All about Ebola

With WHO declaring the current Ebola outbreak an international health emergency, here are some facts about the disease and tips you might want to check out

Published: Monday 11 August 2014

Ebola virus

What is Ebola?
  • Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness
  • EVD outbreaks have a case fatality rate of up to 90%, which means only one in 10 persons infected by the virus is likely to survive
  • It has appeared sporadically since its initial recognition in 1976. The present outbreak in 2014 is the biggest ever in history
  • EVD outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests
What causes it?
  • The disease is caused by infection with Ebola virus, named after a river in the Democratic Republic of the Congo (formerly Zaire) in Africa, where it was first recognised
  • Ebola virus is one of two members of a family of RNA viruses called the Filoviridae
  • There are five identified subtypes of Ebola virus. Four of the five have caused disease in humans: Ebola-Zaire, Ebola-Sudan, Ebola-Ivory Coast and Ebola-Bundibugyo. The fifth, Ebola-Reston, has caused disease in nonhuman primates, but not in humans
Where does it come from?
  • The exact origin, locations, and natural habitat (known as the natural reservoir) of Ebola virus remain unknown. However, on the basis of available evidence and the nature of similar viruses, researchers believe that the virus is zoonotic (animal-borne) with four of the five subtypes occurring in an animal host native to Africa
  • Fruit bats of the Pteropodidae family are considered to be the natural host of the Ebola virus
Where does Ebola occur?
  • Confirmed cases of Ebola virus disease have been reported in the Democratic Republic of the Congo, Gabon, Sudan, the Ivory Coast, Uganda, and the Republic of the Congo
  • Ebola-Reston virus caused severe illness and death in monkeys imported to research facilities in the United States and Italy from the Philippines; during these outbreaks, several research workers became infected with the virus, but did not become ill
How does it spread?
  • The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission
  • In Africa, infection has been documented through the handling of infected chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest
  • Ebola is contracted by exchanging fluids with an infected person, through the mouth, eyes, nose or other access points to inside the body
  • It can also spread through indirect contact with environments contaminated with such fluids
  • Burial ceremonies in which mourners have direct contact with the body of the deceased person can also play a role in the transmission of Ebola
  • People who have recovered from the disease can still transmit the virus through their semen for up to seven weeks after recovery from illness
  • Health-care workers have frequently been infected while treating patients with suspected or confirmed EVD. This has occurred through close contact with patients when infection control precautions are not strictly practised
Symptoms of Ebola
  • The incubation period for Ebola ranges from 2 to 21 days. The onset of illness is abrupt and is characterised by fever, headache, joint and muscle aches, sore throat, and weakness, followed by diarrheoa, vomiting, stomach pain
  • A rash, red eyes, hiccups and internal and external bleeding may be seen in some patients
  • Laboratory findings include low white blood cell and platelet counts and elevated liver enzymes
  • Researchers do not understand why some people are able to recover from Ebola and others are not. However, it is known that patients who die usually have not developed a significant immune response to the virus at the time of death
Treatment for Ebola
  • No licensed vaccine for EVD is available. Several vaccines are being tested, but none are available for clinical use
  • Severely ill patients require intensive supportive care. Patients are frequently dehydrated and require oral rehydration with solutions containing electrolytes or intravenous fluids. Treatment may also require maintaining patients' oxygen status and blood pressure and treating them for any complicating infections
  • No specific treatment is available. New drug therapies are being evaluated
How can Ebola be prevented?
  • Since the identity and location of the natural reservoir of Ebola virus are unknown, there are few established primary prevention measures
  • If cases of the disease do appear, the risk of wildlife-to-human transmission needs to be prevented by avoiding contact with infected fruit bats or monkeys/apes and abstaining from consuming their raw meat. Animals should be handled with gloves and other appropriate protective clothing. Animal products (blood and meat) should be thoroughly cooked before consumption.
  • Risk of human-to-human transmission in the community should be minimised by avoiding direct or close contact with infected patients, particularly with their bodily fluids. Close physical contact with Ebola patients should be avoided. Gloves and appropriate personal protective equipment should be worn when taking care of ill patients at home. Regular hand washing is required after visiting patients in hospital, as well as after taking care of patients at home
  • Communities affected by Ebola should inform the population about the nature of the disease and about outbreak containment measures, including burial of the dead. People who have died from Ebola should be promptly and safely buried
  • Spread of an epidemic within health-care facilities is quite possible
  • It is not always possible to identify patients with EBV early because initial symptoms may be non-specific. For this reason, it is important that health-care workers apply standard precautions consistently with all patients – regardless of their diagnosis – in all work practices at all times
  • These include basic hand hygiene, respiratory hygiene, the use of personal protective equipment (according to the risk of splashes or other contact with infected materials), safe injection practices and safe burial practices

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