What is it?
Influenza is a respiratory illness caused by a virus. Various strains of the influenza virus circulate throughout the world year-round, causing local outbreaks. In Canada, the influenza season usually runs from November to April.
What are the symptoms?
Influenza typically starts with a headache, chills and a cough, followed rapidly by fever, loss of appetite, muscle aches, fatigue, runny nose, sneezing, watery eyes, and throat irritation. Children may also have nausea, vomiting, diarrhea. Most people recover within a week to ten days. Some people experience serious complications.
Who is at risk for serious complications?
Some groups are at greater risk for serious complications, including pneumonia. Those at high risk include:
- Very young children
- People age 65 and older
- People of any age with a medical condition such as chronic respiratory disease (e.g. asthma), heart or kidney disease, diabetes, or a depressed immune system
What is the incubation period?
Usually one to three days.
When is it contagious?
You may be able to infect others beginning one day before symptoms develop, and up to 5-7 days after becoming sick. Children can spread the virus up to 7 days after symptoms appear.
How does influenza spread?
The influenza virus spreads easily and quickly through droplets that are coughed or sneezed into the air by someone who has influenza. The virus is also found on the hands of people with influenza, and on the surfaces they touch. The virus may persist for hours in the environment, particularly in the cold and low humidity.
You can get influenza if:
- you breathe in the droplets through your nose or mouth.
- the droplets land directly on your eyes.
- you shake hands with infected people or touch contaminated surfaces, then transfer the virus to your nose, mouth or eyes.
How can the spread of influenza be reduced?
- By getting the influenza vaccine every fall. Anyone over the age of six months can receive the vaccine free of charge in Ontario. Everyone should get vaccinated, especially those at high risk of influenza-related complications, those capable of transmitting influenza to individuals at high risk of complications, those who provide essential community services.
- By frequent hand washing.
- By following etiquette for coughing/sneezing: cover mouth/nose with a tissue; discard soiled tissues in wastebasket; wash hands with soap and water, or clean with an alcohol-based hand cleaner; wash hands frequently throughout the day.
What do I do if I get sick with influenza?
- Stay home and away from others, especially the elderly.
- Rest in bed, drink lots of fluids.
- Contact your doctor if treatment is required.
Pandemic H1N1 Influenza
Pandemic H1N1 influenza (pH1N1) is a new influenza strain that appeared in April 2009. It has since spread around the world. pH1N1 can infect anyone, although people younger than 60years of age are more likely to become infected than older individuals. Most people recover uneventfully but a few people can develop serious complications. Those at a some what increased risk of complications when they get infected are children less than five years of age,people with other medical problems, pregnant women and women who had a baby in the past four weeks, people who are very overweight and residents of isolated or remote First Nations communities with limited access to health care services.
- Public Health Agency of Canada www.publichealth.ca.
- National Advisory Committee on Immunization (NACI) –Statement on Influenza Vaccine for the 2010-2011 Season.
- Heymann, D. L. (2008). Control of Communicable Disease Manual (19th Ed). Washington, DC: American Public Health Association.
- Ministry of Health and Long Term Care fact sheet, November 2009.