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Information on EBOLA virus

Key Facts

  • Ebola virus disease (EVD) is a severe, often fatal illness in humans.
  • It takes its name from a village in DRC situated near the Ebola River, where in 1976 one of the first recorded cases of the disease in human beings was found.
  • The virus is believed to be transmitted to people from animals, and spreads in the human population through human-to-human transmission.
  • Severely ill patients require intensive supportive care. No licensed specific treatment or vaccine is available for use in people or animals.
  • EVD outbreaks have a case fatality rate of up to 90%.

Transmission

The natural reservoir host of EVD remains unknown, however on the basis of available evidence; researchers believe that the virus is animal-borne. Infection has been documented through the handling of the blood, organs, secretions or other bodily fluids of infected chimpanzees, gorillas, fruit bats, and monkeys found ill or dead in afflicted areas. It then spreads in the community through human-to-human transmission, with infection resulting from direct contact with the blood, diarrhea stool, vomit or other bodily secretions (including saliva, tears, urine, and semen) of infected people. It is also spread through indirect contact with contaminated environments or objects. Thorough washing of the hands after every potential contact is therefore of the utmost importance. Transmission is not by aerial spread (coughing, sneezing etc).

It is important to note that the bodies of EVD victims are highly infectious because of leakage of large amounts of fluid. They should be sealed in bags and burned in chlorine-treated pits.

There are five identified subspecies of EVD. Four of the five have caused disease in humans and four of the five occur in an animal host native to Africa. Confirmed cases have been reported in: Guinea, Liberia, Sierra Leone, DRC, Gabon, South Sudan, Ivory Coast, Uganda, ROC, South Africa (imported) and Nigeria (imported).

Signs and symptoms

Symptoms may appear anywhere from 2 to 21 days after exposure to EVD, though 8-10 days is most common.

  • Stage one: symptoms are initially non-specific to EVD and often similar to those of malaria, making diagnosis difficult in the early stages. They include severe fever (over 40⁰C), joint and muscle pain, sore throat and weakness.
  • This is followed by stomach pain, vomiting and diarrhea.
  • The third stage is rash, accompanied by internal and external bleeding (causing the characteristic red eyes of EVD).
  • The fourth and final stage is organ failure due to hemorrhagic shock.

Diagnosis, vaccine and treatment

EVD can be diagnosed definitively in a laboratory through different types of blood tests:

  • Antibodies that the person produces as a result of exposure to the virus can be tested. However these appear late in the disease and cannot be used to screen people who do not have the symptoms.
  • RNA virus gene testing by a method called PCR identifies the virus itself and the subtype.
  • Samples from patients are an extreme biohazard risk; testing should be conducted under maximum biological containment conditions.

No licensed vaccine or specific treatment for EVD is available for use in people or animals. Several vaccines are being tested, but none are available for clinical use.

Standard treatment for EVD is still largely limited to supportive therapy. Aggressive fluid replacement can help in resuscitation if the patient presents early enough. Health workers should always wear full Personal Protective Equipment (PPE), which consists of an impermeable suit on top of surgical scrubs, rubber boots, 2 pairs of gloves, an N97 mask, head hood, goggles and a full length plastic apron. Other infection control measures are also employed, such as complete equipment sterilization and isolation of EVD patients from unprotected persons.