(Respiratory Tract Infection )
Influenza is a viral infection that attacks your respiratory system — your nose, throat and lungs. Influenza is commonly called the flu, but it's not the same as stomach "flu" viruses that cause diarrhea and vomiting.
If you have flu symptoms and are at risk of complications, see your doctor right away. Taking antiviral drugs may reduce the length of your illness and help prevent more-serious problems.
Usually, you'll need nothing more than bed rest and plenty of fluids to treat the flu. But if you have severe infection or are at higher risk for complications, your doctor may prescribe an antiviral medication,.
Initially, the flu may seem like a common cold with a runny nose, sneezing and sore throat. But colds usually develop slowly, whereas the flu tends to come on suddenly. And although a cold can be a nuisance, you usually feel much worse with the flu.
Common signs and symptoms of the flu include:-
Flu viruses travel through the air in droplets when someone with the infection coughs, sneezes or talks. You can inhale the droplets directly, or you can pick up the germs from an object — such as a telephone or computer keyboard — and then transfer them to your eyes, nose or mouth.
nfluenza viruses are constantly changing, with new strains appearing regularly. If you've had influenza in the past, your body has already made antibodies to fight that particular strain of the virus. If future influenza viruses are similar to those you've encountered before, either by having the disease or by getting vaccinated, those antibodies may prevent infection or lessen its severity.
But antibodies against flu viruses you've encountered in the past can't protect you from new influenza strains that can be very different immunologically from what you had before.