Ebola
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Ebola virus disease 2025 2026 outbreak update
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Here is a comprehensive overview of Ebola virus disease (EVD), incorporating medical textbook content and the latest outbreak data.
Ebola Virus Disease (EVD)
Virology
Ebola virus is a single-stranded, negative-sense RNA virus belonging to the family Filoviridae. There are multiple species: Zaire ebolavirus (most lethal), Sudan ebolavirus, Bundibugyo ebolavirus, Taï Forest ebolavirus, and Reston ebolavirus (not pathogenic in humans). The virus is named for the Ebola River in what is now the Democratic Republic of the Congo (DRC), near the site of the first recognized outbreak in 1976.
- ROSEN's Emergency Medicine, p. 2632
Epidemiology
| Outbreak | Year | Cases | Deaths | CFR |
|---|---|---|---|---|
| First outbreak (DRC/Sudan) | 1976 | ~600 | ~430 | ~70% |
| West Africa epidemic | 2013-2016 | 28,652 | 11,325 | ~70% |
| Eastern DRC outbreak | 2018-2020 | ~3,500 | ~2,300 | ~66% |
| 2026 Bundibugyo outbreak (DRC/Uganda) | 2026 | 1,307+ confirmed | 377+ deaths | ~29% |
The case fatality rate ranges from 25-90% depending on the strain, outbreak setting, and quality of care available. In settings with ICU-level support (as seen with patients treated in Europe and the US), mortality dropped to around 18.5%.
- ROSEN's Emergency Medicine, p. 2632; Harrison's Principles of Internal Medicine 22E, p. 3893
Transmission
- Spread by direct contact with blood, saliva, vomit, feces, semen, or other bodily fluids of an infected (symptomatic) person
- Not airborne - people are not contagious until they develop symptoms
- Unsafe burials (handling infectious bodies) have been a major amplifier of transmission
- Incubation period: 2-21 days (typical 5-7 days)
Clinical Features
Early phase (days 1-5):
- High fever, headache, myalgias, malaise
- Sore throat, profound nausea/vomiting, diarrhea
Late phase (days 5-7+):
- Hemorrhagic manifestations: spontaneous bleeding, ecchymosis, petechiae (though not all patients develop these)
- Erythematous maculopapular rash that eventually desquamates
- Severe hypovolemia and metabolic derangements from GI fluid losses
- Shock and multi-organ failure
Lab findings: Thrombocytopenia, anemia, coagulopathy, elevated transaminases (transaminitis), elevated creatinine, hypocalcemia, hypokalemia.
- ROSEN's Emergency Medicine, p. 2632
Differential Diagnosis
Initial symptoms are nonspecific. Consider:
- Malaria (far more common in endemic regions; co-infection seen in ~11% of EVD patients in Guinea)
- Typhoid fever
- Other viral hemorrhagic fevers (Marburg, bunyaviruses)
- Meningococcemia, leptospirosis
Diagnosis
- RT-PCR on plasma: primary confirmatory test
- Rapid antigen point-of-care test: 15-minute turnaround, good sensitivity/specificity vs. RT-PCR
- Testing only indicated if patient meets both epidemiological exposure criteria AND signs/symptoms of EVD
Management
The guiding principles are: Identify, Isolate, Inform.
Supportive care (cornerstone):
- Aggressive IV fluid and electrolyte repletion
- Empiric malaria treatment and broad-spectrum antibiotics
- Antipyretics
- Renal replacement therapy, mechanical ventilation, vasopressors, blood products as needed
Specific therapies:
- Ervebo (rVSV-ZEBOV): FDA-approved vaccine (2019) for Zaire ebolavirus strain; live attenuated vector using vesicular stomatitis virus backbone; single IM dose; used in ring vaccination strategy
- MAb114 (ansuvimab) and REGN-EB3 (atoltivimab/maftivimab/odesivimab): monoclonal antibody therapies showing the most promise in clinical trials
- Convalescent plasma and other nucleotide analogues have not consistently shown efficacy
PPE and infection control: Full PPE with rigorous donning/doffing protocols is mandatory. Hospitals operate a tiered system: frontline facilities > Ebola assessment hospitals > Ebola treatment centers.
- ROSEN's Emergency Medicine, p. 2632; Goldman-Cecil Medicine, vaccine section
Active 2026 Outbreak - Bundibugyo Strain
A major outbreak declared a WHO Public Health Emergency of International Concern is currently ongoing:
- Cause: Bundibugyo ebolavirus (BVD) - less lethal than Zaire strain (~28-29% CFR so far)
- Epicenter: Ituri Province, DRC - now spread to North Kivu, South Kivu, and reportedly Haut-Uele (bordering South Sudan and CAR)
- Scale (as of June 30, 2026): 1,307 confirmed cases, 377 deaths; 906 suspected cases with 223 additional suspected deaths - DRC's 17th Ebola outbreak
- Spread: Uganda also affected; two suspected cases reported in Italy (travelers from Uganda)
- Response: US HHS is deploying an experimental treatment and developing a Bundibugyo-specific vaccine via BARDA; ring vaccination being scaled up; DRC banned public gatherings in four provinces including Kinshasa
- The CDC modeled projections show that if 70% of patients enter isolation, odds of the outbreak exceeding 10,000 cases within 3 months are roughly 1 in 20
Note: No approved vaccine currently exists for the Bundibugyo strain - Ervebo only covers the Zaire strain, making this outbreak particularly challenging from a prevention standpoint.
Key Points Summary
| Feature | Details |
|---|---|
| Family | Filoviridae |
| CFR range | 25-90% (strain/setting dependent) |
| Incubation | 2-21 days |
| Transmission | Direct contact with bodily fluids (symptomatic patients only) |
| Diagnosis | RT-PCR (gold standard), rapid antigen test |
| Treatment | Supportive care; MAb114 and REGN-EB3 for Zaire strain |
| Prevention | Ervebo vaccine (Zaire strain only); ring vaccination |
| Current outbreak | Bundibugyo strain, DRC/Uganda, 2026 - WHO PHEIC declared |
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