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Cohen JM, Okumu F, Moonen B. The fight against malaria: Diminishing gains and growing challenges. Sci Transl Med 2022; 14:eabn3256. [PMID: 35767649 DOI: 10.1126/scitranslmed.abn3256] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Since the year 2000, historic reductions in malaria incidence and mortality have been driven by the widespread distribution of bed nets, drugs, and insecticides for the prevention and treatment of malaria. Scale-up of these tools has been enabled by an increase in malaria financing compounded by price reductions, yet these trends are unlikely to continue at the same rate. Rapid population growth in high-endemic areas requires procurement of more of these tools just to maintain current coverage, even as prices are likely to increase as resistance to drugs and insecticides forces shifts to newer products. Further progress toward the long-term goal of malaria eradication requires a combination of greater funding, more cost-effective resource allocation, and fundamental changes to the global malaria control strategy.
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Affiliation(s)
| | - Fredros Okumu
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.,School of Life Science and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Bruno Moonen
- Bill & Melinda Gates Foundation, Seattle, WA, USA
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Affiliation(s)
- Kala Pham
- Departments of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
- Houston Premedical Academy, University of Houston and Baylor College of Medicine, Houston, Texas, United States of America
| | - Peter J Hotez
- Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Biology, Baylor University, Waco, Texas, United States of America
- Hagler Institute of Advanced Study, Texas A&M University, College Station, Texas, United States of America
- James A Baker III Institute of Public Policy, Rice University, Houston, Texas, United States of America
- * E-mail:
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Goldlust SM, Thuan PD, Giang DDH, Thang ND, Thwaites GE, Farrar J, Thanh NV, Nguyen TD, Grenfell BT, Boni MF, Hien TT. The decline of malaria in Vietnam, 1991-2014. Malar J 2018; 17:226. [PMID: 29880051 PMCID: PMC5992833 DOI: 10.1186/s12936-018-2372-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 05/28/2018] [Indexed: 02/04/2023] Open
Abstract
Background Despite the well-documented clinical efficacy of artemisinin-based combination therapy (ACT) against malaria, the population-level effects of ACT have not been studied thoroughly until recently. An ideal case study for these population-level effects can be found in Vietnam’s gradual adoption of artemisinin in the 1990s. Methods and results Analysis of Vietnam’s national annual malaria reports (1991–2014) revealed that a 10% increase in artemisinin procurement corresponded to a 32.8% (95% CI 27.7–37.5%) decline in estimated malaria cases. There was no consistent national or regional effect of vector control on malaria. The association between urbanization and malaria was generally negative and sometimes statistically significant. Conclusions The decline of malaria in Vietnam can largely be attributed to the adoption of artemisinin-based case management. Recent analyses from Africa showed that insecticide-treated nets had the greatest effect on lowering malaria prevalence, suggesting that the success of interventions is region-specific. Continuing malaria elimination efforts should focus on both vector control and increased access to ACT. Electronic supplementary material The online version of this article (10.1186/s12936-018-2372-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sandra M Goldlust
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,Department of Biology, Georgetown University, Washington, DC, USA.,Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Phung Duc Thuan
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Dang Duy Hoang Giang
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Ngo Duc Thang
- National Institutes for Malariology, Parasitology, and Entomology, Hanoi, Vietnam
| | - Guy E Thwaites
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jeremy Farrar
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,The Wellcome Trust, London, UK
| | - Ngo Viet Thanh
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Tran Dang Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam
| | - Bryan T Grenfell
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Maciej F Boni
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK. .,Center for Infectious Disease Dynamics, Department of Biology, Pennsylvania State University, University Park, PA, USA.
| | - Tran Tinh Hien
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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K13 Propeller Mutations in Plasmodium falciparum Populations in Regions of Malaria Endemicity in Vietnam from 2009 to 2016. Antimicrob Agents Chemother 2017; 61:AAC.01578-16. [PMID: 28137815 PMCID: PMC5365681 DOI: 10.1128/aac.01578-16] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 01/22/2017] [Indexed: 12/12/2022] Open
Abstract
The spread of artemisinin-resistant Plasmodium falciparum compromises the therapeutic efficacy of artemisinin combination therapies (ACTs) and is considered the greatest threat to current global initiatives to control and eliminate malaria. This is particularly relevant in Vietnam, where dihydroartemisinin-piperaquine (DP) is the recommended ACT for P. falciparum infection. The propeller domain gene of K13, a molecular marker of artemisinin resistance, was successfully sequenced in 1,060 P. falciparum isolates collected at 3 malaria hot spots in Vietnam between 2009 and 2016. Eight K13 propeller mutations (Thr474Ile, Tyr493His, Arg539Thr, Ile543Thr, Pro553Leu, Val568Gly, Pro574Leu, and Cys580Tyr), including several that have been validated to be artemisinin resistance markers, were found. The prevalences of K13 mutations were 29% (222/767), 6% (11/188), and 43% (45/105) in the Binh Phuoc, Ninh Thuan, and Gia Lai Provinces of Vietnam, respectively. Cys580Tyr became the dominant genotype in recent years, with 79.1% (34/43) of isolates in Binh Phuoc Province and 63% (17/27) of isolates in Gia Lai Province carrying this mutation. K13 mutations were associated with reduced ring-stage susceptibility to dihydroartemisinin (DHA) in vitro and prolonged parasite clearance in vivo. An analysis of haplotypes flanking K13 suggested the presence of multiple strains with the Cys580Tyr mutation rather than a single strain expanding across the three sites.
