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Causes of measles

What causes measles?

Measles is caused by a virus. The virus can live in your nose, mouth, eyes and on your skin. It is highly contagious, which means it spreads very easily.

How is measles spread?

The measles virus spreads:

  • through direct contact

  • through the air, such as when an infected person coughs or sneezes

  • on objects that were recently exposed to infected mucous or saliva, such as shared:

  1. utensils

  2. cups

  3. tissues

Symptoms of measles

What are the symptoms of measles?

Small, white spots may also show up inside the mouth and throat. After 3 to 7 days, a red blotchy rash develops on the face and spreads down the body. Symptoms begin 7 to 18 days after exposure. You can spread the virus to others from 4 days before the rash starts until 4 days after the rash appears. The virus is most often spread when people first get sick or before they know they have measles.

Initial symptoms include:

  • fever

  • cough

  • runny nose

  • red eyes

  • sleepiness

  • irritability (feeling cranky or in a bad mood)

Most people recover fully from measles within 2 to 3 weeks. However, measles can be especially dangerous for infants and those with weakened immune systems.

Complications can include:

  • ear infections

  • pneumonia (lung infection)

  • encephalitis (swelling of the brain), which can cause seizures, brain damage or death

What do you do if you become ill?

If you are showing the symptoms of measles, see a health care provider as soon as possible. Describe your symptoms over the phone before your appointment. This way the clinic can arrange to see you without exposing others to measles.

It is very important to identify measles in order to prevent it from spreading.


What are the risks of getting measles? Measles was once a common childhood disease. Thanks to immunization, your risk of getting measles is very low. But since measles is common in other parts of the world, it is still possible for cases to occur in Canada. Immunization is the best way to protect you and your children. The measles vaccination is given in 2 doses, usually in childhood. This can protect you for life.

If you or your children have not been vaccinated and have never had measles, you are at risk of infection. Measles is very contagious and easy to catch when you have contact with someone who is infected with the virus.

Travellers who are not vaccinated may bring measles into Canada. As a result, outbreaks may occur, especially in communities where people do not vaccinate their children. According to the World Health Organization, about 157,700 people died from measles in 2011. It is the leading killer of children whose deaths could have been prevented by vaccines.

Diagnosis and Treatment

How is measles diagnosed?

Measles is diagnosed based on your symptoms. It is also based on possible exposure to the virus (if there has been a recent outbreak in your community). Your health care provider will confirm the measles virus with:

  • a blood test

  • a lab test of your urine

  • a nasopharyngeal swab

How is measles treated?

There is no specific treatment for measles since it is caused by a virus. Most people fully recover within 2 or 3 weeks.

Your health care provider will likely:

  • give you medication (like pain relievers) to reduce your fever

  • tell you to drink plenty of fluids, eat healthy foods and get lots of rest

If you have measles, you should stay at home until 4 days after the rash appeared. This will help to limit the spread of the virus.


How can measles be prevented?

Measles can easily be prevented through 2 doses of the measles-containing vaccine.

The measles vaccine is part of the measles-mumps-rubella (MMR) or measles-mumps-rubella-varicella (MMRV) immunization. These combination vaccinations are given by needle to children at 12 to 15 months of age. They are given again at 18 months or 4 to 6 years of age. The schedules of immunization vary depending on your province or territory.

Measles vaccines are safe, effective and free. Side effects of this vaccine are usually very mild. Your child’s arm or thigh might be a bit red or sore where the needle went in. Your child may also:

  • have a slight fever

  • be fussy

  • have a skin rash

  • have swollen glands (sore or tender to the touch on either side of the neck)

These side effects usually happen 12 to 24 hours after the immunization and go away within a few days.

What if there is a measles outbreak?

If there is a measles outbreak in your community and you have not been immunized, you are at risk. If this is the case and you have been exposed to measles, you should speak to a health care provider. You may be required to get the measles vaccine within 3 days of exposure.

Alternatively, you may receive an injection of measles antibodies (immunoglobulin or Ig) within 6 days of exposure. These antibodies can either prevent measles or make the symptoms less severe.

What do you do if you plan on traveling abroad?

If you are planning to travel abroad:

  • visit your health care provider at least 6 weeks before you leave

  • make sure your immunizations are up to date for you and your children

  • read the Government of Canada’s travel health notices

Note:The information on this site is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images and information, contained on or available through this web site is for general information purposes only. Source of Information: Government of Canada |


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