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Connolly JB, Burt A, Christophides G, Diabate A, Habtewold T, Hancock PA, James AA, Kayondo JK, Lwetoijera DW, Manjurano A, McKemey AR, Santos MR, Windbichler N, Randazzo F. Considerations for first field trials of low-threshold gene drive for malaria vector control. Malar J 2024; 23:156. [PMID: 38773487 PMCID: PMC11110314 DOI: 10.1186/s12936-024-04952-9] [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: 11/29/2023] [Accepted: 04/15/2024] [Indexed: 05/23/2024] Open
Abstract
Sustainable reductions in African malaria transmission require innovative tools for mosquito control. One proposal involves the use of low-threshold gene drive in Anopheles vector species, where a 'causal pathway' would be initiated by (i) the release of a gene drive system in target mosquito vector species, leading to (ii) its transmission to subsequent generations, (iii) its increase in frequency and spread in target mosquito populations, (iv) its simultaneous propagation of a linked genetic trait aimed at reducing vectorial capacity for Plasmodium, and (v) reduced vectorial capacity for parasites in target mosquito populations as the gene drive system reaches fixation in target mosquito populations, causing (vi) decreased malaria incidence and prevalence. Here the scope, objectives, trial design elements, and approaches to monitoring for initial field releases of such gene dive systems are considered, informed by the successful implementation of field trials of biological control agents, as well as other vector control tools, including insecticides, Wolbachia, larvicides, and attractive-toxic sugar bait systems. Specific research questions to be addressed in initial gene drive field trials are identified, and adaptive trial design is explored as a potentially constructive and flexible approach to facilitate testing of the causal pathway. A fundamental question for decision-makers for the first field trials will be whether there should be a selective focus on earlier points of the pathway, such as genetic efficacy via measurement of the increase in frequency and spread of the gene drive system in target populations, or on wider interrogation of the entire pathway including entomological and epidemiological efficacy. How and when epidemiological efficacy will eventually be assessed will be an essential consideration before decisions on any field trial protocols are finalized and implemented, regardless of whether initial field trials focus exclusively on the measurement of genetic efficacy, or on broader aspects of the causal pathway. Statistical and modelling tools are currently under active development and will inform such decisions on initial trial design, locations, and endpoints. Collectively, the considerations here advance the realization of developer ambitions for the first field trials of low-threshold gene drive for malaria vector control within the next 5 years.
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Affiliation(s)
- John B Connolly
- Department of Life Sciences, Silwood Park, Imperial College London, London, UK.
| | - Austin Burt
- Department of Life Sciences, Silwood Park, Imperial College London, London, UK
| | - George Christophides
- Department of Life Sciences, South Kensington Campus, Imperial College London, London, UK
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Tibebu Habtewold
- Department of Life Sciences, South Kensington Campus, Imperial College London, London, UK
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Penelope A Hancock
- MRC Centre for Global Infectious Disease Analysis, St. Mary's Campus, Imperial College London, London, UK
| | - Anthony A James
- Departments of Microbiology & Molecular Genetics and Molecular Biology & Biochemistry, University of California, Irvine, USA
| | - Jonathan K Kayondo
- Entomology Department, Uganda Virus Research Institute (UVRI), Entebbe, Uganda
| | | | - Alphaxard Manjurano
- Malaria Research Unit and Laboratory Sciences, Mwanza Medical Research Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Andrew R McKemey
- Department of Life Sciences, Silwood Park, Imperial College London, London, UK
| | - Michael R Santos
- Foundation for the National Institutes of Health, North Bethesda, MD, USA
| | - Nikolai Windbichler
- Department of Life Sciences, South Kensington Campus, Imperial College London, London, UK
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2
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Mousa A, Cuomo-Dannenburg G, Thompson HA, Chico RM, Beshir KB, Sutherland CJ, Schellenberg D, Gosling R, Alifrangis M, Hocke EF, Hansson H, Chopo-Pizarro A, Mbacham WF, Ali IM, Chaponda M, Roper C, Okell LC. Measuring protective efficacy and quantifying the impact of drug resistance: A novel malaria chemoprevention trial design and methodology. PLoS Med 2024; 21:e1004376. [PMID: 38723040 PMCID: PMC11081503 DOI: 10.1371/journal.pmed.1004376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 03/14/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND Recently revised WHO guidelines on malaria chemoprevention have opened the door to more tailored implementation. Countries face choices on whether to replace old drugs, target additional age groups, and adapt delivery schedules according to local drug resistance levels and malaria transmission patterns. Regular routine assessment of protective efficacy of chemoprevention is key. Here, we apply a novel modelling approach to aid the design and analysis of chemoprevention trials and generate measures of protection that can be applied across a range of transmission settings. METHODS AND FINDINGS We developed a model of genotype-specific drug protection, which accounts for underlying risk of infection and circulating genotypes. Using a Bayesian framework, we fitted the model to multiple simulated scenarios to explore variations in study design, setting, and participant characteristics. We find that a placebo or control group with no drug protection is valuable but not always feasible. An alternative approach is a single-arm trial with an extended follow-up (>42 days), which allows measurement of the underlying infection risk after drug protection wanes, as long as transmission is relatively constant. We show that the currently recommended 28-day follow-up in a single-arm trial results in low precision of estimated 30-day chemoprevention efficacy and low power in determining genotype differences of 12 days in the duration of protection (power = 1.4%). Extending follow-up to 42 days increased precision and power (71.5%) in settings with constant transmission over this time period. However, in settings of unstable transmission, protective efficacy in a single-arm trial was overestimated by 24.3% if recruitment occurred during increasing transmission and underestimated by 15.8% when recruitment occurred during declining transmission. Protective efficacy was estimated with greater precision in high transmission settings, and power to detect differences by resistance genotype was lower in scenarios where the resistant genotype was either rare or too common. CONCLUSIONS These findings have important implications for the current guidelines on chemoprevention efficacy studies and will be valuable for informing where these studies should be optimally placed. The results underscore the need for a comparator group in seasonal settings and provide evidence that the extension of follow-up in single-arm trials improves the accuracy of measures of protective efficacy in settings with more stable transmission. Extension of follow-up may pose logistical challenges to trial feasibility and associated costs. However, these studies may not need to be repeated multiple times, as the estimates of drug protection against different genotypes can be applied to different settings by adjusting for transmission intensity and frequency of resistance.
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Affiliation(s)
- Andria Mousa
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gina Cuomo-Dannenburg
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Hayley A. Thompson
- Malaria and Neglected Tropical Diseases, PATH, Seattle, Washington, United States of America
| | - R. Matthew Chico
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Khalid B. Beshir
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Colin J. Sutherland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - David Schellenberg
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Roly Gosling
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Malaria Elimination Initiative, Institute of Global Health, University of California, San Francisco, California, United States of America
| | - Michael Alifrangis
- Center for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Emma Filtenborg Hocke
- Center for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Helle Hansson
- Center for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Ana Chopo-Pizarro
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Wilfred F. Mbacham
- The Biotechnology Centre, University of Yaoundé, Yaoundé, Cameroon
- The Fobang Institutes for Innovation in Science and Technology, Yaoundé, Cameroon
- The Faculty of Northwest University, Faculty of Natural and Agricultural Sciences, Potchefstroom, South Africa
| | - Innocent M. Ali
- The Biotechnology Centre, University of Yaoundé, Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Mike Chaponda
- Department of Clinical Sciences, Tropical Diseases Research Centre, Ndola, Zambia
| | - Cally Roper
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Lucy C. Okell
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
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3
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Evans MV, Ihantamalala FA, Randriamihaja M, Aina AT, Bonds MH, Finnegan KE, Rakotonanahary RJL, Raza-Fanomezanjanahary M, Razafinjato B, Raobela O, Raholiarimanana SH, Randrianavalona TH, Garchitorena A. Applying a zero-corrected, gravity model estimator reduces bias due to heterogeneity in healthcare utilization in community-scale, passive surveillance datasets of endemic diseases. Sci Rep 2023; 13:21288. [PMID: 38042891 PMCID: PMC10693580 DOI: 10.1038/s41598-023-48390-0] [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: 03/13/2023] [Accepted: 11/26/2023] [Indexed: 12/04/2023] Open
Abstract
Data on population health are vital to evidence-based decision making but are rarely adequately localized or updated in continuous time. They also suffer from low ascertainment rates, particularly in rural areas where barriers to healthcare can cause infrequent touch points with the health system. Here, we demonstrate a novel statistical method to estimate the incidence of endemic diseases at the community level from passive surveillance data collected at primary health centers. The zero-corrected, gravity-model (ZERO-G) estimator explicitly models sampling intensity as a function of health facility characteristics and statistically accounts for extremely low rates of ascertainment. The result is a standardized, real-time estimate of disease incidence at a spatial resolution nearly ten times finer than typically reported by facility-based passive surveillance systems. We assessed the robustness of this method by applying it to a case study of field-collected malaria incidence rates from a rural health district in southeastern Madagascar. The ZERO-G estimator decreased geographic and financial bias in the dataset by over 90% and doubled the agreement rate between spatial patterns in malaria incidence and incidence estimates derived from prevalence surveys. The ZERO-G estimator is a promising method for adjusting passive surveillance data of common, endemic diseases, increasing the availability of continuously updated, high quality surveillance datasets at the community scale.
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Affiliation(s)
- Michelle V Evans
- MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France.
- NGO Pivot, Ranomafana, Ifanadiana, Madagascar.
- Department of Global Health and Social Medicine, Blavatnik Institute at Harvard Medical School, Boston, MA, USA.
| | - Felana A Ihantamalala
- NGO Pivot, Ranomafana, Ifanadiana, Madagascar
- Department of Global Health and Social Medicine, Blavatnik Institute at Harvard Medical School, Boston, MA, USA
| | - Mauricianot Randriamihaja
- MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France
- NGO Pivot, Ranomafana, Ifanadiana, Madagascar
| | | | - Matthew H Bonds
- NGO Pivot, Ranomafana, Ifanadiana, Madagascar
- Department of Global Health and Social Medicine, Blavatnik Institute at Harvard Medical School, Boston, MA, USA
| | - Karen E Finnegan
- NGO Pivot, Ranomafana, Ifanadiana, Madagascar
- Department of Global Health and Social Medicine, Blavatnik Institute at Harvard Medical School, Boston, MA, USA
| | - Rado J L Rakotonanahary
- NGO Pivot, Ranomafana, Ifanadiana, Madagascar
- Department of Global Health and Social Medicine, Blavatnik Institute at Harvard Medical School, Boston, MA, USA
| | | | | | - Oméga Raobela
- National Malaria Program, Ministry of Health, Antananarivo, Madagascar
| | | | | | - Andres Garchitorena
- MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France
- NGO Pivot, Ranomafana, Ifanadiana, Madagascar
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Cook J, Sternberg E, Aoura CJ, N'Guessan R, Kleinschmidt I, Koffi AA, Thomas MB, Assi SB. Housing modification for malaria control: impact of a "lethal house lure" intervention on malaria infection prevalence in a cluster randomised control trial in Côte d'Ivoire. BMC Med 2023; 21:168. [PMID: 37143050 PMCID: PMC10161487 DOI: 10.1186/s12916-023-02871-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 04/19/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND In recent years, the downward trajectory of malaria transmission has slowed and, in some places, reversed. New tools are needed to further reduce malaria transmission. One approach that has received recent attention is a novel house-based intervention comprising window screening (S) and general house repairs to make the house more mosquito proof, together with EaveTubes (ET) that provide an innovative way of targeting mosquitoes with insecticides as they search for human hosts at night. The combined approach of Screening + EaveTubes (SET) essentially turns the house into a 'lure and kill' device. METHODS This study evaluated the impact of SET on malaria infection prevalence in Côte d'Ivoire and compares the result in the primary outcome, malaria case incidence. Malaria infection prevalence was measured in a cross-sectional survey in 40 villages, as part of a cluster-randomised trial evaluating the impact of SET on malaria case incidence. RESULTS Infection prevalence, measured by rapid diagnostic test (RDT), was 50.4% and 36.7% in the control arm and intervention arm, respectively, corresponding to an odds ratio of 0.57 (0.45-0.71), p < 0.0001). There was moderate agreement between RDT and microscopy results, with a reduction in odds of infection of 36% recorded when infection was measured by microscopy. Prevalence measured by RDT correlated strongly with incidence at a cluster level. CONCLUSIONS In addition to reducing malaria case incidence, house screening and EaveTubes substantially reduced malaria infection prevalence 18 months after installation. Infection prevalence may be a good metric to use for evaluating malaria interventions in areas of similar transmission levels to this setting. TRIAL REGISTRATION ISRCTN18145556, registered 1 February 2017.
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Affiliation(s)
- Jackie Cook
- International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK.
| | | | | | - Raphael N'Guessan
- Institut Pierre Richet, Bouaké, Côte d'Ivoire
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Immo Kleinschmidt
- International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
- Wits Research Institute for Malaria, School of Pathology, University of Witwatersrand, Johannesburg, South Africa
- Southern African Development Community Malaria Elimination Eight Secretariat, Windhoek, Namibia
| | | | - Matthew B Thomas
- Department of Entomology & Nematology and the Invasion Science Research Institute, University of Florida, Gainesville, USA
| | - Serge-Brice Assi
- Institut Pierre Richet, Bouaké, Côte d'Ivoire
- Institut National de Sante Publique, Abidjan, Côte d'Ivoire
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Epstein A, Namuganga JF, Nabende I, Kamya EV, Kamya MR, Dorsey G, Sturrock H, Bhatt S, Rodríguez-Barraquer I, Greenhouse B. Mapping malaria incidence using routine health facility surveillance data in Uganda. BMJ Glob Health 2023; 8:e011137. [PMID: 37208120 PMCID: PMC10201255 DOI: 10.1136/bmjgh-2022-011137] [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: 11/02/2022] [Accepted: 04/11/2023] [Indexed: 05/21/2023] Open
Abstract
INTRODUCTION Maps of malaria risk are important tools for allocating resources and tracking progress. Most maps rely on cross-sectional surveys of parasite prevalence, but health facilities represent an underused and powerful data source. We aimed to model and map malaria incidence using health facility data in Uganda. METHODS Using 24 months (2019-2020) of individual-level outpatient data collected from 74 surveillance health facilities located in 41 districts across Uganda (n=445 648 laboratory-confirmed cases), we estimated monthly malaria incidence for parishes within facility catchment areas (n=310) by estimating care-seeking population denominators. We fit spatio-temporal models to the incidence estimates to predict incidence rates for the rest of Uganda, informed by environmental, sociodemographic and intervention variables. We mapped estimated malaria incidence and its uncertainty at the parish level and compared estimates to other metrics of malaria. To quantify the impact that indoor residual spraying (IRS) may have had, we modelled counterfactual scenarios of malaria incidence in the absence of IRS. RESULTS Over 4567 parish-months, malaria incidence averaged 705 cases per 1000 person-years. Maps indicated high burden in the north and northeast of Uganda, with lower incidence in the districts receiving IRS. District-level estimates of cases correlated with cases reported by the Ministry of Health (Spearman's r=0.68, p<0.0001), but were considerably higher (40 166 418 cases estimated compared with 27 707 794 cases reported), indicating the potential for underreporting by the routine surveillance system. Modelling of counterfactual scenarios suggest that approximately 6.2 million cases were averted due to IRS across the study period in the 14 districts receiving IRS (estimated population 8 381 223). CONCLUSION Outpatient information routinely collected by health systems can be a valuable source of data for mapping malaria burden. National Malaria Control Programmes may consider investing in robust surveillance systems within public health facilities as a low-cost, high benefit tool to identify vulnerable regions and track the impact of interventions.
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Affiliation(s)
- Adrienne Epstein
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Isaiah Nabende
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Hugh Sturrock
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
- Malaria Elimination Initiative, University of California San Francisco, San Francisco, California, USA
| | - Samir Bhatt
- Department of Public Health, University of Copenhagen, Kobenhavn, Denmark
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | | | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
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Dzianach PA, Rumisha SF, Lubinda J, Saddler A, van den Berg M, Gelaw YA, Harris JR, Browne AJ, Sanna F, Rozier JA, Galatas B, Anderson LF, Vargas-Ruiz CA, Cameron E, Gething PW, Weiss DJ. Evaluating COVID-19-Related Disruptions to Effective Malaria Case Management in 2020-2021 and Its Potential Effects on Malaria Burden in Sub-Saharan Africa. Trop Med Infect Dis 2023; 8:216. [PMID: 37104342 PMCID: PMC10143572 DOI: 10.3390/tropicalmed8040216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 04/09/2023] Open
Abstract
The COVID-19 pandemic has led to far-reaching disruptions to health systems, including preventative and curative services for malaria. The aim of this study was to estimate the magnitude of disruptions in malaria case management in sub-Saharan Africa and their impact on malaria burden during the COVID-19 pandemic. We used survey data collected by the World Health Organization, in which individual country stakeholders reported on the extent of disruptions to malaria diagnosis and treatment. The relative disruption values were then applied to estimates of antimalarial treatment rates and used as inputs to an established spatiotemporal Bayesian geostatistical framework to generate annual malaria burden estimates with case management disruptions. This enabled an estimation of the additional malaria burden attributable to pandemic-related impacts on treatment rates in 2020 and 2021. Our analysis found that disruptions in access to antimalarial treatment in sub-Saharan Africa likely resulted in approximately 5.9 (4.4-7.2 95% CI) million more malaria cases and 76 (20-132) thousand additional deaths in the 2020-2021 period within the study region, equivalent to approximately 1.2% (0.3-2.1 95% CI) greater clinical incidence of malaria and 8.1% (2.1-14.1 95% CI) greater malaria mortality than expected in the absence of the disruptions to malaria case management. The available evidence suggests that access to antimalarials was disrupted to a significant degree and should be considered an area of focus to avoid further escalations in malaria morbidity and mortality. The results from this analysis were used to estimate cases and deaths in the World Malaria Report 2022 during the pandemic years.
