Measles is preventable through immunization. Measles is a highly contagious infection of the respiratory system. Measles is caused by the measles virus. The measles virus is found worldwide. The virus multiplies in cells of the respiratory tract in infected persons and is released into fluids of the nose, throat, and mouth.
People get measles when they breathe in tiny droplets that contain the measles virus.
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.