Health authorities in Toronto say they've seen more than 1,000 cases of influenza so far this season — more than triple the number they usually see.
There have been reports of flu at schools, hospitals and seniors' facilities.
"We know the hospitals are very busy," said Dr. Barbara Yaffe of Toronto Public Health, "and everybody knows somebody who has come down with it — and it is hitting people very hard."
About 20,000 people in Toronto have been given a flu shot this year, fewer than normal.
According to Public Health Ontario, three children in the province under the age of four have died as a result of the flu since September.
On Tuesday the coroner's office said it is investigating the death of a two-year-old Toronto boy who died a day earlier, possibly after a bout of influenza.
His five year-old brother is being treated a Sick Children's Hospital.
Dr. Yaseer Mansour, a pediatrician, says there are signs parents should look for.
"Persistent fever — more than usually two to three days," he said. "Shivering or any kind of persistent vomiting, or change of mental status, lethargic or any confusion."
But he also says parents should trust their instincts. If they notice a change in their child's condition "just come, we can have a look."
Public health officials also say there's still time to get a flu shot before the next wave hits, probably in February.
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There may be no more promoted solution to avoiding the flu this year (besides the flu shot, of course) than diligent hand washing. As many as 80 percent of infections are transmitted via contact like sneezing, coughing or touching surfaces that have been sneezed or coughed on, says Tierno, and then touching "your mouth, eyes or nose, which are the conduits of viruses into the body." He recommends scrubbing before eating, drinking or touching your face, and disinfecting shared surfaces in the home (like the bathroom) and the office, like phones, computers and fridge door handles.
While you're off in dreamland, your body gets to work repairing cells and injuries you may have incurred during the normal day's wear and tear, says Tierno. Getting your seven to nine hours a night means your body can repair and heal itself and ward off infections. "If you don't get the appropriate sleep, that system is not operating and you're on a steady decline over time," he says. In fact, skimping on sleep is <a href="http://www.huffingtonpost.com/2012/02/16/circadian-rhythms-immunity-immune-system_n_1281654.html">as disruptive to the immune system as stress</a>, according to a 2012 study. And earlier research suggested that sleep patterns may play a role in a gene that helps fight off bacteria and viruses.
Getting your blood pumping regularly can <a href="http://www.huffingtonpost.com/2012/01/07/exercise-immunity_n_1190296.html">increase the activity of a type of white blood cells</a> that attacks viruses. Shoot for an hour a day, says Tierno -- but not necessarily all at once. "Even if it's walking around the office, up stairs, down stairs, to and from work -- it doesn't have to be continuous," he says.
Getting the proper amount of the right nutrients and minerals as part of a healthy diet "leaves the body in optimal condition to fight the battle," says Tierno. This means cutting back on sugary, fatty foods and upping your intake of vegetables, fruit and lean protein, he says. One of those nutrients that gets a particularly healthy reputation during cold and flu season is zinc, and for good reason. "Zinc interferes with viruses gaining full access to our cells," he says. "Zinc may block certain metabolic activity." While it's <a href="http://www.huffingtonpost.com/2012/05/07/zinc-cold-symptoms_n_1497827.html">not the end-all cure</a>, foods rich in zinc, like <a href="http://www.huffingtonpost.com/lisa-turner/cold-prevention_b_2124507.html#slide=1771069">oysters</a> and <a href="http://www.huffingtonpost.com/2012/01/04/immune-boosting-superfood_n_1181192.html#s585162&title=Wheat_Germ">wheat germ</a>, may offer some protection.
The anti-microbial properties of this pungent bulb (and its relative, the onion) can fight off certain bacteria and viruses, says Tierno, as can the compounds in <a href="http://www.huffingtonpost.com/2012/11/08/healthy-herbs-spices-healthiest_n_2089007.html">other herbs and spices</a>, like thyme. It's likely due to the compound <a href="http://www.nytimes.com/2009/10/20/health/20real.html?_r=0">allicin, which seems to block infections</a>. Try it in your next bowl of soothing chicken soup!
Thankfully, most of us are inhabiting cozy-warm homes this winter, but those cranking radiators come with a downside. Indoor winter air is much dryer than our bodies would like. Without sufficient moisture, says Tierno, "immune system cells can't optimally work," so it's important to stay hydrated. (A <a href="http://articles.cnn.com/2009-02-11/health/healthmag.humidifier.flu_1_humidity-water-vapor-winter-flu-season?_s=PM:HEALTH">humidifier can also help</a>.)
Skipping Happy Hour
<a href="http://www.huffingtonpost.com/2012/12/28/alcohol-effects-body-infographic_n_2333328.html">Alcohol suppresses both the part of the immune system</a> that protects you from coming down with something and the part that fights off the germs already in your system, so knocking a few too many back can put you at increased risk for catching the bug going around -- and having trouble kicking it.
A positive attitude can take you far -- even, maybe, <a href="http://www.huffingtonpost.com/2012/07/06/personality-longevity_n_1652685.html#slide=1190731">to age 100</a>. But along the way, a life of laughter and optimism could also help you sniffle through fewer bouts of the flu or colds. While there's much that's still not well understood about the process, it seems that <a href="http://www.webmd.com/balance/features/give-your-body-boost-with-laughter">certain immune cells are produced</a> by a big belly laugh, says Tierno.
A <a href="http://www.huffingtonpost.com/2012/02/08/massage-benefits-health_n_1261178.html">favorite solution for de-stressing</a>, massage can also help you stay physically healthy. While there's been <a href="http://nccam.nih.gov/research/results/spotlight/090110.htm">little research into exactly how it works</a>, massage certainly increases circulation, which may help promote the general "state of wellness in the body," says Tierno. "Nutrients are passed around better, the blood flow is better," he says. "It's a very useful thing to get a massage."
A 1999 study found that getting frisky a couple of times a week can <a href="http://news.bbc.co.uk/2/hi/health/319070.stm">boost immunoglobin A</a>, an antibody that fights off colds. Just make sure your partner isn't already sick!