Measles is a highly contagious disease. It is caused by a virus – an extremely tiny organism that can only reproduce itself by residing within living cells. Humans are the only living creatures who can develop measles, and they can only get it if they are exposed to the measles virus.
The most common way that people get infected with the disease is by breathing in tiny droplets of water vapor containing the measles virus. An uninfected person can get measles just by breathing the air in a room that was previously occupied by an infected person.
Once introduced into a person’s respiratory system, the measles virus proceeds to attach itself to the lining of the airways. Drawing energy from this new host, the virus begins to multiply and spread through the body.
Measles: an infection of the respiratory system
