Ebola virus disease

Ebola disease is a severe, often fatal illness affecting humans and other primates.

The virus is transmitted to people from wild animals (such as fruit bats, porcupines and non-human primates) and then spreads in the human population through direct contact with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids.

The average Ebola disease case fatality rate is around 50%. Case fatality rates have varied from 25–90% in past outbreaks.

The first Ebola disease outbreak occurred in remote villages in Central Africa, near tropical rainforests. The 2014–2016 Ebola virus disease outbreak in West Africa was the largest and most complex Ebola outbreak since the virus was first discovered in 1976. There were more cases and deaths in this outbreak than all others combined. It also spread between countries, starting in Guinea then moving across land borders to Sierra Leone and Liberia.

It is thought that fruit bats of the Pteropodidae family are natural hosts of the orthoebolavirus. 

The incubation period, that is, the time interval from infection with the virus to onset of symptoms, is from 2 to 21 days. A person infected with Ebola cannot spread the disease until they develop symptoms.

Symptoms of Ebola disease can be sudden and include: fever, fatigue, malaise, muscle, pain, headache, and sore throat. These are followed by vomiting, diarrhoea, abdominal pain, rash, and symptoms of impaired kidney and liver function. In less frequent cases, internal and external bleeding (e.g. oozing from the gums, blood in the stools), can occur.

It can be difficult to clinically distinguish Ebola from other infectious diseases such as malaria, typhoid fever and meningitis. A range of diagnostic tests have been developed to confirm the presence of the virus.

Early intensive supportive care – rehydration with oral or intravenous fluids – and treatment of specific symptoms improves survival. A range of potential treatments is currently being evaluated.