Influenza (flu)

Influenza is commonly known as the flu. It is a respiratory infection caused by a virus. The flu virus affects people of any age and can cause mild to severe illness. It is most common from November to April.

Those at highest risk of complications from the flu are the very young and the very old, pregnant women and people with chronic medical conditions.

• fever
• headache
• sore throat
• extreme weakness
• chills
• cough
• stuffy nose
• muscle aches
• fatigue

The elderly may not have a fever. Children can also have earaches, nausea, vomiting and diarrhea. While most symptoms usually go away in a few days, the cough and fatigue can last for several weeks.

You should see a health care provider if the illness seems to be causing more serious symptoms.

Is it a cold or the flu? [PDF, Public Health Agency of Canada]

Influenza viruses are found in the nose and throat. They can be spread from person to person by kissing and through droplets from coughing and sneezing that reach another person’s nose or mouth. These droplets may also land on objects and surfaces in the environment and can be picked up by the hands and spread to the nose and mouth, causing infection. The virus can live for hours on some surfaces.

Most people who get the flu do not require any special treatments. Certain medications may be given to people who are at high risk of having complications from the infection, such as pregnant women, the elderly and people with weak immune systems.

You can treat mild symptoms at home.

• We offer a vaccine that protects against the flu.
• Simple preventative measures can reduce the spread of infection.
• The Chief Medical Officer of Health has made specific recommendations for workers in the swine (PDF, 112KB), poultry (PDF, 64KB) and animal shelter (PDF, 87KB) industries.

FluWatch is Canada’s national surveillance system that monitors the spread of flu and flu-like illnesses on an on going basis. FluWatch reports, posted every Friday, contain specific information on flu viruses circulating in Canada.

Yes, Public Health posts information online for outbreaks related to respiratory and enteric diseases when there are no personal privacy concerns related to the situation.