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Angwe MK, Mwebaza N, Nsobya SL, Vudriko P, Dralabu S, Omali D, Tumwebaze MA, Ocan M. Day 3 parasitemia and Plasmodium falciparum Kelch 13 mutations among uncomplicated malaria patients treated with artemether-lumefantrine in Adjumani district, Uganda. PLoS One 2024; 19:e0305064. [PMID: 38837973 PMCID: PMC11152288 DOI: 10.1371/journal.pone.0305064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 05/22/2024] [Indexed: 06/07/2024] Open
Abstract
Artemisinin resistance threatens malaria control and elimination efforts globally. Recent studies have reported the emergence of Plasmodium falciparum parasites tolerant to artemisinin agents in sub-Saharan Africa, including Uganda. The current study assessed the day 3 parasite clearance and its correlation with P. falciparum K13 propeller gene (pfkelch13) mutations in P. falciparum parasites isolated from patients with uncomplicated malaria under artemether-lumefantrine (AL) treatment. This study enrolled 100 P. falciparum-positive patients to whom AL was prescribed between 09/September/2022 and 06/November/2022. Blood samples were collected in EDTA tubes before treatment initiation (day 0) and on day 3. Parasitemia was assessed by microscopy from blood smears and quantitative polymerase chain reaction (qPCR) from the DNA extracted. The day 0 parasite K13 gene was sequenced using Sanger sequencing. Sequence data were analysed using MEGA version 11 software. The data were analysed using STATA version 15, and the Mann‒Whitney U test was used to compare PCR parasite clearance on day 3 using the comparative CT value method and pfkelch13 mutations. The prevalence of day 3 parasitaemia was 24% (24/100) by microscopy and 63% (63/100) by qPCR from the AL-treated patients. P. falciparum K13-propeller gene polymorphism was detected in 18.8% (15/80) of the day 0 DNA samples. The K13 mutations found were C469Y, 12.5% (10/80); A675V, 2.5% (2/80); A569S, 1.25%, (1/80), A578S, 1.25%, (1/80) and; F491S, 1.25%, (1/80) a new allele not reported anywhere. The C469Y mutation, compared to the wild-type, was associated with delayed parasite clearance p = 0.0278, Hodges-Lehmann estimation 3.2108 on the log scale, (95%CI 1.7076, 4.4730). There was a high prevalence of day 3 P. falciparum among malaria patients treated using artemether-lumefantrine. We conclude the presence of the K13 mutation associated with artemisinin resistance by P. falciparum in Adjumani district, Uganda, necessitates regular surveillance of the effectiveness and efficacy of artemether-lumefantrine in the country.
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Affiliation(s)
- Martin Kamilo Angwe
- Department of Pharmacology and Therapeutics, College of Health Science, Makerere University, Kampala, Uganda
- Research Center for Tropical Diseases and Vector Control, Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
- Department of Biomolecular Resources and Biolab Sciences, School of Biosecurity, Biotechnical and Laboratory Science, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Norah Mwebaza
- Department of Pharmacology and Therapeutics, College of Health Science, Makerere University, Kampala, Uganda
| | - Sam Lubwama Nsobya
- Infectious Diseases Research Collaboration, Makerere University, Kampala, Uganda
| | - Patrick Vudriko
- Research Center for Tropical Diseases and Vector Control, Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Saviour Dralabu
- Research Center for Tropical Diseases and Vector Control, Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Denis Omali
- Department of Pharmacology and Therapeutics, College of Health Science, Makerere University, Kampala, Uganda
- Infectious Disease Institute, Makerere University, Kampala, Uganda
| | - Maria Agnes Tumwebaze
- Research Center for Tropical Diseases and Vector Control, Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Moses Ocan
- Department of Pharmacology and Therapeutics, College of Health Science, Makerere University, Kampala, Uganda
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Goodwin J, Kajubi R, Wang K, Li F, Wade M, Orukan F, Huang L, Whalen M, Aweeka FT, Mwebaza N, Parikh S. Persistent and multiclonal malaria parasite dynamics despite extended artemether-lumefantrine treatment in children. Nat Commun 2024; 15:3817. [PMID: 38714692 PMCID: PMC11076639 DOI: 10.1038/s41467-024-48210-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 04/24/2024] [Indexed: 05/10/2024] Open
Abstract
Standard diagnostics used in longitudinal antimalarial studies are unable to characterize the complexity of submicroscopic parasite dynamics, particularly in high transmission settings. We use molecular markers and amplicon sequencing to characterize post-treatment stage-specific malaria parasite dynamics during a 42 day randomized trial of 3- versus 5 day artemether-lumefantrine in 303 children with and without HIV (ClinicalTrials.gov number NCT03453840). The prevalence of parasite-derived 18S rRNA is >70% in children throughout follow-up, and the ring-stage marker SBP1 is detectable in over 15% of children on day 14 despite effective treatment. We find that the extended regimen significantly lowers the risk of recurrent ring-stage parasitemia compared to the standard 3 day regimen, and that higher day 7 lumefantrine concentrations decrease the probability of ring-stage parasites in the early post-treatment period. Longitudinal amplicon sequencing reveals remarkably dynamic patterns of multiclonal infections that include new and persistent clones in both the early post-treatment and later time periods. Our data indicate that post-treatment parasite dynamics are highly complex despite efficacious therapy, findings that will inform strategies to optimize regimens in the face of emerging partial artemisinin resistance in Africa.
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Affiliation(s)
- Justin Goodwin
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
- Yale School of Medicine, New Haven, CT, USA
| | - Richard Kajubi
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Kaicheng Wang
- Yale Center for Analytical Sciences, Yale School of Public Health, New Haven, CT, USA
| | - Fangyong Li
- Yale Center for Analytical Sciences, Yale School of Public Health, New Haven, CT, USA
| | - Martina Wade
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Francis Orukan
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Liusheng Huang
- University of California, San Francisco, San Francisco, CA, USA
| | - Meghan Whalen
- University of California, San Francisco, San Francisco, CA, USA
| | | | - Norah Mwebaza
- Infectious Disease Research Collaboration, Kampala, Uganda
- Department of Pharmacology and Therapeutics, Makerere University College of Health Sciences, Kampala, Uganda
| | - Sunil Parikh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA.
- Yale School of Medicine, New Haven, CT, USA.
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Angwe MK, Mwebaza N, Nsobya SL, Vudriko P, Dralabu S, Omali D, Tumwebaze MA, Ocan M. Day 3 parasitemia and Plasmodium falciparum Kelch 13 mutations among uncomplicated malaria patients treated with artemether-lumefantrine in Adjumani district, Uganda. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.04.26.24306433. [PMID: 38712186 PMCID: PMC11071562 DOI: 10.1101/2024.04.26.24306433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Artemisinin resistance threatens malaria control and elimination efforts globally. Recent studies have reported the emergence of Plasmodium falciparum parasites tolerant to artemisinin agents in sub-Saharan Africa, including Uganda. The current study assessed the day 3 parasite clearance and its correlation with P. falciparum K13 propeller gene (pfkelch13) mutations in P. falciparum parasites isolated from patients with uncomplicated malaria under artemether-lumefantrine (AL) treatment. This study enrolled 100 P. falciparum-positive patients to whom AL was prescribed between 09/September/2022 and 06/November/2022. Blood samples were collected in EDTA tubes before treatment initiation (day 0) and on day 3. Parasitemia was assessed by microscopy from blood smears and quantitative polymerase chain reaction (qPCR) from the DNA extracted. The day 0 parasite K13 gene was sequenced using Sanger sequencing. Sequence data were analysed using MEGA version 11 software. The data were analysed using STATA version 15, and the Mann‒Whitney U test was used to compare PCR parasite clearance on day 3 using the comparative CT value method and pfkelch13 mutations. The prevalence of day 3 parasitaemia was 24% (24/100) by microscopy and 63% (63/100) by qPCR from the AL-treated patients. P. falciparum K13-propeller gene polymorphism was detected in 18.8% (15/80) of the day 0 DNA samples. The K13 mutations found were C469Y, 12.5% (10/80); A675V, 2.5% (2/80); A569S, 1.25%, (1/80), A578S, 1.25%, (1/80) and; F491S, 1.25%, (1/80) a new allele not reported anywhere. The C469Y mutation, compared to the wild-type, was associated with delayed parasite clearance p=0.0278, Hodges-Lehmann estimation 3.2108 on the log scale, (95%CI 1.7076, 4.4730). There was a high prevalence of day 3 P. falciparum among malaria patients treated using artemether-lumefantrine. We conclude that the K13 mutation associated with artemisinin resistance by P. falciparum is present in Adjumani district, Uganda. This necessitates regular surveillance of the effectiveness and efficacy of artemether-lumefantrine in the country.
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Affiliation(s)
- Martin Kamilo Angwe
- Department of Pharmacology and Therapeutics, College of Health Science, Makerere University
- Research Center for Tropical Diseases and Vector Control, Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University
- Department of Biomolecular Resources and Biolab Sciences, School of Biosecurity, Biotechnical and Laboratory Science, College of Veterinary Medicine, Animal Resources and Biosecurity Makerere University
| | - Norah Mwebaza
- Department of Pharmacology and Therapeutics, College of Health Science, Makerere University
| | | | - Patrick Vudriko
- Research Center for Tropical Diseases and Vector Control, Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University
| | - Savior Dralabu
- Research Center for Tropical Diseases and Vector Control, Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University
| | - Denis Omali
- Department of Pharmacology and Therapeutics, College of Health Science, Makerere University
- Infectious Disease Institute, Makerere University
| | - Maria Agnes Tumwebaze
- Research Center for Tropical Diseases and Vector Control, Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University
| | - Moses Ocan
- Department of Pharmacology and Therapeutics, College of Health Science, Makerere University
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Mawuli MA, Amoah LE, Cui L, Quashie NB, Afrane YA. Effectiveness of artemether-lumefantrine for treating uncomplicated malaria in low- and high-transmission areas of Ghana. Malar J 2024; 23:40. [PMID: 38317164 PMCID: PMC10845584 DOI: 10.1186/s12936-024-04850-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 01/11/2024] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND Artemisinin-based combination therapy (ACT) has been effective in the supervised treatment of uncomplicated malaria in Ghana. Since ACT usage is primarily unsupervised, this study aimed to determine the effectiveness of artemether-lumefantrine (AL) for treating malaria patients in two transmission settings in Ghana. METHODS Eighty-four individuals with uncomplicated Plasmodium falciparum malaria were recruited from Lekma Hospital (LH) in Accra (low-transmission area; N = 28), southern Ghana, and King's Medical Centre (KMC) in Kumbungu (high-transmission area; N = 56), northern Ghana. Participants were followed up for 28 days after unsupervised treatment with AL. The presence of asexual parasites was determined by microscopic examination of Giemsa-stained blood smears. Plasmodium species identification was confirmed using species-specific primers targeting the 18S rRNA gene. Parasite recrudescence or reinfection was determined by genotyping the Pfmsp 1 and Pfmsp 2 genes. RESULTS After AL treatment, 3.6% (2/56) of the patients from KMC were parasitaemic on day 3 compared to none from the LH patients. One patient from KMC with delayed parasite clearance on day 3 remained parasite-positive by microscopy on day 7 but was parasite-free by day 14. While none of the patients from LH experienced parasite recurrence during the 28-day follow-up, three and two patients from KMC had recurrent parasitaemia on days 21 and 28, respectively. Percentage reduction in parasite densities from day 1, 2, and 3 for participants from the KMC was 63.2%, 89.5%, and 84.5%. Parasite densities for participants from the LH reduced from 98.2%, 99.8% on day 1, and 2 to 100% on day 3. The 28-day cumulative incidence rate of treatment failure for KMC was 12.8% (95% confidence interval: 1.9-23.7%), while the per-protocol effectiveness of AL in KMC was 89.47%. All recurrent cases were assigned to recrudescence after parasite genotyping by Pfmsp 1 and Pfmsp 2. CONCLUSION While AL is efficacious in treating uncomplicated malaria in Ghana, when taken under unsupervised conditions, it showed an 89.4% PCR-corrected cure rate in northern Ghana, which is slightly below the WHO-defined threshold.
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Affiliation(s)
- Mawusi Adepa Mawuli
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana.
- Department of Pathology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana.
| | - Linda Eva Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Liwang Cui
- Department of Internal Medicine, University of South Florida, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| | - Neils Ben Quashie
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
- Centre for Tropical Clinical Pharmacology and Therapeutics, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Yaw Asare Afrane
- Department of Medical Microbiology, University of Ghana Medical School College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
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Ansah F, Nyame K, Laryea R, Owusu R, Amon D, Boyetey MJB, Ayeke D, Razak N, Kornu VE, Ashitei S, Owusu-Appiah C, Chirawurah JD, Abugri J, Aniweh Y, Opoku N, Sutherland CJ, Binka FN, Kweku M, Awandare GA, Dinko B. The temporal dynamics of Plasmodium species infection after artemisinin-based combination therapy (ACT) among asymptomatic children in the Hohoe municipality, Ghana. Malar J 2023; 22:271. [PMID: 37710288 PMCID: PMC10500816 DOI: 10.1186/s12936-023-04712-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 09/11/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND The routine surveillance of asymptomatic malaria using nucleic acid-based amplification tests is essential in obtaining reliable data that would inform malaria policy formulation and the implementation of appropriate control measures. METHODS In this study, the prevalence rate and the dynamics of Plasmodium species among asymptomatic children (n = 1697) under 5 years from 30 communities within the Hohoe municipality in Ghana were determined. RESULTS AND DISCUSSION The observed prevalence of Plasmodium parasite infection by polymerase chain reaction (PCR) was 33.6% (571/1697), which was significantly higher compared to that obtained by microscopy [26.6% (451/1697)] (P < 0.0001). Based on species-specific analysis by nested PCR, Plasmodium falciparum infection [33.6% (570/1697)] was dominant, with Plasmodium malariae, Plasmodium ovale and Plasmodium vivax infections accounting for 0.1% (1/1697), 0.0% (0/1697), and 0.0% (0/1697), respectively. The prevalence of P. falciparum infection among the 30 communities ranged from 0.0 to 82.5%. Following artesunate-amodiaquine (AS + AQ, 25 mg/kg) treatment of a sub-population of the participants (n = 184), there was a substantial reduction in Plasmodium parasite prevalence by 100% and 79.2% on day 7 based on microscopy and nested PCR analysis, respectively. However, there was an increase in parasite prevalence from day 14 to day 42, with a subsequent decline on day 70 by both microscopy and nested PCR. For parasite clearance rate analysis, we found a significant proportion of the participants harbouring residual Plasmodium parasites or parasite genomic DNA on day 1 [65.0% (13/20)], day 2 [65.0% (13/20)] and day 3 [60.0% (12/20)] after initiating treatment. Of note, gametocyte carriage among participants was low before and after treatment. CONCLUSION Taken together, the results indicate that a significant number of individuals could harbour residual Plasmodium parasites or parasite genomic DNA after treatment. The study demonstrates the importance of routine surveillance of asymptomatic malaria using sensitive nucleic acid-based amplification techniques.
