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Ebola Virus and Marburg Virus Infections

By

Thomas M. Yuill

, PhD, University of Wisconsin-Madison

Last full review/revision May 2020| Content last modified May 2020
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Marburg and Ebola virus infections cause bleeding and organ malfunction. These infections often result in death.

  • Marburg and Ebola infections are spread through handling live or dead infected animals or by contact with skin or body fluids of an infected person who has symptoms or who has died.

  • Symptoms begin with a fever, muscle and body aches, headache, cough, and a sore throat, followed by vomiting and diarrhea as well as bleeding from the mouth, nose, or internal organs.

  • To confirm the diagnosis, doctors do blood and urine tests.

  • Strict isolation and sanitary precautions (and, for health care practitioners, use of protective clothing) are needed to prevent spread of the infection.

  • Treatment includes giving fluids by vein and other treatments to maintain body functions.

Marburg and Ebola virus infections are hemorrhagic fevers, characterized by bleeding. They are caused by viruses called filoviruses. (Other viruses can cause other hemorrhagic fevers.)

Outbreaks of Ebola and Marburg virus infections started in Central and West Africa, probably because the infections are common in wild animals there. Such outbreaks are rare and, in the past, have not spread very far because they typically occurred in isolated, rural areas. However, travelers from those areas sometimes carry the infection to nearby areas or, rarely, outside of Africa.

In December 2013, a large Ebola virus outbreak began in rural Guinea (West Africa), then spread to densely populated urban regions in Guinea and to neighboring Liberia and Sierra Leone. It was first recognized in March 2014. Ebola outbreaks involved thousands of people, and about 59% of infected people died. A very small number of infected travelers (including health care workers returning home) have spread Ebola virus to Europe and North America. A few health care workers who helped treat the infected people in Europe and North America also acquired the infection. Sierra Leone, Guinea, and Liberia were declared free of Ebola in 2016.

An outbreak of Ebola also occurred in the Democratic Republic of the Congo in 2017 but was quickly contained. However, another outbreak there was confirmed in May 2018 and is ongoing.

Transmission of Ebola and Marburg viruses

The Ebola and Marburg viruses are highly contagious.

These viruses usually infect animals and only occasionally spread to people. Because the original animal source of these viruses has not yet been identified precisely, doctors are not sure how the virus infects the first person in an outbreak. However, experts think that the first person is infected by handling or eating an infected animal, such as a fruit bat or primate (apes and monkeys). Marburg virus infections have occurred in people exposed to bats (for example, in mines or caves).

Once a person has been infected, the infection can then spread from person to person when people come in direct contact with the skin or body fluids (saliva, blood, vomit, urine, stool, sweat, breast milk, or semen) of an infected person. Evidence shows that people cannot transmit the infection before they develop symptoms. However, body fluids from dead people often transmit the infection, particularly to people who transport and prepare corpses for burial, but even touching a body can spread the infection.

Ebola is not thought to spread through the air (for example, in droplets dispersed when people cough or sneeze). If such spread does occur, it is probably very rare.

In some people who recover, the Ebola virus is eventually completely eliminated from their system, and they are no longer contagious. In other people, the virus remains for a time in areas of the body that are protected from attack by the immune system (such as the eyes or semen). The genetic material of the Ebola virus can remain in semen for a year or longer after men no longer have symptoms. However, the presence of the virus's genetic material does not mean that live Ebola virus, which can cause infection, is present.

The Marburg virus can remain in semen for up to 7 weeks after men no longer have symptoms.

Symptoms

People develop the first symptoms about 2 to 20 days after exposure to the virus. At first, the symptoms usually resemble those of other, less dangerous viral infections. People have muscle aches, headache, sore throat, and cough. People also become sensitive to light, and the whites of the eyes may turn red.

Within a few days, more serious symptoms, such as the following, develop:

  • Abdominal pain

  • Yellow skin (jaundice)

  • Severe vomiting and diarrhea

  • A tendency to bleed

  • Confusion, delirium, and coma

The vomiting and diarrhea cause dehydration, which, if untreated leads to low blood pressure (shock), abnormal heart rhythms, and death.

