Ebola << eh BOH luh >> virus is the microorganism that causes the rare but deadly Ebola virus disease (EVD). The virus is named for the Ebola River in the northern part of the Democratic Republic of the Congo (DRC). EVD first emerged in that region. Ebola virus is one of a group of several related viruses called ebolaviruses.
The Ebola virus and related viruses typically have a host, often a rodent or insect, that carries the virus but does not become ill. Scientists suspect that fruit bats are the hosts of the Ebola virus.
Symptoms
of EVD include fever, headache, diarrhea, vomiting, and massive internal bleeding. Symptoms appear within 2 to 21 days of infection.
Fatality rates for Ebola infection are different in each outbreak. In the first known outbreaks, about 80 to 90 percent of people who became infected died. Some outbreaks have had fatality rates as low as 25 percent. The average fatality rate is about 50 percent.
Transmission.
The Ebola virus is spread by contact with the blood or other bodily fluids of an infected person, or by contact with infected body tissue or unsterilized needles or other equipment that has been exposed to the virus. Because health care workers must have close contact with infected patients, they are at especially high risk of Ebola infection.
Outbreaks.
Animals such as gorillas, chimpanzees, monkeys, and antelopes can be infected by the Ebola virus. Outbreaks of disease among these animals are often observed shortly before, or at the same time as, EVD outbreaks among humans. An outbreak of EVD typically begins when a person handles an infected animal and becomes sick. The disease then spreads from person to person.
The first known EVD outbreaks occurred in central Africa in 1976. Since then, numerous other outbreaks have occurred in central and western Africa.
The largest epidemic (widespread outbreak) began in 2013, and spread widely from 2014 to 2016. It began in Guinea and spread to Liberia and Sierra Leone, and later to Mali, Nigeria, and Senegal. Global health care organizations sent medical doctors, nurses, and support staff to the region to help stop the outbreak.
During this epidemic, a few people in the United States and Europe contracted the disease. Most EVD patients outside Africa had unknowingly contracted the disease in Africa and then traveled home. The others were health care workers who had treated infected travelers.
Another severe epidemic of EVD occurred in the DRC from 2018 to 2020. More than 3,400 people were infected, and more than 2,200 people died.
Treatment and prevention.
Drugs are available to treat certain cases of EVD. These drugs are a type of monoclonal antibody treatment. Even without these drugs, many patients survive EVD when doctors aggressively treat the various symptoms. People who recover from EVD develop immunity to the virus.
Prevention efforts include educating people about how the virus is transmitted, vaccinating individuals, and quarantining (isolating) infected patients.
Related viruses.
Some other ebolaviruses are also known to cause deadly disease in humans. These include Sudan virus, which causes Sudan virus disease, and Bundibugyo virus, which causes Bundibugyo virus disease. Ebolavirus-caused diseases are collectively referred to as Ebola disease.
