Ebola virus disease (EVD; also Ebola hemorrhagic fever, or EHF), or simply Ebola, is a disease of humans and other primates caused by ebolaviruses. Signs and symptoms typically start between two days and three weeks after contracting the virus with a fever, sore throat, muscle pain, and headaches. Then, vomiting, diarrhea and rash usually follow, along with decreased function of the liver and kidneys. At this time some people begin to bleed both internally and externally.The disease has a high risk of death, killing between 25 percent and 90 percent of those infected with an average of about 50 percent. This is often due to low blood pressure from fluid loss, and typically follows six to sixteen days after symptoms appear.
The virus spreads by direct contact with body fluids, such as blood, of an infected human or other animals. It may also spread through contact with a recently contaminated item or surface. Spread of the disease through the air between primates, including humans, has not been documented in either laboratory or natural conditions. Semen or breast milk of a person after recovery from EVD may still carry the virus for several weeks to months.Fruit bats are believed to be the normal carrier in nature, able to spread the virus without being affected by it. Other diseases such as malaria, cholera, typhoid fever, meningitis and other viral hemorrhagic fevers may resemble EVD. Blood samples are tested for viral RNA, viral antibodies or for the virus itself to confirm the diagnosis.
Control of outbreaks requires coordinated medical services, alongside a certain level of community engagement. The medical services include: rapid detection of cases of disease, contact tracing of those who have come into contact with infected individuals, quick access to laboratory services, proper healthcare for those who are infected and proper disposal of the dead through cremation or burial. Prevention includes limiting the spread of disease from infected animals to humans.This may be done by handling potentially infected bush meat only while wearing protective clothing and by thoroughly cooking it before eating it. It also includes wearing proper protective clothing and washing hands when around a person with the disease. Samples of body fluids and tissues from people with the disease should be handled with special caution.
No specific treatment or vaccine for the virus is available, although a number of potential treatments are being studied. Efforts to help those who are infected are supportive. This includes either oral rehydration therapy (drinking slightly sweetened and salty water) or giving intravenous fluids as well as treating symptoms. Supportive care improves outcomes. The disease was first described in 1976 in two outbreaks that occurred at the same time, one in Nzara, and the other in Yambuku. The one in Yambuku occurred in a village near the Ebola River from where the disease takes its name. EVD outbreaks typically occur intermittently in tropical regions of sub-Saharan Africa.Through 2013, the World Health Organization reported a total of 1,716 cases in 24 outbreaks. The largest outbreak to date is the ongoing epidemic in West Africa, which is centered in Guinea, Sierra Leone and Liberia. As of 3 January 2015, this outbreak has 20,834 reported cases resulting in 8,251 deaths.