Infectious Disease and Microbiology – Ebola and Marburg Viral Diseases

Overview

Ebola virus and Marburg virus belong to the filovirus group and cause severe systemic illnesses known as viral hemorrhagic fevers. Both infections are uncommon but potentially life-threatening, with rapid onset of fever, constitutional symptoms, gastrointestinal manifestations, and, in severe cases, hemorrhage, shock, and multiorgan dysfunction.

Microbiologic Characteristics

Ebola and Marburg viruses are filoviruses characterized by:

• Single-stranded RNA genomes

• Helical nucleocapsid symmetry

• Lipid envelopes

• Characteristic filamentous viral particles

Because they are enveloped viruses, appropriate infection-control and disinfection procedures are important for preventing transmission.

Important Species

The two major viruses in this group are:

Ebola virus → causes Ebola virus disease (EVD)

Marburg virus → causes Marburg virus disease (MVD)

Both can produce severe viral hemorrhagic fever syndromes.

Incubation Period

For Ebola virus disease, the incubation period is approximately:

2–21 days

For Marburg virus disease, the source describes an incubation period of:

3–9 days

Symptoms begin after the incubation period rather than immediately following exposure.

Epidemiology

Ebola and Marburg virus infections are relatively rare.

Ebola virus outbreaks have primarily occurred in Africa.

Marburg virus disease has also been associated mainly with Africa, although historically cases have been recognized in Europe following exposure to infected animals or imported infections.

Transmission

Transmission can occur through direct contact with the blood or other body fluids of an infected person, contaminated materials, or infected animals.

Healthcare-associated transmission can occur when appropriate infection-control precautions are not followed.

Clinical Manifestations

The illness typically begins abruptly.

Early manifestations may include:

• High fever

• Severe headache

• Myalgia

• Malaise

• Pharyngitis

These symptoms may initially resemble several other acute febrile illnesses.

Gastrointestinal Manifestations

Prominent gastrointestinal manifestations may develop, including:

• Vomiting

• Diarrhea

• Abdominal symptoms

Severe vomiting and diarrhea can contribute to major fluid and electrolyte losses.

Skin Manifestations

A maculopapular rash may develop during the course of illness.

The rash can occur together with progressive systemic manifestations.

Hemorrhagic Manifestations

Despite the traditional term “hemorrhagic fever,” clinically obvious bleeding does not occur in every patient.

Severe disease may nevertheless produce:

• Mucosal bleeding

• Gastrointestinal bleeding

• Coagulopathy

• Thrombocytopenia

• Disseminated intravascular coagulation

Severe Disease

Severe Ebola or Marburg virus disease may progress to:

Profound fluid loss → hypotension → shock → multiorgan dysfunction

The illnesses have historically been associated with high case-fatality rates, although mortality varies considerably between outbreaks and according to the viral species, supportive care, and availability of specific therapies.

Diagnosis

The source describes diagnosis using:

• Cell culture

• Serologic testing

Because these are highly hazardous pathogens, viral culture requires specialized high-containment laboratory facilities.

Molecular Diagnosis

In contemporary clinical practice, RT-PCR or other nucleic-acid amplification testing is particularly important for confirming acute Ebola or Marburg virus infection.

Serologic testing may also have a role depending on the stage of infection.

Treatment

The foundation of management is intensive supportive care, including:

• Fluid and electrolyte replacement

• Hemodynamic support

• Management of shock

• Oxygen and organ support when required

• Treatment of associated complications

Early, high-quality supportive care can substantially influence outcome.

Ebola-Specific Therapy

The source states that there is no specific antiviral treatment; however, this reflects older management information.

For certain forms of Ebola virus disease, particularly disease caused by Zaire ebolavirus, specific monoclonal-antibody therapies have subsequently become available.

This is an important distinction when interpreting older infectious-disease references.

Marburg Virus Treatment

Management of Marburg virus disease remains primarily supportive, with careful management of fluid loss, shock, and organ dysfunction.

Infection Control

Patients with suspected or confirmed filovirus infection require strict infection-control precautions.

Important measures include:

• Appropriate patient isolation

• Personal protective equipment

• Careful handling of blood and body fluids

• Safe injection practices

• Appropriate environmental decontamination

• Safe handling of laboratory specimens

Healthcare workers require particularly rigorous protection because direct exposure to infected body fluids can transmit disease.

Sexual Transmission and Survivors

Filoviruses can persist in certain body fluids after recovery, including semen.

The source recommends avoiding sexual intercourse for 3 months or until semen is demonstrated to be free of virus.

Modern survivor guidance may use testing-based and public-health recommendations rather than relying exclusively on a fixed 3-month period.

High-Yield Clinical Pattern

Recent exposure in an outbreak or contact with an infected person

• ●

Abrupt high fever + severe headache + myalgia

• ●

Vomiting and profuse diarrhea

• ●

Possible rash, bleeding, shock, and multiorgan dysfunction

→ Consider Ebola or Marburg virus disease

Exam Essentials

Virus group: Filovirus

Important viruses: Ebola virus and Marburg virus

Genome: Single-stranded RNA

Envelope: Present

Symmetry: Helical

Ebola incubation: 2–21 days

Marburg incubation in source: 3–9 days

Typical onset: Abrupt febrile illness

Major symptoms: Fever, headache, myalgia, vomiting, diarrhea, pharyngitis, rash

Severe complications: Shock, coagulopathy, hemorrhage, multiorgan dysfunction

Modern acute diagnosis: RT-PCR

Core treatment: Intensive supportive care

Ebola: Specific monoclonal-antibody treatment is available for some Ebola virus infections

Marburg: Primarily supportive management

Prevention: Strict infection-control precautions and avoidance of exposure to infected blood/body fluids

Key clinical pearl: Think of filovirus disease when a patient with an appropriate epidemiologic exposure develops abrupt fever, severe constitutional symptoms, vomiting and diarrhea followed by possible rash, coagulopathy, shock, or multiorgan failure; hemorrhage is an important manifestation but is not required for the diagnosis.