Stomach Flu Outbreak 2024. Norovirus infection causes acute gastroenteritis (inflammation of the stomach and intestines). About the current norovirus season.

The stomach flu (norovirus) is an acute form of gastroenteritis, or inflamed stomach or intestinal lining caused by a virus, bacteria or parasite. Gastroenteritis can be caused by viruses, most commonly norovirus, bacteria and parasites.