The flu is a respiratory infection caused by influenza A and B viruses, according to Toronto Public Health.
In Canada, about 12,200 people are hospitalized and 3,500 die from the flu each year.
People tend to get the flu in the late fall and winter months. It is spread by direct contact or droplets expelled during breathing, talking, sneezing or coughing.
Symptoms include sudden onset of headache, chills, cough, fever, loss of appetite, muscle aches, fatigue, runny nose, sneezing, watery eyes and throat irritation. Nausea, vomiting and diarrhea may also occur, particularly in children.
Most people will recover within a week to 10 days, but some people are at greater risk of complications, such as worsening of underlying medical conditions, pneumonia, and sometimes death.
See the below infographic courtesy of Sunnybrook hospital on six ways to avoid getting the flu. Mobile viewers, click here.