What Is the Flu?
The flu, more scientifically known as influenza, is a highly contagious respiratory infection caused by influenza viruses. The influenza virus usually enters the body through mucus membranes in the mouth, nose, or eyes.
When a person with the flu coughs or sneezes, the virus then becomes airborne and can be inhaled by anyone nearby. You can also get the flu if you've touched a contaminated surface like a telephone or a doorknob and then touch your nose or mouth. Of course, the risk of infection is greater in highly populated areas like schools, buses, and crowded urban settings
Is It a Cold or the Flu?
The cold and flu are both respiratory illnesses, but they are caused by different types of viruses with different symptoms. Use this chart to learn the difference between the two.
| Signs and Symptoms | Influenza | Cold |
|---|---|---|
| Symptom onset | Abrupt | Gradual |
| Fever | Usual; lasts 3-4 days | Rare |
| Aches | Usual; often severe | Slight |
| Chills | Fairly common | Uncommon |
| Fatigue, weakness | Usual | Sometimes |
| Sneezing | Sometimes | Common |
| Stuffy nose | Sometimes | Common |
| Sore throat | Sometimes | Common |
| Chest discomfort, cough | Common; can be severe | Mild to moderate; hacking cough |
| Headache | Common | Rare |
If you or a family member are experiencing symptoms that sound more like the flu than a cold, download our list of helpfulQuestions to Ask Your Doctor and call your doctor right away.
Viruses vs Bacteria
Viruses
A virus is a capsule of protein that contains genetic material. A virus cannot reproduce on its own and must infect a living cell to grow. Colds and influenza are both respiratory illnesses caused by different viruses -- and it's often hard to distinguish between the two.
Bacteria
Bacteria are independent, 1-celled organisms that live on their own. They can multiply and reproduce by subdivision.
Know the F.A.C.T.S.
Flu symptoms can be mild or severe, and can come on suddenly -- be sure you know your flu treatment options so you can be prepared. Symptoms generally appear 1 to 4 days after exposure to the virus.
Symptoms of the flu include chills, fever, aches, and tiredness.
The common symptoms of the flu include:
- Fever (100°F or greater)
- Headache
- Muscle aches
- Chills
- Tiredness
- Cough
- Runny nose (more common in children than adults)
If you have one or more of these
symptoms, it could be the flu.
Prescription antivirals can shorten the duration of the flu if taken within 12-48 hours of first symptoms. So act fast.
