The start of the new year means peak season for a host of viruses and illnesses.
The Centers for Disease Control and Prevention has previously signaled that influenza A, COVID and RSV are on the rise across the U.S. Now, the risk of catching norovirus — more commonly known as the stomach flu — is escalating, as well.
Between Aug. 1 and Dec. 11 last year, roughly 500 outbreaks were reported by the 14 U.S. states participating in the NoroSTAT network, up from 363 during the same period in 2023.
Over the past month, norovirus has been especially prevalent on cruise ships. In December, multiple cruise ships reported outbreaks, including two Holland America cruises, Princess Cruises’ Ruby Princess and Cunard Line’s Queen Mary 2.
“The total number of outbreaks reported during the 2024–2025 seasonal year is above the range reported during the same period during the 2012–2020 and 2021-2024 seasonal years,” the health agency said on its website.
What is norovirus?
Norovirus causes an inflammation of the stomach or intestines called acute gastroenteritis, according to the CDC. The illness can spread through direct contact with others and contaminated food, drinks and surfaces.
What are the symptoms of norovirus?
The virus is “highly contagious,” and symptoms include vomiting, diarrhea, stomach pain, fever, headache and others.
Symptoms begin within one to two days, and most recover within one to three days. However, even after a few days of recovery, those infected can still spread the virus.
Are norovirus cases up in Iowa?
Since individual norovirus infections are not reportable in Iowa, the number of cases in the state is hard to come by. However, hospitals, labs and public health agencies must report all potential outbreaks.
In central Iowa, Polk County Public Health’s communicable disease team has been seeing an increase in calls with questions regarding “stomach illnesses that are consistent with norovirus,” said Addie Olson, he department’s communications officer.
“We’re also hearing norovirus get brought up more frequently from our local providers,” Olson said. “Based on that, it’s safe to say we are seeing the national trend reflected here locally.”
Between 19 and 21 million cases of norovirus occur each year in the U.S., causing 109,000 hospitalizations and 900 deaths., according to the CDC. Fatalities primarily occur among people 65 and older.
Is Iowa experiencing more influenza and COVID-19 cases?
The CDC estimates that influenza and COVID-19 infections are growing in Iowa, according to the most recent data. The estimates are based on data from COVID-19 and influenza emergency department visits.
In its latest respiratory virus surveillance report, the Iowa Department of Health and Human Services described the overall Influenza and COVID-19 activity in the state as “moderate” and “low,” respectively. Individual influenza cases are not reportable in Iowa, but Iowa HHS requires reporting of novel influenza and outbreaks. Positive COVID-19 tests are also not required to be reported.
Nathan Diller is a consumer travel reporter for USA TODAY based in Nashville. You can reach him at ndiller@usatoday.com.
Cooper Worth is a service/trending reporter for the Des Moines Register. Reach him at cworth@gannett.com or follow him on X @CooperAWorth.
This article originally appeared on Des Moines Register: What is norovirus? What to know as stomach flu cases rise in Iowa, US
