Illinois is now experiencing high levels of respiratory illness, up from moderate levels the previous week, the state health department reported Tuesday. The increase is not a surprise, given that this is the typical season for spikes in the flu,

The Illinois Department of Public Health is asking residents to stay vigilant against the rise of norovirus. In a Facebook post on Monday, department officials said the virus is making its rounds across the state.

Cases of norovirus, a highly contagious stomach bug, are surging in the Chicago area and nationwide, according to the U.S. Centers for Disease Control and Prevention.​

Washing your hands, using hand sanitizer, not sharing food and drinks, and washing and drying your clothing in high heat are your best bets to preventing this virus from getting in your system. "To prevent the virus from spreading, experts also recommend washing and drying clothes in a high-heat setting.

The common virus spreads easily and quickly through contaminated food and water. Cases often surge around the holidays as people gather with family and friends.

So far this year, there have been 16 outbreaks on cruise ships, from norovirus, salmonella, e. coli or other unidentified pathogens that cause gastrointestinal symptoms such as diarrhea or vomiting. That's the largest number of cruise ship outbreaks in 12 years.

Outbreaks of the stomach flu are spreading across the U.S and are far higher than average for December over the past 12 years, according to CDC figures.

The highly contagious norovirus is common during the winter season because of the many holiday gatherings. “If you are sick, your tiny droplets of vomit or

The CDC reported 91 cases of Norovirus in the first week of December, 20 more cases than there were in the last week of November.

According to the CDC, there are between 19 million to 21 million cases of norovirus a year, and an estimated 900 people die from it while 109,000 are hospitalized. It's estimated that one in every 15 people per year are infected.