Ebola Virus Clinical Presentation

  • Author: John W King, MD; Chief Editor: Burke A Cunha, MD   more...
 
Updated: Apr 20, 2010
 

History

In patients who have Ebola infection, 2 types of exposure history are recognized: primary and secondary.

  • Primary exposure
    • These histories usually involve travel to or work in an Ebola-endemic area such as sub-Saharan Africa, especially the Democratic Republic of Congo (formerly Zaire), Sudan, Gabon, and Côte d'Ivoire.
    • Because the natural reservoir(s) of Ebola has not been identified, the relationship between specific exposure to potential arthropod, animal, or plant vectors and disease remains unproven. Bats are now considered to be a likely candidate species for a natural reservoir.
    • A history of exposure to tropical African forests is more common in patients with primary exposure to Ebola than is a history of working within cities in the same region.
  • Secondary exposure
    • This refers to human-to-human or primate-to-human exposures.
    • In each major outbreak, medical personnel or family members who cared for patients or those who prepared deceased patients for burial were at very high risk.
    • Another group at risk for infection is animal care workers who provide care for primates. This group includes patients who developed infection with the Reston species of Ebola as evidenced by antibody production, but did not develop Ebola disease.
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Physical

The findings upon physical examination depend on the stage of disease in which patients present. Early in the disease, patients may present with fever, pharyngitis, and severe constitutional signs and symptoms. A maculopapular rash, more easily seen on white skin than on dark skin, may be present around day 5 of infection and is most evident on the trunk. Bilateral conjunctival injection is also common. Late in the disease, patients often develop an expressionless facies. At this point in the disease, bleeding from intravenous puncture sites and mucous membranes is common. Of interest is that, in the 1976 Ebola outbreak, bleeding was seen in most cases, whereas, in the 1995 Ebola outbreak, bleeding occurred in only half the patients. Myocarditis and pulmonary edema also are seen in the later stages of the disease. Terminally ill patients often die tachypneic, hypotensive, anuric, and in a coma.

  • Clinical course
    • Human infections with African-derived species are characterized by an incubation period of 3-8 days in primary cases and slightly longer in secondary cases. However, cases with incubation periods of 19 and 21 days have been observed.
    • The onset of clinical symptoms is sudden. Severe headache (50%-74%), arthralgias or myalgias (50%-79%), fever with or without chills (95%), anorexia (45%), and asthenia (85%-95%) occur early in the disease.
    • Gastrointestinal symptoms, including abdominal pain (65%), nausea and vomiting (68%-73%), and diarrhea (85%), soon follow. Evidence of mucous membrane involvement includes conjunctivitis (45%), odynophagia or dysphagia (57%), and bleeding from multiple sites in the gastrointestinal tract. Bleeding from mucous membranes and puncture sites is reported in 40%-50% of patients.
    • A rash, which in survivors desquamates during convalescence, is seen in approximately 15% of patients. Terminally ill patients often are obtunded, anuric, tachypneic, normothermic, and in shock.
    • Although the mechanism is unclear, hiccups have been noted in fatal cases of Ebola in both the 1976 and the 1995 outbreaks in the DRC. In the 1995 Ebola outbreak in Kikwit, DRC, tachypnea was the single-most discriminating sign that separated survivors (0% had tachypnea) from patients who died (37% had tachypnea) (P = 0.027).
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Causes

  • Human Ebola hemorrhagic fever is caused by infection with 4 of the 5 presently known species of Ebola: EBO-Z, Ebola virus Sudan (EBO-S), Ebola virus Côte-d'Ivoire (EBO-C), and Ebola virus Bundibugyo (EBO-B). The fifth species, Ebola virus Reston (EBO-R), has caused human infection but, to date, has not been documented to cause human disease.
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Contributor Information and Disclosures
Author

John W King, MD  Professor of Medicine, Chief, Section of Infectious Diseases, Director, Viral Therapeutics Clinics for Hepatitis, Louisiana State University Health Sciences Center; Consultant in Infectious Diseases, Overton Brooks Veterans Affairs Medical Center

John W King, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Federation for Medical Research, American Society for Microbiology, Association of Subspecialty Professors, Infectious Diseases Society of America, and Sigma Xi

Disclosure: emedicine $50.00 author of chapter

Coauthor(s)

Rushdah Malik, MD  Fellow, Department of Infectious Diseases, Louisiana State University Health Science Center

Rushdah Malik, MD is a member of the following medical societies: American College of Physicians and Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Specialty Editor Board

Martin J Wood, MD †  Former Consulting Staff, Department of Infection and Tropical Medicine, Birmingham Heartlands Hospital, UK

Martin J Wood, MD † is a member of the following medical societies: Alliance for the Prudent Use of Antibiotics, American Society for Microbiology, Infectious Diseases Society of America, International Society for Infectious Diseases, and Royal College of Physicians

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Senior Pharmacy Editor, eMedicine

Disclosure: eMedicine Salary Employment

Thomas M Kerkering, MD  Chief of Infectious Diseases, Virginia Tech, Carilion School of Medicine, Roanoke, Virginia

Thomas M Kerkering, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Public Health Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Medical Society of Virginia, and Wilderness Medical Society

Disclosure: Nothing to disclose.

Eleftherios Mylonakis, MD  Clinical and Research Fellow, Department of Internal Medicine, Division of Infectious Diseases, Massachusetts General Hospital

Eleftherios Mylonakis, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Society for Microbiology, and Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Chief Editor

Burke A Cunha, MD  Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital

Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, and Infectious Diseases Society of America

Disclosure: Nothing to disclose.

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Ebola virus. Courtesy of the US Centers for Disease Control and Prevention.
Table 1. History of Ebola Virus Sudan Outbreaksa
YearLocationReported Cases, No.Deaths, No. (%)
1976Sudan284151 (53)
1976Englandb10 (0)
1979Sudan3422 (65)
2000-2001Uganda425224 (53)
2004Sudan1717 (41)
Total761414 (54.4)
Table 2. History of Ebola Virus Zaire Outbreaksa
YearLocationReported Cases, No.Deaths, No. (%)
1976Zaire318280 (88)
1977Zaire11 (100)
1994Gabon5231 (60)
1995DRC315250 (81)
Jan 1996 to Apr 1996Gabon3721 (57)
Jul 1996 to Jan 1997Gabon6045 (74)
1996South Africa (acquired in Gabon)11 (100)
Oct 2001 to Mar 2002Gabon6553 (82)
Oct 2001 to Mar 2002DRC5944 (75)
Dec 2002 to Apr 2003DRC143128 (89)
Nov 2003 to Dec 2004DRC3529 (83)
2007DRC264187 (71)
Total1,3501,070 (79.3)
Table 3. History of Ebola Virus Côte-d’Ivoire Outbreaks (No Deaths Reported)a
YearLocationReported Cases, No.
1994Côte-d’Ivoire1
1995Liberia1
Total2
Table 4. History of Ebola Virus Reston Outbreaks (No Deaths Reported)a
YearLocationProven bCases Reported, No.
1989Virginia, Texas, Pennsylvania0
1990Virginia and Texas4
1989 -1990Philippines3
1992Italy0
1990Alice, Tex0
1996Philippines0
Nov 2008Philippinesc6
Total13
Table 5. History of Ebola Virus Bundibugyo Outbreaka
YearLocationReported Cases, No.Deaths, No. (%)
Dec 2007 to Jan 2008Uganda14937 (25)
Total14937 (25)
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