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Affiliation(s)
- Felix Ansah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Kwamina Nyame
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Rukaya Laryea
- Department of Epidemiology and Biostatistics, Fred Newton Binka School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Richard Owusu
- Department of Epidemiology and Biostatistics, Fred Newton Binka School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Denick Amon
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Mark-Jefferson Buer Boyetey
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Dzidzor Ayeke
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Nasibatu Razak
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Victor E Kornu
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Sarah Ashitei
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Caleb Owusu-Appiah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Jersley D Chirawurah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - James Abugri
- Department of Biochemistry and Forensic Sciences, School of Chemical and Biochemical Sciences, C. K. Tedam University of Technology and Applied Sciences, Navrongo, Ghana
| | - Yaw Aniweh
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Nicholas Opoku
- Department of Epidemiology and Biostatistics, Fred Newton Binka School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Colin J Sutherland
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Fred N Binka
- Department of Epidemiology and Biostatistics, Fred Newton Binka School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Margaret Kweku
- Department of Epidemiology and Biostatistics, Fred Newton Binka School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Legon, Accra, Ghana
| | - Bismarck Dinko
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana.
- Department of Clinical Microbiology, School of Medicine and Dentistry College of Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ashanti Region, Ghana.
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Guan L, Wang H, Xu X, Fan H. Therapeutical Utilization and Repurposing of Artemisinin and Its Derivatives: A Narrative Review. Adv Biol (Weinh) 2023; 7:e2300086. [PMID: 37178448 DOI: 10.1002/adbi.202300086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/08/2023] [Indexed: 05/15/2023]
Abstract
Artemisinin (ART) and its derivatives have great therapeutical utility as antimalarials and can be repurposed for other indications, such as viral infections, autoimmune diseases, and cancer. This review presents a comprehensive overview of the therapeutic effects of ART-based drugs, beyond their antimalarial effects. This review also summarizes the information on their repurposing in other pathologies, with the hope that it will guide the future optimization of the use of ART-based drugs and of the treatment strategies for the listed diseases. By reviewing related literature, ART extraction and structure as well as the synthesis and structure of its derivatives are presented. Subsequently, the traditional roles of ART and its derivatives against malaria are reviewed, including antimalarial mechanism and occurrence of antimalarial resistance. Finally, the potential of ART and its derivatives to be repurposed for the treatment of other diseases are summarized. The great repurposing potential of ART and its derivatives may be useful for the control of emerging diseases with corresponding pathologies, and future research should be directed toward the synthesis of more effective derivatives or better combinations.
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Affiliation(s)
- Lin Guan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Huiyong Wang
- Wuhan Humanwell Pharmaceutical Co. Ltd., Wuhan, 430206, P. R. China
| | - Xiaolong Xu
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Institute of Traditional Chinese Medicine, Beijing, 100010, P. R. China
| | - Huahao Fan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
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Muema JM, Mutunga JM, Obonyo MA, Getahun MN, Mwakubambanya RS, Akala HM, Cheruiyot AC, Yeda RA, Juma DW, Andagalu B, Johnson JL, Roth AL, Bargul JL. Isoliensinine from Cissampelos pariera rhizomes exhibits potential gametocytocidal and anti-malarial activities against Plasmodium falciparum clinical isolates. Malar J 2023; 22:161. [PMID: 37208735 DOI: 10.1186/s12936-023-04590-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 05/15/2023] [Indexed: 05/21/2023] Open
Abstract
BACKGROUND The unmet demand for effective malaria transmission-blocking agents targeting the transmissible stages of Plasmodium necessitates intensive discovery efforts. In this study, a bioactive bisbenzylisoquinoline (BBIQ), isoliensinine, from Cissampelos pariera (Menispermaceae) rhizomes was identified and characterized for its anti-malarial activity. METHODS Malaria SYBR Green I fluorescence assay was performed to evaluate the in vitro antimalarial activity against D6, Dd2, and F32-ART5 clones, and immediate ex vivo (IEV) susceptibility for 10 freshly collected P. falciparum isolates. To determine the speed- and stage-of-action of isoliensinine, an IC50 speed assay and morphological analyses were performed using synchronized Dd2 asexuals. Gametocytocidal activity against two culture-adapted gametocyte-producing clinical isolates was determined using microscopy readouts, with possible molecular targets and their binding affinities deduced in silico. RESULTS Isoliensinine displayed a potent in vitro gametocytocidal activity at mean IC50gam values ranging between 0.41 and 0.69 µM for Plasmodium falciparum clinical isolates. The BBIQ compound also inhibited asexual replication at mean IC50Asexual of 2.17 µM, 2.22 µM, and 2.39 µM for D6, Dd2 and F32-ART5 respectively, targeting the late-trophozoite to schizont transition. Further characterization demonstrated a considerable immediate ex vivo potency against human clinical isolates at a geometric mean IC50IEV = 1.433 µM (95% CI 0.917-2.242). In silico analyses postulated a probable anti-malarial mechanism of action by high binding affinities for four mitotic division protein kinases; Pfnek1, Pfmap2, Pfclk1, and Pfclk4. Additionally, isoliensinine was predicted to possess an optimal pharmacokinetics profile and drug-likeness properties. CONCLUSION These findings highlight considerable grounds for further exploration of isoliensinine as an amenable scaffold for malaria transmission-blocking chemistry and target validation.
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Affiliation(s)
- Jackson M Muema
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya.
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya.
| | - James M Mutunga
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
- Department of Biological Sciences, School of Pure and Applied Sciences, Mount Kenya University, Thika, Kenya
- School of Engineering Design, Technology and Professional Programs, Pennsylvania State University, University Park, PA, 16802, USA
| | - Meshack A Obonyo
- Department of Biochemistry and Molecular Biology, Egerton University, Egerton, Kenya
| | - Merid N Getahun
- International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya
| | | | - Hoseah M Akala
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Agnes C Cheruiyot
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Redemptah A Yeda
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Dennis W Juma
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Ben Andagalu
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Jaree L Johnson
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Amanda L Roth
- U.S. Army Medical Research Directorate-Africa (USAMRD-A), Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Joel L Bargul
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya.
- International Centre of Insect Physiology and Ecology (Icipe), Nairobi, Kenya.
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Andagalu B, Watson OJ, Onyango I, Opot B, Okoth R, Chemwor G, Sifuna P, Juma D, Cheruiyot A, Yeda R, Okudo C, Wafubwa J, Yalwala S, Abuom D, Ogutu B, Cowden J, Akala HM, Kamau E. Malaria Transmission Dynamics in a High-Transmission Setting of Western Kenya and the Inadequate Treatment Response to Artemether-Lumefantrine in an Asymptomatic Population. Clin Infect Dis 2023; 76:704-712. [PMID: 35767269 PMCID: PMC9938745 DOI: 10.1093/cid/ciac527] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 06/13/2022] [Accepted: 06/24/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Assessing the infectious reservoir is critical in malaria control and elimination strategies. We conducted a longitudinal epidemiological study in a high-malaria-burden region in Kenya to characterize transmission in an asymptomatic population. METHODS 488 study participants encompassing all ages in 120 households within 30 clusters were followed for 1 year with monthly sampling. Malaria was diagnosed by microscopy and molecular methods. Transmission potential in gametocytemic participants was assessed using direct skin and/or membrane mosquito feeding assays, then treated with artemether-lumefantrine. Study variables were assessed using mixed-effects generalized linear models. RESULTS Asexual and sexual parasite data were collected from 3792 participant visits, with 903 linked with feeding assays. Univariate analysis revealed that the 6-11-year-old age group was at higher risk of harboring asexual and sexual infections than those <6 years old (odds ratio [OR] 1.68, P < .001; and OR 1.81, P < .001), respectively. Participants with submicroscopic parasitemia were at a lower risk of gametocytemia compared with microscopic parasitemia (OR 0.04, P < .001), but they transmitted at a significantly higher rate (OR 2.00, P = .002). A large proportion of the study population who were infected at least once remained infected (despite treatment) with asexual (71.7%, 291/406) or sexual (37.4%, 152/406) parasites. 88.6% (365/412) of feeding assays conducted in individuals who failed treatment the previous month resulted in transmissions. CONCLUSIONS Individuals with asymptomatic infection sustain the transmission cycle, with the 6-11-year age group serving as an important reservoir. The high rates of artemether-lumefantrine treatment failures suggest surveillance programs using molecular methods need to be expanded for accurate monitoring and evaluation of treatment outcomes.
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Affiliation(s)
- Ben Andagalu
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Oliver J Watson
- Medical Research Council, Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Irene Onyango
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Benjamin Opot
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Raphael Okoth
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Gladys Chemwor
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Peter Sifuna
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Dennis Juma
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Agnes Cheruiyot
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Redemptah Yeda
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Charles Okudo
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Jackline Wafubwa
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Santos Yalwala
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - David Abuom
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | | | - Jessica Cowden
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Hoseah M Akala
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya
| | - Edwin Kamau
- Department of Emerging and Infectious Diseases (DEID), US Army Medical Research Directorate-Africa (USAMRD-A), Kenya Medical Research Institute (KEMRI)/Walter Reed Project, Kisumu, Kenya.,US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA.,Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
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9
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Funwei RI, Uyaiabasi GN, Hammed WA, Ojurongbe O, Walker O, Falade CO. High prevalence of persistent residual parasitemia on days 3 and 14 after artemether-lumefantrine or pyronaridine-artesunate treatment of uncomplicated Plasmodium falciparum malaria in Nigeria. Parasitol Res 2023; 122:519-526. [PMID: 36510009 DOI: 10.1007/s00436-022-07753-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 12/02/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Microscopic evaluation of parasite clearance is the gold standard in antimalarial drug efficacy trials. However, the presence of sub-microscopic residual parasitemia after artemisinin-based combination therapy (ACT) needs to be investigated. METHODS One hundred and twenty (AL: n = 60, PA: n = 60) days 3 and 14 dried blood spots, negative by microscopy were analysed for residual parasitemia using nested PCR. Isolates with residual parasitemia on days 3 and 14 were further genotyped with their corresponding day-0 isolates using merozoite surface proteins msp-1, msp-2, and glurp genes for allelic similarity. RESULTS Persistent PCR-determined sub-microscopic residual parasitemia at day 3 post ACT treatment was 83.3 (AL) and 88.3% (PA), respectively (ρ = 0.600), while 63.6 and 36.4% (ρ = 0.066) isolates were parasitemic at day 14 for AL and PA, respectively. Microscopy-confirmed gametocytemia persisted from days 0 to 7 and from days 0 to 21 for AL and PA. When the alleles of day 3 versus day 0 were compared according to base pair sizes, 59% of parasites shared identical alleles for glurp, 36% each for 3D7 and FC27, while K1 was 77%, RO33 64%, and MAD20 23%, respectively. Similarly, day 14 versus day 0 was 36% (glurp), 64% (3D7), and 32% (FC27), while 73% (K1), 77% (RO33), and 41% (MAD20), respectively. CONCLUSION The occurrence of residual parasitemia on days 3 and 14 following AL or PA treatment may be attributable to the presence of either viable asexual, gametocytes, or dead parasite DNAs, which requires further investigation.
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Affiliation(s)
- Roland I Funwei
- Department of Pharmacology, Babcock University, Ilishan-Remo, Ogun State, Nigeria. .,Center for Advanced Medical Research and Biotechnology (CAMRAB), Babcock University, Ilishan-Remo, Ogun State, Nigeria.
| | - Gabriel N Uyaiabasi
- Department of Pharmacology, Babcock University, Ilishan-Remo, Ogun State, Nigeria.,Center for Advanced Medical Research and Biotechnology (CAMRAB), Babcock University, Ilishan-Remo, Ogun State, Nigeria
| | - Wasiu A Hammed
- Center for Advanced Medical Research and Biotechnology (CAMRAB), Babcock University, Ilishan-Remo, Ogun State, Nigeria
| | - Olusola Ojurongbe
- Department of Medical Microbiology, Ladoke Akintola University of Technology, Ogbomosho, Oyo State, Nigeria.,Center for Emerging and Re-Emerging Infectious Diseases (CERID), Ladoke Akintola University of Technology, Ogbomosho, Oyo State, Nigeria
| | - Oladapo Walker
- Department of Pharmacology, Babcock University, Ilishan-Remo, Ogun State, Nigeria.,Center for Advanced Medical Research and Biotechnology (CAMRAB), Babcock University, Ilishan-Remo, Ogun State, Nigeria
| | - Catherine O Falade
- Department of Pharmacology and Therapeutics, University of Ibadan, Ibadan, Nigeria.,Institute for Advanced Medical Research and Training (IAMRAT), University of Ibadan, Ibadan, Nigeria
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10
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Oulton T, Mahamar A, Sanogo K, Diallo M, Youssouf A, Niambele SM, Samaké S, Keita S, Sinaba Y, Sacko A, Traore SF, Lanke K, Collins KA, Bradley J, Drakeley C, Stone WJR, Dicko A. Persistence of Plasmodium falciparum HRP-2 antigenaemia after artemisinin combination therapy is not associated with gametocytes. Malar J 2022; 21:372. [PMID: 36474274 PMCID: PMC9724264 DOI: 10.1186/s12936-022-04387-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 11/16/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND In some settings, sensitive field diagnostic tools may be needed to achieve elimination of falciparum malaria. To this end, rapid diagnostic tests (RDTs) based on the detection of the Plasmodium falciparum protein HRP-2 are being developed with increasingly lower limits of detection. However, it is currently unclear how parasite stages that are unaffected by standard drug treatments may contribute to HRP-2 detectability and potentially confound RDT results even after clearance of blood stage infection. This study assessed the detectability of HRP-2 in periods of post-treatment residual gametocytaemia. METHODS A cohort of 100 P. falciparum infected, gametocyte positive individuals were treated with or without the gametocytocidal drug primaquine (PQ), alongside standard artemisinin-based combination therapy (ACT), in the context of a randomised clinical trial in Ouelessebougou, Mali. A quantitative ELISA was used to measure levels of HRP-2, and compared time to test negativity using a standard and ultra-sensitive RDT (uRDT) between residual gametocyte positive and negative groups. RESULTS Time to test negativity was longest by uRDT, followed by ELISA and then standard RDT. No significant difference in time to negativity was found between the treatment groups with and without residual gametocytes: uRDT (HR 0.79 [95% CI 0.52-1.21], p = 0.28), RDT (HR 0.77 [95% CI 0.51-1.15], p = 0.20) or ELISA (HR 0.88 [95% CI 0.59-1.32], p = 0.53). Similarly, no difference was observed when adjusting for baseline asexual parasite density. Quantified levels of HRP-2 over time were similar between groups, with differences attributable to asexual parasite densities. Furthermore, no difference in levels of HRP-2 was found between individuals who were or were not infectious to mosquitoes (OR 1.19 [95% CI 0.98-1.46], p = 0.077). CONCLUSIONS Surviving sexual stage parasites after standard ACT treatment do not contribute to the persistence of HRP-2 antigenaemia, and appear to have little impact on RDT results.
