In Japan, ebola Virus Disease is managed by tropical medicines. Ebola virus disease is a severe and often fatal filoviral illness transmitted through direct contact with the blood or other body fluids of infected people, primates, or fruit bats, with case-fatality rates of 25-90% across outbreaks and a median around 50%. The 2014-2016 West African outbreak — the largest in recorded history — caused 28,616 confirmed and probable cases and 11,310 deaths across Guinea, Liberia, and Sierra Leone; the 10th Democratic Republic of Congo outbreak in 2018-2020 caused 3,470 cases and 2,287 deaths; and the 2022 Sudan-strain outbreak in Uganda killed 55 of 142 confirmed cases.
Ebola virus disease (ICD-10: A98.4) is a severe, often fatal viral hemorrhagic fever caused by infection with one of six recognized Ebola virus species in the family Filoviridae: Zaire ebolavirus (most virulent, responsible for the largest outbreaks and the target of approved vaccines and antibody treatments), Sudan ebolavirus (case-fatality 40-60% across outbreaks), Bundibugyo ebolavirus (case-fatality 25-40%), Taï Forest ebolavirus (a single recorded human case), Reston ebolavirus (asymptomatic in humans), and Bombali ebolavirus (recently identified, no confirmed human disease). Ebola virus is a single-stranded negative-sense RNA filovirus that infects monocytes, macrophages, and dendritic cells, then spreads systemically to liver, spleen, adrenal glands, and endothelium, causing massive cytokine release, coagulopathy, vascular leakage, and multi-organ failure. The natural reservoir is the African fruit bat (Pteropodidae family); primary human infection follows contact with infected bats or non-human primates, after which the virus spreads person-to-person through direct contact with blood, vomitus, stool, sweat, breast milk, semen, saliva, and contaminated surfaces. Outbreaks occur predominantly in equatorial sub-Saharan Africa, with sporadic cases imported by infected travellers.
The key symptoms of Ebola Virus Disease are: Sudden onset of fever above 38 °C, severe frontal headache, profound fatigue, and diffuse muscle and joint pain 2-21 days (average 8-10 days) after exposure., Sore throat with painful swallowing, chest pain, dry cough, and conjunctival injection in the first 3-5 days., Profuse watery diarrhoea, recurrent vomiting, severe epigastric and right-upper-quadrant abdominal pain, and progressive dehydration starting day 3-7., Maculopapular rash on the trunk, back, and limbs around day 5-7 — present in roughly 25-50% of patients and easily missed on dark skin., Hemorrhagic features in roughly 30-50% of severe cases: bleeding from injection sites, gums, nose, gastrointestinal tract, vagina, and conjunctivae; petechiae; and ecchymoses., Confusion, agitation, lethargy progressing to coma in late disease, reflecting both metabolic disturbance and direct central nervous system involvement., Hiccups in late disease — a frequently described, poorly understood feature that often precedes death..
Clinical diagnosis is suspected in any patient with fever and compatible symptoms who has had potential exposure within 21 days (the maximum incubation period): travel from an active outbreak zone, contact with a known case, healthcare or laboratory work with Ebola samples, contact with bushmeat or wildlife, or unprotected sexual contact with a male survivor. Laboratory confirmation is by real-time reverse transcription polymerase chain reaction (RT-PCR) on blood, performed in a designated biosafety level 3 or 4 facility or with WHO-approved field cartridge platforms (such as GeneXpert). Detection of viral antigen by ELISA and IgM/IgG serology confirm exposure and recovery. Diagnostic yield rises after symptom day 3 — early in illness, viral load may be below detection thresholds and a negative test must be repeated 48-72 hours later if clinical suspicion remains high. Differential diagnosis is broad and includes other viral hemorrhagic fevers (Marburg, Lassa, Crimean-Congo, yellow fever), malaria (which must be ruled out and treated empirically while awaiting Ebola results), typhoid, shigellosis, leptospirosis, meningococcaemia, and severe sepsis from any cause. All suspected cases are isolated immediately in a designated Ebola treatment unit with strict PPE protocols. Imaging and ancillary investigations focus on assessing the severity of dehydration, organ injury, and coagulopathy: complete blood count typically shows leukopenia early, thrombocytopenia, and lymphopenia, with transaminitis (AST > ALT), elevated creatinine, and prolonged prothrombin time.
Outcomes depend on viral strain, time to treatment, viral load at presentation, and quality of supportive care. Historical case-fatality rates ranged from 60-90% for Zaire ebolavirus in resource-limited outbreaks. Modern care with structured fluid resuscitation, monoclonal antibodies, and intensive supportive care has cut mortality to 33-35% for Zaire ebolavirus treated early. Patients with low initial viral load (PCR cycle threshold above 22) have mortality under 20% with either Inmazeb or Ebanga. Sudan and Bundibugyo strains retain higher mortality (40-60%) in the absence of approved species-specific therapy. Survivors face a high burden of post-Ebola syndrome: arthralgia in roughly 75%, ocular symptoms or uveitis in 25-50%, hearing changes, headache, fatigue, depression, anxiety, post-traumatic stress, and prolonged amenorrhoea. Persistent virus in semen, breast milk, ocular fluid, and the central nervous system has caused late relapses and onward transmission events years after initial recovery. Most physical symptoms improve over 1-2 years; mental-health sequelae and social stigma can persist longer and need ongoing support. Outbreak duration and total case count have shortened dramatically as vaccine ring strategy and antibody therapy have matured: the 2018-2020 DRC outbreak was contained within 22 months despite armed conflict and the Uganda Sudan outbreak in 2022 was declared over within five months.
Suspected Ebola requires immediate isolation in a designated treatment unit staffed by infectious disease, emergency, and critical care teams trained in biosafety protocols. Outside outbreak zones, suspected imported cases are coordinated by national public-health authorities, with reference laboratories handling all sample testing. Antibody treatment must be available within 24-48 hours of confirmation.
Find specialists →Acute illness lasts 6-16 days; survivors typically improve from day 7-10 onwards. Most patients are discharged once two consecutive RT-PCR tests are negative on blood. Convalescence with fatigue, arthralgia, and weight loss lasts 1-3 months in mild cases and up to 12 months in severe cases. Post-Ebola syndrome symptoms (joint pain, eye disease, mental-health symptoms) follow a variable course and require structured 1-year follow-up. Semen RT-PCR is repeated monthly until negative twice consecutively, often 6-12 months and sometimes longer.
Gradual return to physical activity is appropriate during convalescence. Many survivors experience fatigue and arthralgia for weeks to months; structured rehabilitation including low-impact aerobic exercise, joint mobility, and graded muscle strengthening accelerates recovery. Avoid contact sports until laboratory follow-up and clinical recovery are complete.
In an outbreak setting, care is delivered through designated Ebola treatment units coordinated by the ministry of health, WHO, MSF, and partners. In non-endemic regions, suspected cases are referred to a national high-consequence infectious disease unit (CDC-designated regional Ebola treatment centre in the US; high-consequence infectious diseases network in the UK). Patients should not be transported to non-designated facilities once Ebola is suspected.
Medically reviewed by AIHealz Medical Editorial Board · May 13, 2026
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