Predicting when and where novel and exotic pathogens will emerge is difficult, yet as recent Ebola and Zika epidemics demonstrate, despite progress in infectious disease interventions, effective and timely responses to emerging pathogens are still vital. In particular, it is critical to transition from relying on reactive responses to proactive management of these pathogens. To improve the identification of priority settings we present a cohesive framework to bring together disparate methodologies and data sources to assess subnational pandemic potential for four viral haemorrhagic fevers in Africa.
Methods: We quantify three key stages that underlie the potential of a widespread epidemic. Stage 1 uses environmental factors that drive potential disease transmission and populations to define areas of possible spillover. Stage 2 assesses local outbreak receptivity by aggregating data on population vulnerabilities and infrastructural response capacities to identify areas of outbreak potential. Stage 3 utilises connectivity data to evaluate the potential for outbreak spread at both local and international scales.
Findings: Epidemic potential varied within Africa, highlighting not only regions where viral haemorrhagic fever outbreaks have previously occurred (e.g. Western Africa), but also regions that are generally viewed as non-endemic. Differences by stage both across and within countries in Africa, highlighted where differnet preparedness or monitoring activities should be prioritised. Subnational levels of outbreak receptivity pointed to areas of particular vulnerability in much of Middle, Northern, and Eastern Africa.
Interpretation: This study provides a unified assessment of potential trajectories of an epidemic, allowing national and international agencies to pre-emptively evaluate needs and target resources prior to any spillover event. Subnational regions can be identified for improving surveillance, diagnostic capabilities and health system strengthening in parallel with designing policies and guidelines for optimal response at each stage. In conjunction with pandemic preparedness activities, assessments such as this can help identify those regions where preparedness needs and provisions do not currently align.
Funding: Paul G Allen Family Foundation, Bill & Melinda Gates Foundation, the Wellcome Trust, and the UK Department for International Development.