Publications
12 results found
Charnley G, Green N, Malembaka E, et al., 2024, Evaluating the risk of conflict on recent Ebola outbreaks in Guinea and the Democratic Republic of the Congo, BMC Public Health, ISSN: 1471-2458
Charnley G, Yennan S, Ochu C, et al., 2023, Cholera past and future in Nigeria: are the Global Task Force on Cholera Control’s 2030 targets achievable?, PLoS Neglected Tropical Diseases, Vol: 17, Pages: 1-18, ISSN: 1935-2727
BackgroundUnderstanding and continually assessing the achievability of global health targets is key to reducing disease burden and mortality. The Global Task Force on Cholera Control (GTFCC) Roadmap aims to reduce cholera deaths by 90% and eliminate the disease in twenty countries by 2030. The Roadmap has three axes focusing on reporting, response and coordination. Here, we assess the achievability of the GTFCC targets in Nigeria and identify where the three axes could be strengthened to reach and exceed these goals.Methodology/Principal findingsUsing cholera surveillance data from Nigeria, cholera incidence was calculated and used to model time-varying reproduction number (R). A best fit random forest model was identified using R as the outcome variable and several environmental and social covariates were considered in the model, using random forest variable importance and correlation clustering. Future scenarios were created (based on varying degrees of socioeconomic development and emission reductions) and used to project future cholera transmission, nationally and sub-nationally to 2070. The projections suggest that significant reductions in cholera cases could be achieved by 2030, particularly in the more developed southern states, but increases in cases remain a possibility. Meeting the 2030 target, nationally, currently looks unlikely and we propose a new 2050 target focusing on reducing regional inequities, while still advocating for cholera elimination being achieved as soon as possible.Conclusion/SignificanceThe 2030 targets could potentially be reached by 2030 in some parts of Nigeria, but more effort is needed to reach these targets at a national level, particularly through access and incentives to cholera testing, sanitation expansion, poverty alleviation and urban planning. The results highlight the importance of and how modelling studies can be used to inform cholera policy and the potential for this to be applied in other contexts.
Liggett D, Herbert A, Badhe R, et al., 2023, Researchers on ice? How the COVID-19 pandemic has impacted Antarctic researchers, Antarctic Science, Vol: 35, Pages: 141-160, ISSN: 0954-1020
The COVID-19 pandemic and pandemic-related measures have impacted the lives and work-related activities of Antarctic researchers. To explore these impacts, we designed, piloted and disseminated an online survey in English, Russian, Spanish and Chinese in late 2020 and early 2021. The survey explored how the pandemic affected the productivity of Antarctic researchers, their career prospects and their mental wellbeing. Findings exposed patterns of inequities. For instance, of the 406 unique responses to the survey, women appeared to have been affected more adversely than men, especially in relation to mental health, and early-career researchers were disadvantaged more than their mid- or late-career colleagues. Overall, a third of the research participants reported at least one major negative impact from the pandemic on their mental health. Approximately half of the participants also mentioned that the COVID-19 pandemic had some positive effects, especially in terms of the advantages that working from home brought and opportunities to attend events, network or benefit from training workshops online. We conclude with a series of recommendations for science administrators and policymakers to mitigate the most serious adverse impacts of the pandemic on Antarctic research communities, with implications for other contexts where scientific activities are conducted under extreme circumstances.
