Stomach Bug Going Around December 2024 Gif. Norovirus is a virus that causes gastroenteritis (gastro). Gastroenteritis can be caused by viruses, most commonly norovirus, bacteria and parasites.
The most common way to develop viral gastroenteritis — often called stomach flu — is through contact with an infected person or by consuming contaminated food or water. Norovirus causes diarrhoea and vomiting.