Measles is a highly contagious, serious disease caused by a virus. It remains a leading cause of death among young children globally, despite the availability of a safe and effective vaccine. An estimated 197 000 people died from measles in 2007, mostly children under the age of five.
Measles is caused by a virus in the paramyxovirus family. The measles virus normally grows in the cells that line the back of the throat and the lungs. It is a human disease not known to occur in animals.