Periodic global One Health threats update

Reperant, Leslie A.; MacKenzie, John; Osterhaus, Albert D.M.E.

In late 2013, an unprecedented outbreak of Ebola virus infections emerged in West Africa. The virus emerged in Guinea and spread to neighboring Sierra Leone and Liberia, resulting in a massive epidemic, with close to 20,500 reported cases of infection (Table 5 ). Imported cases of Ebola virus infection were reported in other African countries, as well as in Europe and North America. The massive epidemic covered a period of about a year, yet cases of infection continue to be reported in Guinea in a staggering epidemic tail (Fig. 5) . It remains unsure whether new epidemic flares will occur. Early Ebola virus outbreaks proved to be largely self-limiting. The devastating nature of the infection resulted in the rapid implementation of precautionary measures at the local level, thereby interrupting chains of human-to-human transmission after initial zoonotic events [29] . The reasons why this apparently failed to control the recent Ebola epidemic are unclear. However, its emergence in more uniformly and densely inhabited West African regions, poverty, larger scale movement and travel, as well as distrusting societal and behavioral responses to public health measures, are likely to have contributed to the escape of the virus into wider geographical areas, and to its associated exponential growth phase [30] . No specific medical interventions, including the use of antiviral drugs, antibodies or vaccines, were available at the time of the crisis, in spite of promising data indicating avenues for their development. One of the reasons behind the absence of specific medical interventions is related to "the industry paradox" based on a generally perceived absence of return on investment [26] . However, the scale of the epidemic, a trend towards fast-track registration for medicines against emerging pathogens,