What Is Ebola?

Ebola (Ebola Virus Disease, EVD) is a severe and often fatal illness caused by Ebola virus, a member of the Filoviridae family. The virus causes hemorrhagic fever — a syndrome of high fever, organ failure, and in severe cases internal and external bleeding. First identified in 1976 near the Ebola River in the DRC, it has a case fatality rate averaging 50%, ranging from 25% to 90% depending on the viral species and access to care. Two vaccines and two monoclonal antibody treatments are now approved for the most common species, Zaire ebolavirus.

Ebola spreads through direct contact with blood, secretions, organs, or other body fluids of infected people or surfaces and materials contaminated with them. It does not spread through air, water, or food. Bats are believed to be the natural reservoir. Healthcare workers caring for patients without adequate protective equipment and family members providing close care face the highest exposure risk. Bodies of Ebola victims remain infectious for days after death — safe burial protocols are a critical outbreak control measure.

Symptoms appear 2–21 days after exposure (average 8–10 days) and progress in two phases. Early phase (days 1–5): Sudden onset fever, severe headache, muscle pain, weakness, sore throat, vomiting, diarrhoea, rash. Late phase (day 5+): Impaired kidney and liver function. Some patients develop internal and external bleeding — bleeding gums, blood in stool — though bleeding is not present in all cases. Multi-organ failure is the primary cause of death, typically occurring 6–16 days after symptom onset.

Two vaccines are approved for Zaire ebolavirus: Ervebo (rVSV-ZEBOV, single dose) and the two-dose Zabdeno+Mvabea regimen. Two monoclonal antibody treatments are FDA-approved for active Zaire Ebola infection: Inmazeb (a 3-antibody cocktail) and Ebanga (ansuvimab). These cut fatality rates dramatically when given early. No licensed countermeasures exist for Sudan or other Ebola species, though trials are ongoing. All types benefit from supportive care: IV fluids, electrolyte replacement, treatment of infections.

Can Ebola be transmitted before symptoms appear?: No. Ebola patients are not infectious during the incubation period. Transmission requires direct contact with body fluids of a symptomatic person. This is why contact tracing — monitoring exposed people during their incubation period — effectively contains outbreaks without requiring quarantine of asymptomatic contacts.
How long can Ebola survive outside the body?: On dry surfaces, hours to days at room temperature. In liquid, potentially longer. The virus is killed by heat (60°C for 30 minutes), UV light, and common disinfectants including 0.5% bleach solution. Healthcare environments must be systematically decontaminated during outbreaks.
What is Post-Ebola Syndrome?: Many survivors experience prolonged health problems: joint pain, vision loss (uveitis), hearing loss, fatigue, and cognitive difficulties. Ebola virus can persist in immunologically privileged sites — eyes, testes, spinal fluid — for months to years after blood tests are negative. Male survivors should use condoms for at least 12 months post-recovery and undergo regular semen testing.