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Affiliation(s)
- Paulina A. Dzianach
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Susan F. Rumisha
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Jailos Lubinda
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Adam Saddler
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | | | - Yalemzewod A. Gelaw
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Joseph R. Harris
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Annie J. Browne
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Francesca Sanna
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Jennifer A. Rozier
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
| | - Beatriz Galatas
- Strategic Information for Response, Global Malaria Programme, World Health Organization, 1211 Geneva, Switzerland
| | - Laura F. Anderson
- Strategic Information for Response, Global Malaria Programme, World Health Organization, 1211 Geneva, Switzerland
| | - Camilo A. Vargas-Ruiz
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
| | - Ewan Cameron
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
| | - Peter W. Gething
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
| | - Daniel J. Weiss
- Child Health Analytics, Telethon Kids Institute, Nedlands, WA 6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
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7
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Okell LC, Kwambai TK, Dhabangi A, Khairallah C, Nkosi-Gondwe T, Winskill P, Opoka R, Mousa A, Kühl MJ, Lucas TCD, Challenger JD, Idro R, Weiss DJ, Cairns M, Ter Kuile FO, Phiri K, Robberstad B, Mori AT. Projected health impact of post-discharge malaria chemoprevention among children with severe malarial anaemia in Africa. Nat Commun 2023; 14:402. [PMID: 36697413 PMCID: PMC9876927 DOI: 10.1038/s41467-023-35939-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 01/09/2023] [Indexed: 01/26/2023] Open
Abstract
Children recovering from severe malarial anaemia (SMA) remain at high risk of readmission and death after discharge from hospital. However, a recent trial found that post-discharge malaria chemoprevention (PDMC) with dihydroartemisinin-piperaquine reduces this risk. We developed a mathematical model describing the daily incidence of uncomplicated and severe malaria requiring readmission among 0-5-year old children after hospitalised SMA. We fitted the model to a multicentre clinical PDMC trial using Bayesian methods and modelled the potential impact of PDMC across malaria-endemic African countries. In the 20 highest-burden countries, we estimate that only 2-5 children need to be given PDMC to prevent one hospitalised malaria episode, and less than 100 to prevent one death. If all hospitalised SMA cases access PDMC in moderate-to-high transmission areas, 38,600 (range 16,900-88,400) malaria-associated readmissions could be prevented annually, depending on access to hospital care. We estimate that recurrent SMA post-discharge constitutes 19% of all SMA episodes in moderate-to-high transmission settings.
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Affiliation(s)
- Lucy C Okell
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College, London, W2 1PG, UK.
| | - Titus K Kwambai
- Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
- Department of Clinical Sciences, Liverpool School of Tropical Medicine (LSTM), Liverpool, UK
| | - Aggrey Dhabangi
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Carole Khairallah
- Department of Clinical Sciences, Liverpool School of Tropical Medicine (LSTM), Liverpool, UK
| | - Thandile Nkosi-Gondwe
- Kamuzu University of Health Sciences, Blantyre, Malawi
- Training and Research Unit of Excellence, Blantyre, Malawi
| | - Peter Winskill
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College, London, W2 1PG, UK
| | - Robert Opoka
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Andria Mousa
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College, London, W2 1PG, UK
| | - Melf-Jakob Kühl
- Section for Ethics and Health Economics, Department of Global Public Health and Primary Care, University of Bergen, P.O. Box 7804, 5020, Bergen, Norway
| | - Tim C D Lucas
- Big Data Institute, University of Oxford, Oxford, UK
| | - Joseph D Challenger
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College, London, W2 1PG, UK
| | - Richard Idro
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Daniel J Weiss
- Malaria Atlas Project, Telethon Kids Institute, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, Australia
- Curtin University, Bentley, Australia
| | - Matthew Cairns
- International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Feiko O Ter Kuile
- Centre for Global Health Research (CGHR), Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
- Department of Clinical Sciences, Liverpool School of Tropical Medicine (LSTM), Liverpool, UK
| | - Kamija Phiri
- Kamuzu University of Health Sciences, Blantyre, Malawi
- Training and Research Unit of Excellence, Blantyre, Malawi
| | - Bjarne Robberstad
- Section for Ethics and Health Economics, Department of Global Public Health and Primary Care, University of Bergen, P.O. Box 7804, 5020, Bergen, Norway
| | - Amani Thomas Mori
- Section for Ethics and Health Economics, Department of Global Public Health and Primary Care, University of Bergen, P.O. Box 7804, 5020, Bergen, Norway.
- Chr. Michelsen Institute, P.O. Box 6033, N-5892, Bergen, Norway.
- Muhimbili University of Health and Allied Sciences, P.O.Box 65001, Dar es Salaam, Tanzania.
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8
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Golumbeanu M, Yang GJ, Camponovo F, Stuckey EM, Hamon N, Mondy M, Rees S, Chitnis N, Cameron E, Penny MA. Leveraging mathematical models of disease dynamics and machine learning to improve development of novel malaria interventions. Infect Dis Poverty 2022; 11:61. [PMID: 35659301 PMCID: PMC9167503 DOI: 10.1186/s40249-022-00981-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 05/04/2022] [Indexed: 01/04/2023] Open
Abstract
Background Substantial research is underway to develop next-generation interventions that address current malaria control challenges. As there is limited testing in their early development, it is difficult to predefine intervention properties such as efficacy that achieve target health goals, and therefore challenging to prioritize selection of novel candidate interventions. Here, we present a quantitative approach to guide intervention development using mathematical models of malaria dynamics coupled with machine learning. Our analysis identifies requirements of efficacy, coverage, and duration of effect for five novel malaria interventions to achieve targeted reductions in malaria prevalence. Methods A mathematical model of malaria transmission dynamics is used to simulate deployment and predict potential impact of new malaria interventions by considering operational, health-system, population, and disease characteristics. Our method relies on consultation with product development stakeholders to define the putative space of novel intervention specifications. We couple the disease model with machine learning to search this multi-dimensional space and efficiently identify optimal intervention properties that achieve specified health goals. Results We apply our approach to five malaria interventions under development. Aiming for malaria prevalence reduction, we identify and quantify key determinants of intervention impact along with their minimal properties required to achieve the desired health goals. While coverage is generally identified as the largest driver of impact, higher efficacy, longer protection duration or multiple deployments per year are needed to increase prevalence reduction. We show that interventions on multiple parasite or vector targets, as well as combinations the new interventions with drug treatment, lead to significant burden reductions and lower efficacy or duration requirements. Conclusions Our approach uses disease dynamic models and machine learning to support decision-making and resource investment, facilitating development of new malaria interventions. By evaluating the intervention capabilities in relation to the targeted health goal, our analysis allows prioritization of interventions and of their specifications from an early stage in development, and subsequent investments to be channeled cost-effectively towards impact maximization. This study highlights the role of mathematical models to support intervention development. Although we focus on five malaria interventions, the analysis is generalizable to other new malaria interventions. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s40249-022-00981-1.
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Affiliation(s)
- Monica Golumbeanu
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland
| | - Guo-Jing Yang
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,Key Laboratory of Tropical Translational Medicine of Ministry of Education and School of Tropical Medicine and Laboratory Medicine, The First and Second Affiliated Hospital of Hainan Medical University, Hainan Medical University, Haikou, Hainan, People's Republic of China.,University of Basel, Basel, Switzerland
| | - Flavia Camponovo
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland.,Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA
| | | | | | | | - Sarah Rees
- Innovative Vector Control Consortium, Liverpool, UK
| | - Nakul Chitnis
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland
| | - Ewan Cameron
- Malaria Atlas Project, Big Data Institute, University of Oxford, Oxford, UK.,Curtin University, Perth, Australia.,Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
| | - Melissa A Penny
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland. .,University of Basel, Basel, Switzerland.
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9
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Burgert L, Reiker T, Golumbeanu M, Möhrle JJ, Penny MA. Model-informed target product profiles of long-acting-injectables for use as seasonal malaria prevention. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000211. [PMID: 36962305 PMCID: PMC10021282 DOI: 10.1371/journal.pgph.0000211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 01/23/2022] [Indexed: 12/17/2022]
Abstract
Seasonal malaria chemoprevention (SMC) has proven highly efficacious in reducing malaria incidence. However, the continued success of SMC is threatened by the spread of resistance against one of its main preventive ingredients, Sulfadoxine-Pyrimethamine (SP), operational challenges in delivery, and incomplete adherence to the regimens. Via a simulation study with an individual-based model of malaria dynamics, we provide quantitative evidence to assess long-acting injectables (LAIs) as potential alternatives to SMC. We explored the predicted impact of a range of novel preventive LAIs as a seasonal prevention tool in children aged three months to five years old during late-stage clinical trials and at implementation. LAIs were co-administered with a blood-stage clearing drug once at the beginning of the transmission season. We found the establishment of non-inferiority of LAIs to standard 3 or 4 rounds of SMC with SP-amodiaquine was challenging in clinical trial stages due to high intervention deployment coverage. However, our analysis of implementation settings where the achievable SMC coverage was much lower, show LAIs with fewer visits per season are potential suitable replacements to SMC. Suitability as a replacement with higher impact is possible if the duration of protection of LAIs covered the duration of the transmission season. Furthermore, optimising LAIs coverage and protective efficacy half-life via simulation analysis in settings with an SMC coverage of 60% revealed important trade-offs between protective efficacy decay and deployment coverage. Our analysis additionally highlights that for seasonal deployment for LAIs, it will be necessary to investigate the protective efficacy decay as early as possible during clinical development to ensure a well-informed candidate selection process.
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Affiliation(s)
- Lydia Burgert
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Theresa Reiker
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Monica Golumbeanu
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jörg J Möhrle
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Melissa A Penny
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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10
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Reiker T, Golumbeanu M, Shattock A, Burgert L, Smith TA, Filippi S, Cameron E, Penny MA. Emulator-based Bayesian optimization for efficient multi-objective calibration of an individual-based model of malaria. Nat Commun 2021; 12:7212. [PMID: 34893600 PMCID: PMC8664949 DOI: 10.1038/s41467-021-27486-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 11/18/2021] [Indexed: 11/21/2022] Open
Abstract
Individual-based models have become important tools in the global battle against infectious diseases, yet model complexity can make calibration to biological and epidemiological data challenging. We propose using a Bayesian optimization framework employing Gaussian process or machine learning emulator functions to calibrate a complex malaria transmission simulator. We demonstrate our approach by optimizing over a high-dimensional parameter space with respect to a portfolio of multiple fitting objectives built from datasets capturing the natural history of malaria transmission and disease progression. Our approach quickly outperforms previous calibrations, yielding an improved final goodness of fit. Per-objective parameter importance and sensitivity diagnostics provided by our approach offer epidemiological insights and enhance trust in predictions through greater interpretability.
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Affiliation(s)
- Theresa Reiker
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Monica Golumbeanu
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Andrew Shattock
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Lydia Burgert
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Thomas A Smith
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | | | - Ewan Cameron
- Malaria Atlas Project, Big Data Institute, University of Oxford, Oxford, UK
- Curtin University, Perth, Australia
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
| | - Melissa A Penny
- Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
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11
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Toh KB, Millar J, Psychas P, Abuaku B, Ahorlu C, Oppong S, Koram K, Valle D. Guiding placement of health facilities using multiple malaria criteria and an interactive tool. Malar J 2021; 20:455. [PMID: 34861874 PMCID: PMC8641186 DOI: 10.1186/s12936-021-03991-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 11/18/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Access to healthcare is important in controlling malaria burden and, as a result, distance or travel time to health facilities is often a significant predictor in modelling malaria prevalence. Adding new health facilities may reduce overall travel time to health facilities and may decrease malaria transmission. To help guide local decision-makers as they scale up community-based accessibility, the influence of the spatial allocation of new health facilities on malaria prevalence is evaluated in Bunkpurugu-Yunyoo district in northern Ghana. A location-allocation analysis is performed to find optimal locations of new health facilities by separately minimizing three district-wide objectives: malaria prevalence, malaria incidence, and average travel time to health facilities. METHODS Generalized additive models was used to estimate the relationship between malaria prevalence and travel time to the nearest health facility and other geospatial covariates. The model predictions are then used to calculate the optimisation criteria for the location-allocation analysis. This analysis was performed for two scenarios: adding new health facilities to the existing ones, and a hypothetical scenario in which the community-based healthcare facilities would be allocated anew. An interactive web application was created to facilitate efficient presentation of this analysis and allow users to experiment with their choice of health facility location and optimisation criteria. RESULTS Using malaria prevalence and travel time as optimisation criteria, two locations that would benefit from new health facilities were identified, regardless of scenarios. Due to the non-linear relationship between malaria incidence and prevalence, the optimal locations chosen based on the incidence criterion tended to be inequitable and was different from those based on the other optimisation criteria. CONCLUSIONS This study findings underscore the importance of using multiple optimisation criteria in the decision-making process. This analysis and the interactive application can be repurposed for other regions and criteria, bridging the gap between science, models and decisions.
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Affiliation(s)
- Kok Ben Toh
- School of Natural Resources and Environment, University of Florida, Gainesville, USA.
| | - Justin Millar
- School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, USA
| | - Paul Psychas
- Centers for Disease Control, US President's Malaria Initiative, Atlanta, USA
| | - Benjamin Abuaku
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Collins Ahorlu
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | - Kwadwo Koram
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Denis Valle
- School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, USA
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12
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Lucas TCD, Nandi AK, Chestnutt EG, Twohig KA, Keddie SH, Collins EL, Howes RE, Nguyen M, Rumisha SF, Python A, Arambepola R, Bertozzi‐Villa A, Hancock P, Amratia P, Battle KE, Cameron E, Gething PW, Weiss DJ. Mapping malaria by sharing spatial information between incidence and prevalence data sets. J R Stat Soc Ser C Appl Stat 2021. [DOI: 10.1111/rssc.12484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Andre Python
- Big Data Institute University of Oxford Oxford UK
| | | | - Amelia Bertozzi‐Villa
- Big Data Institute University of Oxford Oxford UK
- Institute for Disease Modeling Bellevue Washington USA
| | | | | | | | - Ewan Cameron
- Big Data Institute University of Oxford Oxford UK
| | - Peter W. Gething
- Big Data Institute University of Oxford Oxford UK
- Telethon Kids Institute Perth Children's Hospital Perth Australia
- Curtin University Perth Australia
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13
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Jones RT, Pretorius E, Ant TH, Bradley J, Last A, Logan JG. The use of islands and cluster-randomized trials to investigate vector control interventions: a case study on the Bijagós archipelago, Guinea-Bissau. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190807. [PMID: 33357055 PMCID: PMC7776941 DOI: 10.1098/rstb.2019.0807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2020] [Indexed: 12/30/2022] Open
Abstract
Vector-borne diseases threaten the health of populations around the world. While key interventions continue to provide protection from vectors, there remains a need to develop and test new vector control tools. Cluster-randomized trials, in which the intervention or control is randomly allocated to clusters, are commonly selected for such evaluations, but their design must carefully consider cluster size and cluster separation, as well as the movement of people and vectors, to ensure sufficient statistical power and avoid contamination of results. Island settings present an opportunity to conduct these studies. Here, we explore the benefits and challenges of conducting intervention studies on islands and introduce the Bijagós archipelago of Guinea-Bissau as a potential study site for interventions intended to control vector-borne diseases. This article is part of the theme issue 'Novel control strategies for mosquito-borne diseases'.
