Ebola Virus Disease: Uniquely Challenging Among the Viral Hemorrhagic Fevers.

Viral hemorrhagic fever is a severe illness characterized by constitutional signs and symptoms accompanied by coagulopathy, shock, and multiorgan failure caused by dozens of enveloped RNA viruses spanning 6 viral families: Flaviviridae, Arenaviridae, Hantaviridae, Nairoviridae, Phenuiviridae, and Filoviridae. Ebola virus (EBOV), the etiologic agent of Ebola virus disease (EVD), is among the deadliest and accounts for the majority of known human infections and deaths within the family Filoviridae. EBOV was responsible for the 2013-2016 West Africa epidemic and the 2018-2020 Democratic Republic of the Congo epidemic, both of which were declared public health emergencies of international concern by the World Health Organization. The ecology of Ebola virus is poorly characterized, with its animal reservoir and drivers of zoonotic spillover unknown. Once spillover has occurred, EBOV's human-to-human transmission makes containment challenging and poses significant nosocomial risk. Vaccines and targeted therapeutics have been developed, tested, and approved by regulatory agencies over the past decade, but some uncertainty remains regarding efficacy. Infrastructure is often insufficient to effectively provide efficient public health responses and advanced supportive clinical care in EVD outbreak areas. Further research of EBOV in closer proximity to areas most affected by EVD is needed, but the containment facilities required for such work require nontrivial investment and personnel. These factors combine to make EBOV a uniquely challenging virus and cannot be easily overcome. The escalation of impacts from EVD over the past decade serves as a warning, however, that approaching these challenges should not wait until the next major outbreak.