1. What is Ebola virus disease?
Ebola virus disease (formerly known as Ebola haemorrhagic fever) is a severe, often fatal illness, with a death rate of up to 90%. The illness affects humans and nonhuman primates (monkeys, gorillas, and chimpanzees).
Ebola first appeared in 1976 in two simultaneous outbreaks, one in a village near the Ebola River in the Democratic Republic of Congo, and the other in a remote area of Sudan.
The origin of the virus is unknown but fruit bats (Pteropodidae) are considered the likely host of the Ebola virus, based on available evidence.
2. How do people become infected with the virus?
Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals. In Africa, infection has occurred through the handling of infected chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest. It is important to reduce contact with high-risk animals (i.e. fruit bats, monkeys or apes) including not picking up dead animals found lying in the forest or handling their raw meat.
Once a person comes into contact with an animal that has Ebola, it can spread within the community from human to human. Infection occurs from direct contact (through broken skin or mucous membranes) with the blood, or other bodily fluids or secretions (stool, urine, saliva, semen) of infected people. Infection can also occur if broken skin or mucous membranes of a healthy person come into contact with environments that have become contaminated with an Ebola patient’s infectious fluids such as soiled clothing, bed linen, or used needles.
Health workers have frequently been exposed to the virus when caring for Ebola patients. This happens because they are not wearing personal protection equipment, such as gloves, when caring for the patients. Health care providers at all levels of the health system – hospitals, clinics and health posts – should be briefed on the nature of the disease and how it is transmitted, and strictly follow recommended infection control precautions.
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. Persons who have died of Ebola must be handled using strong protective clothing and gloves, and be buried immediately.
People are infectious as long as their blood and secretions contain the virus. For this reason, infected patients receive close monitoring from medical professionals and receive laboratory tests to ensure the virus is no longer circulating in their systems before they return home. When the medical professionals determine it is okay for the patient to return home, they are no longer infectious and cannot infect anyone else in their communities. Men who have recovered from the illness can still spread the virus to their partner through their semen for up to 7 weeks after recovery. For this reason, it is important for men to avoid sexual intercourse for at least 7 weeks after recovery or to wear condoms if having sexual intercourse during 7 weeks after recovery.
3. Who is most at risk?
During an outbreak, those at higher risk of infection are:
- health workers;
- family members or others in close contact with infected people;
- mourners who have direct contact with the bodies of the deceased as part of burial ceremonies; and
- hunters in the rain forest who come into contact with dead animals found lying in the forest.
More research is needed to understand if some groups, such as immuno-compromised people or those with other underlying health conditions, are more susceptible than others to contracting the virus.
Exposure to the virus can be controlled through the use of protective measures in clinics and hospitals, at community gatherings, or at home.
Global Alert and Response (GAR)
Epidemic & Pandemic Alert and Response (EPR) – http://www.who.int/mediacentre/factsheets/fs103/en/
Africa WHO – http://www.afro.who.int/