Emerging

Ebola Virus

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Ebola Virus, Ebola Hemorrhagic Fever, Marburg Hemorrhagic Fever, Marburg Virus Disease, Filoviral Hemorrhagic Fever

  • Epidemiology
  1. Marburg Virus
    1. Outbreaks in Europe 1967, Congo 2000, Angola 2005
  2. Ebola Virus
    1. Five species with varying regions affected and mortality rates
    2. Outbreaks in Zaire 1976, Sudan 1970, Philipines 1989, Zaire 1995, Uganda 2000, Sudan 2004, Uganda 2007
    3. Ebola epidemic in West Africa (2014) in Sierra Leone, Guinea and Liberia
      1. By far, the largest Ebola or Marburg outbreak
      2. As of November 2014, West Africa: 13000 cases (nearly 8000 lab confirmed) and 4800 deaths
      3. A few cases have presented in Mali, Senegal, Nigeria, Spain and the U.S.
  • Pathophysiology
  1. Ebola Virus (Filovirus family)
    1. Nonsegmented, negative-sense, single-stranded RNA Virus
    2. Structurally similar to Rhabdovirus (Rabies) and Paramyxovirus (Measles)
  2. Hemorrhagic Fever viruses (associated coagulation deficits, DIC)
    1. Other hemorrhagic fever viruses include Lassa Fever, Yellow Fever, Dengue Fever
  3. Host organism
    1. Small animal primary reservoir is suspected (e.g. fruit bats)
    2. Primates appear to be as susceptible as humans to high mortality rates
      1. Exposure to infected primates has been responsible for many of the initial source cases in epidemics
  4. Spread by close contact to infected bats, primates or other humans
    1. Infected blood
    2. Body fluid
      1. Especially blood, stool and vomit
      2. Semen transmission from previously infected source has been reported
    3. Body tissue
    4. Air borne transmission is unlikely (unless aerosolized, typically during medical procedures)
  • Precautions
  1. Initial presentation may be non-specific and mild
  2. Maintain vigilance and ask a careful travel history in febrile patients
  3. Immediately and completely isolate patients suspected of Viral Hemorrhagic Fever (see prevention below)
  • Course
  1. Incubation period: 8-12 days (ranges from 2 to 21 days)
  2. Mortality is highest days 6 to 16
  3. Surviving patients start to improve by the second week of illness
  4. Virus may persist in semen and Breast Milk for a prolonged period beyond recovery
  5. Prolonged recovery characterized by weakness, Fatigue and persistent weight loss
  • Symptoms
  • Common
  1. Fever (87%)
  2. Fatigue (76%)
  3. Vomiting (68%)
  4. Diarrhea (66%)
  5. Anorexia (65%)
  • Findings
  • Manifestations
  1. Influenza-Like Illness
    1. Abrupt onset fever, chills and malaise
    2. Weakness and Anorexia
    3. Severe Headache
    4. Trunk and back pain (myalgias)
    5. Nonproductive cough and Sore Throat
    6. May rapidly progress to Septic Shock and multi-organ failure
  2. Dermatitis
    1. Variably present by day 5-7 of illness
    2. Non-pruritic diffuse erythematous rash that may spare the legs (with or without Desquamation)
  3. Gastrointestinal symptoms
    1. Onset within a few days of initial symptoms
    2. Diarrhea, Vomiting and severe Abdominal Pain
    3. Bloody stools may occur (6% of cases)
  4. Bleeding
    1. Variably present in 20% of cases and a late manifestation
    2. Signs include Petechiae or Ecchymosis, mucosal bleeding or gastrointestinal Hemorrhage
  5. Neurologic
    1. Seizures, confusion and cerebral edema may occur
  6. Cardiopulonary
    1. Chest Pain, Shortness of Breath, Hiccups may occur
  7. Other findings
    1. Dark-red palatal discoloration
    2. Conjunctival injection
  • Labs
  1. Precautions
    1. CDC recommends that labs be performed on dedicated machine (e.g. iStat) not used for other patient's blood
    2. Logistically, labs are typically being deferred to tertiary center or department of health testing in high suspicion cases
  2. Complete Blood Count (CBC) with differential and Platelet Count
    1. Leukopenia
    2. Thrombocytopenia
  3. Coagulation tests
    1. Findings consistent with Disseminated Intravascular Coagulation (DIC)
    2. Prothrombin (PT/INR) prolonged
    3. Partial Thromboplastin Time (PTT) prolonged
  4. Liver Function Tests
    1. Serum Aspartate Aminotransferase (AST) increased (more than ALT)
    2. Alanine Aminotransferase (ALT) increased
  5. Ebola specific testing (coordinated with local health department and CDC)
    1. Ebola PCR
    2. Ebola ELISA
    3. Ebola serology (IgM, IgG)
    4. Ebola Virus isolation
  • Management
  1. Supportive care in isolation suite by medical team using Full Personal Protective Equipment (see below)
  2. IV Fluid and electrolyte replacement
  3. Supplemental Oxygen
  4. Vasopressors
  5. Mechanical Ventilation
  • Prognosis
  1. Mortality rates range from 50-90%
  2. West African Ebola epidemic in 2014 mortality: 70%
  3. Findings suggestive or worse prognosis
    1. Tachypnea
    2. Anuria
    3. Delirium to coma
    4. Refractory shock
    5. Persistently high or increasing Ebola Virus RNA titers
  • Prevention
  1. Full Personal Protective Equipment (PPE) for healthcare workers (donning and doffing)
    1. http://www.cdc.gov/HAI/pdfs/ppe/ppeposter148.pdf
  • References
  1. Black, Martin, DeVos (2018) Crit Dec Emerg Med 32(8): 3-12
  2. Bray in Hirsch (2014) Ebola and Marburg Virus Disease, UpToDate, accessed online 11/5/2014
  3. (1995) MMWR Morb Mortal Wkly Rep 44:381-2 [PubMed]