The virus attaches to the lining of the airways, multiplies, and causes disease. People can also be infected by direct contact with fluid from the nose or mouth of an infected person. Measles is very contagious. An uninfected person can get measles simply by breathing the air in a room where an infected person has been. The virus can live in the air for 2 hours after an infected person leaves a room.
Infected persons are usually infectious to others even before symptoms appear.
Measles symptoms usually show up in two stages. The first stage begins with a runny nose, cough, and a slight fever. As the infection progresses, the person's eyes become red and sensitive to light, and the fever rises. The second stage begins after 3 to 7 days. The fever reaches 103 o F-105 o F, and a red blotchy rash appears.