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Disparities between malaria infection and treatment rates: Evidence from a cross-sectional analysis of households in Uganda. PLoS One 2017; 12:e0171835. [PMID: 28241041 PMCID: PMC5328248 DOI: 10.1371/journal.pone.0171835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 01/26/2017] [Indexed: 12/04/2022] Open
Abstract
Background In Sub-Saharan Africa, both under-treatment and over-treatment of malaria are common since illnesses are often diagnosed and treated on the basis of symptoms. We investigate whether malaria treatment rates among febrile individuals correspond to observed patterns of malaria infection by age and by local prevalence. Methods and findings We use data on treatment of febrile illnesses from a household survey that was conducted between March and May 2012 in 92 villages in six districts in Eastern Uganda. All household members were also tested for malaria using a rapid diagnostic test. We show that both the age of the febrile individual and the village prevalence rate are strongly associated with the odds that a febrile patient was infected with malaria, but not with the odds of ACT treatment. Compared to individuals who were aged 15 or above, febrile individuals aged 5–14 had 3.21 times the odds of testing positive for malaria (95% CI: [2.36 4.37], P<0·001), and febrile individuals who were under age 5 had 2.66 times the odds of testing positive for malaria (95% CI: [1.99 3.56], P<0·001). However, ACT treatment rates for febrile illnesses were not significantly higher for either children ages 5–14 (Unadjusted OR: 1.19, 95% CI: [0.88 1.62], P = 0.255) or children under the age of 5 (Unadjusted OR: 1.24, 95% CI: [0.92 1.68], P = 0·154). A one standard deviation increase in the village malaria prevalence rate was associated with a 2.03 times higher odds that a febrile individual under the age of five tested positive for malaria (95% CI: [1.63 2.54], p<0·001), but was not significantly associated with the odds of ACT treatment (Un-adjusted OR: 0.83, 95% CI: [0.66 1.05], P = 0·113). We present some evidence that this discrepancy may be because caregivers do not suspect a higher likelihood of malaria infection, conditional on fever, in young children or in high-prevalence villages. Conclusion Our findings suggest that households have significant mis-perceptions about malaria likelihood that may contribute to the under-treatment of malaria. Policies are needed to encourage caregivers to seek immediate diagnostic testing and treatment for febrile illnesses, particularly among young children.
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Woodrow CJ, White NJ. The clinical impact of artemisinin resistance in Southeast Asia and the potential for future spread. FEMS Microbiol Rev 2016; 41:34-48. [PMID: 27613271 PMCID: PMC5424521 DOI: 10.1093/femsre/fuw037] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/11/2016] [Accepted: 07/31/2016] [Indexed: 11/25/2022] Open
Abstract
Artemisinins are the most rapidly acting of currently available antimalarial drugs. Artesunate has become the treatment of choice for severe malaria, and artemisinin-based combination therapies (ACTs) are the foundation of modern falciparum malaria treatment globally. Their safety and tolerability profile is excellent. Unfortunately, Plasmodium falciparum infections with mutations in the ‘K13’ gene, with reduced ring-stage susceptibility to artemisinins, and slow parasite clearance in patients treated with ACTs, are now widespread in Southeast Asia. We review clinical efficacy data from the region (2000–2015) that provides strong evidence that the loss of first-line ACTs in western Cambodia, first artesunate-mefloquine and then DHA-piperaquine, can be attributed primarily to K13 mutated parasites. The ring-stage activity of artemisinins is therefore critical for the sustained efficacy of ACTs; once it is lost, rapid selection of partner drug resistance and ACT failure are inevitable consequences. Consensus methods for monitoring artemisinin resistance are now available. Despite increased investment in regional control activities, ACTs are failing across an expanding area of the Greater Mekong subregion. Although multiple K13 mutations have arisen independently, successful multidrug-resistant parasite genotypes are taking over and threaten to spread to India and Africa. Stronger containment efforts and new approaches to sustaining long-term efficacy of antimalarial regimens are needed to prevent a global malaria emergency. Artemisinin resistance in Plasmodium falciparum malaria is causing failure of artemisinin-based combination therapies across an expanding area of Southeast Asia, undermining control and elimination efforts. The potential global consequences can only be avoided by new approaches that ensure sustained efficacy for antimalarial regimens in malaria affected populations.
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Affiliation(s)
- Charles J Woodrow
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6, Rajvithi Road, Bangkok 10400, Thailand
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6, Rajvithi Road, Bangkok 10400, Thailand
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Landier J, Parker DM, Thu AM, Carrara VI, Lwin KM, Bonnington CA, Pukrittayakamee S, Delmas G, Nosten FH. The role of early detection and treatment in malaria elimination. Malar J 2016; 15:363. [PMID: 27421656 PMCID: PMC4946177 DOI: 10.1186/s12936-016-1399-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/17/2016] [Indexed: 12/30/2022] Open
Abstract
Falciparum malaria persists in hard-to-reach areas or demographic groups that are missed by conventional healthcare systems but could be reached by trained community members in a malaria post (MP). The main focus of a MP is to provide uninterrupted and rapid access to rapid diagnostic tests (RDTs) and artemisinin-based combination therapy (ACT) too all inhabitants of a village. RDTs allow trained community members to perform malaria diagnosis accurately and prescribe appropriate treatment, reducing as much as possible any delay between the onset of fever and treatment. Early treatment with ACT and with a low-dose of primaquine prevents further transmission from human to mosquito. A functioning MP represents an essential component of any malaria elimination strategy. Implementing large-scale, high-coverage, community-based early diagnosis and treatment through MPs requires few technological innovations but relies on a very well structured organization able to train, supervise and supply MPs, to monitor activity and to perform strict malaria surveillance.
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Affiliation(s)
- Jordi Landier
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.
| | - Daniel M Parker
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Aung Myint Thu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Verena I Carrara
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Khin Maung Lwin
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Craig A Bonnington
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | | | - Gilles Delmas
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - François H Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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