How do I know I have the Flu?

Influenza (the flu) is a highly contagious respiratory illness caused by a virus.  This year is unusual because we have at least two predominant flu strains circulating:  seasonal flu (“regular” flu, which normally circulates in the Fall and Winter), and H1N1 flu (which is currently widespread in San Diego County).  This may lead to more flu-like illness than usual in the community this Fall. Seasonal flu and H1N1 flu cause similar symptoms and are treated similarly. 

The flu can cause symptoms that resemble many other infections of the respiratory tract, so it can be difficult to tell if the symptoms you’re having are caused by an influenza virus or another organism.  Most often, symptoms of influenza infection start abruptly, and are accompanied by a fever over 100 F.

Symptoms of the Flu

The symptoms of flu (either H1N1 flu or seasonal flu) may include any or all of the following:

• fever over 100 degrees F
• cough
• sore throat
• runny or stuffy nose
• body aches
• headache
• chills
• fatigue
• possibly diarrhea and vomiting

Other respiratory infections, such as the common cold, are less likely to cause fever over 100 degrees F, chills, body aches, diarrhea, or vomiting.   See the comparison of common illnesses on the Student Health Center website to help you determine if your illness is due to the flu.

Most symptoms of the flu improve in 2-5 days but some symptoms, such as cough and fatigue, can last 1-3 weeks.  Most people do not require medical care for the flu.  Remember that if you have flu symptoms, it is extremely important that you stay home or in your room for at least 24 hours after your fever is gone except to get medical care or for other necessities. (Your fever should be gone without the use of a fever-reducing medicine.) 

How is the Flu Spread?

People usually catch influenza by being in close contact (within 6 feet) of a person sick with the flu. While in close contact, a person may breathe the virus into his lungs, or may pick up virus on his hands and transfer it to his mouth, nose, or eyes.  Influenza symptoms usually start 1-4 days after you’ve been exposed to the virus.

For more information on warning signs and treatment of the flu, see What to Do and How to Treat the Flu.