Charnley G, Yennan S, Ochu C, et al., 2022, The impact of social and environmental extremes on cholera time varying reproduction number in Nigeria, PLOS Global Public Health, Vol: 2, ISSN: 2767-3375
Nigeria currently reports the second highest number of cholera cases in Africa, with numerous socioeconomic and environmental risk factors. Less investigated are the role of extreme events, despite recent work showing their potential importance. To address this gap, we used a machine learning approach to understand the risks and thresholds for cholera outbreaks and extreme events, taking into consideration pre-existing vulnerabilities. We estimated time varying reproductive number (R) from cholera incidence in Nigeria and used a machine learning approach to evaluate its association with extreme events (conflict, flood, drought) and pre-existing vulnerabilities (poverty, sanitation, healthcare). We then created a traffic-light system for cholera outbreak risk, using three hypothetical traffic-light scenarios (Red, Amber and Green) and used this to predict R. The system highlighted potential extreme events and socioeconomic thresholds for outbreaks to occur. We found that reducing poverty and increasing access to sanitation lessened vulnerability to increased cholera risk caused by extreme events (monthly conflicts and the Palmers Drought Severity Index). The main limitation is the underreporting of cholera globally and the potential number of cholera cases missed in the data used here. Increasing access to sanitation and decreasing poverty reduced the impact of extreme events in terms of cholera outbreak risk. The results here therefore add further evidence of the need for sustainable development for disaster prevention and mitigation and to improve health and quality of life.
Charnley G, Jean K, Kelman I, et al., 2022, Association between conflict and Cholera in Nigeria and the Democratic Republic of the Congo, Emerging Infectious Diseases, Vol: 28, Pages: 2472-2481, ISSN: 1080-6040
Cholera outbreaks contribute substantially to illness and death in low- and middle-income countries. Cholera outbreaks are associated with several social and environmental risk factors, and extreme conditions can act as catalysts. A social extreme known to be associated with infectious disease outbreaks is conflict, causing disruption to services, loss of income, and displacement. To determine the extent of this association, we used the self-controlled case-series method and found that conflict increased the risk for cholera in Nigeria by 3.6 times and in the Democratic Republic of the Congo by 2.6 times. We also found that 19.7% of cholera outbreaks in Nigeria and 12.3% of outbreaks in the Democratic Republic of the Congo were attributable to conflict. Our results highlight the value of providing rapid and sufficient assistance during conflict-associated cholera outbreaks and working toward conflict resolution and addressing preexisting vulnerabilities, such as poverty and access to healthcare.
Harris M, Charnley G, 2022, Disaster risk management: a resilient health system, Disaster Risk Reduction for Resilience, Editors: Eslamian, Eslamian, Publisher: Springer Nature, Pages: 147-176, ISBN: 978-3-030-72195-4
Defining disasters and their impacts has several difficulties and limitations due to the complexity of the term. In this chapter, we focus on health disasters, including how disasters impact health systems and how widespread health emergencies can create disasters. A health disaster describes an event that has a direct or indirect negative impact on people’s physical and psychological health. Disasters of all kinds are most impactful to vulnerable groups both in developed and developing countries, and it is important to implement effective disaster risk management to facilitate health systems resilience, mobilising them to resist, withstand and recover from disasters. Barriers and ways in which health systems are resilient are multi-faceted, some of which include financing, human resources, management, infrastructure, access, trust and education. Two case studies illustrate how these barriers have played out in real-world contexts and historical lessons learnt. These include the Chernobyl nuclear and health disaster of 1986 and the 2018 Ebola outbreak in the Democratic Republic of Congo. This chapter identifies four priorities for action: understand risk, strengthen governance, invest in resilience and enhance preparedness and considers these on all levels from international to individual. Hazards themselves will not cause health disasters but instead how society reacts and the barriers to resilience. By moving health system resilience to the forefront of legislation and governance, disasters can be mitigated and promote sustainable development throughout the world.
Charnley GEC, Gaythorpe KAM, Kelman I, et al., 2022, Accessing sub-national cholera epidemiological data for Nigeria and the Democratic Republic of Congo during the seventh pandemic, BMC Infectious Diseases, Vol: 22, ISSN: 1471-2334
Background:Vibrio cholerae is a water-borne pathogen with a global burden estimate at 1.4 to 4.0 million annual cases. Over 94% of these cases are reported in Africa and more research is needed to understand cholera dynamics in the region. Cholera data are lacking, mainly due to reporting issues, creating barriers for widespread research on cholera epidemiology and management in Africa.Main body:Here, we present datasets that were created to help address this gap, collating freely available sub-national cholera data for Nigeria and the Democratic Republic of Congo. The data were collated from a variety of English and French publicly available sources, including the World Health Organization, PubMed, UNICEF, EM-DAT, the Nigerian CDC and peer-reviewed literature. These data include information on cases, deaths, age, gender, oral cholera vaccination, risk factors and interventions.Conclusion:These datasets can facilitate qualitative, quantitative and mixed methods research in these two high burden countries to assist in public health planning. The data can be used in collaboration with organisations in the two countries, which have also collected data or undertaking research. By making the data and methods available, we aim to encourage their use and further data collection and compilation to help improve the data gaps for cholera in Africa.