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Affiliation(s)
- Tate Oulton
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Almahamoudou Mahamar
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Koualy Sanogo
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Makonon Diallo
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Ahamadou Youssouf
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Sidi M Niambele
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Siaka Samaké
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekouba Keita
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Youssouf Sinaba
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Adama Sacko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekou F Traore
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Kjerstin Lanke
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, University of Nijmegen, Nijmegen, The Netherlands
| | - Katharine A Collins
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, University of Nijmegen, Nijmegen, The Netherlands
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Will J R Stone
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK.
| | - Alassane Dicko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
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11
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Paris L, Tackie RG, Beshir KB, Tampuori J, Awandare GA, Binka FN, Urban BC, Dinko B, Sutherland CJ. Parasite clearance dynamics in children hospitalised with severe malaria in the Ho Teaching Hospital, Volta Region, Ghana. Parasite Epidemiol Control 2022; 19:e00276. [PMID: 36263093 PMCID: PMC9574762 DOI: 10.1016/j.parepi.2022.e00276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 08/07/2022] [Accepted: 09/30/2022] [Indexed: 11/21/2022] Open
Abstract
Background Over 90% of severe malaria (SM) cases occur in African children. Parenteral artesunate is currently the recommended treatment for SM. Studies of parasite clearance in paediatric SM cases are needed for assessment of therapeutic outcomes but are lacking in Africa. Methods Severe malaria patients were recruited in the children's emergency ward at Ho Teaching Hospital, Ghana, in 2018. Blood samples were taken upon admission, every 24 h for 3 days and 1 week after treatment, and DNA extracted. Parasitaemia and parasite densities were performed by microscopy at enrolment and the follow-up days wherever possible. Relative parasite density was measured at each timepoint by duplex qPCR and parameters of parasite clearance estimated. Results Of 25 evaluable SM patients, clearance of qPCR-detectable parasites occurred within 48 h for 17 patients, but three out of the remaining eight were still qPCR-positive on day 3. Increased time to parasite clearance was seen in children ≥5 years old, those with lower haemoglobin levels and those with a high number of previous malaria diagnoses, but these associations were not statistically significant. Conclusion We examined parasite clearance dynamics among paediatric cases of SM. Our observations suggest that daily sampling for qPCR estimation of P. falciparum peripheral density is a useful method for assessing treatment response in hospitalised SM cases. The study demonstrated varied parasite clearance response, thus illuminating the complex nature of the mechanism in this important patient group, and further investigations utilizing larger sample sizes are needed to confirm our findings.
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Affiliation(s)
- Laura Paris
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Richmond G. Tackie
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Khalid B. Beshir
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - John Tampuori
- Department of Urology, Ho Teaching Hospital, Ho, Ghana
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Fred N. Binka
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Ho, Ghana
| | - Britta C. Urban
- Department of Tropical Disease Biology, Faculty of Biological Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Bismarck Dinko
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Colin J. Sutherland
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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12
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Persistence of Residual Submicroscopic P. falciparum Parasitemia following Treatment of Artemether-Lumefantrine in Ethio-Sudan Border, Western Ethiopia. Antimicrob Agents Chemother 2022; 66:e0000222. [PMID: 35993723 PMCID: PMC9487599 DOI: 10.1128/aac.00002-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The emergence of artemisinin-resistant parasites in Africa has had a devastating impact, causing most malaria cases and related deaths reported on the continent. In Ethiopia, artemether-lumefantrine (AL) is the first-line drug for the treatment of uncomplicated falciparum malaria. This study is one of the earliest evaluations of artemether-lumefantrine (AL) efficacy in western Ethiopia, 17 years after the introduction of this drug in the study area. This study aimed at assessing PCR- corrected clinical and parasitological responses at 28 days following AL treatment. Sixty uncomplicated falciparum malaria patients were enrolled, treated with standard doses of AL, and monitored for 28 days with clinical and parasitological assessments from September 15 to December 15, 2020. Microscopy was used for patient recruitment and molecular diagnosis of P. falciparum was performed by Var gene acidic terminal sequence (varATS) real-time PCR on dried blood spots collected from each patient from day 0 and on follow-up days 1, 2, 3, 7, 14, 21, and 28. MspI and msp2 genotyping was done to confirm occurrence of recrudescence. Data entry and analysis were done by using the WHO-designed Excel spreadsheet and SPSS version 20 for Windows. A P value of less or equal to 0.05 was considered significant. From a total of 60 patients enrolled in this efficacy study, 10 were lost to follow-up; the results were analyzed for 50 patients. All the patients were fever-free on day 3. The asexual parasite positivity rate on day 3 was zero. However; 60% of the patients were PCR positive on day 3. PCR positivity on day 3 was more common among patients <15 years old as compared with those ≥15 years old (AOR = 6.44, P = 0.027). Only two patients met the case definition of treatment failure. These patients were classified as a late clinical failure as they showed symptoms of malaria and asexual stages of the parasite detected by microscopy on day 14 of their follow-ups. Hence, the Kaplan-Meier analysis of PCR- corrected adequate clinical and parasitological response (ACPR) rate of AL among study participants was 96% (95% CI: 84.9-99). In seven patients, the residual submicroscopic parasitemia persists from day 0 to day 28 of the follow-up. In addition, 16% (8/50) of patients were PCR- and then turned PCR+ after day 7 of the follow-up. AL remains efficacious for the treatment of uncomplicated falciparum malaria in the study area. However, the persistence of PCR-detected residual submicroscopic parasitemia following AL might compromise this treatment and need careful monitoring.
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13
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Muema JM, Bargul JL, Obonyo MA, Njeru SN, Matoke-Muhia D, Mutunga JM. Contemporary exploitation of natural products for arthropod-borne pathogen transmission-blocking interventions. Parasit Vectors 2022; 15:298. [PMID: 36002857 PMCID: PMC9404607 DOI: 10.1186/s13071-022-05367-8] [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: 02/24/2022] [Accepted: 06/16/2022] [Indexed: 11/26/2022] Open
Abstract
An integrated approach to innovatively counter the transmission of various arthropod-borne diseases to humans would benefit from strategies that sustainably limit onward passage of infective life cycle stages of pathogens and parasites to the insect vectors and vice versa. Aiming to accelerate the impetus towards a disease-free world amid the challenges posed by climate change, discovery, mindful exploitation and integration of active natural products in design of pathogen transmission-blocking interventions is of high priority. Herein, we provide a review of natural compounds endowed with blockade potential against transmissible forms of human pathogens reported in the last 2 decades from 2000 to 2021. Finally, we propose various translational strategies that can exploit these pathogen transmission-blocking natural products into design of novel and sustainable disease control interventions. In summary, tapping these compounds will potentially aid in integrated combat mission to reduce disease transmission trends.
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Affiliation(s)
- Jackson M Muema
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000, Nairobi, 00200, Kenya.
| | - Joel L Bargul
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000, Nairobi, 00200, Kenya.,International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772, Nairobi, 00100, Kenya
| | - Meshack A Obonyo
- Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, Egerton, 20115, Kenya
| | - Sospeter N Njeru
- Centre for Traditional Medicine and Drug Research (CTMDR), Kenya Medical Research Institute (KEMRI), P.O. Box 54840, Nairobi, 00200, Kenya
| | - Damaris Matoke-Muhia
- Centre for Biotechnology Research Development (CBRD), Kenya Medical Research Institute (KEMRI), P.O. Box 54840, Nairobi, 00200, Kenya
| | - James M Mutunga
- Department of Biological Sciences, Mount Kenya University (MKU), P.O. Box 54, Thika, 01000, Kenya.,School of Engineering Design, Technology and Professional Programs, Pennsylvania State University, University Park, PA, 16802, USA
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14
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Obonyo CO, Ogutu BR. Quinine plus clindamycin vs artemether-lumefantrine for treatment of uncomplicated falciparum malaria in western Kenya. Malar J 2022; 21:198. [PMID: 35729571 PMCID: PMC9214994 DOI: 10.1186/s12936-022-04222-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Charles O Obonyo
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | - Bernhards R Ogutu
- Centre for Clinical Research, Kenya Medical Research Institute, P.O. Box 20778, Nairobi, Kenya
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15
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Topazian HM, Moser KA, Ngasala B, Oluoch PO, Forconi CS, Mhamilawa LE, Aydemir O, Kharabora O, Deutsch-Feldman M, Read AF, Denton M, Lorenzo A, Mideo N, Ogutu B, Moormann AM, Mårtensson A, Odwar B, Bailey JA, Akala H, Ong'echa JM, Juliano JJ. Low Complexity of Infection Is Associated With Molecular Persistence of Plasmodium falciparum in Kenya and Tanzania. FRONTIERS IN EPIDEMIOLOGY 2022; 2:852237. [PMID: 38455314 PMCID: PMC10910917 DOI: 10.3389/fepid.2022.852237] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 05/06/2022] [Indexed: 03/09/2024]
Abstract
Background Plasmodium falciparum resistance to artemisinin-based combination therapies (ACTs) is a threat to malaria elimination. ACT-resistance in Asia raises concerns for emergence of resistance in Africa. While most data show high efficacy of ACT regimens in Africa, there have been reports describing declining efficacy, as measured by both clinical failure and prolonged parasite clearance times. Methods Three hundred children aged 2-10 years with uncomplicated P. falciparum infection were enrolled in Kenya and Tanzania after receiving treatment with artemether-lumefantrine. Blood samples were taken at 0, 24, 48, and 72 h, and weekly thereafter until 28 days post-treatment. Parasite and host genetics were assessed, as well as clinical, behavioral, and environmental characteristics, and host anti-malarial serologic response. Results While there was a broad range of clearance rates at both sites, 85% and 96% of Kenyan and Tanzanian samples, respectively, were qPCR-positive but microscopy-negative at 72 h post-treatment. A greater complexity of infection (COI) was negatively associated with qPCR-detectable parasitemia at 72 h (OR: 0.70, 95% CI: 0.53-0.94), and a greater baseline parasitemia was marginally associated with qPCR-detectable parasitemia (1,000 parasites/uL change, OR: 1.02, 95% CI: 1.01-1.03). Demographic, serological, and host genotyping characteristics showed no association with qPCR-detectable parasitemia at 72 h. Parasite haplotype-specific clearance slopes were grouped around the mean with no association detected between specific haplotypes and slower clearance rates. Conclusions Identifying risk factors for slow clearing P. falciparum infections, such as COI, are essential for ongoing surveillance of ACT treatment failure in Kenya, Tanzania, and more broadly in sub-Saharan Africa.
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Affiliation(s)
- Hillary M. Topazian
- Department of Infectious Disease Epidemiology, Imperial College, London, United Kingdom
| | - Kara A. Moser
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, NC, United States
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Peter O. Oluoch
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
- Center for Global Health Research, Kenyan Medical Research Institute, Kisumu, Kenya
| | - Catherine S. Forconi
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Lwidiko E. Mhamilawa
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
- Department of Women's and Children's Health, International Maternal and Child Health, Uppsala University, Uppsala, Sweden
| | - Ozkan Aydemir
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States
| | - Oksana Kharabora
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, NC, United States
| | - Molly Deutsch-Feldman
- Department of Epidemiology, Gillings School of Global Public Health, Chapel Hill, NC, United States
| | - Andrew F. Read
- Department of Entomology, Penn State University, University Park, PA, United States
| | - Madeline Denton
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, NC, United States
| | - Antonio Lorenzo
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Nicole Mideo
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Bernhards Ogutu
- Center for Global Health Research, Kenyan Medical Research Institute, Kisumu, Kenya
| | - Ann M. Moormann
- Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Andreas Mårtensson
- Department of Women's and Children's Health, International Maternal and Child Health, Uppsala University, Uppsala, Sweden
| | - Boaz Odwar
- Center for Global Health Research, Kenyan Medical Research Institute, Kisumu, Kenya
| | - Jeffrey A. Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States
| | - Hoseah Akala
- Center for Global Health Research, Kenyan Medical Research Institute, Kisumu, Kenya
| | | | - Jonathan J. Juliano
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, NC, United States
- Department of Epidemiology, Gillings School of Global Public Health, Chapel Hill, NC, United States
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
- Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
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16
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O’Flaherty K, Chan JA, Cutts JC, Zaloumis SG, Ashley EA, Phyo AP, Drew DR, Dondorp AM, Day NP, Dhorda M, Fairhurst RM, Lim P, Amaratunga C, Pukrittayakamee S, Hien TT, Htut Y, Mayxay M, Faiz MA, Mokuolu OA, Onyamboko MA, Fanello C, Takashima E, Tsuboi T, Theisen M, Nosten F, Beeson JG, Simpson JA, White NJ, Fowkes FJI. Anti-Gametocyte Antigen Humoral Immunity and Gametocytemia During Treatment of Uncomplicated Falciparum Malaria: A Multi-National Study. Front Cell Infect Microbiol 2022; 12:804470. [PMID: 35463638 PMCID: PMC9022117 DOI: 10.3389/fcimb.2022.804470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/11/2022] [Indexed: 11/16/2022] Open
Abstract
Introduction Understanding the human immune response to Plasmodium falciparum gametocytes and its association with gametocytemia is essential for understanding the transmission of malaria as well as progressing transmission blocking vaccine candidates. Methods In a multi-national clinical efficacy trial of artemisinin therapies (13 sites of varying transmission over South-East Asia and Africa), we measured Immunoglobulin G (IgG) responses to recombinant P. falciparum gametocyte antigens expressed on the gametocyte plasma membrane and leading transmission blocking vaccine candidates Pfs230 (Pfs230c and Pfs230D1M) and Pfs48/45 at enrolment in 1,114 participants with clinical falciparum malaria. Mixed effects linear and logistic regression were used to determine the association between gametocyte measures (gametocytemia and gametocyte density) and antibody outcomes at enrolment. Results Microscopy detectable gametocytemia was observed in 11% (127/1,114) of participants at enrolment, and an additional 9% (95/1,114) over the follow-up period (up to day 42) (total 20% of participants [222/1,114]). IgG levels in response to Pfs230c, Pfs48/45 and Pfs230D1M varied across study sites at enrolment (p < 0.001), as did IgG seroprevalence for anti-Pfs230c and D1M IgG (p < 0.001), but not for anti-Pfs48/45 IgG (p = 0.159). In adjusted analyses, microscopy detectable gametocytemia at enrolment was associated with an increase in the odds of IgG seropositivity to the three gametocyte antigens (Pfs230c OR [95% CI], p: 1.70 [1.10, 2.62], 0.017; Pfs48/45: 1.45 [0.85, 2.46], 0.174; Pfs230D1M: 1.70 [1.03, 2.80], 0.037), as was higher gametocyte density at enrolment (per two-fold change in gametocyte density Pfs230c OR [95% CI], p: 1.09 [1.02, 1.17], 0.008; Pfs48/45: 1.05 [0.98, 1.13], 0.185; Pfs230D1M: 1.07 [0.99, 1.14], 0.071). Conclusion Pfs230 and Pfs48/45 antibodies are naturally immunogenic targets associated with patent gametocytemia and increasing gametocyte density across multiple malaria endemic settings, including regions with emerging artemisinin-resistant P. falciparum.
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Affiliation(s)
| | - Jo-Anne Chan
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Julia C. Cutts
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
| | - Sophie G. Zaloumis
- Centre for Epidemiology and Biostatistics, School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Elizabeth A. Ashley
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Damien R. Drew
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
| | - Arjen M. Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas P. Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Mehul Dhorda
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- WorldWide Antimalarial Resistance Network, Asia-Pacific Regional Centre, Bangkok, Thailand
| | - Rick M. Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Pharath Lim
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Chanaki Amaratunga
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | | | - Tran Tinh Hien
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Ye Htut
- Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Mayfong Mayxay
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust-Research Unit, Mahosot Hospital, Vientiane, Laos
- Institute of Research and Education Development, University of Health Sciences, Vientiane, Laos
| | - M. Abul Faiz
- Malaria Research Group and Dev Care Foundation, Chittagong, Bangladesh
| | - Olugbenga A. Mokuolu
- Department of Paediatrics and Child Health, University of Ilorin, Ilorin, Nigeria
| | - Marie A. Onyamboko
- Kinshasa School of Public Health, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Caterina Fanello
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Kinshasa School of Public Health, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Francois Nosten
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - James G. Beeson
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
- Department of Immunology, Monash University, Melbourne, VIC, Australia
- Department of Microbiology and Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Nicholas J. White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Freya J. I. Fowkes
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia
- Centre for Epidemiology and Biostatistics, School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia
- Department of Infectious Diseases and Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, VIC, Australia
- *Correspondence: Freya J. I. Fowkes,
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Consalvi S, Tammaro C, Appetecchia F, Biava M, Poce G. Malaria transmission blocking compounds: a patent review. Expert Opin Ther Pat 2022; 32:649-666. [PMID: 35240899 DOI: 10.1080/13543776.2022.2049239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Despite substantial progress in the field, malaria remains a global health issue and currently available control strategies are not sufficient to achieve eradication. Agents able to prevent transmission are likely to have a strong impact on malaria control and have been prioritized as a primary objective to reduce the number of secondary infections. Therefore, there is an increased interest in finding novel drugs targeting sexual stages of Plasmodium and innovative methods to target malaria transmission from host to vector, and vice versa. AREAS COVERED This review covers innovative transmission-blocking inventions patented between 2015 and October 2021. The focus is on chemical interventions which could be used as "chemical vaccines" to prevent transmission (small molecules, carbohydrates, and polypeptides). EXPERT OPINION Even though the development of novel strategies to block transmission still requires fundamental additional research and a deeper understanding of parasite sexual stages biology, the research in this field has significantly accelerated. Among innovative inventions patented over the last six years, the surface-delivery of antimalarial drugs to kill transmission-stages parasites in mosquitoes holds the highest promise for success in malaria control strategies, opening completely new scenarios in malaria transmission-blocking drug discovery.
