ORCID Profile
0000-0003-2401-2615
Current Organisations
Bill & Melinda Gates Foundation
,
University of Oxford
,
Institute for Disease Modeling
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Publisher: Springer Science and Business Media LLC
Date: 18-08-2015
Abstract: Measures of clinical incidence are necessary to help estimate the burden of a disease. Incidence is a metric not commonly measured in malariology because the longitudinal surveys required are costly and labour intensive. This database is an effort to collate published incidence records obtained using active case detection for Plasmodium falciparum and Plasmodium vivax malaria. The literature search methods, data abstraction procedures and data processing procedures are described here. A total of 1,680 spatio-temporally unique incidence records were collected for the database: 1,187 for P. falciparum and 493 for P. vivax . These data were gathered to model the relationship between clinical incidence and prevalence of infection and can be used for a variety of modelling exercises including the assessment of change in disease burden in relation to age and control interventions. The subset of data that have been used for such modelling exercises are described and identified.
Publisher: Springer Science and Business Media LLC
Date: 11-06-2021
DOI: 10.1038/S41467-021-23707-7
Abstract: Insecticide-treated nets (ITNs) are one of the most widespread and impactful malaria interventions in Africa, yet a spatially-resolved time series of ITN coverage has never been published. Using data from multiple sources, we generate high-resolution maps of ITN access, use, and nets-per-capita annually from 2000 to 2020 across the 40 highest-burden African countries. Our findings support several existing hypotheses: that use is high among those with access, that nets are discarded more quickly than official policy presumes, and that effectively distributing nets grows more difficult as coverage increases. The primary driving factors behind these findings are most likely strong cultural and social messaging around the importance of net use, low physical net durability, and a mixture of inherent commodity distribution challenges and less-than-optimal net allocation policies, respectively. These results can inform both policy decisions and downstream malaria analyses.
Publisher: Public Library of Science (PLoS)
Date: 31-01-2019
Publisher: Springer Science and Business Media LLC
Date: 16-09-2015
DOI: 10.1038/NATURE15535
Publisher: The Royal Society
Date: 19-03-2013
Abstract: The primary aim of this review was to evaluate the state of knowledge of the geographical distribution of all infectious diseases of clinical significance to humans. A systematic review was conducted to enumerate cartographic progress, with respect to the data available for mapping and the methods currently applied. The results helped define the minimum information requirements for mapping infectious disease occurrence, and a quantitative framework for assessing the mapping opportunities for all infectious diseases. This revealed that of 355 infectious diseases identified, 174 (49%) have a strong rationale for mapping and of these only 7 (4%) had been comprehensively mapped. A variety of ambitions, such as the quantification of the global burden of infectious disease, international biosurveillance, assessing the likelihood of infectious disease outbreaks and exploring the propensity for infectious disease evolution and emergence, are limited by these omissions. An overview of the factors hindering progress in disease cartography is provided. It is argued that rapid improvement in the landscape of infectious diseases mapping can be made by embracing non-conventional data sources, automation of geo-positioning and mapping procedures enabled by machine learning and information technology, respectively, in addition to harnessing labour of the volunteer ‘cognitive surplus’ through crowdsourcing.
Publisher: Springer Science and Business Media LLC
Date: 11-01-2016
Publisher: Public Library of Science (PLoS)
Date: 05-08-2016
DOI: 10.1371/JOURNAL.PNTD.0004915
Abstract: Infection by the simian malaria parasite, Plasmodium knowlesi, can lead to severe and fatal disease in humans, and is the most common cause of malaria in parts of Malaysia. Despite being a serious public health concern, the geographical distribution of P. knowlesi malaria risk is poorly understood because the parasite is often misidentified as one of the human malarias. Human cases have been confirmed in at least nine Southeast Asian countries, many of which are making progress towards eliminating the human malarias. Understanding the geographical distribution of P. knowlesi is important for identifying areas where malaria transmission will continue after the human malarias have been eliminated. A total of 439 records of P. knowlesi infections in humans, macaque reservoir and vector species were collated. To predict spatial variation in disease risk, a model was fitted using records from countries where the infection data coverage is high. Predictions were then made throughout Southeast Asia, including regions where infection data are sparse. The resulting map predicts areas of high risk for P. knowlesi infection in a number of countries that are forecast to be malaria-free by 2025 (Malaysia, Cambodia, Thailand and Vietnam) as well as countries projected to be eliminating malaria (Myanmar, Laos, Indonesia and the Philippines). We have produced the first map of P. knowlesi malaria risk, at a fine-scale resolution, to identify priority areas for surveillance based on regions with sparse data and high estimated risk. Our map provides an initial evidence base to better understand the spatial distribution of this disease and its potential wider contribution to malaria incidence. Considering malaria elimination goals, areas for prioritised surveillance are identified.
