Ebola virus disease (EVD) is a severe disease that causes haemorrhagic fever in humans and animals. Diseases that cause haemorrhagic fevers affect the body’s vascular system (how blood moves through the body). They can lead to significant internal bleeding, organ failure, and are often fatal.
Background
EVD was first identified in 1976 in two simultaneous outbreaks in Africa, including one near the Ebola river, where the disease got its name. There are five known species of Ebola: Zaire, Bundibugyo, Sudan, Taï Forest and Reston. The first three species, Zaire, Bundibugyo, and Sudan, have been associated with large outbreaks in Africa. The Reston species is not associated with disease in humans. The virus causing the 2014 West African outbreak belongs to the Zaire species.
Symptoms
Recent studies have shown that 95 per cent of patients that become infected by an exposure to EVD will show symptoms in two to 21 days. Humans are not infectious until they develop symptoms. The first symptoms are the sudden onset of fever, intense weakness and fatigue, muscle pain, headache and sore throat. The disease progresses to vomiting, diarrhoea, rash, symptoms of impaired kidney and liver function, and in some cases, both internal and external bleeding (e.g. oozing from the gums, blood in stool). Laboratory findings include low white blood cell and platelet counts, and elevated liver enzymes.EVD infections can only be confirmed through laboratory testing.