Measles is caused by infection with the rubeola virus.
The virus lives in the mucus of the nose and throat of an infected either child or adult.
The disease is contagious for 4 days before the rash appears, and it continues to be contagious for about 4 to 5 days after.
Infection spreads through:
- Physical contact with an infected person
- Being near infected people if they cough or sneeze
- Touching a surface that has infected droplets of mucus and then putting fingers into the mouth, or rubbing the nose or eyes.
The virus remains active on an object for 2 hours.
Development of infection:
- As soon as the virus enters the body, it multiplies in the back of the throat, lungs, and the lymphatic system.
- It later infects and replicates in the urinary tract, eyes, blood vessels, and central nervous system.
- The virus takes 1 to 3 weeks to establish itself, but symptoms appear between 9 and 11 days after initial infection.
- Anyone who has never been infected or vaccinated is likely to become ill if they breathe in infected droplets or are in close physical contact with an infected person.
- Approximately 90 percent of people who are not immune will develop measles if they share a house with an infected person. [3]