The WA health department has issued a Measles alert issued for WAmeasles alert after someone who travelled to Perth from Thailand was confirmed to have the contagious illness.

A measles alert has been issued after a person who travelled to Perth from Thailand this week was confirmed to have the contagious illness.

The person arrived at Perth International Airport after flying Thai Airways from Bangkok on Sunday.

Between then and Tuesday, the person visited Alexander Heights Shopping Centre, caught the train between Greenwood Station and Elizabeth Quay, and visited Westralia Square and Kingsway City Shopping Centre.

People with measles typically develop symptoms about 10 days after being exposed to the virus, but this can vary from seven to 18 days.

Early symptoms include fever, cough, runny nose and sore eyes, followed by a red blotchy rash three or four days later. The rash usually starts on the face and spreads to the rest of the body.