This year is shaping up to be one of the worst flu seasons in ages. If you have the sniffles and fear it's the flu, or are just worried that you'll get it, what's the best way to find out if it's circulating in your community?

If you think the answer is the Centers for Disease Control and Prevention (CDC), think again. Although the CDC does have a weekly FluView report, the best place to check may be Google Flu Trends, which is what the CDC sometimes uses to get up-to-date flu info.

This is how it works: If you plug a search term such as "flu symptoms" in Google, it will register on Google Flu Trends as disease activity in your region--and all these millions of searches have been proven to correlate with actual cases.

"We think this is a really exciting tool," says Lyn Finelli, PhD, chief of surveillance and outbreak response in the CDC's Influenza Division. "It was one of the first tools of this type to use internet-based searching and a social-networking approach. We do look at it all the time. It gives us a daily snapshot of what might be going on from state-to-state."

In fact, the info on Google Flu Trends shows disease activity about one to two weeks before the CDC confirms actual cases, says Kelly Mason, a spokeswoman for

The info can help the average person to better understand the severity of the flu season and take basic steps to protect themselves, especially since it's often not too late to get a flu shot, Mason says.

"If people have a hint that there's flu in their area, they can check Google," says Finelli.

Google has been tracking flu trends since 2007, but the information seems especially important given the severity of this year's flu. As of Friday morning, the Google site showed 41 states with "intense" flu activity (indicated in red) while the remaining nine states had "high" activity (indicated in orange).

Google Flu Trends is also available for other countries around the world although some data has not been correlated with official reports.

You can see flu trends on the globe using Google Earth and Google is even experimenting with tracking flu in major U.S. cities.

You can also use Google Trends to check other health issues. You can see what's trending for dengue fever ("low" and "moderate" activity in a few patches of the globe and pretty much none in the U.S.), sunburn, and allergies.

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