Measles is the most infections common disease. An infected person in a crowded room will give it to almost everyone. Epidemics used to happen every two to three years. Even as recent as the late 1980s and early 1990s, the U.S. experienced large outbreaks among inner-city African-American and Hispanic children.

Especially in Africa, measles can cause death from pneumonia, diarrhea, and malnutrition.

The first case of measles was reported a thousand years ago by a Persian physician named Abu Bakr Muhammad ibn Zakariyâ, who was also known as al-Rhazes of Baghdad. (850-923) It was so common, that he believed it was a natural episode of childhood like losing your baby teeth.

To sustain itself indefinitely, it needs a local population of about 300,000 to 400,000. This will provide the virus with a continuous supply of "virgin" bodies. Such a settlement did not exist before the Sumerian cities in the Middle East around 2,500 B.C. Historians believe the measles evolved shortly after this date from viruses that infected cattle or dogs.

Greek and Roman writers did not mention this disease, but that could be because it was classified with other severe rash afflictions. Al-Rhazes was the first person to distinguish measles from smallpox. However, he believed they had the same cause. This view persisted for almost 800 years.

Al-Rhazes called measles "hasbah" which meant eruption. The term "measles" was first used in the 14th century. The word stems from "miser" which referred to the wretchedness of lepers.