Western African Ebola virus epidemic in the context of Ebola virus epidemic in Sierra Leone

Orthoebolavirus zairense or Zaire ebolavirus, more commonly known as Ebola virus (/iˈboʊlə, ɪ-/; EBOV), is one of six known species within the genus Ebolavirus. Four of the six known ebolaviruses, including EBOV, cause a severe and often fatal hemorrhagic fever in humans and other mammals, known as Ebola virus disease (EVD). Ebola virus has caused the majority of human deaths from EVD, and was the cause of the 2013–2016 epidemic in western Africa, which resulted in at least 28,646 suspected cases and 11,323 confirmed deaths.

Ebola virus and its genus were both originally named for Zaire (now the Democratic Republic of the Congo), the country where it was first described, and was at first suspected to be a new "strain" of the closely related Marburg virus. The virus was renamed "Ebola virus" in 2010 to avoid confusion. Ebola virus is the single member of the species Zaire ebolavirus, which is assigned to the genus Ebolavirus, family Filoviridae, order Mononegavirales. The members of the species are called Zaire ebolaviruses. The natural reservoir of Ebola virus is believed to be bats, particularly fruit bats, and it is primarily transmitted between humans and from animals to humans through body fluids.

The Kivu Ebola epidemic was an outbreak of Ebola virus disease (EVD) mainly in eastern Democratic Republic of the Congo (DRC), and in other parts of Central Africa, from 2018 to 2020. Between 1 August 2018 and 25 June 2020 it resulted in 3,470 reported cases. The Kivu outbreak also affected Ituri Province, whose first case was confirmed on 13 August 2018. In November 2018, the outbreak became the biggest Ebola outbreak in the DRC's history, and had become the second-largest Ebola outbreak in recorded history worldwide, behind only the 2013–2016 Western Africa epidemic. In June 2019, the virus reached Uganda, having infected a 5-year-old Congolese boy who entered Uganda with his family, but was contained.

A military conflict in the region that had begun in January 2015 hindered treatment and prevention efforts. The World Health Organization (WHO) described the combination of military conflict and civilian distress as a potential "perfect storm" that could lead to a rapid worsening of the outbreak. In May 2019, the WHO reported that since January, 85 health workers had been wounded or killed in 42 attacks on health facilities. In some areas, aid organizations had to stop their work due to violence. Health workers also had to deal with misinformation spread by opposing politicians.

An alternate care site (ACS) is a medical treatment facility established in a non-traditional setting during a public-health crisis (or other event causing strain on local medical resources) as a means of providing additional capacity to deliver medical care within a given area. The term encompasses both civilian-operated medical facilities established in non-traditional places such as hotels, gymnasiums, and convention centers, or other "structure[s] of opportunity," as well as military field medical units being used for public-health purposes. Usually, the option of establishing an ACS becomes relevant once the scale of an emergency extends beyond a single metropolitan area. Though commonly established (or, at a minimum, overseen) by public-health authorities, ACSes can also be established by private entities, such as large employers. ACSes have been widely used as part of the response to the COVID-19 pandemic, and in other recent crises such as the Western African Ebola virus epidemic.