Charnley GEC, Kelman I, Murray KA, 2022, Drought-related cholera outbreaks in Africa and the implications for climate change: a narrative review., Pathogens and Global Health, Vol: 116, Pages: 3-12, ISSN: 2047-7724
Africa has historically seen several periods of prolonged and extreme droughts across the continent, causing food insecurity, exacerbating social inequity and frequent mortality. A known consequence of droughts and their associated risk factors are infectious disease outbreaks, which are worsened by malnutrition, poor access to water, sanitation and hygiene and population displacement. Cholera is a potential causative agent of such outbreaks. Africa has the highest global cholera burden, several drought-prone regions and high levels of inequity. Despite this, research on cholera and drought in Africa is lacking. Here, we review available research on drought-related cholera outbreaks in Africa and identify a variety of potential mechanisms through which these outbreaks occurred, including poor access to water, marginalization of refugees and nomadic populations, expansion of informal urban settlements and demographic risks. Future climate change may alter precipitation, temperature and drought patterns, resulting in more extremes, although these changes are likely to be spatially heterogeneous. Despite high uncertainty in future drought projections, increases in drought frequency and/or durations have the potential to alter these related outbreaks into the future, potentially increasing cholera burden in the absence of countermeasures (e.g. improved sanitation infrastructure). To enable effective planning for a potentially more drought-prone Africa, inequity must be addressed, research on the health implications of drought should be enhanced, and better drought diplomacy is required to improve drought resilience under climate change.
Charnley GEC, Kelman I, Green N, et al., 2021, Exploring relationships between drought and epidemic cholera in Africa using generalised linear models, BMC Infectious Diseases, Vol: 21
BackgroundTemperature and precipitation are known to affect Vibrio cholerae outbreaks. Despite this, the impact of drought on outbreaks has been largely understudied. Africa is both drought and cholera prone and more research is needed in Africa to understand cholera dynamics in relation to drought.MethodsHere, we analyse a range of environmental and socioeconomic covariates and fit generalised linear models to publicly available national data, to test for associations with several indices of drought and make cholera outbreak projections to 2070 under three scenarios of global change, reflecting varying trajectories of CO2 emissions, socio-economic development, and population growth.ResultsThe best-fit model implies that drought is a significant risk factor for African cholera outbreaks, alongside positive effects of population, temperature and poverty and a negative effect of freshwater withdrawal. The projections show that following stringent emissions pathways and expanding sustainable development may reduce cholera outbreak occurrence in Africa, although these changes were spatially heterogeneous.ConclusionsDespite an effect of drought in explaining recent cholera outbreaks, future projections highlighted the potential for sustainable development gains to offset drought-related impacts on cholera risk. Future work should build on this research investigating the impacts of drought on cholera on a finer spatial scale and potential non-linear relationships, especially in high-burden countries which saw little cholera change in the scenario analysis.
