Ebola Virus Disease

Ebola virus disease is a dangerous and highly contagious viral infection that causes severe haemorrhaging (bleeding) from the skin and the mucous membranes (the thin, moist tissue that lines body cavities). Ebola fever occurs predominantly in Africa. There is no specific treatment for the disease, which is fatal in many cases.

Ebola virus is a filovirus. See: Filoviruses for a detailed article about Ebola.

Filoviruses - non-technical

Ebola virus (EBOV, formerly designated Zaire ebolavirus) is one of five known viruses within the genus Ebolavirus. Four of the five known ebolaviruses, including EBOV, cause a severe and often fatal hemorrhagic fever in humans and other mammals, known as Ebola virus disease (EVD). Ebola virus has caused the majority of human deaths from EVD, and is the cause of the 2013–2014 Ebola virus epidemic in West Africa, which has resulted in over 4000 deaths and has spread beyond Africa to Europe and North America.

Ebola is the most famous of the Filoviridae, a virus family that also includes the Marburg virus. Ebola is endemic to Africa, particularly the Republic of the Congo and Sudan; the Marburg virus is found in sub- Saharan Africa. The natural reservoir of filoviruses is unknown. The incubation period, or time between infection and appearance of symptoms, is thought to last three to eight days, possibly longer.

Symptoms appear suddenly, and include severe headache, fever, chills, muscle aches, malaise, and appetite loss. These symptoms may be accompanied by nausea, vomiting, diarrhea, and abdominal pain. Victims become apathetic and disoriented. Severe bleeding commonly occurs from the gastrointestinal tract, nose and throat, and vagina. Other bleeding symptoms include petechiae and oozing from injection sites. Ebola is fatal in 30–90% of cases.

Symptoms start two days to three weeks after contracting the virus, with a fever, sore throat, muscle pain and headaches. Typically, vomiting, diarrhea and rash follow, along with decreased function of the liver and kidneys. Around this time, affected people may begin to bleed both within the body and externally.

The virus may be acquired upon contact with blood or other bodily fluids of an infected human or other animal. Spreading through the air has not been documented in the natural environment. Fruit bats are believed to be the normal carrier in nature, able to spread the virus without being affected. Humans become infected by contact with the bats or living or dead animals that have been infected by bats. Once human infection occurs, the disease may spread between people as well. Male survivors may be able to transmit the disease via semen for nearly two months. To diagnose EVD, other diseases with similar symptoms such as malaria, cholera and other viral hemorrhagic fevers are first excluded. Blood samples are tested for viral antibodies, viral RNA, or the virus itself to confirm the diagnosis