Bleeding begins within the first few days. Bleeding under the skin can be seen as purplish spots or patches (bruises), and the gums, nose, rectum, or internal organs may bleed, as may puncture wounds (as result from drawing blood or starting an intravenous line).

After about 5 days, a rash, mainly on the trunk, appears.

During the second week of symptoms, the fever breaks and either people begin to recover or their organs malfunction (called organ failure). From 25 to 90% of infected people die depending in large part on the level of medical care available. Compared with Marburg virus infection, Ebola is more likely to be fatal, averaging a 59% death rate. Recovery takes a long time.

Diagnosis

  • Blood and urine tests

Identifying Ebola in people who have been infected for only a few days is difficult because early symptoms, such as fever, can be caused by more common infections. However, if people with these symptoms have traveled from areas where Ebola is occurring, doctors suspect Ebola. The Centers for Disease Control and Prevention (CDC) has provided guidelines for health care practitioners to enable them to evaluate travelers returning from such areas.

If doctors suspect Ebola, they take samples of blood and urine from the person and test them to confirm the infection.

A similar approach can be used if Marburg virus infection is suspected.

Public health officials are notified if an Ebola or a Marburg virus infection is diagnosed.

Prevention

Several vaccines and antiviral drugs have been developed. An Ebola vaccine in use in West Africa on a limited scale during outbreaks since 2016 was approved by the US Food and Drug Administration in December 2019 for use in people 18 years of age and older. Two vaccines are being used in the current DRC outbreak.

Strict isolation is needed to prevent spread. Isolating people with symptoms of possible Ebola or Marburg virus infection in facilities used only for that purpose can help. These facilities can safely handle the infected body fluids. Individuals who have been in contact with infected people should be vaccinated.

Staff members caring for people with Ebola must be completely covered in protective clothing, including head gear equipped with a respirator. Even though the infections are not thought to be spread through the air, precautions against such spread are taken. Other staff members must be available to help those wearing protective clothing remove the protective clothing.

Diligently cleaning and disinfecting surfaces and equipment that may be contaminated is crucial, as is making sure that body fluids (such as blood, sweat, vomit, feces, and urine) are handled safely.

For people who have traveled to or are in an area affected by an Ebola outbreak, the following is recommended:

  • Using good hygiene, such as washing their hands with soap and water or an alcohol-based hand sanitizer and avoiding contact with other people's blood and body fluids

  • Not handling items that may have come in contact with an infected person’s blood or body fluids (such as clothes, bedding, needles, and medical equipment)

  • Not participating in funeral or burial rituals that require handling the body of someone who has died of Ebola

  • Avoiding contact with bats and primates (such as apes and monkeys) and not eating raw or inadequately cooked meat prepared from these animals

  • Avoiding facilities in West Africa where Ebola patients are being treated

  • After returning, monitoring their health for 21 days and seeking medical care immediately if they develop symptoms suggesting Ebola

Although no infections are known to have been transmitted by sexual intercourse or breastfeeding, the number of people studied has been low. Thus, there are no firm guidelines on how long people should abstain from unprotected sexual intercourse, breastfeeding, or close personal contact. However, to be safe, doctors from the World Health Organization (WHO) recommend that men refrain from sexual intercourse for at least 7 weeks after recovery. If the men do have intercourse before 7 weeks, they should wear a condom.

Treatment

  • Supportive care

  • Drug treatment

Supportive treatment involves

  • Giving fluids intravenously (IV) to maintain blood pressure and the balance of electrolytes (such as sodium, potassium, and calcium)

  • Transfusing clotting factors to help slow or stop the bleeding

  • Treating symptoms, including giving pain relievers

Drugs are being tested in the current Ebola outbreak in eastern DRC (2019–2020). Two monoclonal antibodies have been very effective, curing about 90% of people when the drug is given within the first few days after infection. Because these drugs are so effective, they are now being given to all infected people in eastern DRC.

These new drugs have not been tested in people with Marburg virus infection, so there is still no effective treatment for infection with that virus.

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