There has been a significant surge in the flu virus around Ontario this year, warn the province's top doctors, especially during this last week.

"We're noticing a significant load of influenza not seen since H1N1 [broke out in 2009]," said Dr. Robin Williams, the associate chief medical officer for Ontario.

The flu shot offers about 60 per cent protection each year, research suggests. (Pawel Dwulit/Canadian Press)

The strains of flu viruses that are circulating vary in North America this year.

In Canada, the influenza A(H3N2) strain predominates, while in the U.S., a mix of A(H3N2) and influenza B have been detected. In Mexico, influenza B is predominant, according to the Public Health Agency of Canada.

Dr. Williams added the province carefully monitors the spread of the flu virus.

In Toronto, some walk-in clinics reported about a quarter of their patients suffering from the influenza, she said.

Influenza, also called "the flu," is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness and at times it can lead to death.

Older people, young children and people with certain health conditions are at high risk for serious flu complications.

3 proven ways to avoid the flu

Dr. Michael Gardam, director of the infection prevention and control unit at the University Health Network in Toronto, suggested three proven ways to avoid getting sick with flu, colds and other respiratory illnesses:

• Get a flu shot.
• Wash your hands.
• Don't touch your face.

"The flu shot definitely works," Gardam said.

"Overall, [it gives] roughly 60 per cent protection each year, so it's certainly better than doing nothing and there's really no downside."

Handwashing also has support in the medical literature, he said.

"Studies have shown that if you wash your hands at least five times a day you will significantly reduce your risk" of getting respiratory viruses.