If you're feeling unwell this season, it may not be easy to tell exactly what is making you sick; multiple viruses are circulating in Michigan this winter, making vaccination and healthy habits crucial, experts say.

This season, the nation is facing what's being called a "quademic," with high levels of the flu, COVID-19, respiratory syncytial virus or RSV, and norovirus spreading, according to Endeavor Health and Dignity Health.

The three respiratory viruses, plus norovirus, a gastrointestinal virus, are the "main players in our winter virus pantheon," said Dr. Thomas Russo, who heads the infectious diseases department at the University at Buffalo School of Medicine. Russo added that they can circulate at other times of year, but tend to peak in winter.

"Do we have a lot of cases? The answer is yes," Russo told USA TODAY. "The 'emic' part of it is a bit of a gimmick, but we do have these viruses circulating and causing infections right now."

A Centers for Disease Control and Prevention flu report for the week of Jan. 25 showed almost 30% of lab tests for flu were positive and the rate was trending higher. There were also 16 deaths related to influenza, bringing the total to 47 deaths this season, according to the report.

The quademic comes amid growing concern around the avian flu and a recent spike in pertussis or whooping cough cases.