Norovirus is a very contagious virus that can infect anyone, mainly by person-to-person contact or by contaminated food and water. Norvovirus (NoVs) is classified into at least five types (genogroup I [GI] to genogroup V [GV]) and 34 genotypes. Human NoVs are in GI, GII, and GIV. In addition, NoVs have been detected in pigs (GII), cows (GIII), mice (GV), large carnivores (GIV.2) and dogs (GIV.2) and can spread easily across a group of animals.
The virus causes your stomach or intestines or both to get inflamed. This leads you to have stomach pain, nausea, and diarrhea and to throw up. These symptoms can be serious for some people, especially young children and older adults.