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Affiliation(s)
- Sara Consalvi
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Chiara Tammaro
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Federico Appetecchia
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Mariangela Biava
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Giovanna Poce
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
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Osborne A, Manko E, Takeda M, Kaneko A, Kagaya W, Chan C, Ngara M, Kongere J, Kita K, Campino S, Kaneko O, Gitaka J, Clark TG. Characterizing the genomic variation and population dynamics of Plasmodium falciparum malaria parasites in and around Lake Victoria, Kenya. Sci Rep 2021; 11:19809. [PMID: 34615917 PMCID: PMC8494747 DOI: 10.1038/s41598-021-99192-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/22/2021] [Indexed: 11/08/2022] Open
Abstract
Characterising the genomic variation and population dynamics of Plasmodium falciparum parasites in high transmission regions of Sub-Saharan Africa is crucial to the long-term efficacy of regional malaria elimination campaigns and eradication. Whole-genome sequencing (WGS) technologies can contribute towards understanding the epidemiology and structural variation landscape of P. falciparum populations, including those within the Lake Victoria basin, a region of intense transmission. Here we provide a baseline assessment of the genomic diversity of P. falciparum isolates in the Lake region of Kenya, which has sparse genetic data. Lake region isolates are placed within the context of African-wide populations using Illumina WGS data and population genomic analyses. Our analysis revealed that P. falciparum isolates from Lake Victoria form a cluster within the East African parasite population. These isolates also appear to have distinct ancestral origins, containing genome-wide signatures from both Central and East African lineages. Known drug resistance biomarkers were observed at similar frequencies to those of East African parasite populations, including the S160N/T mutation in the pfap2mu gene, which has been associated with delayed clearance by artemisinin-based combination therapy. Overall, our work provides a first assessment of P. falciparum genetic diversity within the Lake Victoria basin, a region targeting malaria elimination.
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Affiliation(s)
- Ashley Osborne
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Emilia Manko
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Mika Takeda
- Department of Protozoology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Akira Kaneko
- Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, Japan
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Wataru Kagaya
- Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, Japan
| | - Chim Chan
- Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, Japan
| | - Mtakai Ngara
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - James Kongere
- Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, Japan
- Centre for Research in Tropical Medicine and Community Development (CRTMCD), Hospital Road Next to Kenyatta National Hospital, Nairobi, Kenya
| | - Kiyoshi Kita
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Osamu Kaneko
- Department of Protozoology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | - Jesse Gitaka
- Directorate of Research and Innovation, Mount Kenya University, Thika, Kenya
- Centre for Malaria Elimination, Mount Kenya University, Thika, Kenya
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK.
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Serrano D, Santos-Reis A, Silva C, Dias A, Dias B, Toscano C, Conceição C, Baptista-Fernandes T, Nogueira F. Imported Malaria in Portugal: Prevalence of Polymorphisms in the Anti-Malarial Drug Resistance Genes pfmdr1 and pfk13. Microorganisms 2021; 9:microorganisms9102045. [PMID: 34683365 PMCID: PMC8538333 DOI: 10.3390/microorganisms9102045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 02/04/2023] Open
Abstract
Malaria is one of the ‘big three’ killer infectious diseases, alongside tuberculosis and HIV. In non-endemic areas, malaria may occur in travelers who have recently been to or visited endemic regions. The number of imported malaria cases in Portugal has increased in recent years, mostly due to the close relationship with the community of Portuguese language countries. Samples were collected from malaria-infected patients attending Centro Hospitalar Lisboa Ocidental (CHLO) or the outpatient clinic of Instituto de Higiene e Medicina Tropical (IHMT-NOVA) between March 2014 and May 2021. Molecular characterization of Plasmodium falciparum pfk13 and pfmdr1 genes was performed. We analyzed 232 imported malaria cases. The majority (68.53%) of the patients came from Angola and only three patients travelled to a non-African country; one to Brazil and two to Indonesia. P. falciparum was diagnosed in 81.47% of the cases, P. malariae in 7.33%, P. ovale 6.47% and 1.72% carried P. vivax. No mutations were detected in pfk13. Regarding pfmdr1, the wild-type haplotype (N86/Y184/D1246) was also the most prevalent (64.71%) and N86/184F/D1246 was detected in 26.47% of the cases. The typical imported malaria case was middle-aged male, traveling from Angola, infected with P. falciparum carrying wild type pfmdr1 and pfk13. Our study highlights the need for constant surveillance of malaria parasites imported into Portugal as an important pillar of public health.
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Affiliation(s)
- Debora Serrano
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT-NOVA), Rua da Junqueira 100, 1349-008 Lisboa, Portugal; (D.S.); (A.S.-R.); (C.S.); (B.D.); (C.C.)
| | - Ana Santos-Reis
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT-NOVA), Rua da Junqueira 100, 1349-008 Lisboa, Portugal; (D.S.); (A.S.-R.); (C.S.); (B.D.); (C.C.)
| | - Clemente Silva
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT-NOVA), Rua da Junqueira 100, 1349-008 Lisboa, Portugal; (D.S.); (A.S.-R.); (C.S.); (B.D.); (C.C.)
| | - Ana Dias
- Laboratório de Microbiologia Clínica e Biologia Molecular, Serviço de Patologia Clínica, Centro Hospitalar Lisboa Ocidental (CHLO), Rua da Junqueira 126, 1349-019 Lisboa, Portugal; (A.D.); (C.T.); (T.B.-F.)
| | - Brigite Dias
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT-NOVA), Rua da Junqueira 100, 1349-008 Lisboa, Portugal; (D.S.); (A.S.-R.); (C.S.); (B.D.); (C.C.)
| | - Cristina Toscano
- Laboratório de Microbiologia Clínica e Biologia Molecular, Serviço de Patologia Clínica, Centro Hospitalar Lisboa Ocidental (CHLO), Rua da Junqueira 126, 1349-019 Lisboa, Portugal; (A.D.); (C.T.); (T.B.-F.)
| | - Cláudia Conceição
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT-NOVA), Rua da Junqueira 100, 1349-008 Lisboa, Portugal; (D.S.); (A.S.-R.); (C.S.); (B.D.); (C.C.)
| | - Teresa Baptista-Fernandes
- Laboratório de Microbiologia Clínica e Biologia Molecular, Serviço de Patologia Clínica, Centro Hospitalar Lisboa Ocidental (CHLO), Rua da Junqueira 126, 1349-019 Lisboa, Portugal; (A.D.); (C.T.); (T.B.-F.)
| | - Fatima Nogueira
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (IHMT-NOVA), Rua da Junqueira 100, 1349-008 Lisboa, Portugal; (D.S.); (A.S.-R.); (C.S.); (B.D.); (C.C.)
- Correspondence: ; Tel.: +351-213652600
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20
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Persistent Submicroscopic Plasmodium falciparum Parasitemia 72 Hours after Treatment with Artemether-Lumefantrine Predicts 42-Day Treatment Failure in Mali and Burkina Faso. Antimicrob Agents Chemother 2021; 65:e0087321. [PMID: 34060901 PMCID: PMC8284475 DOI: 10.1128/aac.00873-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A recent randomized controlled trial, the WANECAM (West African Network for Clinical Trials of Antimalarial Drugs) trial, conducted at seven centers in West Africa, found that artemether-lumefantrine, artesunate-amodiaquine, pyronaridine-artesunate, and dihydroartemisinin-piperaquine all displayed good efficacy. However, artemether-lumefantrine was associated with a shorter interval between clinical episodes than the other regimens. In a further comparison of these therapies, we identified cases of persisting submicroscopic parasitemia by quantitative PCR (qPCR) at 72 h posttreatment among WANECAM participants from 5 sites in Mali and Burkina Faso, and we compared treatment outcomes for this group to those with complete parasite clearance by 72 h. Among 552 evaluable patients, 17.7% had qPCR-detectable parasitemia at 72 h during their first treatment episode. This proportion varied among sites, reflecting differences in malaria transmission intensity, but did not differ among pooled drug treatment groups. However, patients who received artemether-lumefantrine and were qPCR positive at 72 h were significantly more likely to have microscopically detectable recurrent Plasmodium falciparum parasitemia by day 42 than those receiving other regimens and experienced, on average, a shorter interval before the next clinical episode. Haplotypes of pfcrt and pfmdr1 were also evaluated in persisting parasites. These data identify a possible threat to the parasitological efficacy of artemether-lumefantrine in West Africa, over a decade since it was first introduced on a large scale.
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21
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Chijioke-Nwauche I, Oguike MC, Nwauche CA, Beshir KB, Sutherland CJ. Antimalarial drug resistance markers in human immunodeficiency virus (HIV)-positive and HIV-negative adults with asymptomatic malaria infections in Port Harcourt, Nigeria. Trans R Soc Trop Med Hyg 2021; 115:531-537. [PMID: 33823558 DOI: 10.1093/trstmh/trab061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/19/2021] [Accepted: 03/19/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND In Nigeria, indiscriminate use of antimalarial drugs may contribute to the threat of drug resistance, but this has not been evaluated among people living with human immunodeficiency virus (HIV). METHODS HIV-positive adults attending a university hospital HIV clinic and HIV-negative adult volunteers from the university hospital community with a positive blood film were treated with artemether-lumefantrine. Parasite DNA from before and after treatment was polymerase chain reaction amplified to identify molecular markers of drug susceptibility. RESULTS The pfcrt76T genotype was prevalent among both HIV-positive and HIV-negative participants (78.6% and 68.2%, respectively). Three new mutations in the pfmdr1 gene-F73S, S97L and G165R-and the uncommon pfdhps S436F variant were detected, whereas pfdhps K540E and pfdhfr I164L were absent. The A437G allele of pfdhps predominated (62/66 [94%]). The I431 V mutation was found in 19 of 66 pretreatment pfdhps sequences (28.8%). The pfmdr1 86N allele was significantly more common at day 3 post-treatment than at baseline (odds ratio 8.77 [95% confidence interval 1.21 to 380]). CONCLUSIONS We found evidence of continued chloroquine use among HIV-positive individuals. Selection for the pfmdr1 86N after artemether-lumefantrine treatment was observed, indicating a possible threat to antimalarial efficacy in the study area. The complexity of pfdhps haplotypes emphasises the need for careful monitoring of anti-folate susceptibility in Nigeria.
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Affiliation(s)
- Ifeyinwa Chijioke-Nwauche
- Department of Clinical Pharmacy and Management, Faculty of Pharmaceutical Sciences, University of Port Harcourt, PMB 5323 Choba, Rivers State, Nigeria.,Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Mary C Oguike
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Chijioke A Nwauche
- Department of Haematology, Blood Transfusion and Immunology, College of Health Sciences, University of Port Harcourt, PMB 5323 Choba, Rivers State, Nigeria.,Centre for Malaria Research and Phytomedicine, University of Port Harcourt, PMB 5323 Choba, Rivers State, Nigeria
| | - Khalid B Beshir
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Colin J Sutherland
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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Msellem M, Morris U, Soe A, Abbas FB, Ali AW, Barnes R, Frumento P, Ali AS, Mårtensson A, Björkman A. Increased Sensitivity of Plasmodium falciparum to Artesunate/Amodiaquine Despite 14 Years as First-Line Malaria Treatment, Zanzibar. Emerg Infect Dis 2021; 26:1767-1777. [PMID: 32687050 PMCID: PMC7392451 DOI: 10.3201/eid2608.191547] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Artemisinin-based combination therapies (ACTs) are first-line treatments for uncomplicated Plasmodium falciparum malaria. ACT resistance is spreading in Asia but not yet in Africa. Reduced effects of ACT partner drugs have been reported but with little information regarding widely used artesunate/amodiaquine (ASAQ). We studied its efficacy in Zanzibar after 14 years as first-line treatment directly by an in vivo, single-armed trial and indirectly by prevalences of different genotypes in the P. falciparum chloroquine-resistance transporter, multidrug-resistance 1, and Kelch 13 propeller domain genes. In vivo efficacy was higher during 2017 (100%; 95% CI 97.4%-100%) than during 2002-2005 (94.7%; 95% CI 91.9%-96.7%) (p = 0.003). Molecular findings showed no artemisinin resistance-associated genotypes and major increases in genotypes associated with high sensitivity/efficacy for amodiaquine than before ASAQ was introduced. Thus, the efficacy of ASAQ is maintained and appears to be increased after long-term use in contrast to what is observed for other ACTs used in Africa.
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23
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Rodriguez AM, Hambly MG, Jandu S, Simão-Gurge R, Lowder C, Lewis EE, Riffell JA, Luckhart S. Histamine Ingestion by Anopheles stephensi Alters Important Vector Transmission Behaviors and Infection Success with Diverse Plasmodium Species. Biomolecules 2021; 11:719. [PMID: 34064869 PMCID: PMC8151525 DOI: 10.3390/biom11050719] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 04/28/2021] [Accepted: 05/05/2021] [Indexed: 12/20/2022] Open
Abstract
An estimated 229 million people worldwide were impacted by malaria in 2019. The vectors of malaria parasites (Plasmodium spp.) are Anopheles mosquitoes, making their behavior, infection success, and ultimately transmission of great importance. Individuals with severe malaria can exhibit significantly increased blood concentrations of histamine, an allergic mediator in humans and an important insect neuromodulator, potentially delivered to mosquitoes during blood-feeding. To determine whether ingested histamine could alter Anopheles stephensi biology, we provisioned histamine at normal blood levels and at levels consistent with severe malaria and monitored blood-feeding behavior, flight activity, antennal and retinal responses to host stimuli and lifespan of adult female Anopheles stephensi. To determine the effects of ingested histamine on parasite infection success, we quantified midgut oocysts and salivary gland sporozoites in mosquitoes infected with Plasmodium yoelii and Plasmodium falciparum. Our data show that provisioning An. stephensi with histamine at levels consistent with severe malaria can enhance mosquito behaviors and parasite infection success in a manner that would be expected to amplify parasite transmission to and from human hosts. Such knowledge could be used to connect clinical interventions by reducing elevated histamine to mitigate human disease pathology with the delivery of novel lures for improved malaria control.
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Affiliation(s)
- Anna M. Rodriguez
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Malayna G. Hambly
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Sandeep Jandu
- Department of Biology, University of Washington, Seattle, WA 98195-1800, USA; (S.J.); (J.A.R.)
| | - Raquel Simão-Gurge
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Casey Lowder
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Edwin E. Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Jeffrey A. Riffell
- Department of Biology, University of Washington, Seattle, WA 98195-1800, USA; (S.J.); (J.A.R.)
