Name a common viral cause of gastroenteritis.

Norovirus is a leading viral cause of gastroenteritis, known for its ability to spread rapidly and cause outbreaks, especially in crowded environments like cruise ships, schools, and nursing homes. It is characterized by symptoms such as vomiting, diarrhea, stomach cramps, and nausea. Norovirus has a low infectious dose, meaning that even a small number of viral particles can lead to infection, which contributes to its high transmission rate. Additionally, contaminated food or water can serve as a vector for spreading the virus, making it a significant public health concern.

In contrast, the other choices listed are bacterial pathogens that cause gastroenteritis, differentiating them from the viral nature of norovirus. While Escherichia coli, Salmonella, and Campylobacter are all important causes of foodborne illness, they do not fall under the viral category of gastroenteritis. This distinction highlights norovirus specifically as the correct answer to the question posed.