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Affiliation(s)
- Robert T. Jones
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
- ARCTEC, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
| | - Elizabeth Pretorius
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
| | - Thomas H. Ant
- Centre for Virus Research, Bearsden Road, Bearsden, Glasgow G61 1QH, UK
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
| | - Anna Last
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
| | - James G. Logan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
- ARCTEC, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
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14
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Weiss DJ, Bertozzi-Villa A, Rumisha SF, Amratia P, Arambepola R, Battle KE, Cameron E, Chestnutt E, Gibson HS, Harris J, Keddie S, Millar JJ, Rozier J, Symons TL, Vargas-Ruiz C, Hay SI, Smith DL, Alonso PL, Noor AM, Bhatt S, Gething PW. Indirect effects of the COVID-19 pandemic on malaria intervention coverage, morbidity, and mortality in Africa: a geospatial modelling analysis. THE LANCET. INFECTIOUS DISEASES 2021; 21:59-69. [PMID: 32971006 PMCID: PMC7505634 DOI: 10.1016/s1473-3099(20)30700-3] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/12/2020] [Accepted: 08/12/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Substantial progress has been made in reducing the burden of malaria in Africa since 2000, but those gains could be jeopardised if the COVID-19 pandemic affects the availability of key malaria control interventions. The aim of this study was to evaluate plausible effects on malaria incidence and mortality under different levels of disruption to malaria control. METHODS Using an established set of spatiotemporal Bayesian geostatistical models, we generated geospatial estimates across malaria-endemic African countries of the clinical case incidence and mortality of malaria, incorporating an updated database of parasite rate surveys, insecticide-treated net (ITN) coverage, and effective treatment rates. We established a baseline estimate for the anticipated malaria burden in Africa in the absence of COVID-19-related disruptions, and repeated the analysis for nine hypothetical scenarios in which effective treatment with an antimalarial drug and distribution of ITNs (both through routine channels and mass campaigns) were reduced to varying extents. FINDINGS We estimated 215·2 (95% uncertainty interval 143·7-311·6) million cases and 386·4 (307·8-497·8) thousand deaths across malaria-endemic African countries in 2020 in our baseline scenario of undisrupted intervention coverage. With greater reductions in access to effective antimalarial drug treatment, our model predicted increasing numbers of cases and deaths: 224·1 (148·7-326·8) million cases and 487·9 (385·3-634·6) thousand deaths with a 25% reduction in antimalarial drug coverage; 233·1 (153·7-342·5) million cases and 597·4 (468·0-784·4) thousand deaths with a 50% reduction; and 242·3 (158·7-358·8) million cases and 715·2 (556·4-947·9) thousand deaths with a 75% reduction. Halting planned 2020 ITN mass distribution campaigns and reducing routine ITN distributions by 25%-75% also increased malaria burden to a total of 230·5 (151·6-343·3) million cases and 411·7 (322·8-545·5) thousand deaths with a 25% reduction; 232·8 (152·3-345·9) million cases and 415·5 (324·3-549·4) thousand deaths with a 50% reduction; and 234·0 (152·9-348·4) million cases and 417·6 (325·5-553·1) thousand deaths with a 75% reduction. When ITN coverage and antimalarial drug coverage were synchronously reduced, malaria burden increased to 240·5 (156·5-358·2) million cases and 520·9 (404·1-691·9) thousand deaths with a 25% reduction; 251·0 (162·2-377·0) million cases and 640·2 (492·0-856·7) thousand deaths with a 50% reduction; and 261·6 (167·7-396·8) million cases and 768·6 (586·1-1038·7) thousand deaths with a 75% reduction. INTERPRETATION Under pessimistic scenarios, COVID-19-related disruption to malaria control in Africa could almost double malaria mortality in 2020, and potentially lead to even greater increases in subsequent years. To avoid a reversal of two decades of progress against malaria, averting this public health disaster must remain an integrated priority alongside the response to COVID-19. FUNDING Bill and Melinda Gates Foundation; Channel 7 Telethon Trust, Western Australia.
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Affiliation(s)
- Daniel J Weiss
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia; Curtin University, Perth, WA, Australia; Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Amelia Bertozzi-Villa
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Institute for Disease Modeling, Bellevue, WA, USA
| | - Susan F Rumisha
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK; National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Punam Amratia
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia
| | - Rohan Arambepola
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | | | - Ewan Cameron
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia; Curtin University, Perth, WA, Australia
| | - Elisabeth Chestnutt
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Harry S Gibson
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Joseph Harris
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia
| | - Suzanne Keddie
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia
| | - Justin J Millar
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jennifer Rozier
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia
| | - Tasmin L Symons
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Camilo Vargas-Ruiz
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Simon I Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA; Department of Health Metrics Sciences, School of Medicine, University of Washington, Seattle, WA, USA
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA; Department of Health Metrics Sciences, School of Medicine, University of Washington, Seattle, WA, USA
| | - Pedro L Alonso
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Abdisalan M Noor
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Samir Bhatt
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Peter W Gething
- Telethon Kids Institute, Perth Children's Hospital, Perth, WA, Australia; Curtin University, Perth, WA, Australia.
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15
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Arambepola R, Keddie SH, Collins EL, Twohig KA, Amratia P, Bertozzi-Villa A, Chestnutt EG, Harris J, Millar J, Rozier J, Rumisha SF, Symons TL, Vargas-Ruiz C, Andriamananjara M, Rabeherisoa S, Ratsimbasoa AC, Howes RE, Weiss DJ, Gething PW, Cameron E. Spatiotemporal mapping of malaria prevalence in Madagascar using routine surveillance and health survey data. Sci Rep 2020; 10:18129. [PMID: 33093622 PMCID: PMC7581764 DOI: 10.1038/s41598-020-75189-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 10/12/2020] [Indexed: 11/16/2022] Open
Abstract
Malaria transmission in Madagascar is highly heterogeneous, exhibiting spatial, seasonal and long-term trends. Previous efforts to map malaria risk in Madagascar used prevalence data from Malaria Indicator Surveys. These cross-sectional surveys, conducted during the high transmission season most recently in 2013 and 2016, provide nationally representative prevalence data but cover relatively short time frames. Conversely, monthly case data are collected at health facilities but suffer from biases, including incomplete reporting and low rates of treatment seeking. We combined survey and case data to make monthly maps of prevalence between 2013 and 2016. Health facility catchment populations were estimated to produce incidence rates from the case data. Smoothed incidence surfaces, environmental and socioeconomic covariates, and survey data informed a Bayesian prevalence model, in which a flexible incidence-to-prevalence relationship was learned. Modelled spatial trends were consistent over time, with highest prevalence in the coastal regions and low prevalence in the highlands and desert south. Prevalence was lowest in 2014 and peaked in 2015 and seasonality was widely observed, including in some lower transmission regions. These trends highlight the utility of monthly prevalence estimates over the four year period. By combining survey and case data using this two-step modelling approach, we were able to take advantage of the relative strengths of each metric while accounting for potential bias in the case data. Similar modelling approaches combining large datasets of different malaria metrics may be applicable across sub-Saharan Africa.
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Affiliation(s)
- Rohan Arambepola
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK.
| | - Suzanne H Keddie
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
| | - Emma L Collins
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Katherine A Twohig
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Punam Amratia
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Amelia Bertozzi-Villa
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
- Institute for Disease Modeling, Bellevue, WA, USA
| | - Elisabeth G Chestnutt
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Joseph Harris
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
| | - Justin Millar
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Jennifer Rozier
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
| | - Susan F Rumisha
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Tasmin L Symons
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Camilo Vargas-Ruiz
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Mauricette Andriamananjara
- Programme National de Lutte contre le Paludisme, Antananarivo, Madagascar
- Ministère de Santé Publique, Antananarivo, Madagascar
| | - Saraha Rabeherisoa
- Programme National de Lutte contre le Paludisme, Antananarivo, Madagascar
| | - Arsène C Ratsimbasoa
- Programme National de Lutte contre le Paludisme, Antananarivo, Madagascar
- University of Fianarantsoa, Fianarantsoa, Madagascar
| | - Rosalind E Howes
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
- Foundation for Innovative New Diagnostics, Geneva, Switzerland
| | - Daniel J Weiss
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
- Curtin University, Perth, Australia
| | - Peter W Gething
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
- Curtin University, Perth, Australia
| | - Ewan Cameron
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
- Curtin University, Perth, Australia
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16
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Accessibility to First-Mile health services: A time-cost model for rural Uganda. Soc Sci Med 2020; 265:113410. [PMID: 33045653 DOI: 10.1016/j.socscimed.2020.113410] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/10/2020] [Accepted: 09/30/2020] [Indexed: 11/20/2022]
Abstract
This study estimates the geographical disconnection in rural Low-Middle-Income Countries (LMIC) between First-Mile suppliers of healthcare services and end-users. This detachment is due to geographical barriers and to a shortage of technical, financial, and human resources that enable peripheral health facilities to perform effective and prompt diagnosis. End-users typically have easier access to cell-phones than hospitals, so mHealth can help to overcome such barriers, transforming inpatients/outpatients into home-patients, decongesting hospitals, especially during epidemics. This generates savings for patients and the healthcare system. The advantages of mHealth are well known, but there is a literature gap in the description of its economic returns. This study applies a geographical model to a typical LMIC, Uganda, quantifying the time-cost to reach an equipped medical center. Time-cost measures the disconnection between First-Mile hubs and end-users, the potential demand of mHealth by remote end-users, and the consequent savings. The results highlight an average time-cost of 75 min, well above the recommended thresholds, and estimate that mHealth leads to significant savings (1.5 monthly salaries and 21% of public health budget). Community health workers and private actors may re-engineer healthcare resources through Public-Private Partnerships (PPP), remunerated with results-based financing (RBF). These findings can contribute to improving healthcare resource allocation in LMIC.
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17
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Stresman G, Sepúlveda N, Fornace K, Grignard L, Mwesigwa J, Achan J, Miller J, Bridges DJ, Eisele TP, Mosha J, Lorenzo PJ, Macalinao ML, Espino FE, Tadesse F, Stevenson JC, Quispe AM, Siqueira A, Lacerda M, Yeung S, Sovannaroth S, Pothin E, Gallay J, Hamre KE, Young A, Lemoine JF, Chang MA, Phommasone K, Mayxay M, Landier J, Parker DM, Von Seidlein L, Nosten F, Delmas G, Dondorp A, Cameron E, Battle K, Bousema T, Gething P, D'Alessandro U, Drakeley C. Association between the proportion of Plasmodium falciparum and Plasmodium vivax infections detected by passive surveillance and the magnitude of the asymptomatic reservoir in the community: a pooled analysis of paired health facility and community data. THE LANCET. INFECTIOUS DISEASES 2020; 20:953-963. [PMID: 32277908 PMCID: PMC7391005 DOI: 10.1016/s1473-3099(20)30059-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/23/2020] [Accepted: 01/28/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Passively collected malaria case data are the foundation for public health decision making. However, because of population-level immunity, infections might not always be sufficiently symptomatic to prompt individuals to seek care. Understanding the proportion of all Plasmodium spp infections expected to be detected by the health system becomes particularly paramount in elimination settings. The aim of this study was to determine the association between the proportion of infections detected and transmission intensity for Plasmodium falciparum and Plasmodium vivax in several global endemic settings. METHODS The proportion of infections detected in routine malaria data, P(Detect), was derived from paired household cross-sectional survey and routinely collected malaria data within health facilities. P(Detect) was estimated using a Bayesian model in 431 clusters spanning the Americas, Africa, and Asia. The association between P(Detect) and malaria prevalence was assessed using log-linear regression models. Changes in P(Detect) over time were evaluated using data from 13 timepoints over 2 years from The Gambia. FINDINGS The median estimated P(Detect) across all clusters was 12·5% (IQR 5·3-25·0) for P falciparum and 10·1% (5·0-18·3) for P vivax and decreased as the estimated log-PCR community prevalence increased (adjusted odds ratio [OR] for P falciparum 0·63, 95% CI 0·57-0·69; adjusted OR for P vivax 0·52, 0·47-0·57). Factors associated with increasing P(Detect) included smaller catchment population size, high transmission season, improved care-seeking behaviour by infected individuals, and recent increases (within the previous year) in transmission intensity. INTERPRETATION The proportion of all infections detected within health systems increases once transmission intensity is sufficiently low. The likely explanation for P falciparum is that reduced exposure to infection leads to lower levels of protective immunity in the population, increasing the likelihood that infected individuals will become symptomatic and seek care. These factors might also be true for P vivax but a better understanding of the transmission biology is needed to attribute likely reasons for the observed trend. In low transmission and pre-elimination settings, enhancing access to care and improvements in care-seeking behaviour of infected individuals will lead to an increased proportion of infections detected in the community and might contribute to accelerating the interruption of transmission. FUNDING Wellcome Trust.
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Affiliation(s)
- Gillian Stresman
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK.
| | - Nuno Sepúlveda
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK; Centre of Statistics and Its Applications, University of Lisbon, Lisbon, Portugal
| | - Kimberly Fornace
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Lynn Grignard
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Julia Mwesigwa
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia; Department of Global Health, University of Antwerp, Antwerp, Belgium
| | - Jane Achan
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - John Miller
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds Lusaka, Zambia
| | - Daniel J Bridges
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds Lusaka, Zambia
| | - Thomas P Eisele
- Center for Applied Malaria Research and Evaluation, Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Jacklin Mosha
- National Institute for Medical Research, Mwanza Medical Research Centre, Mwanza, Tanzania
| | - Pauline Joy Lorenzo
- Department of Parasitology, Research Institute for Tropical Medicine, Research Drive, Alabang, Muntinlupa, Metro Manila, Philippines
| | - Maria Lourdes Macalinao
- Department of Parasitology, Research Institute for Tropical Medicine, Research Drive, Alabang, Muntinlupa, Metro Manila, Philippines
| | - Fe Esperanza Espino
- Department of Parasitology, Research Institute for Tropical Medicine, Research Drive, Alabang, Muntinlupa, Metro Manila, Philippines
| | - Fitsum Tadesse
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Jennifer C Stevenson
- Macha Research Trust, Choma District, Zambia; Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | | - André Siqueira
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado, Manaus, Brazil; Programa de Pós-graduação em Medicina Tropical, Universidade do Estado do Amazonas, Manaus, Brazil; Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Marcus Lacerda
- Fundacao de Medicine Tropical Dr. Heitor Viera Dourado, Manaus, Brazil; Institutos Nacionais de Ciencia e Technologia (INCT), Instituto Elimina, Manaus, Brazil
| | - Shunmay Yeung
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Siv Sovannaroth
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Emilie Pothin
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; Clinton Health Access Initiative, Boston, MA, USA
| | - Joanna Gallay
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Karen E Hamre
- Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, USA; CDC Foundation, Atlanta, GA, USA
| | - Alyssa Young
- Clinton Health Access Initiative, Port-au-Prince, Haiti
| | - Jean Frantz Lemoine
- Programme National de Contrôle de la Malaria, Ministère de la Santé Publique et de la Population (MSPP), Port-au-Prince, Haiti
| | - Michelle A Chang
- Centers for Disease Control and Prevention, Center for Global Health, Division of Parasitic Diseases and Malaria, Malaria Branch, Atlanta, GA, USA
| | - Koukeo Phommasone
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Institute of Research and Education Development, University of Health Sciences, Vientiane, Laos
| | - Jordi Landier
- Aix Marseille Univ, IRD, INSERM, SESSTIM, Marseille, France
| | - Daniel M Parker
- Department of Population Health and Disease Prevention and Department of Epidemiology, University of California, Irvine, CA, USA
| | - Lorenz Von Seidlein
- Oxford Tropical Medicine Research Unit, Mahidol University Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Francois Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Gilles Delmas
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Arjen Dondorp
- Oxford Tropical Medicine Research Unit, Mahidol University Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ewan Cameron
- Telethon Kids Institute, Perth Children's Hospital, Nedlands, WA, Australia; Curtin University, Bentley, WA, Australia
| | | | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Peter Gething
- Telethon Kids Institute, Perth Children's Hospital, Nedlands, WA, Australia; Curtin University, Bentley, WA, Australia
| | - Umberto D'Alessandro
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK; Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
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18
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Lucas TC, Nandi AK, Keddie SH, Chestnutt EG, Howes RE, Rumisha SF, Arambepola R, Bertozzi-Villa A, Python A, Symons TL, Millar JJ, Amratia P, Hancock P, Battle KE, Cameron E, Gething PW, Weiss DJ. Improving disaggregation models of malaria incidence by ensembling non-linear models of prevalence. Spat Spatiotemporal Epidemiol 2020; 41:100357. [PMID: 35691633 PMCID: PMC9205339 DOI: 10.1016/j.sste.2020.100357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/13/2020] [Accepted: 06/18/2020] [Indexed: 10/24/2022]
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19
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Alegana VA, Okiro EA, Snow RW. Routine data for malaria morbidity estimation in Africa: challenges and prospects. BMC Med 2020; 18:121. [PMID: 32487080 PMCID: PMC7268363 DOI: 10.1186/s12916-020-01593-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/14/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND The burden of malaria in sub-Saharan Africa remains challenging to measure relying on epidemiological modelling to evaluate the impact of investments and providing an in-depth analysis of progress and trends in malaria response globally. In malaria-endemic countries of Africa, there is increasing use of routine surveillance data to define national strategic targets, estimate malaria case burdens and measure control progress to identify financing priorities. Existing research focuses mainly on the strengths of these data with less emphasis on existing challenges and opportunities presented. CONCLUSION Here we define the current imperfections common to routine malaria morbidity data at national levels and offer prospects into their future use to reflect changing disease burdens.
