The H1N1 flu virus has taken another life in Ontario - and this is the youngest patient yet. Health officials have confirmed a six-year-old girl succumbed to the ailment in Peel Region, making her the fourth person to die from the bug since it first surfaced earlier this year.

It's not known if the child had any underlying medical conditions, which have played a role in all the previous deaths in the province. All the other victims have been adults.

The little girl was apparently only suffering from flu symptoms for a day before she passed away.

"Influenza viruses are described as sloppy and promiscuous replicators.  If in fact primary influenza is the cause of the illness, the death can be more rapid,"  said Dr. Arlene King , Ontario Medical Officer of Health.

"If you child does develop symptoms that look like the flu, cough, fever, malaise, then they can call TeleHealth to get info on whether or not their child should be seen.  Secondly, they can contact their physician."

The girl was attending a local Peel school, but reportedly wasn't there when suffering from symptoms, and experts don't believe other students are at risk.

"We haven't recommended the closure of this school.  We don't think there's a good public health reason in this case," said Dr. David Mowat, Peel Region Medical Officer of Health.

Some members of the deceased girl's extended family also have swine flu, but their cases are described as very mild.

The province so far has more than 2,500 confirmed cases, all at a time when the flu is not normally active in this part of the world. There are fears it could come back stronger than ever come the fall and winter, the traditional flu seasons in North America. But so far, the majority of cases in Canada have been mild and patients have recovered.

The World Health Organization officially declared the flu a pandemic earlier this month, because of its rapid spread around the world.

H1N1 Flu Primer