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
- Department of Biological Sciences, University of Idaho, Moscow, ID 83843-3051, USA
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Sutherland CJ, Henrici RC, Artavanis-Tsakonas K. Artemisinin susceptibility in the malaria parasite Plasmodium falciparum: propellers, adaptor proteins and the need for cellular healing. FEMS Microbiol Rev 2021; 45:fuaa056. [PMID: 33095255 PMCID: PMC8100002 DOI: 10.1093/femsre/fuaa056] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/21/2020] [Indexed: 12/12/2022] Open
Abstract
Studies of the susceptibility of Plasmodium falciparum to the artemisinin family of antimalarial drugs provide a complex picture of partial resistance (tolerance) associated with increased parasite survival in vitro and in vivo. We present an overview of the genetic loci that, in mutant form, can independently elicit parasite tolerance. These encode Kelch propeller domain protein PfK13, ubiquitin hydrolase UBP-1, actin filament-organising protein Coronin, also carrying a propeller domain, and the trafficking adaptor subunit AP-2μ. Detailed studies of these proteins and the functional basis of artemisinin tolerance in blood-stage parasites are enabling a new synthesis of our understanding to date. To guide further experimental work, we present two major conclusions. First, we propose a dual-component model of artemisinin tolerance in P. falciparum comprising suppression of artemisinin activation in early ring stage by reducing endocytic haemoglobin capture from host cytosol, coupled with enhancement of cellular healing mechanisms in surviving cells. Second, these two independent requirements limit the likelihood of development of complete artemisinin resistance by P. falciparum, favouring deployment of existing drugs in new schedules designed to exploit these biological limits, thus extending the useful life of current combination therapies.
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Affiliation(s)
- Colin J Sutherland
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK
| | - Ryan C Henrici
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK
- Center for Global Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia 19104, PA, USA
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David OM, Olanlokun JO, Owoniyi BE, Ayeni M, Ebenezer O, Koorbanally NA. Studies on the mitochondrial, immunological and inflammatory effects of solvent fractions of Diospyros mespiliformis Hochst in Plasmodium berghei-infected mice. Sci Rep 2021; 11:6941. [PMID: 33767260 PMCID: PMC7994402 DOI: 10.1038/s41598-021-85790-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 03/05/2021] [Indexed: 01/31/2023] Open
Abstract
The use of medicinal plants in the treatment of malaria is gaining global attention due to their efficacy and cost effectiveness. This study evaluated the bioactivity-guided antiplasmodial efficacy and immunomodulatory effects of solvent fractions of Diospyros mespiliformis in mice infected with a susceptible strain of Plasmodium berghei (NK 65). The crude methanol extract of the stem of D. mespiliformis (DM) was partitioned between n-hexane, dichloromethane, ethyl acetate and methanol. Male Swiss mice (20 ± 2 g) infected with P. berghei were grouped and treated with vehicle (10 mL/kg, control), Artemether lumefantrine (10 mg/kg), 100, 200 and 400 mg/kg of n-hexane, dichloromethane, ethyl acetate and methanol fractions of D. mespiliformis for seven days. Blood was obtained for heme and hemozoin contents while serum was obtained for inflammatory cytokines and immunoglobulins G and M assessments. Liver mitochondria were isolated for mitochondrial permeability transition (mPT), mitochondrial F1F0 ATPase (mATPase) and lipid peroxidation (mLPO) assays. The GC-MS was used to identify the compounds present in the most potent fraction. The dichloromethane fraction had the highest parasite clearance and improved hematological indices relative to the drug control. The heme values increased, while the hemozoin content significantly (P < 0.05) decreased compared with the drug control. The highest dose of HF and MF opened the mPT pore while the reversal effects of DF on mPT, mATPase and mLPO were dose-dependent. The levels of IgG, IgM and TNFα in the DF group were significantly higher than the drug control, while the IL-1β and IL-6 values did not vary linearly with the dose. Lupeol and Stigmastan-3,5-diene were the most abundant phytochemicals in the DF. The outcome of this study showed that the DF has immunomodulatory effects in infected mice, reduced proliferation of the malaria parasite and thus protect liver cells.
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Affiliation(s)
| | - John Oludele Olanlokun
- Laboratories for Biomembrane Research and Biotechnology, Department of Biochemistry, College of Medicine, University of Ibadan, Ibadan, Nigeria.
| | | | - MoyinOluwa Ayeni
- Department of Microbiology, Ekiti State University, Ado-Ekiti, Nigeria
| | - Oluwakemi Ebenezer
- School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
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Ippolito MM, Moser KA, Kabuya JBB, Cunningham C, Juliano JJ. Antimalarial Drug Resistance and Implications for the WHO Global Technical Strategy. CURR EPIDEMIOL REP 2021; 8:46-62. [PMID: 33747712 PMCID: PMC7955901 DOI: 10.1007/s40471-021-00266-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2021] [Indexed: 12/28/2022]
Abstract
PURPOSE OF REVIEW Five years have passed since the World Health Organization released its Global Technical Strategy for Malaria (GTS). In that time, progress against malaria has plateaued. This review focuses on the implications of antimalarial drug resistance for the GTS and how interim progress in parasite genomics and antimalarial pharmacology offer a bulwark against it. RECENT FINDINGS For the first time, drug resistance-conferring genes have been identified and validated before their global expansion in malaria parasite populations. More efficient methods for their detection and elaboration have been developed, although low-density infections and polyclonality remain a nuisance to be solved. Clinical trials of alternative regimens for multidrug-resistant malaria have delivered promising results. New agents continue down the development pipeline, while a nascent infrastructure in sub-Saharan Africa for conducting phase I trials and trials of transmission-blocking agents has come to fruition after years of preparation. SUMMARY These and other developments can help inform the GTS as the world looks ahead to the next two decades of its implementation. To remain ahead of the threat that drug resistance poses, wider application of genomic-based surveillance and optimization of existing and forthcoming antimalarial drugs are essential.
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Affiliation(s)
- Matthew M. Ippolito
- Divisions of Clinical Pharmacology and Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
- The Johns Hopkins Malaria Research Institute, Johns Hopkins University School of Public Health, Baltimore, MD USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Kara A. Moser
- Institute for Global Health and Infectious Diseases, University of North Carolina, Chapel Hill, NC USA
| | | | - Clark Cunningham
- School of Medicine, University of North Carolina, Chapel Hill, NC USA
| | - Jonathan J. Juliano
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of North Carolina, CB#7030, 130 Mason Farm Rd, Chapel Hill, NC 27599 USA
- Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina, Chapel Hill, NC USA
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
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Stiffler DM, Oyieko J, Kifude CM, Rockabrand DM, Luckhart S, Stewart VA. HIV-1 Infection Is Associated With Increased Prevalence and Abundance of Plasmodium falciparum Gametocyte-Specific Transcripts in Asymptomatic Adults in Western Kenya. Front Cell Infect Microbiol 2021; 10:600106. [PMID: 33614525 PMCID: PMC7892447 DOI: 10.3389/fcimb.2020.600106] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/16/2020] [Indexed: 01/05/2023] Open
Abstract
As morbidity and mortality due to malaria continue to decline, the identification of individuals with a high likelihood of transmitting malaria is needed to further reduce the prevalence of malaria. In areas of holoendemic malaria transmission, asymptomatically infected adults may be infected with transmissible gametocytes. The impact of HIV-1 on gametocyte carriage is unknown, but co-infection may lead to an increase in gametocytemia. In this study, a panel of qPCR assays was used to quantify gametocyte stage-specific transcripts present in dried blood spots obtained from asymptomatic adults seeking voluntary HIV testing in Kombewa, Kenya. A total of 1,116 Plasmodium-specific 18S-positive samples were tested and 20.5% of these individuals had detectable gametocyte-specific transcripts. Individuals also infected with HIV-1 were 1.82 times more likely to be gametocyte positive (P<0.0001) and had significantly higher gametocyte copy numbers when compared to HIV-negative individuals. Additionally, HIV-1 positivity was associated with higher gametocyte prevalence in men and increased gametocyte carriage with age. Overall, these data suggest that HIV-positive individuals may have an increased risk of transmitting malaria parasites in regions with endemic malaria transmission and therefore should be at a higher priority for treatment with gametocidal antimalarial drugs.
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Affiliation(s)
- Deborah M Stiffler
- Department of Preventive Medicine and Biostatistics, Division of Tropical Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Janet Oyieko
- Basic Science Laboratory, US Army Medical Research Directorate-Africa/Kenya Medical Research Institute, Kisumu, Kenya
| | - Carolyne M Kifude
- Basic Science Laboratory, US Army Medical Research Directorate-Africa/Kenya Medical Research Institute, Kisumu, Kenya
| | - David M Rockabrand
- Department of Preventive Medicine and Biostatistics, Division of Tropical Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology and Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - V Ann Stewart
- Department of Preventive Medicine and Biostatistics, Division of Tropical Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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Monitoring of the Sensitivity In Vivo of Plasmodium falciparum to Artemether-Lumefantrine in Mali. Trop Med Infect Dis 2021; 6:tropicalmed6010013. [PMID: 33498803 PMCID: PMC7838931 DOI: 10.3390/tropicalmed6010013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/17/2021] [Accepted: 01/19/2021] [Indexed: 11/17/2022] Open
Abstract
In Mali, since 2007, artemether-lumefantrine has been the first choice against uncomplicated malaria. Despite its effectiveness, a rapid selection of markers of resistance to partner drugs has been documented. This work evaluated the treatment according to the World Health Organization's standard 28-day treatment method. The primary endpoint was the clinical and parasitological response corrected by a polymerase chain reaction. It was more than 99.9 percent, the proportion of patients with anemia significantly decrease compared to baseline (p < 0.001), and no serious events were recorded. Plasmodium falciparum remains sensitive to artemether-lumefantrine in Mali.
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Mahamar A, Lanke K, Graumans W, Diawara H, Sanogo K, Diarra K, Niambele SM, Gosling R, Drakeley C, Chen I, Dicko A, Bousema T, Roh ME. Persistence of mRNA indicative of Plasmodium falciparum ring-stage parasites 42 days after artemisinin and non-artemisinin combination therapy in naturally infected Malians. Malar J 2021; 20:34. [PMID: 33422068 PMCID: PMC7797096 DOI: 10.1186/s12936-020-03576-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 12/31/2020] [Indexed: 11/10/2022] Open
Abstract
Background Malaria control in sub-Saharan Africa relies upon prompt case management with artemisinin-based combination therapy (ACT). Ring-stage parasite mRNA, measured by sbp1 quantitative reverse-transcriptase PCR (qRT-PCR), was previously reported to persist after ACT treatment and hypothesized to reflect temporary arrest of the growth of ring-stage parasites (dormancy) following exposure to artemisinins. Here, the persistence of ring-stage parasitaemia following ACT and non-ACT treatment was examined. Methods Samples were used from naturally infected Malian gametocyte carriers who received dihydroartemisinin–piperaquine (DP) or sulfadoxine–pyrimethamine (SP–AQ) with or without gametocytocidal drugs. Gametocytes and ring-stage parasites were quantified by qRT-PCR during 42 days of follow-up. Results At baseline, 89% (64/73) of participants had measurable ring-stage parasite mRNA. Following treatment, the proportion of ring-stage parasite-positive individuals and estimated densities declined for all four treatment groups. Ring-stage parasite prevalence and density was generally lower in arms that received DP compared to SP–AQ. This finding was most apparent days 1, 2, and 42 of follow-up (p < 0.01). Gametocytocidal drugs did not influence ring-stage parasite persistence. Ring-stage parasite density estimates on days 14 and 28 after initiation of treatment were higher among individuals who subsequently experienced recurrent parasitaemia compared to those who remained free of parasites until day 42 after initiation of treatment (pday 14 = 0.011 and pday 28 = 0.068). No association of ring-stage persistence with gametocyte carriage was observed. Conclusions The current findings of lower ring-stage persistence after ACT without an effect of gametocytocidal partner drugs affirms the use of sbp1 as ring-stage marker. Lower persistence of ring-stage mRNA after ACT treatment suggests the marker may not reflect dormant parasites whilst it was predictive of re-appearance of parasitaemia.
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Affiliation(s)
- Almahamoudou Mahamar
- Malaria Research and Training Centre, Faculty of Pharmacy, Medicine, and Dentistry, University of Science, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Kjerstin Lanke
- Radboud Institute for Health Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, PO Box 9101, 6525GA, Nijmegen, The Netherlands
| | - Wouter Graumans
- Radboud Institute for Health Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, PO Box 9101, 6525GA, Nijmegen, The Netherlands
| | - Halimatou Diawara
- Malaria Research and Training Centre, Faculty of Pharmacy, Medicine, and Dentistry, University of Science, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Koualy Sanogo
- Malaria Research and Training Centre, Faculty of Pharmacy, Medicine, and Dentistry, University of Science, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Kalifa Diarra
- Malaria Research and Training Centre, Faculty of Pharmacy, Medicine, and Dentistry, University of Science, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Sidi Mohamed Niambele
- Malaria Research and Training Centre, Faculty of Pharmacy, Medicine, and Dentistry, University of Science, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Roly Gosling
- Global Health Group, Malaria Elimination Initiative, University of California, San Francisco, CA, USA
| | - Chris Drakeley
- Department of Infection & Immunity, London School of Hygiene & Tropical Medicine, London, UK
| | - Ingrid Chen
- Global Health Group, Malaria Elimination Initiative, University of California, San Francisco, CA, USA
| | - Alassane Dicko
- Malaria Research and Training Centre, Faculty of Pharmacy, Medicine, and Dentistry, University of Science, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Teun Bousema
- Radboud Institute for Health Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, PO Box 9101, 6525GA, Nijmegen, The Netherlands. .,Department of Infection & Immunity, London School of Hygiene & Tropical Medicine, London, UK.
| | - Michelle E Roh
- Global Health Group, Malaria Elimination Initiative, University of California, San Francisco, CA, USA
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Gachugia J, Chebore W, Otieno K, Ngugi CW, Godana A, Kariuki S. Evaluation of the colorimetric malachite green loop-mediated isothermal amplification (MG-LAMP) assay for the detection of malaria species at two different health facilities in a malaria endemic area of western Kenya. Malar J 2020; 19:329. [PMID: 32907582 PMCID: PMC7487890 DOI: 10.1186/s12936-020-03397-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 08/30/2020] [Indexed: 01/03/2023] Open
Abstract
Background Prompt diagnosis and effective malaria treatment is a key strategy in malaria control. However, the recommended diagnostic methods, microscopy and rapid diagnostic tests (RDTs), are not supported by robust quality assurance systems in endemic areas. This study compared the performance of routine RDTs and smear microscopy with a simple molecular-based colorimetric loop-mediated isothermal amplification (LAMP) at two different levels of the health care system in a malaria-endemic area of western Kenya. Methods Patients presenting with clinical symptoms of malaria at Rota Dispensary (level 2) and Siaya County Referral Hospital (level 4) were enrolled into the study after obtaining written informed consent. Capillary blood was collected to test for malaria by RDT and microscopy at the dispensary and county hospital, and for preparation of blood smears and dried blood spots (DBS) for expert microscopy and real-time polymerase chain reaction (RT-PCR). Results of the routine diagnostic tests were compared with those of malachite green loop-mediated isothermal amplification (MG-LAMP) performed at the two facilities. Results A total of 264 participants were enrolled into the study. At the dispensary level, the positivity rate by RDT, expert microscopy, MG-LAMP and RT-PCR was 37%, 30%, 44% and 42%, respectively, and 42%, 43%, 57% and 43% at the county hospital. Using RT-PCR as the reference test, the sensitivity of RDT and MG-LAMP was 78.1% (CI 67.5–86.4) and 82.9% (CI 73.0–90.3) at Rota dispensary. At Siaya hospital the sensitivity of routine microscopy and MG-LAMP was 83.3% (CI 65.3–94.4) and 93.3% (CI 77.9–99.2), respectively. Compared to MG-LAMP, there were 14 false positives and 29 false negatives by RDT at Rota dispensary and 3 false positives and 13 false negatives by routine microscopy at Siaya Hospital. Conclusion MG-LAMP is more sensitive than RDTs and microscopy in the detection of malaria parasites at public health facilities and might be a useful quality control tool in resource-limited settings.
