Influenza is a contagious disease caused by a virus prevalent during the winter and early spring. It's primarily transmitted either by direct bodily contact or coughing and sneezing. The virus spreads through the upper and/or lower respiratory tracts. It may result in mild illness or, if left untreated, can be fatal.

The virus can be transmitted from several feet away, so wearing a surgical mask can be an effective preventive measure. An annual vaccine injection is the best form of protection.

SEEK HELP FOR THESE SYMPTOMS:

* Fever, cold sweats and chills

* Headache

* Extreme fatigue

* Achy limbs and joints

* Nausea, vomiting and diarrhea

* Sneezing and hoarseness or sore throat

TREATMENT:

While the symptoms of influenza can be managed with painkillers like aspirin, the disease itself must be ridden out. This can take anywhere from a single day -- the so-called "24-hour-flu" -- up to a week.

Those afflicted should remain at home, quarantined from others as much as possible, and get plenty of bed rest, drink lots of water and avoid alcohol and cigarettes.

In some cases, doctors may dose a patient with antiviral drugs such as neuraminidase inhibitors and M2 protein inhibitors.