Noroviruses are nonenveloped, positive-sense, single-stranded RNA viruses belonging to the Caliciviridae viral family (see Image. Norovirus Virion). The virus was first identified and named “Norwalk virus” when it was discovered as the cause of a 1968 outbreak of gastroenteritis in Norwalk, Ohio. Norovirus is the leading cause of acute gastrointestinal illness worldwide. In developed countries with rotavirus vaccine programs, norovirus surpasses rotavirus as the most common cause of gastroenteritis in children.
Common symptoms of norovirus infection include nausea, vomiting, and diarrhea. These could lead to clinically significant dehydration, requiring hospitalizations. In addition to its clinical effects, norovirus also has a major financial impact on developed nations. As of December 2024, there has been a significant surge in norovirus-associated gastroenteritis in the United States and other regions worldwide.
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