Skip to Main Content

For further information, see CMDT Part 32-04: Viral Hemorrhagic Fevers

Key Features

Essentials of Diagnosis

  • Early stage EVD presents as a nonspecific febrile illness

  • Later stage EVD typically includes severe gastrointestinal symptoms, followed by neurologic ones and hypovolemic shock

  • Hemorrhagic manifestations occur late in course

  • Uveitis is prominent ocular finding

  • Travel and contact history from an Ebola-affected country raise suspicion

  • Diagnosis is confirmed by detection of virus with a real-time polymerase chain reaction

General Considerations

  • The first Ebola outbreak occurred in 1976 as a simultaneous epidemic in the Democratic Republic of Congo and South Sudan

  • The number of EVD cases spread rapidly; there are at least 10 affected countries, especially Guinea, Liberia, and Sierra Leone. Many cases and deaths in these countries occurred among health care workers.

  • As of December 11, 2018, 505 probable and confirmed cases (and 296 deaths) were reported from 12 health zones in the two provinces of Democratic Republic of Congo impacted with EVD, including 51 cases (and 17 deaths) among health care workers

  • Countries with effective viral containment include Sierra Leone, Liberia and Guinea. Outbreaks in the Democratic Republic of Congo have been reported as of 2018.

  • Four species cause human disease

    • Species: Zaire ebolavirus; virus: Ebola virus (EBOV)

    • Species: Sudan ebolavirus; virus: Sudan virus

    • Species: Taï Forest ebolavirus; virus: Taï Forest virus (TAFV)

    • Species: Bundibugyo ebolavirus; virus: Bundibugyo virus

  • Transmission

    • Occurs from direct contact with infected body fluids

    • No evidence supporting airborne transmission

    • However, the virus aerosolizes, meaning that certain settings such as health facilities carry additional risk

    • Virus must enter the body via mucous membranes, nonintact skin, sexual intercourse (virus has been detected in semen up to 9 months after recovery from infection), breastfeeding, or needlestick

    • Prior to symptoms, Ebola is not transmitted

  • Ebola has a 2- to 21-day incubation period (average is 8–10 days)

Clinical Findings

Symptoms and Signs

  • Early stage EVD

    • Headache

    • Weakness

    • Dizziness

    • Fever

    • Malaise, fatigue

    • Myalgia, arthralgia

  • Later stage EVD (after 3–5 days)

    • Abdominal pain, severe nausea, vomiting, and diarrhea accompanying the febrile illness

    • Encephalitis is commonly observed and includes

      • Confusion

      • Slowed cognition

      • Agitation

      • Occasional seizures

    • Shock develops in most patients

    • However, hemorrhagic manifestations develop in only 1–5% of patients

    • Respiratory symptoms (ie, cough) are not typical, although interstitial pneumonia and respiratory failure are reported

Differential Diagnosis

  • Varies with the stage of illness

  • Early stage EVD

    • Malaria, typhoid, and other viral illnesses

    • Viral hepatitis

    • Toxins

    • Leptospirosis

    • Rickettsial diseases

  • In later stage EVD

    • Bacterial, viral, and parasitic illnesses, including cholera

    • In children, rotavirus infection, which can present with severe gastroenteritis and shock

    • Encephalitis must be differentiated from the confusion associated with acute kidney injury and other neurologic manifestations


  • IgM antibodies and IgG antibody response on real-time polymerase chain reaction

  • Low platelet count

  • Leukopenia


Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.