Contagious Norovirus on the Rise

A particularly contagious strain of norovirus, often referred to as “winter vomiting disease,” is making its way through the U.S., including in Illinois. This was highlighted by an analysis of wastewater from two surveillance sites in the state.

Typically, norovirus cases surge following Christmas and New Year celebrations. However, reports show a significant spike in new cases in November, according to data from the Centers for Disease Control and Prevention. The CDC monitors these occurrences through voluntary reporting from clinics and health departments, yet acknowledges that the information is often unreliable. Many individuals experience severe symptoms for a few days but don’t seek medical care or end up hospitalized.

While the CDC doesn’t track viral activity in wastewater directly, data from a program called WastewaterSCAN—developed by Stanford University in collaboration with Emory University—indicates that norovirus rates have been climbing nationally since about mid-October. In Illinois, sites in Wheaton and Glen Ellyn are actively monitoring the situation. Wheaton reported a significant increase in cases during the week of November 10, while Glen Ellyn noted a spike right before Thanksgiving. There’s concern that the holidays may bring even more cases; last year, both areas saw a dramatic rise in norovirus cases in early January.

Dr. Robert Atmar from Baylor College of Medicine mentioned to NBC News that there could be two reasons for this uptick: the virus might have mutated to become more contagious, or there may be broader changes in the population that increase susceptibility. He suggested it’s likely a mixture of both factors, though there’s uncertainty about whether this trend will continue throughout the year.

Symptoms associated with the GII.17 strain include severe vomiting and diarrhea, as well as stomach cramps—particularly affecting young children, seniors over 85, and those with pre-existing health conditions. Dehydration poses a significant risk in these cases. Because GII.17 is relatively new, many people have lower immunity levels, potentially leading to more severe illness.

Lee-Ann Jaykus, a professor at North Carolina State University, noted that the emergence of new strains tends to occur every seven to ten years, and this current situation aligns with that pattern. She emphasized the importance of proper hygiene, particularly vigorous hand-washing with hot water and soap, to help curb the spread of norovirus. This virus spreads easily through contact with infected individuals, contaminated food or liquids, and touching surfaces that harbor the virus.