This winter has seen more norovirus outbreaks than the past six winters in Illinois.
Outbreaks in November and December were over four times higher than the same period in 2023. The stomach bug spike mirrored a national trend, according to the Illinois Department of Public Health.
At least 103 outbreaks were reported to the state health department in November and December. Twenty-two were reported for those two months in 2023. The health department only tracks outbreaks, not individual cases. An outbreak occurs when two or more people get sick from the same exposure.
So far in January, there have been 10 outbreaks in Illinois. During the COVID-19 pandemic, outbreaks were in the single digits in 2020 and 2021. November and December 2018 had 73 outbreaks.
The virus spreads easily and quickly through contaminated food and water. Cases often spike each year as people gather with family and friends during the holidays. But this season, Illinois is experiencing a “more significant rise in infections” earlier than usual, according to the health department.
Norovirus is the leading cause of vomiting and diarrhea in the United States, according to the Centers for Disease Control and Prevention. About 50% of all food-related illness outbreaks are from the virus.
Nationally, from Aug. 1 to Dec. 11, 495 norovirus outbreaks were reported to the CDC’s NoroSTAT system. In that same period a year earlier, there were 363 norovirus outbreaks. NoroSTAT is a national collaborative network between the CDC and 14 state health departments.
How to prevent the spread of norovirus
It doesn’t take long to start developing norovirus symptoms. A person usually starts to feel sick 12 to 48 hours after being exposed, according to the CDC.
The most common symptoms include vomiting, diarrhea and stomach pain. A person might also develop a fever, headaches and body aches.
Dehydration is one of the more serious symptoms that can happen if someone gets extremely ill. If someone can’t keep water down because of constant vomiting and diarrhea, they’ll likely be dehydrated, which causes dizziness and a dry throat and mouth. Children who are dehydrated might also cry with few or no tears and may be unusually fussy and sleepy.
Most people recover after one to three days. There is no specific treatment for norovirus. The CDC advises people to stay hydrated as much as possible and to seek medical help for severe dehydration.
Humans are the only source of norovirus, according to the Illinois Department of Public Health. The virus originates in a person’s feces and infects others when someone doesn’t thoroughly wash their hands after a bowel movement and then handles food. It can also spread in contaminated water.
The most common foods connected to an infection are leafy greens, fruit and shellfish, according to the CDC. Sharing utensils and food with an infected person can spread the virus. Surfaces also can be contaminated.
Frequent hand-washing is the best way to prevent the spread of norovirus, according to the CDC, especially after going to the bathroom or changing a diaper and before eating or preparing food.