The flu has officially gone viral.

Not content to invade just our bodies, influenza is taking over our smartphones with a slew of apps. Now you can look up symptoms, check the spread of the disease and even book a doctor's visit, all at your germ-laden fingertips.

With FluView, scan the Centers for Disease Control and Prevention's weekly flu map, which shades each state according to illness activity levels. You can view the last three weeks of the report, and see how the country went from mostly green (in the clear) to a flood of red (bad news).

Flu Near You is a self-reporting system that takes your ZIP code and symptoms and melds them onto a map. Then you can zoom in to see if there are any snotty-nosed carriers in your vicinity. Its effectiveness, however, depends on widespread use, and there isn't much yet in the Twin Cities metro area.

The slightly buggy Flu Defender provides quick facts about vaccines, complications, how to avoid contagion, etc. There also is a risk assessment quiz that lets you know if you should get a vaccine. The answer is probably yes.

If you're feeling feverish, ZocDoc will find you an appointment with a doctor in your area, stat.

"Anything that gets more information out about influenza can definitely be a good thing, especially if it causes people to take a preventive action," said Andrea Ahneman, infectious disease division spokeswoman at the Minnesota Department of Health.

But as you should with anything you find on the Internet, Ahneman advises that you make sure the information comes from a credible source, "and not have an app replace your doctor's advice."

These apps are free and available in the iTunes App Store. Flu Near You, ZocDoc and the CDC's influenza app also are available in Google Play.

Just be sure to wash your hands after downloading. □