What is influenza (also called flu)?

The flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. It can cause mild to severe illness, and at times can lead to death. The best way to prevent the flu is by getting a flu vaccine each year. An average of 2,800 North Dakotans are reported as having lab-identified flu every year--the number of actual cases occuring in North Dakota each year is likely much higher.

What are the signs and symptoms of flu?

People who have the flu often feel some or all of these signs and symptoms:

  • Fever* or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (very tired)
  • Chills

* It is important to note that not everyone with flu will have a fever.

What about the stomach flu?

The "stomach flu" is a misleading term. Typically, influenza virus is not the cause of stomach bugs. Vomiting and diarrhea are rare but possible symptoms of influenza, generally seen only in small children. Vomiting and diarrhea are slightly more common in children with the 2009 A H1N1 pandemic strain than other strains of influenza. However, these symptoms are typically accompanied by other influenza symptoms that are not secondary symptoms of vomiting and diarrhea. For example, body aches that are not abdominal cramps or the abdominal soreness you may feel after vomiting. An illness characterized by fever, nausea and vomiting is likely not influenza, and should not be considered "flu-like."

How does flu spread?

Most experts believe that flu viruses spread mainly by droplets made when people with flu cough, sneeze or talk.  These droplets can land in the mouths or noses of people who are nearby.  Less often, a person might also get flu by touching a surface or object that has flu virus on it and then touching their own mouth, eyes or possibly their nose.

How long is someone contagious if they have the flu?

You may be able to pass the flu to someone else before you know you are sick, as well as while you are sick.  Most healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick.  Some people, especially young children and people with weakened immune symptoms, might be able to infect others for an even longer time.

How can I prevent the flu?

The single best way to prevent the flu is to get a flu vaccine each season.

Flu vaccination is recommended for everyone 6 months and older. There are a variety of vaccines available for flu, so talk to your health care profession about which ir right for you. After vaccination, it takes about two weeks for your body to develop protection against the flu. Flu vaccines will not protect against flu-like illnesses caused by non-influenza viruses.

In addition to vaccination, you can help prevent the spread of influenza by washing your hands often, staying home when you are ill, and avoiding touching your hands to your face.

When should I get vaccinated?

The typical flu season can fall anywhere between October and May, and usually peaks sometime between January and March. Because the timing of the flu season can be unpredictable, health care providers are encouraged to begin vaccinating as soon as the seasonal vaccine is available. Ideally, vaccination should take place by the end of October. However, it is never too late to get vaccinated. As long as flu is circulating, vaccination is recommended.

Influenza Resources

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Avian Influenza Fact Sheet