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Affiliation(s)
- James Gachugia
- Department of Medical Microbiology, College of Health Sciences, Jomo Kenyatta University of Agriculture and Technology, P. O. Box 62000-00200, Nairobi, Kenya
| | - Winnie Chebore
- Kenya Medical Research Institute, Centre for Global Health Research, P. O. Box 1578-40100, Kisumu, Kenya
| | - Kephas Otieno
- Kenya Medical Research Institute, Centre for Global Health Research, P. O. Box 1578-40100, Kisumu, Kenya
| | - Caroline Wangari Ngugi
- Department of Medical Microbiology, College of Health Sciences, Jomo Kenyatta University of Agriculture and Technology, P. O. Box 62000-00200, Nairobi, Kenya
| | - Adano Godana
- National Malaria Control Programme, Ministry of Health, Kenyatta National Hospital, P. O. Box, Nairobi, 19982-00202, Kenya
| | - Simon Kariuki
- Kenya Medical Research Institute, Centre for Global Health Research, P. O. Box 1578-40100, Kisumu, Kenya.
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Mhamilawa LE, Ngasala B, Morris U, Kitabi EN, Barnes R, Soe AP, Mmbando BP, Björkman A, Mårtensson A. Parasite clearance, cure rate, post-treatment prophylaxis and safety of standard 3-day versus an extended 6-day treatment of artemether-lumefantrine and a single low-dose primaquine for uncomplicated Plasmodium falciparum malaria in Bagamoyo district, Tanzania: a randomized controlled trial. Malar J 2020; 19:216. [PMID: 32576258 PMCID: PMC7310382 DOI: 10.1186/s12936-020-03287-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 06/12/2020] [Indexed: 11/19/2022] Open
Abstract
Background Artemisinin-based combination therapy (ACT) resistant Plasmodium falciparum represents an increasing threat to Africa. Extended ACT regimens from standard 3 to 6 days may represent a means to prevent its development and potential spread in Africa. Methods Standard 3-day treatment with artemether–lumefantrine (control) was compared to extended 6-day treatment and single low-dose primaquine (intervention); in a randomized controlled, parallel group, superiority clinical trial of patients aged 1–65 years with microscopy confirmed uncomplicated P. falciparum malaria, enrolled in Bagamoyo district, Tanzania. The study evaluated parasite clearance, including proportion of PCR detectable P. falciparum on days 5 and 7 (primary endpoint), cure rate, post-treatment prophylaxis, safety and tolerability. Clinical, and laboratory assessments, including ECG were conducted during 42 days of follow-up. Blood samples were collected for parasite detection (by microscopy and PCR), molecular genotyping and pharmacokinetic analyses. Kaplan–Meier survival analyses were done for both parasite clearance and recurrence. Results A total of 280 patients were enrolled, 141 and 139 in the control and intervention arm, respectively, of whom 121 completed 42 days follow-up in each arm. There was no difference in proportion of PCR positivity across the arms at day 5 (80/130 (61.5%) vs 89/134 (66.4%), p = 0.44), or day 7 (71/129 (55.0%) vs 70/134 (52.2%), p = 0.71). Day 42 microscopy determined cure rates (PCR adjusted) were 97.4% (100/103) and 98.3% (110/112), p = 0.65, in the control and intervention arm, respectively. Microscopy determined crude recurrent parasitaemia during follow-up was 21/121 (17.4%) in the control and 14/121 (11.6%) in the intervention arm, p = 0.20, and it took 34 days and 42 days in the respective arms for 90% of the patients to remain without recurrent parasitaemia. Lumefantrine exposure was significantly higher in intervention arm from D3 to D42, but cardiac, biochemical and haematological safety was high and similar in both arms. Conclusion Extended 6-day artemether–lumefantrine treatment and a single low-dose of primaquine was not superior to standard 3-day treatment for ACT sensitive P. falciparum infections but, importantly, equally efficacious and safe. Thus, extended artemether–lumefantrine treatment may be considered as a future treatment regimen for ACT resistant P. falciparum, to prolong the therapeutic lifespan of ACT in Africa. Trial registration ClinicalTrials.gov, NCT03241901. Registered July 27, 2017 https://clinicaltrials.gov/show/NCT03241901
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Affiliation(s)
- Lwidiko E Mhamilawa
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden. .,Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
| | - Billy Ngasala
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden.,Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Ulrika Morris
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Eliford Ngaimisi Kitabi
- Office of Clinical Pharmacology, Division of Pharmacometrics, Food and Drugs Administration, Silver Spring, MD, USA
| | - Rory Barnes
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Aung Paing Soe
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden.,Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Bruno P Mmbando
- Tanga Centre, National Institute for Medical Research, Tanga, Tanzania
| | - Anders Björkman
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Andreas Mårtensson
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden
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Lubis IND, Wijaya H, Lubis M, Lubis CP, Beshir KB, Staedke SG, Sutherland CJ. Recurrence of Plasmodium malariae and P. falciparum Following Treatment of Uncomplicated Malaria in North Sumatera With Dihydroartemisinin-Piperaquine or Artemether-Lumefantrine. Open Forum Infect Dis 2020; 7:ofaa116. [PMID: 32420402 PMCID: PMC7216766 DOI: 10.1093/ofid/ofaa116] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/01/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND We assessed the efficacy of artemisinin-based combination therapies for treatment of uncomplicated falciparum malaria, with or without co-infecting Plasmodium spp., in Sumatera, Indonesia. METHODS Febrile patients aged >6 months with uncomplicated P. falciparum were randomized to receive dihydroartemisinin-piperaquine or artemether-lumefantrine, plus single-dose primaquine, and were followed for 42 days. Mixed Plasmodium infections were included; P. vivax infections received 14 days of primaquine. We retrospectively restricted the analysis to cases with polymerase chain reaction (PCR)-confirmed parasitemia. Recurrent parasitemia in follow-up was identified by species-specific nested PCR. RESULTS Of the 3731 participants screened, 302 were enrolled and randomized. In the dihydroartemisinin-piperaquine arm, P. falciparum infections were confirmed by PCR in 59 participants, with mixed infections in 23 (39.0%). In the artemether-lumefantrine arm, P. falciparum infections were confirmed by PCR in 55 participants, with mixed infections in 16 (29.0%). Both regimens were well tolerated, and symptoms improved rapidly in all treated participants. In the dihydroartemisinin-piperaquine arm, 1 P. falciparum recurrence (on day 7) and 6 P. malariae recurrences (1 had a mixed infection with P. falciparum) were identified during days 3-42 of follow-up. In the artemether-lumefantrine arm, 1 P. falciparum/P. malariae/P. vivax recurrence occurred on day 35. Submicroscopic persistence occurred during follow-up in 21 (37%) of 57 receiving dihydroartemisinin-piperaquine and 20 (39%) of 51 receiving artemether-lumefantrine. CONCLUSIONS In Sumatera, both regimens effectively cleared initial parasitemia, but P. falciparum and P. malariae persisted in some individuals. Molecular species detection should be deployed in antimalarial efficacy trials in Indonesia. TRIAL REGISTRATION NCT02325180.
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Affiliation(s)
- Inke Nadia D Lubis
- Department of Paediatrics, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia
- Infection and Immunity Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Hendri Wijaya
- Department of Paediatrics, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia
| | - Munar Lubis
- Department of Paediatrics, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia
| | - Chairuddin P Lubis
- Department of Paediatrics, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia
| | - Khalid B Beshir
- Infection and Immunity Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sarah G Staedke
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Colin J Sutherland
- Infection and Immunity Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- PHE Malaria Reference Laboratory, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Mwaiswelo R, Ngasala B. Evaluation of residual submicroscopic Plasmodium falciparum parasites 3 days after initiation of treatment with artemisinin-based combination therapy. Malar J 2020; 19:162. [PMID: 32316974 PMCID: PMC7175519 DOI: 10.1186/s12936-020-03235-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 04/15/2020] [Indexed: 11/25/2022] Open
Abstract
Plasmodium falciparum resistance against artemisinin has not emerged in Africa; however, there are reports of the presence of polymerase chain reaction-determined residual submicroscopic parasitaemia detected on day 3 after artemisinin-based combination therapy (ACT). These residual submicroscopic parasites are thought to represent tolerant/resistant parasites against artemisinin, the fast-acting component of the combination. This review focused on residual submicroscopic parasitaemia, what it represents, and its significance on the emergence and spread of artemisinin resistance in Africa. Presence of residual submicroscopic parasitemia on day 3 after treatment initiation leaves question on whether successful treatment is attained with ACT. Thus there is a need to determine the potential public health implication of the PCR-determined residual submicroscopic parasitaemia observed on day 3 after ACT. Robust techniques, such as in vitro cultivation, should be used to evaluate if the residual submicroscopic parasites detected on day 3 after ACT are viable asexual parasites, or gametocytes, or the DNA of the dead parasites waiting to be cleared from the circulation. Such techniques would also evaluate the transmissibility of these residual parasites.
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Affiliation(s)
- Richard Mwaiswelo
- Department of Microbiology, Immunology and Parasitology, Hubert Kairuki Memorial University, Dar es Salaam, Tanzania.
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
| | - Bill Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
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Different Plasmodium falciparum clearance times in two Malian villages following artesunate monotherapy. Int J Infect Dis 2020; 95:399-405. [PMID: 32320811 PMCID: PMC7294218 DOI: 10.1016/j.ijid.2020.03.082] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/28/2020] [Accepted: 03/30/2020] [Indexed: 11/23/2022] Open
Abstract
High prevalence of residual parasitemia at day 3 post-artesunate monotherapy treatment using qPCR while no parasites were detected by microscopy at the same timepoint. A longer parasite clearance time observed in a Malian village. Artesunate treatment is still efficacious on Plasmodium falciparum in Mali.
Background Artemisinin resistance described as increased parasite clearance time (PCT) is rare in Africa. More sensitive methods such as qPCR might better characterize the clearance phenotype in sub-Saharan Africa. Methods PCT is explored in Mali using light microscopy and qPCR after artesunate for uncomplicated malaria. In two villages, patients were followed for 28 days. Blood smears and spots were collected respectively for microscopy and qPCR. Parasitemia slope half-life was calculated after microscopy. Patient residual parasitemia were measured by qPCR. Results Uncorrected adequate clinical and parasitological responses (ACPR) observed in Faladje and Bougoula-Hameau were 78% and 92%, respectively (p = 0.01). This reached 100% for both after molecular correction. Proportions of 24H microscopy positive patients in Faladje and Bougoula-Hameau were 97.2% and 72%, respectively (p < 0.0001). Slope half-life was 2.8 h in Faladje vs 2H in Bougoula-Hameau (p < 0.001) and Proportions of 72H patients with residual parasitemia were 68.5% and 40% in Faladje and Bougoula-Hameau, respectively (p = 0.003). The mean residual parasitemia was 2.9 in Faladje vs. 0.008 in Bougoula-Hameau (p = 0.002). Although artesunate is efficacious in Mali, the longer parasite clearance time with submicroscopic parasitemia observed may represent early signs of developing P. falciparum resistance to artemisinins.
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Mhamilawa LE, Aydin-Schmidt B, Mmbando BP, Ngasala B, Morris U. Detection of Plasmodium falciparum by Light Microscopy, Loop-Mediated Isothermal Amplification, and Polymerase Chain Reaction on Day 3 after Initiation of Artemether-Lumefantrine Treatment for Uncomplicated Malaria in Bagamoyo District, Tanzania: A Comparative Trial. Am J Trop Med Hyg 2020; 101:1144-1147. [PMID: 31549618 DOI: 10.4269/ajtmh.19-0298] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Microscopy-determined Plasmodium falciparum positivity rates exceeding 10% on day 3 after initiation of artemisinin-based combination therapy (ACT) is an important indicator of artemisinin resistance. However, microscopy does not detect low-density parasitemia, contrary to molecular tools such as loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). We compared microscopy, LAMP, and PCR for detection of P. falciparum on day 3 after ACT in 256 patients with uncomplicated malaria in Bagamoyo District, Tanzania. Day 3 positivity rates were 0%, 84.8%, and 84.4% for each method, respectively. The sensitivity and specificity of LAMP against PCR was 100% (95% CI, 96.1-100) and 77.4% (95% CI, 58.9-90.4) when quantitative PCR-determined parasite densities were ≥ two parasites/µL. Loop-mediated isothermal amplification had comparable diagnostic accuracy to PCR and could potentially represent a field-friendly tool for determining day 3 positivity rates. However, what day 3 P. falciparum positivity determined using molecular methods represents needs to be further elucidated.
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Affiliation(s)
- Lwidiko E Mhamilawa
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.,Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden
| | - Berit Aydin-Schmidt
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Bruno P Mmbando
- Tanga Centre, National Institute for Medical Research, Tanga, Tanzania
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.,Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden
| | - Ulrika Morris
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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The Plasmodium falciparum Artemisinin Susceptibility-Associated AP-2 Adaptin μ Subunit is Clathrin Independent and Essential for Schizont Maturation. mBio 2020; 11:mBio.02918-19. [PMID: 32098816 PMCID: PMC7042695 DOI: 10.1128/mbio.02918-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The efficacy of current antimalarial drugs is threatened by reduced susceptibility of Plasmodium falciparum to artemisinin, associated with mutations in pfkelch13 Another gene with variants known to modulate the response to artemisinin encodes the μ subunit of the AP-2 adaptin trafficking complex. To elucidate the cellular role of AP-2μ in P. falciparum, we performed a conditional gene knockout, which severely disrupted schizont organization and maturation, leading to mislocalization of key merozoite proteins. AP-2μ is thus essential for blood-stage replication. We generated transgenic P. falciparum parasites expressing hemagglutinin-tagged AP-2μ and examined cellular localization by fluorescence and electron microscopy. Together with mass spectrometry analysis of coimmunoprecipitating proteins, these studies identified AP-2μ-interacting partners, including other AP-2 subunits, the K10 kelch-domain protein, and PfEHD, an effector of endocytosis and lipid mobilization, but no evidence was found of interaction with clathrin, the expected coat protein for AP-2 vesicles. In reverse immunoprecipitation experiments with a clathrin nanobody, other heterotetrameric AP-complexes were shown to interact with clathrin, but AP-2 complex subunits were absent.IMPORTANCE We examine in detail the AP-2 adaptin complex from the malaria parasite Plasmodium falciparum In most studied organisms, AP-2 is involved in bringing material into the cell from outside, a process called endocytosis. Previous work shows that changes to the μ subunit of AP-2 can contribute to drug resistance. Our experiments show that AP-2 is essential for parasite development in blood but does not have any role in clathrin-mediated endocytosis. This suggests that a specialized function for AP-2 has developed in malaria parasites, and this may be important for understanding its impact on drug resistance.