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Affiliation(s)
- Victor A Alegana
- Population Health Unit, Kenya Medical Research Institute - Wellcome Trust Research Programme, P.O. Box 43640, Nairobi, 00100, Kenya.
- Geography and Environmental Science, University of Southampton, Southampton, SO17 1BJ, UK.
- Faculty of Science and Technology, Lancaster University, Lancaster, LAI 4YW, UK.
| | - Emelda A Okiro
- Population Health Unit, Kenya Medical Research Institute - Wellcome Trust Research Programme, P.O. Box 43640, Nairobi, 00100, Kenya
| | - Robert W Snow
- Population Health Unit, Kenya Medical Research Institute - Wellcome Trust Research Programme, P.O. Box 43640, Nairobi, 00100, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7LJ, UK
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20
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Kamau A, Mogeni P, Okiro EA, Snow RW, Bejon P. A systematic review of changing malaria disease burden in sub-Saharan Africa since 2000: comparing model predictions and empirical observations. BMC Med 2020; 18:94. [PMID: 32345315 PMCID: PMC7189714 DOI: 10.1186/s12916-020-01559-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/16/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The most widely used measures of declining burden of malaria across sub-Saharan Africa are predictions from geospatial models. These models apply spatiotemporal autocorrelations and covariates to parasite prevalence data and then use a function of parasite prevalence to predict clinical malaria incidence. We attempted to assess whether trends in malaria cases, based on local surveillance, were similar to those captured by Malaria Atlas Project (MAP) incidence surfaces. METHODS We undertook a systematic review (PROSPERO International Prospective Register of Systematic Reviews; ID = CRD42019116834) to identify empirical data on clinical malaria in Africa since 2000, where reports covered at least 5 continuous years. The trends in empirical data were then compared with the trends of time-space matched clinical malaria incidence from MAP using the Spearman rank correlation. The correlations (rho) between changes in empirically observed and modelled estimates of clinical malaria were displayed by forest plots and examined by meta-regression. RESULTS Sixty-seven articles met our inclusion criteria representing 124 sites from 24 African countries. The single most important factor explaining the correlation between empirical observations and modelled predictions was the slope of empirically observed data over time (rho = - 0.989; 95% CI - 0.998, - 0.939; p < 0.001), i.e. steeper declines were associated with a stronger correlation between empirical observations and modelled predictions. Factors such as quality of study, reported measure of malaria and endemicity were only slightly predictive of such correlations. CONCLUSIONS In many locations, both local surveillance data and modelled estimates showed declines in malaria burden and hence similar trends. However, there was a weak association between individual surveillance datasets and the modelled predictions where stalling in progress or resurgence of malaria burden was empirically observed. Surveillance data were patchy, indicating a need for improved surveillance to strengthen both empiric reporting and modelled predictions.
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Affiliation(s)
- Alice Kamau
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | | | | | - Robert W Snow
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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21
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Davis CN, Hollingsworth TD, Caudron Q, Irvine MA. The use of mixture density networks in the emulation of complex epidemiological individual-based models. PLoS Comput Biol 2020; 16:e1006869. [PMID: 32176687 PMCID: PMC7098654 DOI: 10.1371/journal.pcbi.1006869] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/26/2020] [Accepted: 02/20/2020] [Indexed: 01/15/2023] Open
Abstract
Complex, highly-computational, individual-based models are abundant in epidemiology. For epidemics such as macro-parasitic diseases, detailed modelling of human behaviour and pathogen life-cycle are required in order to produce accurate results. This can often lead to models that are computationally-expensive to analyse and perform model fitting, and often require many simulation runs in order to build up sufficient statistics. Emulation can provide a more computationally-efficient output of the individual-based model, by approximating it using a statistical model. Previous work has used Gaussian processes (GPs) in order to achieve this, but these can not deal with multi-modal, heavy-tailed, or discrete distributions. Here, we introduce the concept of a mixture density network (MDN) in its application in the emulation of epidemiological models. MDNs incorporate both a mixture model and a neural network to provide a flexible tool for emulating a variety of models and outputs. We develop an MDN emulation methodology and demonstrate its use on a number of simple models incorporating both normal, gamma and beta distribution outputs. We then explore its use on the stochastic SIR model to predict the final size distribution and infection dynamics. MDNs have the potential to faithfully reproduce multiple outputs of an individual-based model and allow for rapid analysis from a range of users. As such, an open-access library of the method has been released alongside this manuscript. Infectious disease modellers have a growing need to expose their models to a variety of stakeholders in interactive, engaging ways that allow them to explore different scenarios. This approach can come with a considerable computational cost that motivates providing a simpler representation of the complex model. We propose the use of mixture density networks as a solution to this problem. MDNs are highly flexible, deep neural network-based models that can emulate a variety of data, including counts and over-dispersion. We explore their use firstly through emulating a negative binomial distribution, which arises in many places in ecology and parasite epidemiology. Then, we explore the approach using a stochastic SIR model. We also provide an accompanying Python library with code for all examples given in the manuscript. We believe that the use of emulation will provide a method to package an infectious disease model such that it can be disseminated to the widest audience possible.
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Affiliation(s)
- Christopher N. Davis
- MathSys CDT, Mathematics Institute, University of Warwick, Coventry, United Kingdom
- Zeeman Institute (SBIDER), University of Warwick, Coventry, United Kingdom
| | - T. Deirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Michael A. Irvine
- Scai Analytics Ltd., Vancouver, Canada
- Institute of Applied Mathematics, University of British Columbia, Vancouver, Canada
- * E-mail:
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22
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Cook J, Owaga C, Marube E, Baidjoe A, Stresman G, Migiro R, Cox J, Drakeley C, Stevenson JC. Risk factors for Plasmodium falciparum infection in the Kenyan Highlands: a cohort study. Trans R Soc Trop Med Hyg 2020; 113:152-159. [PMID: 30496556 PMCID: PMC6391934 DOI: 10.1093/trstmh/try122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/06/2018] [Accepted: 11/22/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Malaria transmission in African highland areas can be prone to epidemics, with minor fluctuations in temperature or altitude resulting in highly heterogeneous transmission. In the Kenyan Highlands, where malaria prevalence has been increasing, characterising malaria incidence and identifying risk factors for infection is complicated by asymptomatic infection. METHODS This all-age cohort study, one element of the Malaria Transmission Consortium, involved monthly follow-up of 3155 residents of the Kisii and Rachuonyo South districts during June 2009-June 2010. Participants were tested for malaria using rapid diagnostic testing at every visit, regardless of symptoms. RESULTS The incidence of Plasmodium falciparum infection was 0.2 cases per person, although infections were clustered within individuals and over time, with the majority of infections detected in the last month of the cohort study. Overall, incidence was higher in the Rachuonyo district and infections were detected most frequently in 5-10-year-olds. The majority of infections were asymptomatic (58%). Travel away from the study area was a notable risk factor for infection. CONCLUSIONS Identifying risk factors for malaria infection can help to guide targeting of interventions to populations most likely to be exposed to malaria.
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Affiliation(s)
- Jackie Cook
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Chrispin Owaga
- Evidence Action, Ngong Road, Nairobi, Kenya.,Kenya Medical Research Institute (KEMRI), KEMRI-Wellcome Trust Research Programme, Kemri Square, Kilifi, Kenya
| | | | | | - Gillian Stresman
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Robin Migiro
- Kenya Medical Research Institute (KEMRI), KEMRI-Wellcome Trust Research Programme, Kemri Square, Kilifi, Kenya
| | - Jon Cox
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Jennifer C Stevenson
- Macha Research Trust, Choma, Southern Province, Zambia.,Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Baltimore, USA
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23
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O'Reilly KM, Hendrickx E, Kharisma DD, Wilastonegoro NN, Carrington LB, Elyazar IRF, Kucharski AJ, Lowe R, Flasche S, Pigott DM, Reiner RC, Edmunds WJ, Hay SI, Yakob L, Shepard DS, Brady OJ. Estimating the burden of dengue and the impact of release of wMel Wolbachia-infected mosquitoes in Indonesia: a modelling study. BMC Med 2019; 17:172. [PMID: 31495336 PMCID: PMC6732838 DOI: 10.1186/s12916-019-1396-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/24/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Wolbachia-infected mosquitoes reduce dengue virus transmission, and city-wide releases in Yogyakarta city, Indonesia, are showing promising entomological results. Accurate estimates of the burden of dengue, its spatial distribution and the potential impact of Wolbachia are critical in guiding funder and government decisions on its future wider use. METHODS Here, we combine multiple modelling methods for burden estimation to predict national case burden disaggregated by severity and map the distribution of burden across the country using three separate data sources. An ensemble of transmission models then predicts the estimated reduction in dengue transmission following a nationwide roll-out of wMel Wolbachia. RESULTS We estimate that 7.8 million (95% uncertainty interval [UI] 1.8-17.7 million) symptomatic dengue cases occurred in Indonesia in 2015 and were associated with 332,865 (UI 94,175-754,203) lost disability-adjusted life years (DALYs). The majority of dengue's burden was due to non-severe cases that did not seek treatment or were challenging to diagnose in outpatient settings leading to substantial underreporting. Estimated burden was highly concentrated in a small number of large cities with 90% of dengue cases occurring in 15.3% of land area. Implementing a nationwide Wolbachia population replacement programme was estimated to avert 86.2% (UI 36.2-99.9%) of cases over a long-term average. CONCLUSIONS These results suggest interventions targeted to the highest burden cities can have a disproportionate impact on dengue burden. Area-wide interventions, such as Wolbachia, that are deployed based on the area covered could protect people more efficiently than individual-based interventions, such as vaccines, in such dense environments.
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Affiliation(s)
- Kathleen M O'Reilly
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.,Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Emilie Hendrickx
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK.,Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Dinar D Kharisma
- Heller School for Social Policy and Management, Brandeis University, Waltham, MA, USA
| | - Nandyan N Wilastonegoro
- Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Lauren B Carrington
- Oxford University Clinical Research Unit, Wellcome Trust Asia-Africa Programme, Ho Chi Minh City, Vietnam.,Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Iqbal R F Elyazar
- Eijkman Oxford Clinical Research Unit, Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Adam J Kucharski
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK.,Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Rachel Lowe
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK.,Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Stefan Flasche
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK.,Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, UK
| | - David M Pigott
- Department of Health Metrics Sciences, Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Robert C Reiner
- Department of Health Metrics Sciences, Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - W John Edmunds
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK.,Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Simon I Hay
- Department of Health Metrics Sciences, Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Laith Yakob
- Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.,Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Donald S Shepard
- Heller School for Social Policy and Management, Brandeis University, Waltham, MA, USA
| | - Oliver J Brady
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK. .,Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Public Health, London School of Hygiene & Tropical Medicine, London, UK.
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24
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Battle KE, Lucas TCD, Nguyen M, Howes RE, Nandi AK, Twohig KA, Pfeffer DA, Cameron E, Rao PC, Casey D, Gibson HS, Rozier JA, Dalrymple U, Keddie SH, Collins EL, Harris JR, Guerra CA, Thorn MP, Bisanzio D, Fullman N, Huynh CK, Kulikoff X, Kutz MJ, Lopez AD, Mokdad AH, Naghavi M, Nguyen G, Shackelford KA, Vos T, Wang H, Lim SS, Murray CJL, Price RN, Baird JK, Smith DL, Bhatt S, Weiss DJ, Hay SI, Gething PW. Mapping the global endemicity and clinical burden of Plasmodium vivax, 2000-17: a spatial and temporal modelling study. Lancet 2019; 394:332-343. [PMID: 31229233 PMCID: PMC6675736 DOI: 10.1016/s0140-6736(19)31096-7] [Citation(s) in RCA: 231] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/12/2019] [Accepted: 04/24/2019] [Indexed: 01/12/2023]
Abstract
BACKGROUND Plasmodium vivax exacts a significant toll on health worldwide, yet few efforts to date have quantified the extent and temporal trends of its global distribution. Given the challenges associated with the proper diagnosis and treatment of P vivax, national malaria programmes-particularly those pursuing malaria elimination strategies-require up to date assessments of P vivax endemicity and disease impact. This study presents the first global maps of P vivax clinical burden from 2000 to 2017. METHODS In this spatial and temporal modelling study, we adjusted routine malariometric surveillance data for known biases and used socioeconomic indicators to generate time series of the clinical burden of P vivax. These data informed Bayesian geospatial models, which produced fine-scale predictions of P vivax clinical incidence and infection prevalence over time. Within sub-Saharan Africa, where routine surveillance for P vivax is not standard practice, we combined predicted surfaces of Plasmodium falciparum with country-specific ratios of P vivax to P falciparum. These results were combined with surveillance-based outputs outside of Africa to generate global maps. FINDINGS We present the first high-resolution maps of P vivax burden. These results are combined with those for P falciparum (published separately) to form the malaria estimates for the Global Burden of Disease 2017 study. The burden of P vivax malaria decreased by 41·6%, from 24·5 million cases (95% uncertainty interval 22·5-27·0) in 2000 to 14·3 million cases (13·7-15·0) in 2017. The Americas had a reduction of 56·8% (47·6-67·0) in total cases since 2000, while South-East Asia recorded declines of 50·5% (50·3-50·6) and the Western Pacific regions recorded declines of 51·3% (48·0-55·4). Europe achieved zero P vivax cases during the study period. Nonetheless, rates of decline have stalled in the past five years for many countries, with particular increases noted in regions affected by political and economic instability. INTERPRETATION Our study highlights important spatial and temporal patterns in the clinical burden and prevalence of P vivax. Amid substantial progress worldwide, plateauing gains and areas of increased burden signal the potential for challenges that are greater than expected on the road to malaria elimination. These results support global monitoring systems and can inform the optimisation of diagnosis and treatment where P vivax has most impact. FUNDING Bill & Melinda Gates Foundation and the Wellcome Trust.
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Affiliation(s)
- Katherine E Battle
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Tim C D Lucas
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Michele Nguyen
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Rosalind E Howes
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Anita K Nandi
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Katherine A Twohig
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Daniel A Pfeffer
- Menzies School of Health Research and Charles Darwin University, Darwin, NT, Australia
| | - Ewan Cameron
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Puja C Rao
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Daniel Casey
- Seattle & King County Public Health, Seattle, WA, USA
| | - Harry S Gibson
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Jennifer A Rozier
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | | | - Suzanne H Keddie
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Emma L Collins
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Joseph R Harris
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Carlos A Guerra
- Medical Care Development International, Silver Spring, MD, USA
| | - Michael P Thorn
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Donal Bisanzio
- Global Health Division, RTI International, Washington, DC, USA; Epidemiology and Public Health Division, School of Medicine, University of Nottingham, Nottingham, UK
| | - Nancy Fullman
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Chantal K Huynh
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Xie Kulikoff
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Michael J Kutz
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Alan D Lopez
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Ali H Mokdad
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Mohsen Naghavi
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Grant Nguyen
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | | | - Theo Vos
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Haidong Wang
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Stephen S Lim
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | | | - Ric N Price
- Menzies School of Health Research and Charles Darwin University, Darwin, NT, Australia; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - J Kevin Baird
- Eijkman-Oxford Clinical Rearch Unit, Jakarta, Indonesia; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | | | - Daniel J Weiss
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Simon I Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Peter W Gething
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK.
