Diseases & Conditions

Ebola virus and Marburg virus

Ebola virus and Marburg virus are related viruses that cause hemorrhagic fevers — illnesses marked by severe bleeding (hemorrhage), organ failure and, in many cases, death. Both Ebola virus and Marburg virus are native to Africa, where sporadic outbreaks have occurred for decades. No human cases of Ebola virus have been reported in the United States.

Ebola and Marburg viruses live in one or more animal hosts, and humans can contract the viruses from infected animals. After the initial transmission, the viruses can spread from person-to-person through contact with body fluids or contaminated needles.

No effective therapy exists for the hemorrhagic fevers caused by Ebola virus and Marburg virus. People diagnosed with Ebola virus or Marburg virus receive supportive care and treatment for complications.

The Marburg and Ebola viruses emerged from tropical rain forests in Africa in the mid-20th century. The viruses live in an animal host or "reservoir." Humans most likely became infected when they encroached on native habitat and encountered the viruses for the first time. Exactly how this initial infection occurred isn't known.

Scientists have identified one species of African fruit bat as a source of the virus. Although humans have been infected with Ebola and Marburg through contact with monkeys, chimpanzees and other nonhuman primates, these animals aren't the viruses' natural reservoir. Instead, they are one link in the chain of infection.

Once a person has been infected with Ebola or Marburg, the virus can spread to others through contact with that person's body fluids or through use of contaminated needles or syringes.

Researchers don't think that humans produce enough Ebola or Marburg virus in airborne droplets to cause infection through casual contact.

Ebola and Marburg hemorrhagic fevers are difficult to diagnose because many of the early signs and symptoms resemble those of other infectious diseases, such as typhoid and malaria. But if doctors suspect that you have been exposed to Ebola virus or Marburg virus, they use laboratory tests that can identify the viruses within a few days.

Most people with Ebola or Marburg hemorrhagic fever have high concentrations of the virus in their blood. Blood tests known as enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (PCR) can detect specific genes or the virus or antibodies to them.

No antiviral medications have proved effective in treating Ebola virus or Marburg virus infection. As a result, treatment consists of supportive hospital care. This includes providing fluids, maintaining adequate blood pressure, replacing blood loss and treating any other infections that develop. Some people receive transfusions of plasma to replenish blood proteins that improve clotting.

Public health officials urge hospitals to keep people with Ebola or Marburg hemorrhagic fever isolated from others in negative-pressure rooms, which maintain the flow of air into, rather than out of, enclosed spaces. Health care workers should follow strict infection-control precautions.