Multiple norovirus outbreaks have been reported in Chicago during the month of January, the Chicago Department of Public Health confirmed this week. According to the city’s health department, while individual cases are not typically reported,

Last year, there were 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.

Norovirus is a very infectious gastrointestinal virus and is also the leading cause of foodborne illness in the U.S.

Officials say one particular strain of norovirus is causing a substantial increase in outbreaks. And more in 3 Things to Know.