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25
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Weiss DJ, Lucas TCD, Nguyen M, Nandi AK, Bisanzio D, Battle KE, Cameron E, Twohig KA, Pfeffer DA, Rozier JA, Gibson HS, Rao PC, Casey D, Bertozzi-Villa A, Collins EL, Dalrymple U, Gray N, Harris JR, Howes RE, Kang SY, Keddie SH, May D, Rumisha S, Thorn MP, Barber R, Fullman N, Huynh CK, Kulikoff X, Kutz MJ, Lopez AD, Mokdad AH, Naghavi M, Nguyen G, Shackelford KA, Vos T, Wang H, Smith DL, Lim SS, Murray CJL, Bhatt S, Hay SI, Gething PW. Mapping the global prevalence, incidence, and mortality of Plasmodium falciparum, 2000-17: a spatial and temporal modelling study. Lancet 2019; 394:322-331. [PMID: 31229234 PMCID: PMC6675740 DOI: 10.1016/s0140-6736(19)31097-9] [Citation(s) in RCA: 228] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/12/2019] [Accepted: 04/24/2019] [Indexed: 01/26/2023]
Abstract
BACKGROUND Since 2000, the scale-up of malaria control interventions has substantially reduced morbidity and mortality caused by the disease globally, fuelling bold aims for disease elimination. In tandem with increased availability of geospatially resolved data, malaria control programmes increasingly use high-resolution maps to characterise spatially heterogeneous patterns of disease risk and thus efficiently target areas of high burden. METHODS We updated and refined the Plasmodium falciparum parasite rate and clinical incidence models for sub-Saharan Africa, which rely on cross-sectional survey data for parasite rate and intervention coverage. For malaria endemic countries outside of sub-Saharan Africa, we produced estimates of parasite rate and incidence by applying an ecological downscaling approach to malaria incidence data acquired via routine surveillance. Mortality estimates were derived by linking incidence to systematically derived vital registration and verbal autopsy data. Informed by high-resolution covariate surfaces, we estimated P falciparum parasite rate, clinical incidence, and mortality at national, subnational, and 5 × 5 km pixel scales with corresponding uncertainty metrics. FINDINGS We present the first global, high-resolution map of P falciparum malaria mortality and the first global prevalence and incidence maps since 2010. These results are combined with those for Plasmodium vivax (published separately) to form the malaria estimates for the Global Burden of Disease 2017 study. The P falciparum estimates span the period 2000-17, and illustrate the rapid decline in burden between 2005 and 2017, with incidence declining by 27·9% and mortality declining by 42·5%. Despite a growing population in endemic regions, P falciparum cases declined between 2005 and 2017, from 232·3 million (95% uncertainty interval 198·8-277·7) to 193·9 million (156·6-240·2) and deaths declined from 925 800 (596 900-1 341 100) to 618 700 (368 600-952 200). Despite the declines in burden, 90·1% of people within sub-Saharan Africa continue to reside in endemic areas, and this region accounted for 79·4% of cases and 87·6% of deaths in 2017. INTERPRETATION High-resolution maps of P falciparum provide a contemporary resource for informing global policy and malaria control planning, programme implementation, and monitoring initiatives. Amid progress in reducing global malaria burden, areas where incidence trends have plateaued or increased in the past 5 years underscore the fragility of hard-won gains against malaria. Efforts towards elimination should be strengthened in such areas, and those where burden remained high throughout the study period. FUNDING Bill & Melinda Gates Foundation.
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Affiliation(s)
- Daniel J Weiss
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Tim C D Lucas
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Michele Nguyen
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Anita K Nandi
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Donal Bisanzio
- Global Health Division, Research Triangle Institute International, Washington, DC, USA; Public Health Division, School of Medicine, University of Nottingham, Nottingham, UK
| | - Katherine E Battle
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Ewan Cameron
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Katherine A Twohig
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Daniel A Pfeffer
- Menzies School of Health Research, Charles Darwin University, Casuarina, NT, Australia
| | - Jennifer A Rozier
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Harry S Gibson
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Puja C Rao
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Daniel Casey
- Seattle and King County Public Health, Seattle, WA, USA
| | | | - Emma L Collins
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Ursula Dalrymple
- Public Health England, Department of Health and Social Care, London, UK
| | - Naomi Gray
- Instruct: An Integrated Structural Biology Infrastructure for Europe, Oxford, UK
| | - Joseph R Harris
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Rosalind E Howes
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Sun Yun Kang
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Suzanne H Keddie
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Daniel May
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Susan Rumisha
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Michael P Thorn
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Ryan Barber
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Nancy Fullman
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Chantal K Huynh
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Xie Kulikoff
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Michael J Kutz
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Alan D Lopez
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Ali H Mokdad
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Mohsen Naghavi
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Grant Nguyen
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | | | - Theo Vos
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Haidong Wang
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Stephen S Lim
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | | | | | - Simon I Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Peter W Gething
- Malaria Atlas Project, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK.
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26
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Dalrymple U, Cameron E, Arambepola R, Battle KE, Chestnutt EG, Keddie SH, Twohig KA, Pfeffer DA, Gibson HS, Weiss DJ, Bhatt S, Gething PW. The contribution of non-malarial febrile illness co-infections to Plasmodium falciparum case counts in health facilities in sub-Saharan Africa. Malar J 2019; 18:195. [PMID: 31186004 PMCID: PMC6560910 DOI: 10.1186/s12936-019-2830-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/04/2019] [Indexed: 01/20/2023] Open
Abstract
Background The disease burden of Plasmodium falciparum malaria illness is generally estimated using one of two distinct approaches: either by transforming P. falciparum infection prevalence estimates into incidence estimates using conversion formulae; or through adjustment of counts of recorded P. falciparum-positive fever cases from clinics. Whilst both ostensibly seek to evaluate P. falciparum disease burden, there is an implicit and problematic difference in the metric being estimated. The first enumerates only symptomatic malaria cases, while the second enumerates all febrile episodes coincident with a P. falciparum infection, regardless of the fever’s underlying cause. Methods Here, a novel approach was used to triangulate community-based data sources capturing P. falciparum infection, fever, and care-seeking to estimate the fraction of P. falciparum-positive fevers amongst children under 5 years of age presenting at health facilities that are attributable to P. falciparum infection versus other non-malarial causes. A Bayesian hierarchical model was used to assign probabilities of malaria-attributable fever (MAF) and non-malarial febrile illness (NMFI) to children under five from a dataset of 41 surveys from 21 countries in sub-Saharan Africa conducted between 2006 and 2016. Using subsequent treatment-seeking outcomes, the proportion of MAF and NMFI amongst P. falciparum-positive febrile children presenting at public clinics was estimated. Results Across all surveyed malaria-positive febrile children who sought care at public clinics across 41 country-years in sub-Saharan Africa, P. falciparum infection was estimated to be the underlying cause of only 37.7% (31.1–45.4, 95% CrI) of P. falciparum-positive fevers, with significant geographical and temporal heterogeneity between surveys. Conclusions These findings highlight the complex nature of the P. falciparum burden amongst children under 5 years of age and indicate that for many children presenting at health clinics, a positive P. falciparum diagnosis and a fever does not necessarily mean P. falciparum is the underlying cause of the child’s symptoms, and thus other causes of illness should always be investigated, in addition to prescribing an effective anti-malarial medication. In addition to providing new large-scale estimates of malaria-attributable fever prevalence, the results presented here improve comparability between different methods for calculating P. falciparum disease burden, with significant implications for national and global estimation of malaria burden. Electronic supplementary material The online version of this article (10.1186/s12936-019-2830-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ursula Dalrymple
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK.,Department of Zoology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Ewan Cameron
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Rohan Arambepola
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Katherine E Battle
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Elisabeth G Chestnutt
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Suzanne H Keddie
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Katherine A Twohig
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Daniel A Pfeffer
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK.,Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Harry S Gibson
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Daniel J Weiss
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Samir Bhatt
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK.,School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Hospital, Norfolk Place, London, W2 1PG, UK
| | - Peter W Gething
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK.
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Kerr CC. Is epidemiology ready for Big Software? Pathog Dis 2019; 77:5304613. [PMID: 30715264 DOI: 10.1093/femspd/ftz006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/29/2019] [Indexed: 01/18/2023] Open
Abstract
Large-scale, open-source software projects like EMOD offer a new approach to epidemiological modeling. Built by a team of professional software developers, EMOD offers significant advantages over 'single-use' models designed by individual research teams, including comprehensive documentation, automated testing and extensive support. In addition, as an individual-based model, it allows much greater complexity and flexibility than the compartmental models that are most commonly used in epidemiology. Adopting modern software development practices, as embodied by EMOD, is essential for ensuring that the best models are available to the greatest number of people.
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Affiliation(s)
- Cliff C Kerr
- A28 Physics Rd, Camperdown, Complex Systems Group, School of Physics, University of Sydney, NSW 2006, Australia
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Hellewell J, Walker P, Ghani A, Rao B, Churcher TS. Using ante-natal clinic prevalence data to monitor temporal changes in malaria incidence in a humanitarian setting in the Democratic Republic of Congo. Malar J 2018; 17:312. [PMID: 30157850 PMCID: PMC6114784 DOI: 10.1186/s12936-018-2460-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/17/2018] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The number of clinical cases of malaria is often recorded in resource constrained or conflict settings as a proxy for disease burden. Interpreting case count data in areas of humanitarian need is challenging due to uncertainties in population size caused by security concerns, resource constraints and population movement. Malaria prevalence in women visiting ante-natal care (ANC) clinics has the potential to be an easier and more accurate metric for malaria surveillance that is unbiased by population size if malaria testing is routinely conducted irrespective of symptoms. METHODS A suite of distributed lag non-linear models was fitted to clinical incidence time-series data in children under 5 years and ANC prevalence data from health centres run by Médecins Sans Frontières in the Democratic Republic of Congo, which implement routine intermittent screening and treatment alongside intermittent preventative treatment in pregnancy. These statistical models enable the temporal relationship between the two metrics to be disentangled. RESULTS There was a strong relationship between the ANC prevalence and clinical incidence suggesting that both can be used to describe current malaria endemicity. There was no evidence that ANC prevalence could predict future clinical incidence, though a change in clinical incidence was shown to influence ANC prevalence up to 3 months into the future. CONCLUSIONS The results indicate that ANC prevalence may be a suitable metric for retrospective evaluations of the impact of malaria interventions and is a useful method for evaluating long-term malaria trends in resource constrained settings.
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Affiliation(s)
- Joel Hellewell
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK.
| | - Patrick Walker
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK
| | - Azra Ghani
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK
| | - Bhargavi Rao
- Manson Unit, Médecins Sans Frontières (Operational Centre Amsterdam), London, UK
| | - Thomas S Churcher
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, UK
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Smith NR, Trauer JM, Gambhir M, Richards JS, Maude RJ, Keith JM, Flegg JA. Agent-based models of malaria transmission: a systematic review. Malar J 2018; 17:299. [PMID: 30119664 PMCID: PMC6098619 DOI: 10.1186/s12936-018-2442-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 08/04/2018] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Much of the extensive research regarding transmission of malaria is underpinned by mathematical modelling. Compartmental models, which focus on interactions and transitions between population strata, have been a mainstay of such modelling for more than a century. However, modellers are increasingly adopting agent-based approaches, which model hosts, vectors and/or their interactions on an individual level. One reason for the increasing popularity of such models is their potential to provide enhanced realism by allowing system-level behaviours to emerge as a consequence of accumulated individual-level interactions, as occurs in real populations. METHODS A systematic review of 90 articles published between 1998 and May 2018 was performed, characterizing agent-based models (ABMs) relevant to malaria transmission. The review provides an overview of approaches used to date, determines the advantages of these approaches, and proposes ideas for progressing the field. RESULTS The rationale for ABM use over other modelling approaches centres around three points: the need to accurately represent increased stochasticity in low-transmission settings; the benefits of high-resolution spatial simulations; and heterogeneities in drug and vaccine efficacies due to individual patient characteristics. The success of these approaches provides avenues for further exploration of agent-based techniques for modelling malaria transmission. Potential extensions include varying elimination strategies across spatial landscapes, extending the size of spatial models, incorporating human movement dynamics, and developing increasingly comprehensive parameter estimation and optimization techniques. CONCLUSION Collectively, the literature covers an extensive array of topics, including the full spectrum of transmission and intervention regimes. Bringing these elements together under a common framework may enhance knowledge of, and guide policies towards, malaria elimination. However, because of the diversity of available models, endorsing a standardized approach to ABM implementation may not be possible. Instead it is recommended that model frameworks be contextually appropriate and sufficiently described. One key recommendation is to develop enhanced parameter estimation and optimization techniques. Extensions of current techniques will provide the robust results required to enhance current elimination efforts.
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Affiliation(s)
- Neal R Smith
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
| | - James M Trauer
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia
| | - Manoj Gambhir
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia
- IBM Research Australia, Melbourne, Australia
| | - Jack S Richards
- Life Sciences, Burnet Institute, Melbourne, Australia
- Department of Medicine, University of Melbourne, Parkville, Australia
- Department of Infectious Diseases, Monash University, Melbourne, Australia
| | - Richard J Maude
- 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, UK
- Harvard TH Chan School of Public Health, Harvard University, Boston, USA
| | - Jonathan M Keith
- School of Mathematical Sciences, Monash University, Clayton, Australia
| | - Jennifer A Flegg
- School of Mathematics and Statistics, University of Melbourne, Parkville, Australia
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Zheng Y, Serban N. Clustering the prevalence of pediatric chronic conditions in the United States using distributed computing. Ann Appl Stat 2018. [DOI: 10.1214/18-aoas1173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Mfueni E, Devleesschauwer B, Rosas-Aguirre A, Van Malderen C, Brandt PT, Ogutu B, Snow RW, Tshilolo L, Zurovac D, Vanderelst D, Speybroeck N. True malaria prevalence in children under five: Bayesian estimation using data of malaria household surveys from three sub-Saharan countries. Malar J 2018; 17:65. [PMID: 29402268 PMCID: PMC5800038 DOI: 10.1186/s12936-018-2211-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 01/30/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria is one of the major causes of childhood death in sub-Saharan countries. A reliable estimation of malaria prevalence is important to guide and monitor progress toward control and elimination. The aim of the study was to estimate the true prevalence of malaria in children under five in the Democratic Republic of the Congo, Uganda and Kenya, using a Bayesian modelling framework that combined in a novel way malaria data from national household surveys with external information about the sensitivity and specificity of the malaria diagnostic methods used in those surveys-i.e., rapid diagnostic tests and light microscopy. METHODS Data were used from the Demographic and Health Surveys (DHS) and Malaria Indicator Surveys (MIS) conducted in the Democratic Republic of the Congo (DHS 2013-2014), Uganda (MIS 2014-2015) and Kenya (MIS 2015), where information on infection status using rapid diagnostic tests and/or light microscopy was available for 13,573 children. True prevalence was estimated using a Bayesian model that accounted for the conditional dependence between the two diagnostic methods, and the uncertainty of their sensitivities and specificities obtained from expert opinion. RESULTS The estimated true malaria prevalence was 20% (95% uncertainty interval [UI] 17%-23%) in the Democratic Republic of the Congo, 22% (95% UI 9-32%) in Uganda and 1% (95% UI 0-3%) in Kenya. According to the model estimations, rapid diagnostic tests had a satisfactory sensitivity and specificity, and light microscopy had a variable sensitivity, but a satisfactory specificity. Adding reported history of fever in the previous 14 days as a third diagnostic method to the model did not affect model estimates, highlighting the poor performance of this indicator as a malaria diagnostic. CONCLUSIONS In the absence of a gold standard test, Bayesian models can assist in the optimal estimation of the malaria burden, using individual results from several tests and expert opinion about the performance of those tests.
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Affiliation(s)
- Elvire Mfueni
- Institute of Health and Society, Université Catholique de Louvain, Brussels, Belgium
| | - Brecht Devleesschauwer
- Department of Public Health and Surveillance, Scientific Institute of Public Health (WIV-ISP), Brussels, Belgium.
