Scientists from the World Health Organization (WHO) say the world is at risk from a disease. However, they do not know its or what it does and looks like. They have called it 'Disease X'. It could be caused by a or another micro- that scientists don't yet know about. The WHO said Disease X could go unnoticed until it is too and it is quickly spreading around the world. The WHO is taking the of Disease X seriously. It is putting a lot of money into and is preparing a plan for a sudden outbreak. It said: "Disease X represents the that a serious international epidemic could be caused by a [virus] unknown to cause human disease."
The scientists said that Disease X could come from different sources. It could come from diseases changing and becoming strong to resist our vaccines; it could come from terrorism and bio-weapons; it could also come from scientists using DNA-changing to make entirely new viruses. The biggest threat could come from . The U.S. Centers for Disease Control and Prevention said: "Scientists estimate that more than 6 out of every 10 known diseases in people are spread from animals." These include Ebola, avian and mad cow disease. Everyone living together in cities and increasing international travel and will make it for diseases to spread.