment regimes.
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TANI H, TADA Y, SASAI K, BABA E. Improvement of DNA Extraction Method for Dried Blood Spots and Comparison of Four PCR Methods for Detection of Babesia gibsoni (Asian Genotype) Infection in Canine Blood Samples. J Vet Med Sci 2008; 70:461-7. [DOI: 10.1292/jvms.70.461] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Hiroyuki TANI
- Laboratory of Veterinary Internal Medicine, Department of Advanced Clinical Medicine, Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Yuji TADA
- Laboratory of Veterinary Internal Medicine, Department of Advanced Clinical Medicine, Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Kazumi SASAI
- Laboratory of Veterinary Internal Medicine, Department of Advanced Clinical Medicine, Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Eiichiroh BABA
- Laboratory of Veterinary Internal Medicine, Department of Advanced Clinical Medicine, Graduate School of Life and Environmental Sciences, Osaka Prefecture University
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Price RN, Hasugian AR, Ratcliff A, Siswantoro H, Purba HLE, Kenangalem E, Lindegardh N, Penttinen P, Laihad F, Ebsworth EP, Anstey NM, Tjitra E. Clinical and pharmacological determinants of the therapeutic response to dihydroartemisinin-piperaquine for drug-resistant malaria. Antimicrob Agents Chemother 2007; 51:4090-7. [PMID: 17846129 PMCID: PMC2151469 DOI: 10.1128/aac.00486-07] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dihydroartemisinin-piperaquine (DHP) is an important new treatment for drug-resistant malaria, although pharmacokinetic studies on the combination are limited. In Papua, Indonesia, we assessed determinants of the therapeutic efficacy of DHP for uncomplicated malaria. Plasma piperaquine concentrations were measured on day 7 and day 28, and the cumulative risk of parasitological failure at day 42 was calculated using survival analysis. Of the 598 patients in the evaluable population 342 had infections with Plasmodium falciparum, 83 with Plasmodium vivax, and 173 with a mixture of both species. The unadjusted cumulative risks of recurrence were 7.0% (95% confidence interval [CI]: 4.6 to 9.4%) for P. falciparum and 8.9% (95% CI: 6.0 to 12%) for P. vivax. After correcting for reinfections the risk of recrudescence with P. falciparum was 1.1% (95% CI: 0.1 to 2.1%). The major determinant of parasitological failure was the plasma piperaquine concentration. A concentration below 30 ng/ml on day 7 was observed in 38% (21/56) of children less than 15 years old and 22% (31/140) of adults (P = 0.04), even though the overall dose (mg per kg of body weight) in children was 9% higher than that in adults (P < 0.001). Patients with piperaquine levels below 30 ng/ml were more likely to have a recurrence with P. falciparum (hazard ratio [HR] = 6.6 [95% CI: 1.9 to 23]; P = 0.003) or P. vivax (HR = 9.0 [95% CI: 2.3 to 35]; P = 0.001). The plasma concentration of piperaquine on day 7 was the major determinant of the therapeutic response to DHP. Lower plasma piperaquine concentrations and higher failure rates in children suggest that dose revision may be warranted in this age group.
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Affiliation(s)
- R N Price
- Information Health Division, Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, Darwin, NT 0811, Australia.
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Greenhouse B, Dokomajilar C, Hubbard A, Rosenthal PJ, Dorsey G. Impact of transmission intensity on the accuracy of genotyping to distinguish recrudescence from new infection in antimalarial clinical trials. Antimicrob Agents Chemother 2007; 51:3096-103. [PMID: 17591848 PMCID: PMC2043236 DOI: 10.1128/aac.00159-07] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Antimalarial clinical trials use genotyping techniques to distinguish new infection from recrudescence. In areas of high transmission, the accuracy of genotyping may be compromised due to the high number of infecting parasite strains. We compared the accuracies of genotyping methods, using up to six genotyping markers, to assign outcomes for two large antimalarial trials performed in areas of Africa with different transmission intensities. We then estimated the probability of genotyping misclassification and its effect on trial results. At a moderate-transmission site, three genotyping markers were sufficient to generate accurate estimates of treatment failure. At a high-transmission site, even with six markers, estimates of treatment failure were 20% for amodiaquine plus artesunate and 17% for artemether-lumefantrine, regimens expected to be highly efficacious. Of the observed treatment failures for these two regimens, we estimated that at least 45% and 35%, respectively, were new infections misclassified as recrudescences. Increasing the number of genotyping markers improved the ability to distinguish new infection from recrudescence at a moderate-transmission site, but using six markers appeared inadequate at a high-transmission site. Genotyping-adjusted estimates of treatment failure from high-transmission sites may represent substantial overestimates of the true risk of treatment failure.
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Affiliation(s)
- Bryan Greenhouse
- Department of Medicine, University of California, San Francisco, Box 0811, San Francisco, CA 94143, USA.
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Bonnet M, Roper C, Félix M, Coulibaly L, Kankolongo GM, Guthmann JP. Efficacy of antimalarial treatment in Guinea: in vivo study of two artemisinin combination therapies in Dabola and molecular markers of resistance to sulphadoxine-pyrimethamine in N'Zérékoré. Malar J 2007; 6:54. [PMID: 17477865 PMCID: PMC1868032 DOI: 10.1186/1475-2875-6-54] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Accepted: 05/03/2007] [Indexed: 11/10/2022] Open
Abstract
Background In the last five years, countries have been faced with changing their malaria treatment policy to an artemisinin-based combination therapy (ACT), many with no national data on which to base their decision. This is particularly true for a number of West African countries, including Guinea, where these studies were performed. Two studies were conducted in 2004/2005 in programmes supported by Medecins Sans Frontieres, when chloroquine was still national policy, but artesunate (AS)/sulphadoxine-pyrimethamine (SP) had been used in refugee camps for two years. Methods In Dabola (central Guinea), 220 children aged 6–59 months with falciparum malaria were randomized to receive either AS/amodiaquine (AQ) or AS/SP. In vivo efficacy was assessed following the 2003 World Health Organization guidelines. In a refugee camp in Laine (south of Guinea), where an in vivo study was not feasible due to the unstable context, a molecular genotyping study in 160 patients assessed the prevalence of mutations in the dihydrofolate reductase (dhfr) (codons 108, 51, 59) and dihydropteroate synthase (dhps) (codons 436, 437, 540) genes of Plasmodium falciparum, which have been associated with resistance to pyrimethamine and sulphadoxine, respectively. Results In Dabola, after 28 days of follow-up, Polymerase Chain Reaction (PCR)-adjusted failure rates were 1.0% (95%CI 0–5.3) for AS/AQ and 1.0% (95%CI 0–5.5) for AS/SP. In the refugee camp in Laine, the molecular genotyping study found three dhfr mutations in 85.6% (95%CI 79.2–90.7) patients and quintuple dhfr/dhps mutations in 9.6% (95%CI 5.2–15.9). Conclusion Both AS/AQ and AS/SP are highly efficacious in Dabola, whereas there is molecular evidence of established SP resistance in Laine. This supports the choice of the national programme of Guinea to adopt AS/AQ as first line antimalarial treatment. The results highlight the difficulties faced by control programmes, which have gone through the upheaval of implementing ACTs, but cannot predict how long their therapeutic life will be, especially in countries which have chosen drugs also available as monotherapies.
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Affiliation(s)
| | - Cally Roper
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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