Publisher: Springer Science and Business Media LLC
Date: 30-01-2014
Publisher: Public Library of Science (PLoS)
Date: 06-2021
DOI: 10.1371/JOURNAL.PMED.1003614
Abstract: In 2017, an estimated 14 million cases of Plasmodium vivax malaria were reported from Asia, Central and South America, and the Horn of Africa. The clinical burden of vivax malaria is largely driven by its ability to form dormant liver stages (hypnozoites) that can reactivate to cause recurrent episodes of malaria. Elimination of both the blood and liver stages of the parasites (“radical cure”) is required to achieve a sustained clinical response and prevent ongoing transmission of the parasite. Novel treatment options and point-of-care diagnostics are now available to ensure that radical cure can be administered safely and effectively. We quantified the global economic cost of vivax malaria and estimated the potential cost benefit of a policy of radical cure after testing patients for glucose-6-phosphate dehydrogenase (G6PD) deficiency. Estimates of the healthcare provider and household costs due to vivax malaria were collated and combined with national case estimates for 44 endemic countries in 2017. These provider and household costs were compared with those that would be incurred under 2 scenarios for radical cure following G6PD screening: (1) complete adherence following daily supervised primaquine therapy and (2) unsupervised treatment with an assumed 40% effectiveness. A probabilistic sensitivity analysis generated credible intervals (CrIs) for the estimates. Globally, the annual cost of vivax malaria was US$359 million (95% CrI: US$222 to 563 million), attributable to 14.2 million cases of vivax malaria in 2017. From a societal perspective, adopting a policy of G6PD deficiency screening and supervision of primaquine to all eligible patients would prevent 6.1 million cases and reduce the global cost of vivax malaria to US$266 million (95% CrI: US$161 to 415 million), although healthcare provider costs would increase by US$39 million. If perfect adherence could be achieved with a single visit, then the global cost would fall further to US$225 million, equivalent to $135 million in cost savings from the baseline global costs. A policy of unsupervised primaquine reduced the cost to US$342 million (95% CrI: US$209 to 532 million) while preventing 2.1 million cases. Limitations of the study include partial availability of country-level cost data and parameter uncertainty for the proportion of patients prescribed primaquine, patient adherence to a full course of primaquine, and effectiveness of primaquine when unsupervised. Our modelling study highlights a substantial global economic burden of vivax malaria that could be reduced through investment in safe and effective radical cure achieved by routine screening for G6PD deficiency and supervision of treatment. Novel, low-cost interventions for improving adherence to primaquine to ensure effective radical cure and widespread access to screening for G6PD deficiency will be critical to achieving the timely global elimination of P . vivax .
Publisher: Public Library of Science (PLoS)
Date: 23-03-2020
Publisher: Public Library of Science (PLoS)
Date: 13-11-2012
Publisher: Wiley
Date: 29-01-2020
Publisher: Springer Science and Business Media LLC
Date: 30-09-2014
Abstract: The leishmaniases are neglected tropical diseases of significant public health importance. However, information on their global occurrence is disparate and sparse. This database represents an attempt to collate reported leishmaniasis occurrences from 1960 to 2012. Methodology for the collection of data from the literature, abstraction of case locations and data processing procedures are described here. In addition, strain archives and online data resources were accessed. A total of 12,563 spatially and temporally unique occurrences of both cutaneous and visceral leishmaniasis comprise the database, ranging in geographic scale from villages to states. These data can be used for a variety of mapping and spatial analyses covering multiple resolutions.
Publisher: Elsevier BV
Date: 03-2014
Publisher: Springer Science and Business Media LLC
Date: 08-09-2015
DOI: 10.1038/NCOMMS9170
Abstract: In many countries health system data remain too weak to accurately enumerate Plasmodium falciparum malaria cases. In response, cartographic approaches have been developed that link maps of infection prevalence with mathematical relationships to predict the incidence rate of clinical malaria. Microsimulation (or ‘agent-based’) models represent a powerful new paradigm for defining such relationships however, differences in model structure and calibration data mean that no consensus yet exists on the optimal form for use in disease-burden estimation. Here we develop a Bayesian statistical procedure combining functional regression-based model emulation with Markov Chain Monte Carlo s ling to calibrate three selected microsimulation models against a purpose-built data set of age-structured prevalence and incidence counts. This allows the generation of ensemble forecasts of the prevalence–incidence relationship stratified by age, transmission seasonality, treatment level and exposure history, from which we predict accelerating returns on investments in large-scale intervention c aigns as transmission and prevalence are progressively reduced.