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Mwaiswelo R, Ngasala B, Jovel I, Xu W, Larsson E, Malmberg M, Gil JP, Premji Z, Mmbando BP, Mårtensson A. Prevalence of and Risk Factors Associated with Polymerase Chain Reaction-Determined Plasmodium falciparum Positivity on Day 3 after Initiation of Artemether-Lumefantrine Treatment for Uncomplicated Malaria in Bagamoyo District, Tanzania. Am J Trop Med Hyg 2020; 100:1179-1186. [PMID: 30860013 PMCID: PMC6493965 DOI: 10.4269/ajtmh.18-0729] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Prevalence of and risk factors associated with polymerase chain reaction (PCR)-determined Plasmodium falciparum positivity were assessed on day 3 after initiation of treatment, pre-implementation and up to 8 years post-deployment of artemether–lumefantrine as first-line treatment for uncomplicated malaria in Bagamoyo district, Tanzania. Samples originated from previously reported trials conducted between 2006 and 2014. Cytochrome b-nested PCR was used to detect malaria parasites from blood samples collected on a filter paper on day 3. Chi-square and McNemar chi-squared tests, logistic regression models, and analysis of variance were used as appropriate. Primary outcome was based on the proportion of patients with day 3 PCR-determined P. falciparum positivity. Overall, 256/584 (43.8%) of screened patients had day 3 PCR-determined positivity, whereas only 2/584 (0.3%) had microscopy-determined asexual parasitemia. Day 3 PCR-determined positivity increased from 28.0% (14/50) in 2006 to 74.2% (132/178) in 2007–2008 and declined, thereafter, to 36.0% (50/139) in 2012–2013 and 27.6% (60/217) in 2014. When data were pooled, pretreatment microscopy-determined asexual parasitemia ≥ 100,000/µL, hemoglobin < 10 g/dL, age < 5 years, temperature ≥ 37.5°C, and year of study 2007–2008 and 2012–2013 were significantly associated with PCR-determined positivity on day 3. Significant increases in P. falciparum multidrug resistance gene 1 N86 and P. falciparum chloroquine resistant transporter K76 across years were not associated with PCR-determined positivity on day 3. No statistically significant association was observed between day 3 PCR-determined positivity and PCR-adjusted recrudescence. Day 3 PCR-determined P. falciparum positivity remained common in patients treated before and after implementation of artemether–lumefantrine in Bagamoyo district, Tanzania. However, its presence was associated with pretreatment characteristics. Trials registration numbers: NCT00336375, ISRCTN69189899, NCT01998295, and NCT02090036.
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Affiliation(s)
- Richard Mwaiswelo
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.,Department of Microbiology and Parasitology, Hubert Kairuki Memorial University, Dar es Salaam, Tanzania
| | - Billy Ngasala
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala Universitet, Uppsala, Sweden.,Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Irina Jovel
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Weiping Xu
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Erik Larsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Maja Malmberg
- SLU Global Bioinformatics Centre, Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.,Section of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jose Pedro Gil
- Drug Resistance Unit, Division of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala Universitet, Uppsala, Sweden
| | - Zul Premji
- Aga Khan University Hospital, Nairobi, Kenya
| | - Bruno P Mmbando
- Tanga Centre, National Institute for Medical Research, Tanga, Tanzania
| | - Andreas Mårtensson
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala Universitet, Uppsala, Sweden
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Modification of pfap2μ and pfubp1 Markedly Reduces Ring-Stage Susceptibility of Plasmodium falciparum to Artemisinin In Vitro. Antimicrob Agents Chemother 2019; 64:AAC.01542-19. [PMID: 31636063 DOI: 10.1128/aac.01542-19] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/10/2019] [Indexed: 12/26/2022] Open
Abstract
Management of uncomplicated malaria worldwide is threatened by the emergence in Asia of Plasmodium falciparum carrying variants of the pfk13 locus and exhibiting reduced susceptibility to artemisinin. Mutations in two other genes, ubp1 and ap2μ, are associated with artemisinin resistance in rodent malaria and with clinical failure of combination therapy in African malaria patients. Transgenic P. falciparum clones, each carrying orthologues of mutations in pfap2μ and pfubp1 associated with artemisinin resistance in Plasmodium chabaudi, were derived by Cas9 gene editing. Susceptibility to artemisinin and other antimalarial drugs was determined. Following exposure to 700 nM dihydroartemisinin in the ring-stage survival assay, we found strong evidence that transgenic parasites expressing the I592T variant (11% survival), but not the S160N variant (1% survival), of the AP2μ adaptin subunit were significantly less susceptible than the parental wild-type parasite population. The V3275F variant of UBP1, but not the V3306F variant, also displayed reduced susceptibility to dihydroartemisinin (8.5% survival versus 0.5% survival). AP2μ and UBP1 variants did not elicit reduced susceptibility to 48 h of exposure to artemisinin or to other antimalarial drugs. Therefore, variants of the AP2 adaptor complex μ-subunit and of the ubiquitin hydrolase UBP1 reduce in vitro artemisinin susceptibility at the early ring stage in P. falciparum These findings confirm the existence of multiple pathways to perturbation of either the mode of action of artemisinin, the parasite's adaptive mechanisms of resistance, or both. The cellular role of UBP1 and AP2μ in Plasmodium parasites should now be elucidated.
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Prevalence of mutations in Plasmodium falciparum genes associated with resistance to different antimalarial drugs in Nyando, Kisumu County in Kenya. INFECTION GENETICS AND EVOLUTION 2019; 78:104121. [PMID: 31756512 DOI: 10.1016/j.meegid.2019.104121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/24/2019] [Accepted: 11/16/2019] [Indexed: 11/22/2022]
Abstract
Resistance to the mainstay antimalarial drugs is a major concern in the control of malaria. Delayed Plasmodium falciparum parasite clearance has been associated with Single Nucleotide Polymorphisms (SNPs) in the kelch propeller region (K13). However, SNPs in the Pf-adaptor protein complex 2 mu subunit (Pfap2-mu), Pfcrt and Pfmdr1 are possible markers associated with multi-drug resistance. Here, we explored the prevalence of SNPs in the K13, Pfap2-mu, Pfcrt, and Pfmdr1 in 94 dried blood spot field isolates collected from children aged below 12 years infected with P. falciparum during a cross-sectional study. The samples were collected in 2015 during the peak malaria transmission season in the Nyando region of Western Kenya before treatment with Artemether-Lumefantrine, the first-line artemisinin-based combination therapy (ACT) in Kenya. However, 47 of the 94 samples had recurrent parasitemia and were interrogated for the presence of the SNPs in K13 and Pfap2-mu. We used PCR amplification and sequencing to evaluate specific regions of K13 (codons 432-702), Pfap2-mu (codons 1-350), Pfmdr1 (codons 86, 1034-1246), and Pfcrt (codons 72-76) gene(s). The majority of parasites harbored the wild type K13 sequence. However, we found a unique non-synonymous W611S change. In silico studies on the impact of the W611S predicted structural changes in the overall topology of the K13 protein. Of the 47 samples analyzed for SNPs in the Pfap2-mu gene, 14 (29%) had S160 N/T mutation. The CVIET haplotype associated with CQ resistance in the Pfcrt yielded a 7.44% (7/94), while CVMNK haplotype was at 92.56%. Mutations in the Pfmdr1 region were detected only in three samples (3/94; 3.19%) at codon D1246Y. Our data suggest that parasites in the western part of Kenya harbor the wildtype strains. However, the detection of the unique SNP in K13 and Pfap2-mu linked with ACT delayed parasite clearance may suggest slow filtering of ACT-resistant parasites.
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Roth JM, Sawa P, Omweri G, Makio N, Osoti V, de Jong MD, Schallig HDFH, Mens PF. Molecular Detection of Residual Parasitemia after Pyronaridine-Artesunate or Artemether-Lumefantrine Treatment of Uncomplicated Plasmodium falciparum Malaria in Kenyan Children. Am J Trop Med Hyg 2019; 99:970-977. [PMID: 30105967 DOI: 10.4269/ajtmh.18-0233] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Artemisinin resistance is rapidly rising in Southeast Asia and may spread to African countries, where efficacy estimates are currently still excellent. Extensive monitoring of parasite clearance dynamics after treatment is needed to determine whether responsiveness to artemisinin-based combination therapies (ACT) is changing in Africa. In this study, Kenyan children with uncomplicated falciparum malaria were randomly assigned to pyronaridine-artesunate (PA) or artemether-lumefantrine (AL) treatment. Parasite clearance was evaluated over 7 days following the start of treatment by quantitative polymerase chain reaction (qPCR) and direct-on-blood PCR nucleic acid lateral flow immunoassay (db-PCR-NALFIA), a simplified molecular malaria diagnostic. Residual parasitemia at day 7 was detected by qPCR in 37.1% (26/70) of AL-treated children and in 46.1% (35/76) of PA-treated participants (P = 0.275). Direct-on-blood PCR nucleic acid lateral flow immunoassay detected residual parasites at day 7 in 33.3% (23/69) and 30.3% (23/76) of AL and PA-treated participants, respectively (P = 0.692). qPCR-determined parasitemia at day 7 was associated with increased prevalence and density of gametocytes at baseline (P = 0.014 and P = 0.003, for prevalence and density, respectively) and during follow-up (P = 0.007 and P = 0.011, respectively, at day 7). A positive db-PCR-NALFIA outcome at day 7 was associated with treatment failure (odds ratio [OR]: 3.410, 95% confidence interval [CI]: 1.513-7.689, P = 0.003), but this association was not found for qPCR (OR: 0.701, 95% CI: 0.312-1.578, P = 0.391). Both qPCR and db-PCR-NALFIA detected substantial residual submicroscopic parasitemia after microscopically successful PA and AL treatment and can be useful tools to monitor parasite clearance. To predict treatment outcome, db-PCR-NALFIA may be more suitable than qPCR.
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Affiliation(s)
- Johanna M Roth
- Department of Medical Microbiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Patrick Sawa
- Human Health Division, International Centre of Insect Physiology and Ecology, Mbita Point, Kenya
| | - George Omweri
- Human Health Division, International Centre of Insect Physiology and Ecology, Mbita Point, Kenya
| | - Nicodemus Makio
- Human Health Division, International Centre of Insect Physiology and Ecology, Mbita Point, Kenya
| | - Victor Osoti
- Human Health Division, International Centre of Insect Physiology and Ecology, Mbita Point, Kenya
| | - Menno D de Jong
- Department of Medical Microbiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Henk D F H Schallig
- Department of Medical Microbiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Pètra F Mens
- Department of Medical Microbiology, Academic Medical Center, Amsterdam, The Netherlands
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Haanshuus CG, Mørch K, Blomberg B, Strøm GEA, Langeland N, Hanevik K, Mohn SC. Assessment of malaria real-time PCR methods and application with focus on low-level parasitaemia. PLoS One 2019; 14:e0218982. [PMID: 31276473 PMCID: PMC6611585 DOI: 10.1371/journal.pone.0218982] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 06/04/2019] [Indexed: 01/04/2023] Open
Abstract
In epidemiological surveys and surveillance the application of molecular tools is essential in detecting submicroscopic malaria. A genus-specific conventional cytochrome b (cytb) PCR has shown high sensitivity in field studies, detecting 70% submicroscopic malaria. The main objective of this study was to assess the conversion from conventional to real-time PCR testing both SYBR and probe protocols, and including quantitative (q) PCR. The protocols were assessed applying well-defined clinical patient material consisting of 33 positive and 80 negative samples. Sequencing of positive PCR products was performed. In addition, a sensitivity comparison of real-time PCR methods was done by including five relevant assays investigating the effect of amplification target and platform. Sensitivity was further examined using field material consisting of 111 P.falciparum positive samples from Tanzanian children (< 5 years), as well as using related patient data to assess the application of q-PCR with focus on low-level parasitaemia. Both the cytb SYBR and probe PCR protocols showed as high sensitivity and specificity as their conventional counterpart, except missing one P. malariae sample. The SYBR protocol was more sensitive and specific than using probe. Overall, choice of amplification target applied is relevant for achieving ultra-sensitivity, and using intercalating fluorescence dye rather than labelled hydrolysis probes is favourable. Application of q-PCR analysis in field projects is important for the awareness and understanding of low-level parasitaemia. For use in clinical diagnosis and epidemiological studies the highly sensitive and user-friendly cytb SYBR q-PCR method is a relevant tool. The genus-specific method has the advantage that species identification by sequencing can be performed as an alternative to species-specific PCR.
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Affiliation(s)
- Christel Gill Haanshuus
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- * E-mail:
| | - Kristine Mørch
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Bjørn Blomberg
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | | | - Nina Langeland
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Kurt Hanevik
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Stein Christian Mohn
- Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
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Mwesigwa J, Achan J, Affara M, Wathuo M, Worwui A, Mohammed NI, Kanuteh F, Prom A, Dierickx S, di Tanna GL, Nwakanma D, Bousema T, Drakeley C, Van Geertruyden JP, D’Alessandro U. Mass Drug Administration With Dihydroartemisinin-piperaquine and Malaria Transmission Dynamics in The Gambia: A Prospective Cohort Study. Clin Infect Dis 2019; 69:278-286. [PMID: 30304511 PMCID: PMC6603267 DOI: 10.1093/cid/ciy870] [Citation(s) in RCA: 20] [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: 05/07/2018] [Accepted: 10/05/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Mass drug administration (MDA) may further reduce malaria transmission in low-transmission areas. The impact of MDA on the dynamics of malaria transmission was determined in a prospective cohort study. METHODS Annual rounds of MDA with dihydroartemisinin-piperaquine (DP) were implemented were implemented in 2014 and 2015 in six village pairs before the malaria transmission season. Blood samples were collected from residents between July and December for microscopy and nested PCR. Incidence and prevalence of infection, clinical disease, and risk of malaria reinfection post-MDA were determined. RESULTS Coverage of three DP doses was 68.2% (2014) and 65.6% (2015), compliance was greater than 80%. Incidence of infection was significantly lower in 2014 (incidence rate [IR] = 0.2 per person year [PPY]) than in 2013 (IR = 1.1 PPY; P < .01); monthly infection prevalence declined in the first three months post-MDA. Clinical malaria incidence was lower in 2014 (IR = 0.1 PPY) and 2015 (IR = 0.2 PPY) than in 2013 (IR = 0.4 PPY; P < .01), but remained higher in eastern Gambia. Individuals infected before MDA had a 2-fold higher odds of reinfection post-MDA (adjusted odds ratio = 2.5, 95% confidence interval 1.5-4.3; P < .01). CONCLUSIONS MDA reduced malaria infection and clinical disease during the first months. The reduction was maintained in low-transmission areas, but not in eastern Gambia. Annual MDA could be followed by focal MDA targeting individuals infected during the dry season. Repeated MDA rounds, some during the dry season over larger geographical areas, may result in a more marked and sustained decrease of malaria transmission.
