Measles is a common, highly dangerous infectious disease. It is caused by a virus which affects the human skin. It is also known as 5-day measles and rubeola. Its symptoms include cough, fever, red eyes etc. It is also known as morbilli or rubeola. It was discovered in 1856 by American physician, Henry Koplik. A Persian alchemist Muhammad ibn Zakariya Razi was the first person who differentiated smallpox from measles.