Charnley GEC, Kelman I, Green N, et al., 2021, Exploring relationships between drought and epidemic cholera in Africa using generalised linear models, Publisher: Cold Spring Harbor Laboratory
Background Temperature and precipitation are known to affect Vibrio cholerae outbreaks. Despite this, the impact of drought on outbreaks has been largely understudied. Africa is both drought and cholera prone and more research is needed in Africa to understand cholera dynamics in relation to drought.Methods Here, we analyse a range of environmental and socioeconomic covariates and fit generalised linear models to publicly available national data, to test for associations with several indices of drought and make cholera outbreak projections to 2070 under three scenarios of global change, reflecting varying trajectories of CO2 emissions, socio-economic development, and population growth.Results The best-fit model implies that drought is a significant risk factor for African cholera outbreaks, alongside positive effects of population, temperature and poverty and a negative effect of freshwater withdrawal. The projections show that following stringent emissions pathways and expanding sustainable development may reduce cholera outbreak occurrence in Africa, although these changes were spatially heterogeneous.Conclusions Despite an effect of drought in explaining recent cholera outbreaks, future projections highlighted the potential for sustainable development gains to offset drought-related impacts on cholera risk. Future work should build on this research investigating the impacts of drought on cholera on a finer spatial scale and potential non-linear relationships, especially in high-burden countries which saw little cholera change in the scenario analysis.Competing Interest StatementThe authors have declared no competing interest.Funding StatementThis work was supported by the Natural Environmental Research Council [NE/S007415] as part of the Grantham Institute for Climate Change and the Environments (Imperial College London) Science and Solutions for a Changing Planet Doctoral Training Partnership. We also acknowledge joint Centre funding from the UK Medical Research
Charnley G, Murray K, Gaythorpe K, et al., 2021, Traits and risk factors of post-disaster infectious disease outbreaks: a systematic review, Scientific Reports, Vol: 11, Pages: 1-14, ISSN: 2045-2322
Infectious disease outbreaks are increasingly recognised as events that exacerbate impacts or prolong recovery following disasters. Yet, our understanding of the frequency, geography, characteristics and risk factors of post-disaster disease outbreaks globally is lacking. This limits the extent to which disease outbreak risks can be prepared for, monitored and responded to following disasters. Here, we conducted a global systematic review of post-disaster outbreaks and found that outbreaks linked to conflicts and hydrological events were most frequently reported, and most often caused by bacterial and water-borne agents. Lack of adequate WASH facilities and poor housing were commonly reported risk factors. Displacement, through infrastructure damage, can lead to risk cascades for disease outbreaks; however, displacement can also be an opportunity to remove people from danger and ultimately protect health. The results shed new light on post-disaster disease outbreaks and their risks. Understanding these risk factors and cascades, could help improve future region-specific disaster risk reduction.
Charnley G, Murray K, Katy G, et al., 2020, Understanding the risks for post-disaster infectious disease outbreaks: a systematic review protocol, BMJ Open, Vol: 10, ISSN: 2044-6055
IntroductionDisasters have many forms, including those related to natural hazards and armed conflict. Human-inducedglobal change, such as climate change, may alter hazard parameters of these disasters. These alterations canhave serious consequences for vulnerable populations, which often experience post-disaster infectiousdisease outbreaks, leading to morbidity and mortality. The risks and drivers for these outbreaks and theirability to form cascades, are somewhat contested. Despite evidence for post-disaster outbreaks, reviewsquantifying them have been on short time scales, specific geographic areas or specific hazards. This reviewaims to fill this gap and gain a greater understanding of the risk factors involved in these contextualoutbreaks on a global level.Methods and analysisUsing the PRISMA-P 2015 checklist and Khan’s methodological framework, a systematic search strategywill be created and carried out in August 2020. The strategy will search MEDLINE, Embase andGlobalHealth electronic databases and reference lists of selected literature will also be screened. Eligiblestudies will include any retrospective cross-sectional, case-control or cohort studies investigating aninfectious disease outbreak in a local disaster affected population. Studies will not be excluded based ongeographic area or publication date. Excluded papers will include non-English studies, reviews, single casestudies and research discussing general risk factors, international refugee camps, public health, mental healthand other non-communicable diseases, pathogen genetics or economics. Following selection, data will beextracted into a data charting form, that will be reviewed by other members of the team. The data will thenbe analysed both numerically and narratively.Ethics and disseminationOnly secondary data will be used and there will be no public or patient involvement; therefore, no ethicalapproval is needed. Our findings will aim to be disseminated through a peer-reviewed journal.
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