A virus known as the stomach bug that has surged across parts of the country is the cause of nearly all diarrhea outbreaks reported on cruise ships that docked at U.S. ports in 2024, federal data shows.

In December alone, the CDC reported five separate outbreaks on four different ships -- sickening more than 800 people. All of the outbreaks were caused by the highly contagious norovirus.

Local health care facilities have advised residents to be on the lookout for patients presenting with norovirus symptoms such as nausea, stomach pain, body ache, headache and fever.

Four cruise ships were affected by five stomach bug outbreaks in December, The Washington Post reported, citing the CDC.

Cruise ships saw the highest number of stomach bug illnesses since 2012 with 16 outbreaks that impacted 1,894 passengers.

The Centers for Disease Control and Prevention has classified 2024 as the worst year for stomach illness outbreaks and cases on cruise ships in over a decade as Norovirus surged in the U.S. In just the past month,