Virus Genomes Reveal the Factors that Spread and Sustained the West African Ebola Epidemic
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD FORT DETRICK United States
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The 2013-2016 epidemic of Ebola virus disease in West Africa was of unprecedented magnitude, duration and impact. Extensive collaborative sequencing projects have produced a comprehensive collection of Ebola virus genomes, representing over 5 of known cases, unprecedented for a single epidemic. In the first comprehensive analysis of this entire collection, we reconstruct a detailed history of migration, proliferation and decline of the virus throughout the region. We test the association of geographical, climatic, administrative, demographic and cultural factors with viral movement between administrative regions. We identify a classic gravity model as the core dynamic, with more intense migration between larger population centers particularly when geographically close. Notably, we show that despite a strong attenuating effect of border closures on international dispersal, localized cross-border transmission had already set the seeds for an international epidemic, rendering these measures relatively ineffective in curbing the epidemic. Finally, we use this empirical evidence to address why the epidemic did not spread into neighboring countries, showing that although these regions were susceptible to developing significant outbreaks, they were also at lower risk of viral introductions.
- Genetic Engineering and Molecular Biology