Measles is a highly contagious viral infection caused by the measles virus. In fact, measles is one of the most contagious diseases in the world. Due to the success of measles immunization programs, cases and deaths due to measles have decreased internationally – and, in Canada, by 99%.

Symptoms of measles commonly begin 10 to 14 days after someone has been exposed to the virus. A high fever is commonly the first symptom to appear. The fever is often accompanied by other symptoms, which can include a runny/stuffy nose, inflamed eyes, a cough, and small white bumps that form on the inside of the cheeks. Usually two to three days after these symptoms begin, a rash appears – typically on the face. The rash then spreads to the upper body (chest and stomach area) and then to the arms and legs. The rash is typically accompanied by a high fever. The full body rash often lasts five to six days. 

The measles virus enters the body through the mouth or nose. Measles is spread through the air (i.e., when someone who has measles coughs or sneezes in the same room as you and you inhale the infected droplets in the air), through close contact with others (e.g., coughing or sneezing next to someone), or through coming into direct contact with an infected person’s mucus or spit and then getting these fluids in your nose or mouth. It is important to remember that measles is extremely contagious.