Illustration of the trimer glycoprotein from the outer envelope of an Ebola virus (EBOV). This glycoprotein is responsible for attachment, fusion and entry of virus to target cells. Ebola causes a severe, and often fatal disease in humans and nonhuman primates (monkeys, gorillas and chimpanzees). Symptoms include fever, fatigue, headache, muscle aches, vomiting, diarrhoea and haemorrhaging (internal bleeding). There is no cure for the disease, but three quarters of patients can recover if provided with sufficient medical support.