An adult from Ontario who recently travelled across Asia has been diagnosed with measles, and authorities are concerned that other travellers passing through Toronto鈥檚 busiest airport could鈥檝e been exposed to the highly contagious disease.

Niagara Region Public Health is investigating the case after it was confirmed by a laboratory on Friday.

Measles can almost always be prevented by the MMR measles vaccine. But those who don鈥檛 have the vaccine could be at risk.

The health agency says anyone who visited Toronto Pearson International Airport on Feb. 22 between 6:20 p.m. and 9:30 p.m. may have been exposed to measles, which can pass easily from person to person.

Symptoms of the disease can appear seven to 18 days after exposure.

Authorities also identified the following flights as possible points of exposure:

  • Departing Flight, Siem Reap, Cambodia on Cathay Pacific Flight #5249 at 11:20 a.m.
  • Arriving Flight, Hong Kong, China, Cathay Pacific #5249 at 3 p.m.
  • Departing Flight, Hong Kong, China, Air Canada #16 at 4:30 p.m.
  • Arriving Flight, Toronto Pearson International Airport, Terminal 1, Air Canada #16 at 6:20 p.m.

As well, anyone who visited West Lincoln Memorial Hospital in Grimsby, Ont. On Feb. 27 between 3 p.m. and midnight may have been exposed.

鈥淢easles starts with cough, runny nose, red watery eyes, and fever. After about four days a rash begins on the face and moves down the body. There may be white spots inside the mouth,鈥� the agency said.

鈥淚f you think you may have measles and need to see a doctor, you must call ahead to the doctor鈥檚 office, walk-in clinic, or emergency department. This will allow health care staff to manage your care appropriately.鈥�

Complications of measles can include ear infections, blindness, lung infection, swelling of the brain, and premature labour, miscarriage and low birth rate if contracted during pregnancy.

The new infection comes just a few days after Toronto Public Health confirmed a case of a baby with measles in the city.

Earlier this year, came down with measles following an outbreak in the Vancouver area.