| | - Angel Rosas-Aguirre
- Institute of Health and Society, Université Catholique de Louvain, Brussels, Belgium
| | - Carine Van Malderen
- Institute of Health and Society, Université Catholique de Louvain, Brussels, Belgium
| | - Patrick T Brandt
- School of Economic, Political and Policy Sciences, The University of Texas, Dallas, TX, USA
| | | | - Robert W Snow
- Population & Health Theme, Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Léon Tshilolo
- Centre Hospitalier Monkole, Kinshasa, Democratic Republic of the Congo
| | - Dejan Zurovac
- Population & Health Theme, Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Dieter Vanderelst
- Department of Biology, University of Cincinnati, Cincinnati, OH, USA
| | - Niko Speybroeck
- Institute of Health and Society, Université Catholique de Louvain, Brussels, Belgium
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McKinley TJ, Vernon I, Andrianakis I, McCreesh N, Oakley JE, Nsubuga RN, Goldstein M, White RG. Approximate Bayesian Computation and Simulation-Based Inference for Complex Stochastic Epidemic Models. Stat Sci 2018. [DOI: 10.1214/17-sts618] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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33
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Korenromp E, Hamilton M, Sanders R, Mahiané G, Briët OJT, Smith T, Winfrey W, Walker N, Stover J. Impact of malaria interventions on child mortality in endemic African settings: comparison and alignment between LiST and Spectrum-Malaria model. BMC Public Health 2017; 17:781. [PMID: 29143637 PMCID: PMC5688465 DOI: 10.1186/s12889-017-4739-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background In malaria-endemic countries, malaria prevention and treatment are critical for child health. In the context of intervention scale-up and rapid changes in endemicity, projections of intervention impact and optimized program scale-up strategies need to take into account the consequent dynamics of transmission and immunity. Methods The new Spectrum-Malaria program planning tool was used to project health impacts of Insecticide-Treated mosquito Nets (ITNs) and effective management of uncomplicated malaria cases (CMU), among other interventions, on malaria infection prevalence, case incidence and mortality in children 0–4 years, 5–14 years of age and adults. Spectrum-Malaria uses statistical models fitted to simulations of the dynamic effects of increasing intervention coverage on these burdens as a function of baseline malaria endemicity, seasonality in transmission and malaria intervention coverage levels (estimated for years 2000 to 2015 by the World Health Organization and Malaria Atlas Project). Spectrum-Malaria projections of proportional reductions in under-five malaria mortality were compared with those of the Lives Saved Tool (LiST) for the Democratic Republic of the Congo and Zambia, for given (standardized) scenarios of ITN and/or CMU scale-up over 2016–2030. Results Proportional mortality reductions over the first two years following scale-up of ITNs from near-zero baselines to moderately higher coverages align well between LiST and Spectrum-Malaria —as expected since both models were fitted to cluster-randomized ITN trials in moderate-to-high-endemic settings with 2-year durations. For further scale-up from moderately high ITN coverage to near-universal coverage (as currently relevant for strategic planning for many countries), Spectrum-Malaria predicts smaller additional ITN impacts than LiST, reflecting progressive saturation. For CMU, especially in the longer term (over 2022–2030) and for lower-endemic settings (like Zambia), Spectrum-Malaria projects larger proportional impacts, reflecting onward dynamic effects not fully captured by LiST. Conclusions Spectrum-Malaria complements LiST by extending the scope of malaria interventions, program packages and health outcomes that can be evaluated for policy making and strategic planning within and beyond the perspective of child survival. Electronic supplementary material The online version of this article (10.1186/s12889-017-4739-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Matthew Hamilton
- Avenir Health, 655 Winding Brook Drive, Glastonbury, CT-06033, USA
| | - Rachel Sanders
- Avenir Health, 655 Winding Brook Drive, Glastonbury, CT-06033, USA
| | - Guy Mahiané
- Avenir Health, 655 Winding Brook Drive, Glastonbury, CT-06033, USA
| | - Olivier J T Briët
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,Epidemiology and Public Health, University of Basel, Basel, Switzerland
| | - Thomas Smith
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.,Epidemiology and Public Health, University of Basel, Basel, Switzerland
| | - William Winfrey
- Avenir Health, 655 Winding Brook Drive, Glastonbury, CT-06033, USA
| | - Neff Walker
- Department of International Health, Institute for International Programs, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe St., Baltimore, MD, 21205, USA
| | - John Stover
- Avenir Health, 655 Winding Brook Drive, Glastonbury, CT-06033, USA
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Abstract
This paper summarises key advances and priorities since the 2011 presentation of the Malaria Eradication Research Agenda (malERA), with a focus on the combinations of intervention tools and strategies for elimination and their evaluation using modelling approaches. With an increasing number of countries embarking on malaria elimination programmes, national and local decisions to select combinations of tools and deployment strategies directed at malaria elimination must address rapidly changing transmission patterns across diverse geographic areas. However, not all of these approaches can be systematically evaluated in the field. Thus, there is potential for modelling to investigate appropriate 'packages' of combined interventions that include various forms of vector control, case management, surveillance, and population-based approaches for different settings, particularly at lower transmission levels. Modelling can help prioritise which intervention packages should be tested in field studies, suggest which intervention package should be used at a particular level or stratum of transmission intensity, estimate the risk of resurgence when scaling down specific interventions after local transmission is interrupted, and evaluate the risk and impact of parasite drug resistance and vector insecticide resistance. However, modelling intervention package deployment against a heterogeneous transmission background is a challenge. Further validation of malaria models should be pursued through an iterative process, whereby field data collected with the deployment of intervention packages is used to refine models and make them progressively more relevant for assessing and predicting elimination outcomes.
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Dalrymple U, Cameron E, Bhatt S, Weiss DJ, Gupta S, Gething PW. Quantifying the contribution of Plasmodium falciparum malaria to febrile illness amongst African children. eLife 2017; 6:29198. [PMID: 29034876 PMCID: PMC5665646 DOI: 10.7554/elife.29198] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 10/12/2017] [Indexed: 12/31/2022] Open
Abstract
Suspected malaria cases in Africa increasingly receive a rapid diagnostic test (RDT) before antimalarials are prescribed. While this ensures efficient use of resources to clear parasites, the underlying cause of the individual's fever remains unknown due to potential coinfection with a non-malarial febrile illness. Widespread use of RDTs does not necessarily prevent over-estimation of clinical malaria cases or sub-optimal case management of febrile patients. We present a new approach that allows inference of the spatiotemporal prevalence of both Plasmodium falciparum malaria-attributable and non-malarial fever in sub-Saharan African children from 2006 to 2014. We estimate that 35.7% of all self-reported fevers were accompanied by a malaria infection in 2014, but that only 28.0% of those (10.0% of all fevers) were causally attributable to malaria. Most fevers among malaria-positive children are therefore caused by non-malaria illnesses. This refined understanding can help improve interpretation of the burden of febrile illness and shape policy on fever case management.
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Affiliation(s)
- Ursula Dalrymple
- Department of Zoology, University of Oxford, Oxford, United Kingdom.,Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Ewan Cameron
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Samir Bhatt
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom.,Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Daniel J Weiss
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Sunetra Gupta
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Peter W Gething
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
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36
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Willem L, Verelst F, Bilcke J, Hens N, Beutels P. Lessons from a decade of individual-based models for infectious disease transmission: a systematic review (2006-2015). BMC Infect Dis 2017; 17:612. [PMID: 28893198 PMCID: PMC5594572 DOI: 10.1186/s12879-017-2699-8] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 08/22/2017] [Indexed: 02/18/2023] Open
Abstract
Background Individual-based models (IBMs) are useful to simulate events subject to stochasticity and/or heterogeneity, and have become well established to model the potential (re)emergence of pathogens (e.g., pandemic influenza, bioterrorism). Individual heterogeneity at the host and pathogen level is increasingly documented to influence transmission of endemic diseases and it is well understood that the final stages of elimination strategies for vaccine-preventable childhood diseases (e.g., polio, measles) are subject to stochasticity. Even so it appears IBMs for both these phenomena are not well established. We review a decade of IBM publications aiming to obtain insights in their advantages, pitfalls and rationale for use and to make recommendations facilitating knowledge transfer within and across disciplines. Methods We systematically identified publications in Web of Science and PubMed from 2006-2015 based on title/abstract/keywords screening (and full-text if necessary) to retrieve topics, modeling purposes and general specifications. We extracted detailed modeling features from papers on established vaccine-preventable childhood diseases based on full-text screening. Results We identified 698 papers, which applied an IBM for infectious disease transmission, and listed these in a reference database, describing their general characteristics. The diversity of disease-topics and overall publication frequency have increased over time (38 to 115 annual publications from 2006 to 2015). The inclusion of intervention strategies (8 to 52) and economic consequences (1 to 20) are increasing, to the detriment of purely theoretical explorations. Unfortunately, terminology used to describe IBMs is inconsistent and ambiguous. We retrieved 24 studies on a vaccine-preventable childhood disease (covering 7 different diseases), with publication frequency increasing from the first such study published in 2008. IBMs have been useful to explore heterogeneous between- and within-host interactions, but combined applications are still sparse. The amount of missing information on model characteristics and study design is remarkable. Conclusions IBMs are suited to combine heterogeneous within- and between-host interactions, which offers many opportunities, especially to analyze targeted interventions for endemic infections. We advocate the exchange of (open-source) platforms and stress the need for consistent “branding”. Using (existing) conventions and reporting protocols would stimulate cross-fertilization between research groups and fields, and ultimately policy making in decades to come. Electronic supplementary material The online version of this article (doi:10.1186/s12879-017-2699-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lander Willem
- Centre for Health Economics Research & Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.
| | - Frederik Verelst
- Centre for Health Economics Research & Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Joke Bilcke
- Centre for Health Economics Research & Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Niel Hens
- Centre for Health Economics Research & Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.,Interuniversity Institute for Biostatistics and statistical Bioinformatics, UHasselt, Hasselt, Belgium
| | - Philippe Beutels
- Centre for Health Economics Research & Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.,School of Public Health and Community Medicine, The University of New South Wales, Sydney, Australia
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Hofmann NE, Karl S, Wampfler R, Kiniboro B, Teliki A, Iga J, Waltmann A, Betuela I, Felger I, Robinson LJ, Mueller I. The complex relationship of exposure to new Plasmodium infections and incidence of clinical malaria in Papua New Guinea. eLife 2017; 6:23708. [PMID: 28862132 PMCID: PMC5606846 DOI: 10.7554/elife.23708] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 08/18/2017] [Indexed: 01/20/2023] Open
Abstract
The molecular force of blood-stage infection (molFOB) is a quantitative surrogate metric for malaria transmission at population level and for exposure at individual level. Relationships between molFOB, parasite prevalence and clinical incidence were assessed in a treatment-to-reinfection cohort, where P.vivax (Pv) hypnozoites were eliminated in half the children by primaquine (PQ). Discounting relapses, children acquired equal numbers of new P. falciparum (Pf) and Pv blood-stage infections/year (Pf-molFOB = 0–18, Pv-molFOB = 0–23) resulting in comparable spatial and temporal patterns in incidence and prevalence of infections. Including relapses, Pv-molFOB increased >3 fold (relative to PQ-treated children) showing greater heterogeneity at individual (Pv-molFOB = 0–36) and village levels. Pf- and Pv-molFOB were strongly associated with clinical episode risk. Yearly Pf clinical incidence rate (IR = 0.28) was higher than for Pv (IR = 0.12) despite lower Pf-molFOB. These relationships between molFOB, clinical incidence and parasite prevalence reveal a comparable decline in Pf and Pv transmission that is normally hidden by the high burden of Pv relapses. Clinical trial registration: ClinicalTrials.gov NCT02143934 Malaria is caused by five different species of parasites that are transmitted to humans by bites from parasite-carrying mosquitos. Once in human blood, the parasites rapidly multiply. People who live in countries where malaria is common may become infected and never show any symptoms because their immune systems are able to keep parasite numbers low. Repeated infections, or infection with more than one species of malaria parasite also are common. Some species of malaria, including Plasmodium vivax, can hibernate in the liver for weeks or months after the infection and only become active later. Asymptomatic infections, multi-parasite infections, and reactivating parasites make it hard to measure how often new malaria infections occur. One way scientists can determine if a new infection has occurred is by genotyping the parasites in a person’s blood. Genotyping involves looking for small differences in the parasite DNA. For example, a study in Papua New Guinea, where P. vivax is very common, showed that reactivations of hibernating parasites were more common than new infections. Now, Hofmann et al. use the same study in Papua New Guinea to compare the frequency and consequences of new infections with P. vivax and another malaria parasite, Plasmodium falciparum. In the study, 466 children from 6 villages were followed for 8 months with tests every 2 to 4 weeks to genotype the parasites in their blood. Some of the children were treated with antimalarial drugs to help wipe out any existing parasites including hibernating ones. While P. vivax was about twice as common in blood samples—likely due to reactivation—genotyping showed that new infections with the two parasites occur at equal rates and often at the same times and locations. Hofmann et al. also showed that some villages and some children had much higher rates of infection than others. This difference could not fully be explained by use of bednets or other preventive measures. Children were more likely to become ill from P. falciparum than P. vivax even though P. vivax was more common. But children with more frequent infections with P. falciparum seemed better able to manage the parasites and were less likely to develop symptoms that those with infrequent infections. The experiments show that genotyping may help scientists better track new malaria infections and develop better strategies to prevent or treat malaria.
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Affiliation(s)
- Natalie E Hofmann
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Stephan Karl
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Rahel Wampfler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Benson Kiniboro
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Albina Teliki
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Jonah Iga
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Andreea Waltmann
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,University of Melbourne, Melbourne, Australia
| | - Inoni Betuela
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Leanne J Robinson
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea.,University of Melbourne, Melbourne, Australia.,Burnet Institute, Melbourne, Australia
| | - Ivo Mueller
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,University of Melbourne, Melbourne, Australia.,ISGlobal, Barcelona Centre for International Health Research, Hospital Clínic-University of Barcelona, Barcelona, Spain.,Institut Pasteur, Paris, France
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38
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Goheen MM, Campino S, Cerami C. The role of the red blood cell in host defence against falciparum malaria: an expanding repertoire of evolutionary alterations. Br J Haematol 2017; 179:543-556. [PMID: 28832963 DOI: 10.1111/bjh.14886] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The malaria parasite has co-evolved with its human host as each organism struggles for resources and survival. The scars of this war are carried in the human genome in the form of polymorphisms that confer innate resistance to malaria. Clinical, epidemiological and genome-wide association studies have identified multiple polymorphisms in red blood cell (RBC) proteins that attenuate malaria pathogenesis. These include well-known polymorphisms in haemoglobin, intracellular enzymes, RBC channels, RBC surface markers, and proteins impacting the RBC cytoskeleton and RBC morphology. A better understanding of how changes in RBC physiology impact malaria pathogenesis may uncover new strategies to combat the disease.
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Affiliation(s)
- Morgan M Goheen
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Susana Campino
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, The London School of Hygiene & Tropical Medicine, London, UK
| | - Carla Cerami
- MRC International Nutrition Group at Keneba, MRC Unit The Gambia, Banjul, The Gambia
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Ajayi IO, Nsungwa-Sabiiti J, Siribié M, Petzold M, Castellani J, Singlovic J, Gomes M. Reply to Brooks et al. Clin Infect Dis 2017; 65:530-531. [PMID: 28838135 DOI: 10.1093/cid/cix383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- IkeOluwapo O Ajayi
- Department of Epidemiology and Medical Statistics, Institute of Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria
| | | | | | - Max Petzold
- Department of Health Services Research, School for Public Health and Primary Care, Maastricht University, The Netherlands
| | - Joëlle Castellani
- Centre for Applied Biostatistics, Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Jan Singlovic
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Melba Gomes
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland
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Smith TA, Chitnis N, Penny M, Tanner M. Malaria Modeling in the Era of Eradication. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a025460. [PMID: 28003280 DOI: 10.1101/cshperspect.a025460] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mathematical models provide the essential basis of rational research and development strategies in malaria, informing the choice of which technologies to target, which deployment strategies to consider, and which populations to focus on. The Internet and remote sensing technologies also enable assembly of ever more relevant field data. Together with supercomputing technology, this has made available timely descriptions of the geography of malaria transmission and disease across the world and made it possible for policy and planning to be informed by detailed simulations of the potential impact of intervention programs. These information technology advances do not replace the basic understanding of the dynamics of malaria transmission that should be embedded in the thinking of anyone planning malaria interventions. The appropriate use of modeling may determine whether we are living in an era of hubris or indeed in an age of eradication.
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Affiliation(s)
- Thomas A Smith
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel CH 4002, Switzerland; and University of Basel, Basel CH 4001, Switzerland
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel CH 4002, Switzerland; and University of Basel, Basel CH 4001, Switzerland
| | - Melissa Penny
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel CH 4002, Switzerland; and University of Basel, Basel CH 4001, Switzerland
| | - Marcel Tanner
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel CH 4002, Switzerland; and University of Basel, Basel CH 4001, Switzerland
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41
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Hamilton M, Mahiane G, Werst E, Sanders R, Briët O, Smith T, Cibulskis R, Cameron E, Bhatt S, Weiss DJ, Gething PW, Pretorius C, Korenromp EL. Spectrum-Malaria: a user-friendly projection tool for health impact assessment and strategic planning by malaria control programmes in sub-Saharan Africa. Malar J 2017; 16:68. [PMID: 28183343 PMCID: PMC5301449 DOI: 10.1186/s12936-017-1705-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/19/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Scale-up of malaria prevention and treatment needs to continue but national strategies and budget allocations are not always evidence-based. This article presents a new modelling tool projecting malaria infection, cases and deaths to support impact evaluation, target setting and strategic planning. METHODS Nested in the Spectrum suite of programme planning tools, the model includes historic estimates of case incidence and deaths in groups aged up to 4, 5-14, and 15+ years, and prevalence of Plasmodium falciparum infection (PfPR) among children 2-9 years, for 43 sub-Saharan African countries and their 602 provinces, from the WHO and malaria atlas project. Impacts over 2016-2030 are projected for insecticide-treated nets (ITNs), indoor residual spraying (IRS), seasonal malaria chemoprevention (SMC), and effective management of uncomplicated cases (CMU) and severe cases (CMS), using statistical functions fitted to proportional burden reductions simulated in the P. falciparum dynamic transmission model OpenMalaria. RESULTS In projections for Nigeria, ITNs, IRS, CMU, and CMS scale-up reduced health burdens in all age groups, with largest proportional and especially absolute reductions in children up to 4 years old. Impacts increased from 8 to 10 years following scale-up, reflecting dynamic effects. For scale-up of each intervention to 80% effective coverage, CMU had the largest impacts across all health outcomes, followed by ITNs and IRS; CMS and SMC conferred additional small but rapid mortality impacts. DISCUSSION Spectrum-Malaria's user-friendly interface and intuitive display of baseline data and scenario projections holds promise to facilitate capacity building and policy dialogue in malaria programme prioritization. The module's linking to the OneHealth Tool for costing will support use of the software for strategic budget allocation. In settings with moderately low coverage levels, such as Nigeria, improving case management and achieving universal coverage with ITNs could achieve considerable burden reductions. Projections remain to be refined and validated with local expert input data and actual policy scenarios.
