The City of New Westminster warns parents and other swimmers that they may have been exposed to the measles virus last weekend.

Someone with measles visited the outdoor pool in Moody Park on Sunday, August 19, the city said in a statement that was posted online Friday.

Everyone who was at the pool between 13.30. and 16.30 hours may have been exposed that day. Measles are spread when an infected person breathes, coughs or sneezes.

The virus can survive for hours in drops in the air.

Symptoms of the serious illness are fever, cough, runny nose and red eyes, and generally appear between a week and two weeks after exposure. Three to seven days later, those with measles will see a rash beginning on the face and neck and spreading to the chest, arms and legs. The results last at least three days, health officials say.

"You may also notice stains in your mouth that look like small grains of sand on a red surface," said the city's statement.

Those who were born before 1970 and who have a history of measles infection are protected, as are those who were born after 1970 if they had two doses of a measles vaccine, such as measles, mumps, and rubella.

Anyone who develops symptoms is advised to stay at home and stay away from others who are not protected. They must contact health officials, a healthcare provider or 811.

When visiting a clinic or a doctor's practice, the public is advised to report in advance that measles are suspected. Patients will be seen quickly and in a way that prevents others from being infected.