The WA Health Department has issued a warning following five confirmed cases of measles reported in the Rockingham area over the weekend.
Treatment and immunisations are in the process of being provided by public health authorities to people who were potentially exposed, but those exposed in public places are impossible to identify
Acting Director of the Communicable Disease Control Directorate Paul Effler, said measles are serious and highly contagious.
"Every measles case is treated as a public health emergency because of the risk of local spread," Dr Effler said.
"With high vaccination coverage, naturally occurring measles has been eliminated from WA for around 20 years, but occasional cases and small outbreaks still occur, usually associated with tourists or WA residents who are infected overseas."
Symptoms tend to develop around 10 days after being exposed to measles, with early symptoms including cough, fever, sore eyes and a runny nose.
A red blotchy rash usually follows three to four days later.
Dr Effler urged anyone who develops any symptoms or who may have been exposed to see a doctor.
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