The WA Department of Health is warning travellers who travelled on Singapore Airlines flight SQ225 departing Singapore for Perth on 26 July 2014 that they may have been exposed to measles.
The warning comes after a passenger who travelled on this flight was confirmed to have been infectious with measles.
This passenger also travelled on Singapore Airlines flight SQ5066 from Davao in the Philippines to Singapore, earlier the same day.
The Communicable Disease Control Directorate's Dr Paul Effler said measles was highly infectious, spread through coughing and sneezing.
Symptoms can include fever, tiredness, runny nose, cough and sore red eyes which usually last for several days before a red, blotchy rash appears.
Complications can include pneumonia or swelling of the brain.
Susceptible passengers who may have been exposed to measles on this flight could expect symptoms to appear any time between August 2 and August 12.
"Passengers who develop these symptoms should seek medical attention, but it is important that they phone ahead first to ensure they don’t share the waiting area with other patients and risk infecting them," Dr Effler said.
“The local public health units are attempting to contact passengers who were seated closest to the infected traveller and are most at risk, however, other passengers seated elsewhere on the plane may have been exposed to the virus and should also be alert for symptoms."
Dr Effler said WA was experiencing a surge in measles cases.
"So far in 2014, we have had 33 measles infections reported; that’s already more than we’ve seen in any previous year for the past decade," Dr Effler said.
Nine of the patients had been hospitalised and half were adults aged between 20 and 49 years of age.
Dr Effler said that many Australians under 50 years of age who have not received two doses of measles vaccine are still susceptible to measles. Persons born before 1966 are usually immune because they had measles during childhood.
Parents are also urged to check that their children are fully immunised.
Children should receive a dose of measles vaccine at both 12 and 18 months of age, as part of the routine childhood immunisation schedule.
For more information on measles, go to www.public.health.wa.gov.au.