Ebola

Ebola virus disease (EVD), also known as Ebola hemorrhagic fever, is a zoonotic viral illness affecting humans and other primates. The disease is caused by four of the six recognized ebolavirus species: Bundibugyo virus, Sudan virus, Taï Forest virus, and Ebola virus (formerly Zaire Ebola virus). Ebolaviruses are filamentous, single-stranded RNA viruses belonging to the Filoviridae family, closely related to marburgviruses. The disease was first identified in 1976 during simultaneous outbreaks in the Democratic Republic of the Congo and South Sudan.

Ebola disease presents with a sudden onset of symptoms following an incubation period of 2 to 21 days, typically 4 to 10 days. Initial manifestations include fever, sore throat, muscle pain, headache, fatigue, and malaise. These prodromal symptoms are followed by progressive gastrointestinal involvement including vomiting, diarrhea, and abdominal pain, often accompanied by a rash. Hepatic and renal dysfunction commonly occur, and some patients develop both internal and external bleeding, typically beginning 5 to 7 days after symptom onset. Bleeding manifestations may include mucosal bleeding, hematoma formation at injection sites, and gastrointestinal hemorrhage. Death, when it occurs, typically follows 6 to 16 days after first symptoms and is often due to shock from fluid loss. Survivors may experience prolonged sequelae including muscular and joint pain, hepatic inflammation, hearing impairment, and persistent fatigue.

Ebola virus disease is endemic to Sub-Saharan Africa, with the first outbreaks documented in 1976 occurring in remote villages near tropical rainforests in Central Africa. The 2014-2016 West African epidemic represented the largest and most complex outbreak in the disease's history, with more cases and deaths than all previous outbreaks combined. This outbreak demonstrated the capacity for international spread, originating in Guinea before crossing land borders to Sierra Leone and Liberia. Intermittent outbreaks have continued to occur across the region, with the specific viral species involved and the quality of supportive care significantly influencing outbreak mortality rates.

Ebola virus is transmitted to humans from wild animal reservoirs, particularly fruit bats, as well as from infected non-human primates and porcupines. Human-to-human transmission occurs through direct contact with the blood, secretions, organs, or other bodily fluids of infected individuals. Transmission can also occur through indirect contact with environments or materials contaminated with such fluids, including bedding, clothing, and medical equipment. There have been no documented cases of airborne transmission between humans or other primates under natural conditions. Individuals become infectious only after developing symptoms; pre-symptomatic transmission does not occur.

Healthcare workers providing direct care to Ebola patients without appropriate infection prevention and control measures face substantial occupational exposure risk. Family members and caregivers who have close contact with infected individuals or their bodily fluids during the symptomatic phase are at elevated risk of transmission. Communities in remote villages near tropical rainforests in Sub-Saharan Africa face ongoing exposure risk from zoonotic spillover events. The 2014-2016 West African epidemic demonstrated that populations with limited access to healthcare infrastructure and those in areas with cross-border movement face heightened vulnerability during outbreak scenarios.

Prevention of Ebola virus disease focuses on avoiding contact with known or suspected reservoir species, particularly fruit bats and forest-dwelling wildlife, and avoiding direct contact with infected individuals or their bodily fluids. Communities affected by outbreaks are advised to practice rigorous hand hygiene and to avoid handling or preparing bodies of deceased individuals without appropriate protective measures. Environmental decontamination of surfaces and materials contaminated with infectious fluids is essential for interrupting transmission chains. Survivors should use condoms for an extended period following recovery, as the virus may persist in certain bodily fluids including semen and breast milk.

Ebola virus disease requires immediate notification and rapid response given its high case fatality rate and potential for explosive outbreak amplification. The 2 to 21 day incubation period necessitates extended surveillance and contact monitoring following the last known exposure. Surveillance systems should maintain heightened awareness during outbreaks in endemic regions, particularly near the tropical rainforest zones of Central and West Africa. The variability in case fatality rates across outbreaks (25-90%) reflects differences in viral species, healthcare infrastructure, and timeliness of supportive care, underscoring the importance of early detection and intervention.

1. 1 WHO Health Topics. Ebola disease.
2. 2 Wikidata. Ebola hemorrhagic fever.
3. 3 Wikipedia. Ebola - Wikipedia.

ICD-10

A98.4

ICD-11

1D60

Total cases

0

Peak month

2012-09

Coverage

3 reporting countries · 2026-01-01 → 2023-03-25