WICHITA, Kan. -

The flu virus is now at epidemic proportions throughout the country. At least 40 states, including Kansas, are showing widespread levels. One of the biggest differences they're seeing in the flu this year has to do with who's catching it.

University students are headed back to class this week. The Centers for Disease Control says they might want to think about more than just their classes. The flu should be a concern, too.

Young and healthy they're not in a group that's usually at high risk. But things are a little different at the emergency room this year.

"Lots of flu patients in the emergency department," said Dr. Michael Martin at Via Christi St. Francis. "We're seeing people of all age brackets with classic flu symptoms."

The CDC says the percentage of those with the flu who are young adults has doubled from last year to this. Epidemiologists believe that's because of the strain of the flu going around, H1N1. Many older adults caught it when it came through in 2009. They now have the antibodies. Younger adults don't have them.

The good news, since they don't have underlying health complications, most are going home to recover.

"Flu is self limiting," said Dr. Martin. "Like any viral illness it will generally get better on its own, with certain exceptions. And people just need to work on staying very well hydrated and then symptomatic treatment."

But a little prevention can make a big difference for everyone.

"Just good hand washing and, you know, people seem to be doing better these days about covering their mouth when they cough, etc," said Dr. Martin.

Doctors say if you're having trouble breathing, confusion, persistent vomiting or sudden dizzines you should get to the E.R. right away. Otherwise, try to get in to see your regular doctor as soon as symptoms start. They'll be able to prescribe an anti-viral that can help you get better faster.

In either case, try to avoid others while you're sick to keep from spreading the flu.