Measles is a highly contagious virus that lives in the nose and throat mucus of an infected person. It can spread to others through coughing and sneezing.
The measles virus can live for up to 1 hour in an airspace where the infected person coughed or sneezed. If other people breathe the contaminated air or touch the infected surface, then touch their eyes, noses, or mouths, they can become infected. Measles is so contagious that if one person has it, up to 90% of the people close to that person who are not immune will also become infected. However, measles does not survive more than 1 hour outside the human body.
Infected people can spread measles to others from four days before through four days after the rash appears.
Measles is a disease of humans; the measles virus is not spread by any other animal species.