Ebola: worldwide dissemination risk and response priorities

The scale of the current outbreak of Ebola virus disease in west Africa is staggering. Thousands of infections and deaths have been reported in recent months, and unless major changes occur in the situation, incidence of Ebola virus disease has been projected to continue to grow and cumulative incidence to exceed 20 000 by November. A humanitarian crisis that stretches far beyond the impact of Ebola virus infections is unfolding in Africa, devastating the health systems and economies in aff ected countries. In the present outbreak, most infections remain confi ned to west Africa, although four cases have been detected outside this region: three cases diagnosed in Dallas, USA (of which one infection was contracted in Liberia and two were associated with nosocomial transmission from the fi rst case), and one case in Madrid, Spain, associated with nosocomial transmission (fi gure). In The Lancet, Isaac Bogoch and colleagues report on the potential for international dissemination of Ebola virus disease. Their assessment of risk for diff erent countries is an advance over previous work, which analysed fl ight networks and connectivity, but did not account for passenger fl ows and fi nal destinations. Because of the assumptions of uniform risk across the population and constant prevalence of infection (whereas, in fact, risk within the population is not likely to be uniform and incidence is doubling every 15–30 days), Published Online October 21, 2014 http://dx.doi.org/10.1016/ S0140-6736(14)61895-X