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Measles: What you need to know

What is measles?

Measles is caused by a virus that can infect anyone who is not immunized or who has not previously had measles.

It would be very unusual for an individual to have lab-confirmed measles disease more than once. Generally, once you have had measles you are protected for life.

Persons born before 1970 are generally considered immune.

How does it spread?

Measles can spread by coughing and sneezing, or through air currents. Because it is an airborne disease, it is extremely contagious.

Measles can survive up to two hours in the air, even if the contagious person has left the space.

A person with measles is contagious even before showing symptoms.

Officials say a person can be contagious anywhere from one day before having any symptoms until four days after the appearance of the rash.

What are the symptoms?

Symptoms of measles include fever, cough, runny nose or red eyes and a red blotchy rash that appears several days after the fever starts.

The rash typically begins behind the ears and on the face, spreading down to the body, and finally to the arms and legs.

Symptoms of measles can be seen within seven to 21 days of being exposed to measles.

If you are at risk for measles, typically you would start seeing symptoms 10 days after exposure.

How dangerous is it?

In addition to the fever, rash and other symptoms, about one in three people with measles will have one or more complications including diarrhea, ear infections (which can lead to permanent hearing loss), pneumonia, encephalitis (inflammation of the brain) or seizures.

A very rare but fatal disease of the brain and spinal cord can also develop months to years after a measles infection.

This fatal disease is called sub-acute sclerosing panencephalitis.

Measles can also lead to death.

Complications are more common among children under five years of age and individuals 20 years of age and older.

What should you do if you think you have measles?

If you have symptoms of measles, do not visit any clinic or hospital.

Instead, stay home, avoid contact with others and call Health Link Alberta (1-866-408-5465) for instructions.

If you or your children are not immunized against measles, and have been exposed to measles, health officials advise staying home for 21 days following the exposure.

They suggest being isolated from all activities including work, school and social gatherings.

How can you prevent it?

There is no treatment for measles but it can be prevented through immunization — although the vaccination has been controversial in the past.

There has been debate over the last decade about the perceived risks, with some suggesting the vaccine could be linked to autism. But Health Canada officials say the science refutes that claim and vaccines are safe for people of all ages.

Alberta Health Services says immunization rates have been dropping in the last decade, which affects "herd immunity" — meaning not enough people are being vaccinated to stop the spread.

The provincial measles, mumps and rubella (MMR) vaccine immunization rate in Alberta is 84 per cent.

Sources: CBC News, Alberta Health Services

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