Publisher: F1000 Research Ltd
Date: 13-11-2018
DOI: 10.12688/GATESOPENRES.12838.2
Abstract: Background: Heterogeneity in malaria transmission has household, temporal, and spatial components. These factors are relevant for improving the efficiency of malaria control by targeting heterogeneity. To quantify variation, we analyzed mosquito counts from entomological surveillance conducted at three study sites in Uganda that varied in malaria transmission intensity. Mosquito biting or exposure is a risk factor for malaria transmission. Methods: Using a Bayesian zero-inflated negative binomial model, validated via a comprehensive simulation study, we quantified household differences in malaria vector density and examined its spatial distribution. We introduced a novel approach for identifying changes in vector abundance hotspots over time by computing the Getis-Ord statistic on ratios of household biting propensities for different scenarios. We also explored the association of household biting propensities with housing and environmental covariates. Results: In each site, there was evidence for hot and cold spots of vector abundance, and spatial patterns associated with urbanicity, elevation, or other environmental covariates. We found some differences in the hotspots in rainy vs. dry seasons or before vs. after the application of control interventions. Housing quality explained a portion of the variation among households in mosquito counts. Conclusion: This work provided an improved understanding of heterogeneity in malaria vector density at the three study sites in Uganda and offered a valuable opportunity for assessing whether interventions could be spatially targeted to be aimed at abundance hotspots which may increase malaria risk. Indoor residual spraying was shown to be a successful measure of vector control interventions in Tororo, Uganda. Cement walls, brick floors, closed eaves, screened airbricks, and tiled roofs were features of a house that had shown reduction of household biting propensity. Improvements in house quality should be recommended as a supplementary measure for malaria control reducing risk of infection.
Publisher: Elsevier
Date: 2012
Publisher: Springer Science and Business Media LLC
Date: 07-05-2015
Publisher: F1000 Research Ltd
Date: 18-07-2018
DOI: 10.12688/GATESOPENRES.12838.1
Abstract: Background: Heterogeneity in malaria transmission has household, temporal, and spatial components. These factors are relevant for improving the efficiency of malaria control by targeting heterogeneity. To quantify variation, we analyzed mosquito counts from entomological surveillance conducted at three study sites in Uganda that varied in malaria transmission intensity. Methods: Using a Bayesian zero-inflated negative binomial model, validated via a comprehensive simulation study, we quantified household differences in malaria vector density and examined its spatial distribution. We introduced a novel approach for identifying changes in malaria hotspots over time by computing the Getis-Ord statistic on ratios of household biting propensities for different scenarios. We also explored the association of household biting propensities with housing and environmental covariates. Results: In each site, there was evidence for hot and cold spots, spatial patterns associated with urbanicity, elevation, or other environmental covariates. We found some differences in the hotspots in rainy vs. dry seasons or before vs. after the application of control interventions. Housing quality explained a portion of the variation among households in mosquito counts. Conclusion: This work provided an improved understanding of heterogeneity in malaria vector density at the three study sites in Uganda and offered a valuable opportunity for assessing whether interventions could be spatially targeted to be aimed at hotspots of malaria risk. Indoor residual spraying was shown to be a successful measure of vector control interventions in Tororo, Uganda. Cement walls, brick floors, closed eaves, screened airbricks, and tiled roofs were features of a house that had shown protective effects towards malaria risk. Improvements in house quality should be recommended as a supplementary measure for malaria control.
Publisher: Elsevier BV
Date: 07-2019
Publisher: Public Library of Science (PLoS)
Date: 23-08-2023
DOI: 10.1371/JOURNAL.PGPH.0002134
Abstract: Access to medical treatment for fever is essential to prevent morbidity and mortality in in iduals and to prevent transmission of communicable febrile illness in communities. Quantification of the rates at which treatment is accessed is critical for health system planning and a prerequisite for disease burden estimates. In this study, national data on the proportion of children under five years old with fever who were taken for medical treatment were collected from all available countries in Africa, Latin America, and Asia (n = 91). We used generalised additive mixed models to estimate 30-year trends in the treatment-seeking rates across the majority of countries in these regions (n = 151). Our results show that the proportions of febrile children brought for medical treatment increased steadily over the last 30 years, with the greatest increases occurring in areas where rates had originally been lowest, which includes Latin America and Caribbean, North Africa and the Middle East (51 and 50% increase, respectively), and Sub-Saharan Africa (23% increase). Overall, the aggregated and population-weighted estimate of children with fever taken for treatment at any type of facility rose from 61% (59–64 95% CI) in 1990 to 71% (69–72 95% CI) in 2020. The overall population-weighted average for fraction of treatment in the public sector was largely unchanged during the study period: 49% (42–58 95% CI) sought care at public facilities in 1990 and 47% (44–52 95% CI) in 2020. Overall, the findings indicate that improvements in access to care have been made where they were most needed, but that despite rapid initial gains, progress can plateau without substantial investment. In 2020 there remained significant gaps in care utilisation that must be factored in when developing control strategies and deriving disease burden estimates.
