Causes

Measles is a highly contagious illness caused by a virus that replicates in the nose and throat of an infected child or adult. Then, when someone with measles coughs, sneezes or talks, infected droplets spray into the air, where other people can inhale them.

The infected droplets may also land on a surface, where they remain active and contagious for several hours. You can contract the virus by putting your fingers in your mouth or nose or rubbing your eyes after touching the infected surface.

About 90% of susceptible people who are exposed to someone with the virus will be infected.