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