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Affiliation(s)
- Matthew Hamilton
- Avenir Health, Geneva, 1 route de Morillons/150 Route de Ferney (WCC, office 164), PO box 2100, 1211 Geneva 2, Switzerland
- Avenir Health, Glastonbury, USA
| | - Guy Mahiane
- Avenir Health, Geneva, 1 route de Morillons/150 Route de Ferney (WCC, office 164), PO box 2100, 1211 Geneva 2, Switzerland
- Avenir Health, Glastonbury, USA
| | - Elric Werst
- Avenir Health, Geneva, 1 route de Morillons/150 Route de Ferney (WCC, office 164), PO box 2100, 1211 Geneva 2, Switzerland
- Avenir Health, Glastonbury, USA
| | - Rachel Sanders
- Avenir Health, Geneva, 1 route de Morillons/150 Route de Ferney (WCC, office 164), PO box 2100, 1211 Geneva 2, Switzerland
- Avenir Health, Glastonbury, USA
| | - Olivier Briët
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Thomas Smith
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Richard Cibulskis
- World Health Organization Global Malaria Programme, Geneva, Switzerland
| | - Ewan Cameron
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Samir Bhatt
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Daniel J. Weiss
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Peter W. Gething
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Carel Pretorius
- Avenir Health, Geneva, 1 route de Morillons/150 Route de Ferney (WCC, office 164), PO box 2100, 1211 Geneva 2, Switzerland
- Avenir Health, Glastonbury, USA
| | - Eline L. Korenromp
- Avenir Health, Geneva, 1 route de Morillons/150 Route de Ferney (WCC, office 164), PO box 2100, 1211 Geneva 2, Switzerland
- Avenir Health, Glastonbury, USA
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42
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Smith JL, Auala J, Haindongo E, Uusiku P, Gosling R, Kleinschmidt I, Mumbengegwi D, Sturrock HJW. Malaria risk in young male travellers but local transmission persists: a case-control study in low transmission Namibia. Malar J 2017; 16:70. [PMID: 28187770 PMCID: PMC5303241 DOI: 10.1186/s12936-017-1719-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 02/03/2017] [Indexed: 11/24/2022] Open
Abstract
Background A key component of malaria elimination campaigns is the identification and targeting of high risk populations. To characterize high risk populations in north central Namibia, a prospective health facility-based case–control study was conducted from December 2012–July 2014. Cases (n = 107) were all patients presenting to any of the 46 health clinics located in the study districts with a confirmed Plasmodium infection by multi-species rapid diagnostic test (RDT). Population controls (n = 679) for each district were RDT negative individuals residing within a household that was randomly selected from a census listing using a two-stage sampling procedure. Demographic, travel, socio-economic, behavioural, climate and vegetation data were also collected. Spatial patterns of malaria risk were analysed. Multivariate logistic regression was used to identify risk factors for malaria. Results Malaria risk was observed to cluster along the border with Angola, and travel patterns among cases were comparatively restricted to northern Namibia and Angola. Travel to Angola was associated with excessive risk of malaria in males (OR 43.58 95% CI 2.12–896), but there was no corresponding risk associated with travel by females. This is the first study to reveal that gender can modify the effect of travel on risk of malaria. Amongst non-travellers, male gender was also associated with a higher risk of malaria compared with females (OR 1.95 95% CI 1.25–3.04). Other strong risk factors were sleeping away from the household the previous night, lower socioeconomic status, living in an area with moderate vegetation around their house, experiencing moderate rainfall in the month prior to diagnosis and living <15 km from the Angolan border. Conclusions These findings highlight the critical need to target malaria interventions to young male travellers, who have a disproportionate risk of malaria in northern Namibia, to coordinate cross-border regional malaria prevention initiatives and to scale up coverage of prevention measures such as indoor residual spraying and long-lasting insecticide nets in high risk areas if malaria elimination is to be realized. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1719-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jennifer L Smith
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, CA, USA.
| | - Joyce Auala
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Erastus Haindongo
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Petrina Uusiku
- National Vector-Borne Disease Control Programme, Ministry of Health and Social Services, Windhoek, Namibia
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, CA, USA
| | - Immo Kleinschmidt
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Davis Mumbengegwi
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Hugh J W Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, CA, USA
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Adamus-Białek W, Lechowicz Ł, Kubiak-Szeligowska AB, Wawszczak M, Kamińska E, Chrapek M. A new look at the drug-resistance investigation of uropathogenic E. coli strains. Mol Biol Rep 2017; 44:191-202. [PMID: 28091786 PMCID: PMC5310551 DOI: 10.1007/s11033-017-4099-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 01/02/2017] [Indexed: 11/01/2022]
Abstract
Bacterial drug resistance and uropathogenic tract infections are among the most important issues of current medicine. Uropathogenic Escherichia coli strains are the primary factor of this issue. This article is the continuation of the previous study, where we used Kohonen relations to predict the direction of drug resistance. The characterized collection of uropathogenic E. coli strains was used for microbiological (the disc diffusion method for antimicrobial susceptibility testing), chemical (ATR/FT-IR) and mathematical (artificial neural networks, Ward's hierarchical clustering method, the analysis of distributions of inhibition zone diameters for antibiotics, Cohen's kappa measure of agreement) analysis. This study presents other potential tools for the epidemiological differentiation of E. coli strains. It is noteworthy that ATR/FT-IR technique has turned out to be useful for the quick and simple identification of MDR strains. Also, diameter zones of resistance of this E. coli population were compared to the population of E. coli strains published by EUCAST. We observed the bacterial behaviors toward particular antibiotics in comparison to EUCAST bacterial collections. Additionally, we used Cohen's kappa to show which antibiotics from the same class are closely related to each other and which are not. The presented associations between antibiotics may be helpful in selecting the proper therapy directions. Here we present an adaptation of interdisciplinary studies of drug resistance of E. coli strains for epidemiological and clinical investigations. The obtained results may be some indication in deciding on antibiotic therapy.
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Affiliation(s)
- Wioletta Adamus-Białek
- Institute of Medical Sciences, Jan Kochanowski University, IX Wieków Kielc 19A Av., 25-317, Kielce, Poland.
| | - Łukasz Lechowicz
- Department of Microbiology, Institute of Biology, Jan Kochanowski University, 15 Swietokrzyska St., 25-406, Kielce, Poland
| | | | - Monika Wawszczak
- Department of Microbiology, Institute of Biology, Jan Kochanowski University, 15 Swietokrzyska St., 25-406, Kielce, Poland
| | - Ewelina Kamińska
- Department of Microbiology, Institute of Biology, Jan Kochanowski University, 15 Swietokrzyska St., 25-406, Kielce, Poland
| | - Magdalena Chrapek
- Institute of Mathematics, Jan Kochanowski University, 15 Swietokrzyska St., 25-406, Kielce, Poland
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Howes RE, Battle KE, Mendis KN, Smith DL, Cibulskis RE, Baird JK, Hay SI. Global Epidemiology of Plasmodium vivax. Am J Trop Med Hyg 2016; 95:15-34. [PMID: 27402513 PMCID: PMC5198891 DOI: 10.4269/ajtmh.16-0141] [Citation(s) in RCA: 253] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/19/2016] [Indexed: 01/09/2023] Open
Abstract
Plasmodium vivax is the most widespread human malaria, putting 2.5 billion people at risk of infection. Its unique biological and epidemiological characteristics pose challenges to control strategies that have been principally targeted against Plasmodium falciparum Unlike P. falciparum, P. vivax infections have typically low blood-stage parasitemia with gametocytes emerging before illness manifests, and dormant liver stages causing relapses. These traits affect both its geographic distribution and transmission patterns. Asymptomatic infections, high-risk groups, and resulting case burdens are described in this review. Despite relatively low prevalence measurements and parasitemia levels, along with high proportions of asymptomatic cases, this parasite is not benign. Plasmodium vivax can be associated with severe and even fatal illness. Spreading resistance to chloroquine against the acute attack, and the operational inadequacy of primaquine against the multiple attacks of relapse, exacerbates the risk of poor outcomes among the tens of millions suffering from infection each year. Without strategies accounting for these P. vivax-specific characteristics, progress toward elimination of endemic malaria transmission will be substantially impeded.
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Affiliation(s)
- Rosalind E. Howes
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Katherine E. Battle
- Spatial Ecology and Epidemiology Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kamini N. Mendis
- Global Malaria Program, World Health Organization, Geneva, Switzerland
| | - David L. Smith
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland
- Sanaria Institute for Global Health and Tropical Medicine, Rockville, Maryland
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
| | | | - J. Kevin Baird
- Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Simon I. Hay
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, United Kingdom
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Impact of mosquito gene drive on malaria elimination in a computational model with explicit spatial and temporal dynamics. Proc Natl Acad Sci U S A 2016; 114:E255-E264. [PMID: 28028208 DOI: 10.1073/pnas.1611064114] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The renewed effort to eliminate malaria and permanently remove its tremendous burden highlights questions of what combination of tools would be sufficient in various settings and what new tools need to be developed. Gene drive mosquitoes constitute a promising set of tools, with multiple different possible approaches including population replacement with introduced genes limiting malaria transmission, driving-Y chromosomes to collapse a mosquito population, and gene drive disrupting a fertility gene and thereby achieving population suppression or collapse. Each of these approaches has had recent success and advances under laboratory conditions, raising the urgency for understanding how each could be deployed in the real world and the potential impacts of each. New analyses are needed as existing models of gene drive primarily focus on nonseasonal or nonspatial dynamics. We use a mechanistic, spatially explicit, stochastic, individual-based mathematical model to simulate each gene drive approach in a variety of sub-Saharan African settings. Each approach exhibits a broad region of gene construct parameter space with successful elimination of malaria transmission due to the targeted vector species. The introduction of realistic seasonality in vector population dynamics facilitates gene drive success compared with nonseasonal analyses. Spatial simulations illustrate constraints on release timing, frequency, and spatial density in the most challenging settings for construct success. Within its parameter space for success, each gene drive approach provides a tool for malaria elimination unlike anything presently available. Provided potential barriers to success are surmounted, each achieves high efficacy at reducing transmission potential and lower delivery requirements in logistically challenged settings.
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Gething PW, Casey DC, Weiss DJ, Bisanzio D, Bhatt S, Cameron E, Battle KE, Dalrymple U, Rozier J, Rao PC, Kutz MJ, Barber RM, Huynh C, Shackelford KA, Coates MM, Nguyen G, Fraser MS, Kulikoff R, Wang H, Naghavi M, Smith DL, Murray CJL, Hay SI, Lim SS. Mapping Plasmodium falciparum Mortality in Africa between 1990 and 2015. N Engl J Med 2016; 375:2435-2445. [PMID: 27723434 PMCID: PMC5484406 DOI: 10.1056/nejmoa1606701] [Citation(s) in RCA: 185] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Malaria control has not been routinely informed by the assessment of subnational variation in malaria deaths. We combined data from the Malaria Atlas Project and the Global Burden of Disease Study to estimate malaria mortality across sub-Saharan Africa on a grid of 5 km2 from 1990 through 2015. METHODS We estimated malaria mortality using a spatiotemporal modeling framework of geolocated data (i.e., with known latitude and longitude) on the clinical incidence of malaria, coverage of antimalarial drug treatment, case fatality rate, and population distribution according to age. RESULTS Across sub-Saharan Africa during the past 15 years, we estimated that there was an overall decrease of 57% (95% uncertainty interval, 46 to 65) in the rate of malaria deaths, from 12.5 (95% uncertainty interval, 8.3 to 17.0) per 10,000 population in 2000 to 5.4 (95% uncertainty interval, 3.4 to 7.9) in 2015. This led to an overall decrease of 37% (95% uncertainty interval, 36 to 39) in the number of malaria deaths annually, from 1,007,000 (95% uncertainty interval, 666,000 to 1,376,000) to 631,000 (95% uncertainty interval, 394,000 to 914,000). The share of malaria deaths among children younger than 5 years of age ranged from more than 80% at a rate of death of more than 25 per 10,000 to less than 40% at rates below 1 per 10,000. Areas with high malaria mortality (>10 per 10,000) and low coverage (<50%) of insecticide-treated bed nets and antimalarial drugs included much of Nigeria, Angola, and Cameroon and parts of the Central African Republic, Congo, Guinea, and Equatorial Guinea. CONCLUSIONS We estimated that there was an overall decrease of 57% in the rate of death from malaria across sub-Saharan Africa over the past 15 years and identified several countries in which high rates of death were associated with low coverage of antimalarial treatment and prevention programs. (Funded by the Bill and Melinda Gates Foundation and others.).
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Affiliation(s)
- Peter W Gething
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Daniel C Casey
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Daniel J Weiss
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Donal Bisanzio
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Samir Bhatt
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Ewan Cameron
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Katherine E Battle
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Ursula Dalrymple
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Jennifer Rozier
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Puja C Rao
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Michael J Kutz
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Ryan M Barber
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Chantal Huynh
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Katya A Shackelford
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Matthew M Coates
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Grant Nguyen
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Maya S Fraser
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Rachel Kulikoff
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Haidong Wang
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Mohsen Naghavi
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - David L Smith
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Christopher J L Murray
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Simon I Hay
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
| | - Stephen S Lim
- From the Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Oxford (P.W.G., D.J.W., D.B., E.C., K.E.B., U.D., J.R.), and the Department of Infectious Disease Epidemiology, Imperial College London, London (S.B.) - both in the United Kingdom; and the Institute for Health Metrics and Evaluation, University of Washington, Seattle (D.C.C., P.C.R., M.J.K., R.M.B., C.H., K.A.S., M.M.C., G.N., M.S.F., R.K., H.W., M.N., D.L.S., C.J.L.M., S.I.H., S.S.L.)