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Affiliation(s)
- Julia Mwesigwa
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
- Department of Global Health, Faculty of Medicine and Health Sciences, University of Antwerp
| | - Jane Achan
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Muna Affara
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Miriam Wathuo
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Archibald Worwui
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Nuredin Ibrahim Mohammed
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Fatoumatta Kanuteh
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Aurelia Prom
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Susan Dierickx
- Centre of Expertise on Gender, Diversity and Intersectionality, Brussels University, Belgium
| | - Gian Luca di Tanna
- Risk Centre, Institut de Recerca en Economia Aplicada, Department of Econometrics, Statistics and Applied Economics, Universitat de Barcelona, Spain
| | - Davis Nwakanma
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | | | - Umberto D’Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
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Molecular quantification of Plasmodium parasite density from the blood retained in used RDTs. Sci Rep 2019; 9:5107. [PMID: 30911048 PMCID: PMC6434039 DOI: 10.1038/s41598-019-41438-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 03/05/2019] [Indexed: 12/27/2022] Open
Abstract
Most malaria-endemic countries are heavily reliant upon rapid diagnostic tests (RDT) for malaria case identification and treatment. RDT previously used for malaria diagnosis can subsequently be used for molecular assays, including qualitative assessment of parasite species present or the carriage of resistance markers, because parasite DNA can be extracted from the blood inside the RDT which remains preserved on the internal components. However, the quantification of parasite density has not previously been possible from used RDT. In this study, blood samples were collected from school-age children in Western Kenya, in the form of both dried blood spots on Whatman filter paper, and the blood spot that is dropped into rapid diagnostic tests during use. Having first validated a robotic DNA extraction method, the parasite density was determined from both types of sample by duplex qPCR, and across a range of densities. The methods showed good agreement. The preservation of both parasite and human DNA on the nitrocellulose membrane inside the RDT was stable even after more than one year's storage. This presents a useful opportunity for researchers or clinicians wishing to gain greater information about the parasite populations that are being studied, without significant investment of resources.
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McCreesh P, Mumbengegwi D, Roberts K, Tambo M, Smith J, Whittemore B, Kelly G, Moe C, Murphy M, Chisenga M, Greenhouse B, Ntuku H, Kleinschmidt I, Sturrock H, Uusiku P, Gosling R, Bennett A, Hsiang MS. Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia. Malar J 2018; 17:480. [PMID: 30567537 PMCID: PMC6299963 DOI: 10.1186/s12936-018-2626-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/11/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Subpatent malaria infections, or low-density infections below the detection threshold of microscopy or standard rapid diagnostic testing (RDT), can perpetuate persistent transmission and, therefore, may be a barrier for countries like Namibia that are pursuing malaria elimination. This potential burden in Namibia has not been well characterized. METHODS Using a two-stage cluster sampling, cross-sectional design, subjects of all age were enrolled during the end of the 2015 malaria transmission season in Zambezi region, located in northeast Namibia. Malaria RDTs were performed with subsequent gold standard testing by loop-mediated isothermal amplification (LAMP) using dried blood spots. Infection prevalence was measured and the diagnostic accuracy of RDT calculated. Relationships between recent fever, demographics, epidemiological factors, and infection were assessed. RESULTS Prevalence of Plasmodium falciparum malaria infection was low: 0.8% (16/1919) by RDT and 2.2% (43/1919) by LAMP. All but one LAMP-positive infection was RDT-negative. Using LAMP as gold standard, the sensitivity and specificity of RDT were 2.3% and 99.2%, respectively. Compared to LAMP-negative infections, a higher portion LAMP-positive infections were associated with fever (45.2% vs. 30.4%, p = 0.04), though 55% of infections were not associated with fever. Agricultural occupations and cattle herding were significantly associated with LAMP-detectable infection (Adjusted ORs 5.02, 95% CI 1.77-14.23, and 11.82, 95% CI 1.06-131.81, respectively), while gender, travel, bed net use, and indoor residual spray coverage were not. CONCLUSIONS This study presents results from the first large-scale malaria cross-sectional survey from Namibia using molecular testing to characterize subpatent infections. Findings suggest that fever history and standard RDTs are not useful to address this burden. Achievement of malaria elimination may require active case detection using more sensitive point-of-care diagnostics or presumptive treatment and targeted to high-risk groups.
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Affiliation(s)
- Patrick McCreesh
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Davis Mumbengegwi
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Kathryn Roberts
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Munyaradzi Tambo
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Jennifer Smith
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Brooke Whittemore
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gerard Kelly
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Caitlin Moe
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Max Murphy
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, UCSF, San Francisco, CA, USA
| | - Mukosha Chisenga
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Bryan Greenhouse
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, UCSF, San Francisco, CA, USA
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Immo Kleinschmidt
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.,Wits Research Institute for Malaria, University of Witwatersrands, Johannesburg, South Africa
| | - Hugh Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Petrina Uusiku
- National Vectorborne Disease Control Programme, Namibia Ministry of Health and Social Services, Windhoek, Namibia
| | - Roland Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA. .,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Department of Pediatrics, UCSF Benioff Children's Hospital, San Francisco, CA, USA.
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45
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Alternative pathway to reduced artemisinin susceptibility in Plasmodium falciparum. Proc Natl Acad Sci U S A 2018; 115:12556-12558. [PMID: 30487214 DOI: 10.1073/pnas.1818287115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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46
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Tyagi RK, Gleeson PJ, Arnold L, Tahar R, Prieur E, Decosterd L, Pérignon JL, Olliaro P, Druilhe P. High-level artemisinin-resistance with quinine co-resistance emerges in P. falciparum malaria under in vivo artesunate pressure. BMC Med 2018; 16:181. [PMID: 30269689 PMCID: PMC6166299 DOI: 10.1186/s12916-018-1156-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/17/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Humanity has become largely dependent on artemisinin derivatives for both the treatment and control of malaria, with few alternatives available. A Plasmodium falciparum phenotype with delayed parasite clearance during artemisinin-based combination therapy has established in Southeast Asia, and is emerging elsewhere. Therefore, we must know how fast, and by how much, artemisinin-resistance can strengthen. METHODS P. falciparum was subjected to discontinuous in vivo artemisinin drug pressure by capitalizing on a novel model that allows for long-lasting, high-parasite loads. Intravenous artesunate was administered, using either single flash-doses or a 2-day regimen, to P. falciparum-infected humanized NOD/SCID IL-2Rγ-/-immunocompromised mice, with progressive dose increments as parasites recovered. The parasite's response to artemisinins and other available anti-malarial compounds was characterized in vivo and in vitro. RESULTS Artemisinin resistance evolved very rapidly up to extreme, near-lethal doses of artesunate (240 mg/kg), an increase of > 3000-fold in the effective in vivo dose, far above resistance levels reported from the field. Artemisinin resistance selection was reproducible, occurring in 80% and 41% of mice treated with flash-dose and 2-day regimens, respectively, and the resistance phenotype was stable. Measuring in vitro sensitivity proved inappropriate as an early marker of resistance, as IC50 remained stable despite in vivo resistance up to 30 mg/kg (ART-S: 10.7 nM (95% CI 10.2-11.2) vs. ART-R30: 11.5 nM (6.6-16.9), F = 0.525, p = 0.47). However, when in vivo resistance strengthened further, IC50 increased 10-fold (ART-R240 100.3 nM (92.9-118.4), F = 304.8, p < 0.0001), reaching a level much higher than ever seen in clinical samples. Artemisinin resistance in this African P. falciparum strain was not associated with mutations in kelch-13, casting doubt over the universality of this genetic marker for resistance screening. Remarkably, despite exclusive exposure to artesunate, full resistance to quinine, the only other drug sufficiently fast-acting to deal with severe malaria, evolved independently in two parasite lines exposed to different artesunate regimens in vivo, and was confirmed in vitro. CONCLUSION P. falciparum has the potential to evolve extreme artemisinin resistance and more complex patterns of multidrug resistance than anticipated. If resistance in the field continues to advance along this trajectory, we will be left with a limited choice of suboptimal treatments for acute malaria, and no satisfactory option for severe malaria.
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Affiliation(s)
- Rajeev K Tyagi
- The Vac4All Initiative, 26 Rue Lecourbe, 75015, Paris, France
- Biomedical Parasitology Unit, Institut Pasteur, Paris, France
- Present Address: Amity Institute of Microbial Technology, Amity University, Noida, Uttar Pradesh, India
| | - Patrick J Gleeson
- The Vac4All Initiative, 26 Rue Lecourbe, 75015, Paris, France
- Biomedical Parasitology Unit, Institut Pasteur, Paris, France
- Present Address: Centre de Recherche sur l'Inflammation, INSERM U1149, Faculté de Médecine, Université Diderot-Site Bichat, 16 rue Henri Huchard, 75018, Paris, France
| | - Ludovic Arnold
- The Vac4All Initiative, 26 Rue Lecourbe, 75015, Paris, France
- Biomedical Parasitology Unit, Institut Pasteur, Paris, France
| | - Rachida Tahar
- Faculté de Pharmacie, Université Paris Descartes, COMUE Sorbonne Paris Cité, Paris, France
- Institut de Recherche pour le Développement, UMR MERIT 216, Paris, France
| | - Eric Prieur
- The Vac4All Initiative, 26 Rue Lecourbe, 75015, Paris, France
- Biomedical Parasitology Unit, Institut Pasteur, Paris, France
| | - Laurent Decosterd
- Division of Clinical Pharmacology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Jean-Louis Pérignon
- The Vac4All Initiative, 26 Rue Lecourbe, 75015, Paris, France
- Biomedical Parasitology Unit, Institut Pasteur, Paris, France
- Present Address: Laboratoire de Biochimie, Hôpital Necker-Enfants Malades, Paris, France
| | - Piero Olliaro
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Pierre Druilhe
- The Vac4All Initiative, 26 Rue Lecourbe, 75015, Paris, France.
- Biomedical Parasitology Unit, Institut Pasteur, Paris, France.
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Cohen J, Saran I. The impact of packaging and messaging on adherence to malaria treatment: Evidence from a randomized controlled trial in Uganda. JOURNAL OF DEVELOPMENT ECONOMICS 2018; 134:68-95. [PMID: 30177864 PMCID: PMC6088513 DOI: 10.1016/j.jdeveco.2018.04.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 04/19/2018] [Accepted: 04/25/2018] [Indexed: 05/07/2023]
Abstract
Despite substantial public and private costs of non-adherence to infectious disease treatments, patients often do not finish their medication. We explore adherence to medication for malaria, a major cause of morbidity and health system costs in Africa. We conducted a randomized trial in Uganda testing specialized packaging and messaging, designed to increase antimalarial adherence. We find that stickers with short, targeted messages on the packaging increase adherence by 9% and reduce untaken pills by 29%. However, the currently used method of boosting adherence through costly, specialized packaging with pictorial instructions had no significant impacts relative to the standard control package. We develop a theoretical framework of the adherence decision, highlighting the role of symptoms, beliefs about being cured, and beliefs about drug effectiveness to help interpret our results. Patients whose symptoms resolve sooner are substantially less likely to adhere, and the sticker interventions have the strongest impact among these patients.
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Affiliation(s)
- Jessica Cohen
- Harvard T.H. Chan School of Public Health and J-PAL, Building 1, Room 1209, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Indrani Saran
- Harvard T.H. Chan School of Public Health, Building 1, 665 Huntington Avenue, Boston, MA 02115, USA
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48
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Identifying Recrudescent Plasmodium falciparum in Treated Malaria Patients by Real-time PCR and High Resolution Melt Analysis of Genetic Diversity. Sci Rep 2018; 8:10097. [PMID: 29973679 PMCID: PMC6031682 DOI: 10.1038/s41598-018-28179-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/18/2018] [Indexed: 12/24/2022] Open
Abstract
Recurrent parasitaemia during follow up of clinical trials of antimalarial drug efficacy results from either recrudescence of parasites surviving treatment or from parasites newly emerging from the hepatic stage of infection. Nested PCR is used to distinguish these two possibilities and the technique is difficult to standardise. There is risk of both false positive and false negative results, leading to misclassification errors. The high-resolution melt (HRM) assay was developed with pairs of conserved primers targeting blocks of merozoite surface protein 1 and 2 (msp1 and msp2) genes, and polymorphisms were compared using sequence-confirmed Plasmodium falciparum DNA samples from laboratory isolates. In this study, the HRM dissociation profiles of msp1 and msp2 amplicons were determined and validated against parasite isolates from malaria patients. The msp1 and msp2 profiles of both laboratory and clinical isolates were reproducibly differentiated by HRM. These rapid assays are performed in a closed-tube system, and so avoid cross-contamination while increasing throughput, which are two major advantages. The HRM assays offer significant gains in simplicity, speed and interpretation of results, and reduced analysis cost, for studies that require discrimination of parasite clones. Assay performance in large-scale studies utilizing DNA samples derived from filter-paper bloodspots should now be evaluated.
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Dinko B, Ansah F, Agyare-Kwabi C, Tagboto S, Amoah LE, Urban BC, Sutherland CJ, Awandare GA, Williamson KC, Binka FN, Deitsch KW. Gametocyte Development and Carriage in Ghanaian Individuals with Uncomplicated Plasmodium falciparum Malaria. Am J Trop Med Hyg 2018; 99:57-64. [PMID: 29692310 PMCID: PMC6085798 DOI: 10.4269/ajtmh.18-0077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 02/23/2018] [Indexed: 01/29/2023] Open
Abstract
Plasmodium falciparum gametocytes develop over 9-12 days while sequestered in deep tissues. On emergence into the bloodstream, they circulate for varied amounts of time during which certain host factors might influence their further development. We aimed to evaluate the potential association of patient clinical parameters with gametocyte development and carriage via in vivo methods. Seventy-two patients were enrolled from three hospitals in the Volta region of Ghana in 2016. Clinical parameters were documented for all patients, and gametocyte prevalence by microscopy was estimated at 12.5%. By measuring RNA transcripts representing two distinct gametocyte developmental stages using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), we obtained a more precise estimate of gametocyte carriage while also inferring gametocyte maturation. Fifty-three percent of the study participants harbored parasites expressing transcripts of the immature gametocyte-specific gene (PF3D7_1477700), whereas 36% harbored PF3D7_1438800 RNA-positive parasites, which is enriched in mid and mature gametocytes, suggesting the presence of more immature stages. Linear logistic regression showed that patients older than 5 years but less than 16 years were more likely to carry gametocytes expressing both PF3D7_1477700 and PF3D7_1438800 compared with younger participants, and gametocytemia was more likely in mildly anemic individuals compared with those with severe/moderate anemia. These data provide further evidence that a greater number of malaria patients harbor gametocytes than typically estimated by microscopy and suggest a possible association between age, fever, anemia, and gametocytemia.
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Affiliation(s)
- Bismarck Dinko
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Felix Ansah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Comfort Agyare-Kwabi
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Senyo Tagboto
- Department of Internal Medicine, School of Medicine, University of Health and Allied Sciences, Ho, Volta Region, Ghana
| | - Linda Eva Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Britta C. Urban
- Faculty of Biological Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Colin J. Sutherland
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Kim C. Williamson
- Microbiology and Immunology Department, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Fred N. Binka
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Ho, Volta Region, Ghana
| | - Kirk W. Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York
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50
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Koepfli C, Yan G. Plasmodium Gametocytes in Field Studies: Do We Measure Commitment to Transmission or Detectability? Trends Parasitol 2018; 34:378-387. [PMID: 29544966 DOI: 10.1016/j.pt.2018.02.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/07/2018] [Accepted: 02/21/2018] [Indexed: 01/05/2023]
Abstract
The proportion of Plasmodium spp. infections carrying gametocytes, and gametocyte densities, are often reported as surrogate markers for transmission potential. It remains unclear whether parasites under natural conditions adjust commitment to transmission depending on external factors. Population-based surveys comprising mostly asymptomatic low-density infections are always impacted by the sensitivity of the assays used to diagnose infections and detect gametocytes. Asexual parasite density is an important predictor for the probability of detecting gametocytes, and in many cases it can explain patterns in gametocyte carriage without the need for an adjustment of the gametocyte conversion rate. When reporting gametocyte data, quantification of blood-stage parasitemia and its inclusion as a confounder in multivariable analyses is essential.
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Affiliation(s)
- Cristian Koepfli
- Program in Public Health, University of California, Irvine, CA, 92697, USA.
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, 92697, USA
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