This outbreak differs from previous Ebola outbreaks in terms of its scale (more than 28,000 cases) and duration (nearly two years). It occurred primarily in three African countries—Guinea, Sierra Leone, and Liberia—which had never experienced such an outbreak before. Neighboring Mali and Senegal faced more limited outbreaks.

Furthermore, long-distance travel is easier in the three countries affected by the 2014–2016 outbreak than in countries more accustomed to the disease. In the Democratic Republic of the Congo, for example, Ebola outbreaks are regularly detected in remote rural areas and quickly brought under control. In 2014–2016 in West Africa, the virus reached urban and hyper-urban areas for the first time, where population size and density make interventions more difficult.

Alongside these dramatic aspects, this epidemic also sparked an unprecedented mobilization: many countries, both African and non-African, sent teams of healthcare workers, epidemiologists, social workers, virologists, and researchers to the region. Several UN agencies, such as UNICEF and the World Food Programme, provided strong support to the populations alongside the WHO. Finally, NGOs, which were the first on the ground, worked with patients, families, and survivors for nearly two years, requiring them to adapt to the unusual context of a highly contagious and very prolonged epidemic.

The exceptional nature of the situation also called for an exceptional response in France: three of the affected countries in West Africa are French-speaking (Guinea, Mali, and Senegal), and a smaller-scale outbreak occurred in the DRC in 2014. These countries have close ties with France: many of their nationals live in France, and the French community there is sizable. For these reasons, several mathematical models estimated that the risk of seeing one or more cases of Ebola virus infection in France was not negligible and could even reach an average of one imported case every 10 months during the outbreak. It was therefore necessary to strengthen surveillance to address this possibility.

Ebola virus infections are highly contagious. If a case had emerged within the country, the challenge was twofold: on the one hand, to prevent the spread of the virus among the population in France, and on the other hand, to ensure that the sick person received appropriate care without endangering healthcare workers. The enhanced surveillance system was therefore designed to identify individuals who were ill and potentially infected with the virus as early as possible, prior to their medical care. First responders to patients, particularly emergency medical services (SAMU), were involved very early in the system as the entry point for suspected cases into surveillance, classifying suspected cases in collaboration with the ARS physician and Santé publique France (suspicion ruled out and “standard” care for the patient, or referral to a dedicated and protected care pathway, along with the initiation of an epidemiological investigation to identify individuals who had been in contact with the patient). When the decision to rule out or retain a suspected Ebola virus infection required expert advice, a virologist from the National Reference Center for Viral Hemorrhagic Fevers and an infectious disease specialist were consulted. Thus, all healthcare professionals involved in the situation acted in concert as soon as an alert was issued regarding a suspected case.

No imported cases of Ebola virus infection have been identified in France, but two cases diagnosed in West Africa were safely evacuated to France for hospitalization, and both have recovered. Between March 2014 and January 2016, 1,097 patients were reported through the enhanced surveillance system. Only 34 were classified as strong suspected cases requiring hospitalization in a protected, dedicated unit. This enhanced surveillance demonstrated significant benefits in terms of daily operations during the African epidemic, as well as the safety of the multidisciplinary approach that simultaneously addresses the detection of suspected cases and the risk of virus transmission. However, it also highlighted the difficulty for all involved professionals to maintain a high level of expertise and vigilance over such a long period. Therefore, such a system must be implemented with full awareness of the implications and reserved for situations that cannot be adequately addressed by a less intensive approach.