They're contagious, they're worrisome - and they're apparently here.

Toronto Public Health is warning parents about an alarming increase in measles in the GTA. Three cases have been reported here so far and at least one more is being probed. And another possible instance is being looked at in Halton Region.

It's not an unheard of childhood ailment, but experts are raising the alarm only because of the sudden frequency of the disease. We usually only get about three cases reported here in a year, and it's been that way for the last decade. Having the potential for five at once is unusual and raises red flags - if not red spots.

In addition to those tell-tale red blotches on the face, other symptoms include a persistent cough, a runny nose, a fever and red watery eyes that are sensitive to light. The rash can last up to six days and it can take any where from a week to 18 days for the signs to show up.

If it hits your home, you need to be sure whoever is infected wears a mask and is kept in a separate room from four days before and four days after the rash appears or disappears.

If there's any good news it's this - most people are immune to the disease either because they had it when they were kids or they were vaccinated against it.

While it's never fun for kids, they usually tolerate it well and it runs its course. But for very small infants, adults or pregnant women, the consequences can be more severe and they should be sure to protect themselves from its effects as much as possible.

If you think you have the measles or have been in contact with anyone who has, see your doctor and click here for more information about the ailment.

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