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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 November 2019, 3298 probable and confirmed cases (and 2197 deaths) were reported from 28 health zones in the Democratic Republic of Congo, including 163 cases 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

    • Hypovolemic shock develops in most patients

    • However, hemorrhagic manifestations (gastrointestinal bleeding, diffuse mucosal bleeding, conjunctival bleeding) 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

  • As nonspecific symptoms progress to a severe systemic inflammatory response, coagulopathy with evidence of platelet dysfunction and DIC often ...

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