25 years
What are the causes of the Ebola virus? How can we prevent catching it?
Oct 8, 2014
Ebola virus disease (EVD), formerly known as Ebola hemorrhagic fever, is a severe illness in humans that often leads to mortality.
The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission.
There are 5 species that have been identified: Zaire, Bundibugyo, Sudan, Reston and Taï Forest. The first 3, Bundibugyo ebolavirus, Zaire ebolavirus, and Sudan ebolavirus have been associated with large outbreaks in Africa. The virus causing the 2014 west African outbreak belongs to the Zaire species.
It is thought that fruit bats of the Pteropodidae family are natural Ebola virus hosts. Ebola can have access into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals such as chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest.
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 measures are not vigorously implemented.
Burial ceremonies in which mourners have direct contact with the body of the deceased person have also been implicated in the transmission of Ebola.
The incubation period (the time interval from infection with the virus to onset of symptoms) varies from 2 to 21 days. Humans are not contagious until they develop symptoms. First symptoms are the sudden onset of fever fatigue, muscle pain, headache and sore throat. This is followed by vomiting, diarrhea, rash, symptoms of impaired kidney and liver function, and in some cases, both internal and external bleeding (e.g. oozing from the gums, blood in the stools). Laboratory findings include low white blood cell and platelet counts and elevated liver enzymes.
Supportive care-rehydration with oral or intravenous fluids- and treatment of specific symptoms, improves survival. There is as yet no proven treatment available for EVD. However, a range of potential treatments including blood products, immune therapies and drug therapies are currently being evaluated. No licensed vaccines are available yet, but 2 potential vaccines are undergoing human safety testing.
Good outbreak control is based upon:
-case management,
-surveillance and contact tracing,
-a good laboratory service,
-safe burials and social mobilization. Raising awareness of risk factors for Ebola infection and protective measures to be followed is essential.
In Africa, reducing the risk of wildlife-to-human transmission (from contact with infected fruit bats or monkeys/apes and the consumption of their raw meat) must be done.
Reducing the risk of human-to-human transmission from direct or close contact with people with Ebola symptoms, particularly with their bodily fluids. 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.
Outbreak containment measures including prompt and safe burial of the dead, identifying people who may have been in contact with someone infected with Ebola, monitoring the health of contacts for 21 days, the importance of separating the healthy from the sick to prevent further spread, the importance of good hygiene and maintaining a clean environment.
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