Upward trend: Norovirus cases are up on cruises. What travelers should know.
Norovirus cases are up on cruises, but that doesn't necessarily mean travelers should panic.
The Centers for Disease Control and Prevention has logged 13 outbreaks on cruise ships that met its threshold for public notification so far this year, more than any year between 2017 and 2019.
The most recent outbreak occurred on a Viking sailing on its Viking Neptune ship in June.
During the voyage, 110 of the the ship’s 838 guests reported being ill – more than 13% of all passengers on board –as well as 9 out of 455 crew members, according to the CDC's website. Their main symptoms were abdominal cramps, vomiting and diarrhea.
The public health agency said the causative agent was norovirus, as was the case in all other 2023 outbreaks.
But while norovirus is often associated with cruise ships, Ben Lopman, a professor of epidemiology at Emory University’s Rollins School of Public Health told Paste BN in February that those represent a "tiny minority of norovirus outbreaks," while the vast majority are in health care settings like nursing homes.
What is norovirus?
Norovirus is a virus that causes diarrhea and vomiting, according to the CDC's website. The illness is highly contagious, and people can get infected by interacting directly with someone who is infected, consuming food or water that is contaminated, or putting unwashed hands in their mouths after touching contaminated surfaces.
Other symptoms of norovirus can include stomach pain, nausea, headache, body aches and fever.
"You can get norovirus illness many times in your life because there are many different types of noroviruses," the CDC said on its website. "Infection with one type of norovirus may not protect you against other types."
There's no particular medicine to treat norovirus, but the agency recommends drinking lots of fluids to prevent dehydration.
Should travelers be worried about catching norovirus?
Traveling – particularly internationally – puts people at increased risk of contracting illnesses like norovirus, however, due, in part, to changes in behavior.
"We interact with different people and more people and eat different foods," Lopman said. "And also, we're potentially exposed to pathogens, bacteria, viruses that are not so common often in our home countries."
When it comes to cruise ships, Lopman added, "The other thing is that they're pretty easy to recognize on a cruise ship: people come together, people start getting sick, we'll see that there's a cluster of cases. That may not be true if, for example, people are eating contaminated food at a restaurant, but then they're all going home and going their separate ways."
Norovirus cases also plummeted on cruises in the wake of the pandemic.
How can travelers protect themselves?
Lopman said travelers protect themselves by washing their hands frequently with soap and water. "Those alcohol-based hand sanitizers don't work very well for norovirus, so soap and water is really the way to go," he said.
In the wake of Viking Neptune's outbreak, the cruise line and the ship’s crew took steps such as implementing heightened cleaning and disinfection processes “according to the ship’s outbreak prevention and response plan,” and sharing updates on the number of gastrointestinal illness cases with the CDC Vessel Sanitation Program twice a day, the agency said on its website.
When cooking, the CDC recommends washing vegetables and fruits carefully and cooking oysters and other shellfish to a minimum internal temperature of 145 degrees. "Be aware that noroviruses are relatively resistant to heat," the agency said on its website. "They can survive temperatures as high as 145 (degrees Fahrenheit). Quick steaming processes that are often used for cooking shellfish may not heat foods enough to kill noroviruses."
Lopman also recommended those infected isolate themselves. Most people recover within three days, but he noted that they can remain infectious even after they feel better, making hand-washing especially important.
Nathan Diller is a consumer travel reporter for Paste BN based in Nashville. You can reach him at ndiller@usatoday.com.