EbolaEbola outbreak: where we are now and what happens next
Ever since its discovery, it has been appreciated that Ebola poses a serious risk to global public health. Infectious diseases represent a global threat, not just to those within the country or region of emergence. With the current increase in the movement of people (rural to urban, within countries and across borders), this risk will inevitably increase. While the current priority should be to contain the present outbreak, there is a great need to plan for prevention of future events. The development of an international response group tasked with immediate assessment of and initial response to emerging pathogens is needed, backed by sufficient international political will, clinical expertise, and funding. This needs to be agile and responsive, with clear chains of command, and able to engage early.
Ebola virus disease was first discovered in the Democratic Republic of the Congo in 1976, and by 2013 had caused about twenty recorded outbreaks across East and Central Africa. These had been restricted to rural areas and confined to small clusters of villages. In each case containment was achieved within a few months and after fewer than 500 confirmed cases. The world assumed that Ebola was too efficient at killing its hosts, doomed to quickly burn out wherever it arose.
The 2014 West African outbreak has changed everything. It was the “Black Swan” — the inevitable consequence we did not foresee. As we head into mid-January 2015, there have been more than 21,000 reported cases spread across nearly every region in three adjacent countries, and more than 8,000 people are known to have died.
Cases have cropped up in the United States, Mali, Senegal, and Nigeria. Patients have been treated across Western Europe. Until early November 2014, there was no sign of a reduction in transmission and case numbers were rising exponentially. As we wrote in the journal Tropical Doctor, though numbers are now slowing in Guinea and Liberia, there is still an increase in cases in Sierra Leone where 500 healthcare workers have died. There is no certainty the other affected countries will not again see an upsurge in new cases.
Estimates of how many people could be affected have varied widely and included projections of up to 1.4 million, or up to 25,000 cases per day by mid-January 2015. This was a dramatic increase since the World Health Organization (WHO) projected a maximum of 20,000 cases in August 2014, highlighting how difficult it is to predict the future epidemic direction, though organizations such as Médecins Sans Frontières highlighted their concern as early as March 2014.
Current expert opinion suggests that an overall decline will be likely in the next few months, however the “tail” of the epidemic curve will be protracted and punctuated by many smaller, localized outbreaks.
Mathematical modelling is challenging and cannot easily account for conflict, mass movement of people, or breakdown of civil society, but though the very high case numbers may not be reached, one thing is certain: this will be a terrifyingly large outbreak, something never before faced on a global scale.
