Ebola virus

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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.

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
  • Stomach pain
  • Severe weight loss
  • Bleeding, usually from the eyes, and bruising (people near death may bleed from other orifices, such as 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 or Marburg viruses (hemorrhagic fevers) is low. The risk increases if you:

  • Travel to Africa
  • Conduct animal research with monkeys imported from Africa or the Philippines
  • Provide medical or personal care
  • Prepare people for burial

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

Tests and diagnosis

Ebola and Marburg hemorrhagic fevers are difficult to diagnose because early signs and symptoms resemble those of other diseases, such as typhoid and malaria. If doctors suspect you have Ebola or Marburg viruses, they use blood tests to quickly identify the virus, including:

  • Enzyme-linked immunosorbent assay (ELISA)
  • Reverse transcriptase polymerase chain reaction (PCR)

The Centers for Disease Control and Prevention monitors the United States for conditions such as Ebola infection, and its labs can test for the Ebola virus. Mayo Clinic does not test for the Ebola and Marburg viruses.

Treatments and drugs

No antiviral medications have proved effective in treating infection with either virus. Supportive hospital care includes:

  • Providing fluids
  • Maintaining blood pressure
  • Providing oxygen as needed
  • Replacing lost blood
  • Treating other infections that develop

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.
  • Wash your hands frequently.
  • Avoid bush meat.
  • Avoid contact with infected people.
  • Follow infection-control procedures.
  • Don’t handle remains.

Vaccine development

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

 

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