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Vos T, Allen C, Arora M, Barber RM, Bhutta ZA, Brown A, Carter A, Casey DC, Charlson FJ, Chen AZ, Coggeshall M, Cornaby L, Dandona L, Dicker DJ, Dilegge T, Erskine HE, Ferrari AJ, Fitzmaurice C, Fleming T, Forouzanfar MH, Fullman N, Gething PW, Goldberg EM, Graetz N, Haagsma JA, Hay SI, Johnson CO, Kassebaum NJ, Kawashima T, Kemmer L, Khalil IA, Kinfu Y, Kyu HH, Leung J, Liang X, Lim SS, Lopez AD, Lozano R, Marczak L, Mensah GA, Mokdad AH, Naghavi M, Nguyen G, Nsoesie E, Olsen H, Pigott DM, Pinho C, Rankin Z, Reinig N, Salomon JA, Sandar L, Smith A, Stanaway J, Steiner C, Teeple S, Thomas BA, Troeger C, Wagner JA, Wang H, Wanga V, Whiteford HA, Zoeckler L, Abajobir AA, Abate KH, Abbafati C, Abbas KM, Abd-Allah F, Abraham B, Abubakar I, Abu-Raddad LJ, Abu-Rmeileh NME, Ackerman IN, Adebiyi AO, Ademi Z, Adou AK, Afanvi KA, Agardh EE, Agarwal A, Kiadaliri AA, Ahmadieh H, Ajala ON, Akinyemi RO, Akseer N, Al-Aly Z, Alam K, Alam NKM, Aldhahri SF, Alegretti MA, Alemu ZA, Alexander LT, Alhabib S, Ali R, Alkerwi A, Alla F, Allebeck P, Al-Raddadi R, Alsharif U, Altirkawi KA, Alvis-Guzman N, Amare AT, Amberbir A, Amini H, Ammar W, Amrock SM, Andersen HH, Anderson GM, Anderson BO, Antonio CAT, Aregay AF, Ärnlöv J, Artaman A, Asayesh H, Assadi R, Atique S, Avokpaho EFGA, Awasthi A, Quintanilla BPA, Azzopardi P, Bacha U, Badawi A, Balakrishnan K, Banerjee A, Barac A, Barker-Collo SL, Bärnighausen T, Barregard L, Barrero LH, Basu A, Bazargan-Hejazi S, Beghi E, Bell B, Bell ML, Bennett DA, Bensenor IM, Benzian H, Berhane A, Bernabé E, Betsu BD, Beyene AS, Bhala N, Bhatt S, Biadgilign S, Bienhoff K, Bikbov B, Biryukov S, Bisanzio D, Bjertness E, Blore J, Borschmann R, Boufous S, Brainin M, Brazinova A, Breitborde NJK, Brown J, Buchbinder R, Buckle GC, Butt ZA, Calabria B, Campos-Nonato IR, Campuzano JC, Carabin H, Cárdenas R, Carpenter DO, Carrero JJ, Castañeda-Orjuela CA, Rivas JC, Catalá-López F, Chang JC, Chiang PPC, Chibueze CE, Chisumpa VH, Choi JYJ, Chowdhury R, Christensen H, Christopher DJ, Ciobanu LG, Cirillo M, Coates MM, Colquhoun SM, Cooper C, Cortinovis M, Crump JA, Damtew SA, Dandona R, Daoud F, Dargan PI, das Neves J, Davey G, Davis AC, Leo DD, Degenhardt L, Gobbo LCD, Dellavalle RP, Deribe K, Deribew A, Derrett S, Jarlais DCD, Dharmaratne SD, Dhillon PK, Diaz-Torné C, Ding EL, Driscoll TR, Duan L, Dubey M, Duncan BB, Ebrahimi H, Ellenbogen RG, Elyazar I, Endres M, Endries AY, Ermakov SP, Eshrati B, Estep K, Farid TA, Farinha CSES, Faro A, Farvid MS, Farzadfar F, Feigin VL, Felson DT, Fereshtehnejad SM, Fernandes JG, Fernandes JC, Fischer F, Fitchett JRA, Foreman K, Fowkes FGR, Fox J, Franklin RC, Friedman J, Frostad J, Fürst T, Futran ND, Gabbe B, Ganguly P, Gankpé FG, Gebre T, Gebrehiwot TT, Gebremedhin AT, Geleijnse JM, Gessner BD, Gibney KB, Ginawi IAM, Giref AZ, Giroud M, Gishu MD, Giussani G, Glaser E, Godwin WW, Gomez-Dantes H, Gona P, Goodridge A, Gopalani SV, Gotay CC, Goto A, Gouda HN, Grainger R, Greaves F, Guillemin F, Guo Y, Gupta R, Gupta R, Gupta V, Gutiérrez RA, Haile D, Hailu AD, Hailu GB, Halasa YA, Hamadeh RR, Hamidi S, Hammami M, Hancock J, Handal AJ, Hankey GJ, Hao Y, Harb HL, Harikrishnan S, Haro JM, Havmoeller R, Hay RJ, Heredia-Pi IB, Heydarpour P, Hoek HW, Horino M, Horita N, Hosgood HD, Hoy DG, Htet AS, Huang H, Huang JJ, Huynh C, Iannarone M, Iburg KM, Innos K, Inoue M, Iyer VJ, Jacobsen KH, Jahanmehr N, Jakovljevic MB, Javanbakht M, Jayaraman SP, Jayatilleke AU, Jee SH, Jeemon P, Jensen PN, Jiang Y, Jibat T, Jimenez-Corona A, Jin Y, Jonas JB, Kabir Z, Kalkonde Y, Kamal R, Kan H, Karch A, Karema CK, Karimkhani C, Kasaeian A, Kaul A, Kawakami N, Keiyoro PN, Kemp AH, Keren A, Kesavachandran CN, Khader YS, Khan AR, Khan EA, Khang YH, Khera S, Khoja TAM, Khubchandani J, Kieling C, Kim P, Kim CI, Kim D, Kim YJ, Kissoon N, Knibbs LD, Knudsen AK, Kokubo Y, Kolte D, Kopec JA, Kosen S, Kotsakis GA, Koul PA, Koyanagi A, Kravchenko M, Defo BK, Bicer BK, Kudom AA, Kuipers EJ, Kumar GA, Kutz M, Kwan GF, Lal A, Lalloo R, Lallukka T, Lam H, Lam JO, Langan SM, Larsson A, Lavados PM, Leasher JL, Leigh J, Leung R, Levi M, Li Y, Li Y, Liang J, Liu S, Liu Y, Lloyd BK, Lo WD, Logroscino G, Looker KJ, Lotufo PA, Lunevicius R, Lyons RA, Mackay MT, Magdy M, Razek AE, Mahdavi M, Majdan M, Majeed A, Malekzadeh R, Marcenes W, Margolis DJ, Martinez-Raga J, Masiye F, Massano J, McGarvey ST, McGrath JJ, McKee M, McMahon BJ, Meaney PA, Mehari A, Mejia-Rodriguez F, Mekonnen AB, Melaku YA, Memiah P, Memish ZA, Mendoza W, Meretoja A, Meretoja TJ, Mhimbira FA, Millear A, Miller TR, Mills EJ, Mirarefin M, Mitchell PB, Mock CN, Mohammadi A, Mohammed S, Monasta L, Hernandez JCM, Montico M, Mooney MD, Moradi-Lakeh M, Morawska L, Mueller UO, Mullany E, Mumford JE, Murdoch ME, Nachega JB, Nagel G, Naheed A, Naldi L, Nangia V, Newton JN, Ng M, Ngalesoni FN, Nguyen QL, Nisar MI, Pete PMN, Nolla JM, Norheim OF, Norman RE, Norrving B, Nunes BP, Ogbo FA, Oh IH, Ohkubo T, Olivares PR, Olusanya BO, Olusanya JO, Ortiz A, Osman M, Ota E, PA M, Park EK, Parsaeian M, de Azeredo Passos VM, Caicedo AJP, Patten SB, Patton GC, Pereira DM, Perez-Padilla R, Perico N, Pesudovs K, Petzold M, Phillips MR, Piel FB, Pillay JD, Pishgar F, Plass D, Platts-Mills JA, Polinder S, Pond CD, Popova S, Poulton RG, Pourmalek F, Prabhakaran D, Prasad NM, Qorbani M, Rabiee RHS, Radfar A, Rafay A, Rahimi K, Rahimi-Movaghar V, Rahman M, Rahman MHU, Rahman SU, Rai RK, Rajsic S, Ram U, Rao P, Refaat AH, Reitsma MB, Remuzzi G, Resnikoff S, Reynolds A, Ribeiro AL, Blancas MJR, Roba HS, Rojas-Rueda D, Ronfani L, Roshandel G, Roth GA, Rothenbacher D, Roy A, Sagar R, Sahathevan R, Sanabria JR, Sanchez-Niño MD, Santos IS, Santos JV, Sarmiento-Suarez R, Sartorius B, Satpathy M, Savic M, Sawhney M, Schaub MP, Schmidt MI, Schneider IJC, Schöttker B, Schwebel DC, Scott JG, Seedat S, Sepanlou SG, Servan-Mori EE, Shackelford KA, Shaheen A, Shaikh MA, Sharma R, Sharma U, Shen J, Shepard DS, Sheth KN, Shibuya K, Shin MJ, Shiri R, Shiue I, Shrime MG, Sigfusdottir ID, Silva DAS, Silveira DGA, Singh A, Singh JA, Singh OP, Singh PK, Sivonda A, Skirbekk V, Skogen JC, Sligar A, Sliwa K, Soljak M, Søreide K, Sorensen RJD, Soriano JB, Sposato LA, Sreeramareddy CT, Stathopoulou V, Steel N, Stein DJ, Steiner TJ, Steinke S, Stovner L, Stroumpoulis K, Sunguya BF, Sur P, Swaminathan S, Sykes BL, Szoeke CEI, Tabarés-Seisdedos R, Takala JS, Tandon N, Tanne D, Tavakkoli M, Taye B, Taylor HR, Ao BJT, Tedla BA, Terkawi AS, Thomson AJ, Thorne-Lyman AL, Thrift AG, Thurston GD, Tobe-Gai R, Tonelli M, Topor-Madry R, Topouzis F, Tran BX, Truelsen T, Dimbuene ZT, Tsilimbaris M, Tura AK, Tuzcu EM, Tyrovolas S, Ukwaja KN, Undurraga EA, Uneke CJ, Uthman OA, van Gool CH, Varakin YY, Vasankari T, Venketasubramanian N, Verma RK, Violante FS, Vladimirov SK, Vlassov VV, Vollset SE, Wagner GR, Waller SG, Wang L, Watkins DA, Weichenthal S, Weiderpass E, Weintraub RG, Werdecker A, Westerman R, White RA, Williams HC, Wiysonge CS, Wolfe CDA, Won S, Woodbrook R, Wubshet M, Xavier D, Xu G, Yadav AK, Yan LL, Yano Y, Yaseri M, Ye P, Yebyo HG, Yip P, Yonemoto N, Yoon SJ, Younis MZ, Yu C, Zaidi Z, Zaki MES, Zeeb H, Zhou M, Zodpey S, Zuhlke LJ, Murray CJL. Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015. Lancet 2016; 388:1545-1602. [PMID: 27733282 PMCID: PMC5055577 DOI: 10.1016/s0140-6736(16)31678-6] [Citation(s) in RCA: 4522] [Impact Index Per Article: 565.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/11/2016] [Accepted: 08/16/2016] [Indexed: 01/06/2023]
Abstract
BACKGROUND Non-fatal outcomes of disease and injury increasingly detract from the ability of the world's population to live in full health, a trend largely attributable to an epidemiological transition in many countries from causes affecting children, to non-communicable diseases (NCDs) more common in adults. For the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015), we estimated the incidence, prevalence, and years lived with disability for diseases and injuries at the global, regional, and national scale over the period of 1990 to 2015. METHODS We estimated incidence and prevalence by age, sex, cause, year, and geography with a wide range of updated and standardised analytical procedures. Improvements from GBD 2013 included the addition of new data sources, updates to literature reviews for 85 causes, and the identification and inclusion of additional studies published up to November, 2015, to expand the database used for estimation of non-fatal outcomes to 60 900 unique data sources. Prevalence and incidence by cause and sequelae were determined with DisMod-MR 2.1, an improved version of the DisMod-MR Bayesian meta-regression tool first developed for GBD 2010 and GBD 2013. For some causes, we used alternative modelling strategies where the complexity of the disease was not suited to DisMod-MR 2.1 or where incidence and prevalence needed to be determined from other data. For GBD 2015 we created a summary indicator that combines measures of income per capita, educational attainment, and fertility (the Socio-demographic Index [SDI]) and used it to compare observed patterns of health loss to the expected pattern for countries or locations with similar SDI scores. FINDINGS We generated 9·3 billion estimates from the various combinations of prevalence, incidence, and YLDs for causes, sequelae, and impairments by age, sex, geography, and year. In 2015, two causes had acute incidences in excess of 1 billion: upper respiratory infections (17·2 billion, 95% uncertainty interval [UI] 15·4-19·2 billion) and diarrhoeal diseases (2·39 billion, 2·30-2·50 billion). Eight causes of chronic disease and injury each affected more than 10% of the world's population in 2015: permanent caries, tension-type headache, iron-deficiency anaemia, age-related and other hearing loss, migraine, genital herpes, refraction and accommodation disorders, and ascariasis. The impairment that affected the greatest number of people in 2015 was anaemia, with 2·36 billion (2·35-2·37 billion) individuals affected. The second and third leading impairments by number of individuals affected were hearing loss and vision loss, respectively. Between 2005 and 2015, there was little change in the leading causes of years lived with disability (YLDs) on a global basis. NCDs accounted for 18 of the leading 20 causes of age-standardised YLDs on a global scale. Where rates were decreasing, the rate of decrease for YLDs was slower than that of years of life lost (YLLs) for nearly every cause included in our analysis. For low SDI geographies, Group 1 causes typically accounted for 20-30% of total disability, largely attributable to nutritional deficiencies, malaria, neglected tropical diseases, HIV/AIDS, and tuberculosis. Lower back and neck pain was the leading global cause of disability in 2015 in most countries. The leading cause was sense organ disorders in 22 countries in Asia and Africa and one in central Latin America; diabetes in four countries in Oceania; HIV/AIDS in three southern sub-Saharan African countries; collective violence and legal intervention in two north African and Middle Eastern countries; iron-deficiency anaemia in Somalia and Venezuela; depression in Uganda; onchoceriasis in Liberia; and other neglected tropical diseases in the Democratic Republic of the Congo. INTERPRETATION Ageing of the world's population is increasing the number of people living with sequelae of diseases and injuries. Shifts in the epidemiological profile driven by socioeconomic change also contribute to the continued increase in years lived with disability (YLDs) as well as the rate of increase in YLDs. Despite limitations imposed by gaps in data availability and the variable quality of the data available, the standardised and comprehensive approach of the GBD study provides opportunities to examine broad trends, compare those trends between countries or subnational geographies, benchmark against locations at similar stages of development, and gauge the strength or weakness of the estimates available. FUNDING Bill & Melinda Gates Foundation.
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Korenromp E, Mahiané G, Hamilton M, Pretorius C, Cibulskis R, Lauer J, Smith TA, Briët OJT. Malaria intervention scale-up in Africa: effectiveness predictions for health programme planning tools, based on dynamic transmission modelling. Malar J 2016; 15:417. [PMID: 27538889 PMCID: PMC4991118 DOI: 10.1186/s12936-016-1461-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 07/29/2016] [Indexed: 12/22/2022] Open
Abstract
Background Scale-up of malaria prevention and treatment needs to continue to further important gains made in the past decade, but national strategies and budget allocations are not always evidence-based. Statistical models were developed summarizing dynamically simulated relations between increases in coverage and intervention impact, to inform a malaria module in the Spectrum health programme planning tool. Methods The dynamic Plasmodiumfalciparum transmission model OpenMalaria was used to simulate health effects of scale-up of insecticide-treated net (ITN) usage, indoor residual spraying (IRS), management of uncomplicated malaria cases (CM) and seasonal malaria chemoprophylaxis (SMC) over a 10-year horizon, over a range of settings with stable endemic malaria. Generalized linear regression models (GLMs) were used to summarize determinants of impact across a range of sub-Sahara African settings. Results Selected (best) GLMs explained 94–97 % of variation in simulated post-intervention parasite infection prevalence, 86–97 % of variation in case incidence (three age groups, three 3-year horizons), and 74–95 % of variation in malaria mortality. For any given effective population coverage, CM and ITNs were predicted to avert most prevalent infections, cases and deaths, with lower impacts for IRS, and impacts of SMC limited to young children reached. Proportional impacts were larger at lower endemicity, and (except for SMC) largest in low-endemic settings with little seasonality. Incremental health impacts for a given coverage increase started to diminish noticeably at above ~40 % coverage, while in high-endemic settings, CM and ITNs acted in synergy by lowering endemicity. Vector control and CM, by reducing endemicity and acquired immunity, entail a partial rebound in malaria mortality among people above 5 years of age from around 5–7 years following scale-up. SMC does not reduce endemicity, but slightly shifts malaria to older ages by reducing immunity in child cohorts reached. Conclusion Health improvements following malaria intervention scale-up vary with endemicity, seasonality, age and time. Statistical models can emulate epidemiological dynamics and inform strategic planning and target setting for malaria control. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1461-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | - Richard Cibulskis
- World Health Organization Global Malaria Programme, Geneva, Switzerland
| | - Jeremy Lauer
- World Health Organization Health Systems Governance and Financing dept., Geneva, Switzerland
| | - Thomas A Smith
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Olivier J T Briët
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
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Rodriguez-Barraquer I, Arinaitwe E, Jagannathan P, Boyle MJ, Tappero J, Muhindo M, Kamya MR, Dorsey G, Drakeley C, Ssewanyana I, Smith DL, Greenhouse B. Quantifying Heterogeneous Malaria Exposure and Clinical Protection in a Cohort of Ugandan Children. J Infect Dis 2016; 214:1072-80. [PMID: 27481862 DOI: 10.1093/infdis/jiw301] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/12/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Plasmodium falciparum malaria remains a leading cause of childhood morbidity and mortality. There are important gaps in our understanding of the factors driving the development of antimalaria immunity as a function of age and exposure. METHODS We used data from a cohort of 93 children participating in a clinical trial in Tororo, Uganda, an area of very high exposure to P. falciparum We jointly quantified individual heterogeneity in the risk of infection and the development of immunity against infection and clinical disease. RESULTS Results showed significant heterogeneity in the hazard of infection and independent effects of age and cumulative number of infections on the risk of infection and disease. The risk of developing clinical malaria upon infection decreased on average by 6% (95% confidence interval [CI], 0%-12%) for each additional year of age and by 2% (95% CI, 1%-3%) for each additional prior infection. Children randomly assigned to receive dihydroartemisinin-piperaquine for treatment appeared to develop immunity more slowly than those receiving artemether-lumefantrine. CONCLUSIONS Heterogeneity in P. falciparum exposure and immunity can be independently evaluated using detailed longitudinal studies. Improved understanding of the factors driving immunity will provide key information to anticipate the impact of malaria-control interventions and to understand the mechanisms of clinical immunity.
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Affiliation(s)
| | | | - Prasanna Jagannathan
- Department of Medicine, San Francisco General Hospital, University of California-San Francisco
| | - Michelle J Boyle
- Department of Medicine, San Francisco General Hospital, University of California-San Francisco Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Jordan Tappero
- Division of Global Health Protection, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Moses R Kamya
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, San Francisco General Hospital, University of California-San Francisco
| | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, United Kingdom
| | | | - David L Smith
- London School of Hygiene and Tropical Medicine, United Kingdom
| | - Bryan Greenhouse
- Department of Medicine, San Francisco General Hospital, University of California-San Francisco
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Evaluation of new scientific information on Phyllosticta citricarpa in relation to the EFSA PLH Panel (2014) Scientific Opinion on the plant health risk to the EU. EFSA J 2016. [DOI: 10.2903/j.efsa.2016.4513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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