Overview

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 viruses are native to Africa, where sporadic outbreaks have occurred for decades.

Ebola virus and Marburg virus live in 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 drug has been approved to treat either virus. People diagnosed with Ebola or Marburg virus receive supportive care and treatment for complications. Scientists are coming closer to developing vaccines for these deadly diseases.

Symptoms

Signs and symptoms typically begin abruptly within five to 10 days of infection with Ebola or Marburg virus. Early signs and symptoms include:

  • Fever
  • Severe headache
  • Joint and muscle aches
  • Chills
  • Weakness

Over time, symptoms become increasingly severe and may include:

  • Nausea and vomiting
  • Diarrhea (may be bloody)
  • Red eyes
  • Raised rash
  • Chest pain and cough
  • Sore throat
  • Stomach pain
  • Severe weight loss
  • Bruising
  • Bleeding, usually from the eyes, and when close to death, possible bleeding from the ears, nose and rectum
  • Internal bleeding

Causes

Ebola virus has been found in African monkeys, chimps and other nonhuman primates. A milder strain of Ebola has been discovered in monkeys and pigs in the Philippines.

Marburg virus has been found in monkeys, chimps and fruit bats in Africa.

Transmission from animals to humans

Experts suspect that both viruses are transmitted to humans through an infected animal's bodily fluids. Examples include:

  • Blood. Butchering or eating infected animals can spread the viruses. Scientists who have operated on infected animals as part of their research have also contracted the virus.
  • Waste products. Tourists in certain African caves and some underground mine workers have been infected with the Marburg virus, possibly through contact with the feces or urine of infected bats.

Transmission from person to person

Infected people typically don't become contagious until they develop symptoms. Family members are often infected as they care for sick relatives or prepare the dead for burial.

Medical personnel can be infected if they don't use protective gear, such as surgical masks and gloves. Medical centers in Africa are often so poor that they must reuse needles and syringes. Some of the worst Ebola epidemics have occurred because contaminated injection equipment wasn't sterilized between uses.

There's no evidence that Ebola virus or Marburg virus can be spread via insect bites.

Risk factors

For most people, the risk of getting Ebola hemorrhagic fever or Marburg hemorrhagic fever is low. The risk increases if you:

  • Travel to Africa. You're at increased risk if you visit or work in areas where Ebola virus or Marburg virus outbreaks have occurred.
  • Conduct animal research. People are more likely to contract the Ebola or Marburg virus if they conduct animal research with monkeys imported from Africa or the Philippines.
  • Provide medical or personal care. Family members are often infected as they care for sick relatives. Medical personnel also can be infected if they don't use protective gear, such as surgical masks and gloves.
  • Prepare people for burial. The bodies of people who have died of Ebola or Marburg hemorrhagic fever are still contagious. Helping prepare these bodies for burial can increase your risk of developing the disease.

Complications

Both Ebola and Marburg hemorrhagic fevers lead to death for a high percentage of people who are affected. As the illness progresses, it can cause:

  • Multiple organ failure
  • Severe bleeding
  • Jaundice
  • Delirium
  • Seizures
  • Coma
  • Shock

One reason the viruses are so deadly is that they interfere with the immune system's ability to mount a defense. But scientists don't understand why some people recover from Ebola and Marburg and others don't.

For people who survive, recovery is slow. It may take months to regain weight and strength, and the viruses remain in the body for weeks. People may experience:

  • Hair loss
  • Sensory changes
  • Liver inflammation (hepatitis)
  • Weakness
  • Fatigue
  • Headaches
  • Eye inflammation
  • Testicular inflammation

Prevention

Prevention focuses on avoiding contact with the viruses. The following precautions can help prevent infection and spread of Ebola and Marburg.

  • Avoid areas of known outbreaks. Before traveling to Africa, find out about current epidemics by checking the Centers for Disease Control and Prevention website.
  • Wash your hands frequently. As with other infectious diseases, one of the most important preventive measures is frequent hand-washing. Use soap and water, or use alcohol-based hand rubs containing at least 60 percent alcohol when soap and water aren't available.
  • Avoid bush meat. In developing countries, avoid buying or eating the wild animals, including nonhuman primates, sold in local markets.
  • Avoid contact with infected people. In particular, caregivers should avoid contact with an infected person's body fluids and tissues, including blood, semen, vaginal secretions and saliva. People with Ebola or Marburg are most contagious in the later stages of the disease.
  • Follow infection-control procedures. If you're a health care worker, wear protective clothing, such as gloves, masks, gowns and eye shields. Keep infected people isolated from others. Dispose of needles and sterilize other instruments.
  • Don't handle remains. The bodies of people who have died of Ebola or Marburg disease are still contagious. Specially organized and trained teams should bury the remains, using appropriate safety equipment.

Vaccine development

Scientists are working on a variety of vaccines that would protect people from Ebola and Marburg viruses. Some of the results have been promising, but further testing is needed.