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Lancet. 2017 Dec 16;390(10113):2662-2672. doi: 10.1016/S0140-6736(17)32092-5. Epub 2017 Oct 12.

Local, national, and regional viral haemorrhagic fever pandemic potential in Africa: a multistage analysis.

Author information

1
Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA.
2
Department of Zoology, University of Oxford, Oxford, UK; Harvard Medical School, Harvard University, Boston, MA, USA; Boston Children's Hospital, Boston, MA, USA.
3
Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, ON, Canada.
4
Divisions of General Internal Medicine and Infectious Diseases, Toronto General Hospital, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada.
5
School of Geography and the Environment, University of Oxford, Oxford, UK; School of Interdisciplinary Area Studies, University of Oxford, Oxford, UK.
6
Warwick Medical School, University of Warwick, Coventry, UK.
7
Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK.
8
Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
9
Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
10
WorldPop, Department of Geography and Environment, University of Southampton, Southampton, UK; Flowminder Foundation, Stockholm Sweden.
11
The Start Network, London, UK.
12
European Commission, Joint Research Centre, Ispra, Italy.
13
Quantitative and Applied Ecology Group, School of BioSciences, University of Melbourne, Parkville, VIC, Australia.
14
Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
15
Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD, USA.
16
SJL Global Consulting, Seattle, WA, USA.
17
Director's Office, London School of Hygiene & Tropical Medicine, London, UK.
18
INDEPTH Network, Accra, Ghana.
19
Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA; Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK. Electronic address: sihay@uw.edu.

Abstract

BACKGROUND:

Predicting when and where pathogens will emerge is difficult, yet, as shown by the recent Ebola and Zika epidemics, effective and timely responses are key. It is therefore crucial to transition from reactive to proactive responses for these pathogens. To better identify priorities for outbreak mitigation and prevention, we developed a cohesive framework combining disparate methods and data sources, and assessed subnational pandemic potential for four viral haemorrhagic fevers in Africa, Crimean-Congo haemorrhagic fever, Ebola virus disease, Lassa fever, and Marburg virus disease.

METHODS:

In this multistage analysis, we quantified three stages underlying the potential of widespread viral haemorrhagic fever epidemics. Environmental suitability maps were used to define stage 1, index-case potential, which assesses populations at risk of infection due to spillover from zoonotic hosts or vectors, identifying where index cases could present. Stage 2, outbreak potential, iterates upon an existing framework, the Index for Risk Management, to measure potential for secondary spread in people within specific communities. For stage 3, epidemic potential, we combined local and international scale connectivity assessments with stage 2 to evaluate possible spread of local outbreaks nationally, regionally, and internationally.

FINDINGS:

We found epidemic potential to vary within Africa, with regions where viral haemorrhagic fever outbreaks have previously occurred (eg, western Africa) and areas currently considered non-endemic (eg, Cameroon and Ethiopia) both ranking highly. Tracking transitions between stages showed how an index case can escalate into a widespread epidemic in the absence of intervention (eg, Nigeria and Guinea). Our analysis showed Chad, Somalia, and South Sudan to be highly susceptible to any outbreak at subnational levels.

INTERPRETATION:

Our analysis provides a unified assessment of potential epidemic trajectories, with the aim of allowing national and international agencies to pre-emptively evaluate needs and target resources. Within each country, our framework identifies at-risk subnational locations in which to improve surveillance, diagnostic capabilities, and health systems in parallel with the design of policies for optimal responses at each stage. In conjunction with pandemic preparedness activities, assessments such as ours can identify regions where needs and provisions do not align, and thus should be targeted for future strengthening and support.

FUNDING:

Paul G Allen Family Foundation, Bill & Melinda Gates Foundation, Wellcome Trust, UK Department for International Development.

PMID:
29031848
PMCID:
PMC5735217
DOI:
10.1016/S0140-6736(17)32092-5
[Indexed for MEDLINE]
Free PMC Article

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