Publisher: Springer Science and Business Media LLC
Date: 15-04-2014
Publisher: Elsevier BV
Date: 07-2019
Publisher: Public Library of Science (PLoS)
Date: 20-11-2015
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-01-2017
DOI: 10.1161/CIRCULATIONAHA.116.022535
Abstract: Exercise and competitive sports should be associated with a wide range of health benefits with the potential to inspire a positive community health legacy. However, the reputation of sports is being threatened by an ever-expanding armamentarium of agents with real or perceived benefits in performance enhancement. In addition to the injustice of unfair advantage for dishonest athletes, significant potential health risks are associated with performance-enhancing drugs. Performance-enhancing drugs may have an effect on the cardiovascular system by means of directly altering the myocardium, vasculature, and metabolism. However, less frequently considered is the potential for indirect effects caused through enabling athletes to push beyond normal physiological limits with the potential consequence of exercise-induced arrhythmias. This review will summarize the known health effects of PEDs but will also focus on the potentially greater health threat posed by the covert search for performance-enhancing agents that have yet to be recognized by the World Anti-Doping Agency. History has taught us that athletes are subjected to unmonitored trials with experimental drugs that have little or no established efficacy or safety data. One approach to decrease drug abuse in sports would be to accept that there is a delay from when athletes start experimenting with novel agents to the time when authorities become aware of these drugs. This provides a window of opportunity for athletes to exploit with relative immunity. It could be argued that all off-label use of any agent should be deemed illegal.
Publisher: Public Library of Science (PLoS)
Date: 06-09-2012
Publisher: eLife Sciences Publications, Ltd
Date: 27-06-2014
DOI: 10.7554/ELIFE.02851
Abstract: The leishmaniases are vector-borne diseases that have a broad global distribution throughout much of the Americas, Africa, and Asia. Despite representing a significant public health burden, our understanding of the global distribution of the leishmaniases remains vague, reliant upon expert opinion and limited to poor spatial resolution. A global assessment of the consensus of evidence for leishmaniasis was performed at a sub-national level by aggregating information from a variety of sources. A database of records of cutaneous and visceral leishmaniasis occurrence was compiled from published literature, online reports, strain archives, and GenBank accessions. These, with a suite of biologically relevant environmental covariates, were used in a boosted regression tree modelling framework to generate global environmental risk maps for the leishmaniases. These high-resolution evidence-based maps can help direct future surveillance activities, identify areas to target for disease control and inform future burden estimation efforts.
Publisher: Public Library of Science (PLoS)
Date: 10-06-2015
Publisher: Cambridge University Press (CUP)
Date: 10-2014
DOI: 10.1017/DMP.2014.93
Abstract: In Cambodia, a highly landmine-contaminated country with endemic malaria, symptomatic falciparum malaria has been observed in patients presenting with traumatic landmine injuries. Because a link between recrudescence of symptomatic Plasmodium falciparum malaria and severe trauma is well established, we explored whether a link could be demonstrated between the geolocation of landmine utations and malaria cases. Landmine utation data in Cambodia (2005–2008) were compared with predicted measures of malaria endemicity. Data of injuries that had resulted in utation were plotted over a surface of P falciparum parasite rates. No statistically significant correlation was found, possibly because the P falciparum endemicity surface was drawn from a model-based geostatistical prediction of infection prevalence and did not distinguish cases of recrudescence. The implication of this finding is that where symptomatic falciparum malaria has been observed in patients with landmine injuries, the cases were likely to be reactivated falciparum infections and not new cases. Further research is needed to understand the relationship between P falciparum and trauma. To distinguish P falciparum recrudescence from new cases, a prospective registry is needed. Also, practitioners need to be aware of the possibility of post-injury malaria recrudescence in complex emergencies. ( Disaster Med Public Health Preparedness . 2014 :1-5)
Publisher: Springer Science and Business Media LLC
Date: 15-11-2013
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Katherine Battle.