Norovirus is a very contagious virus that can cause inflammation in your stomach or intestines causing you to have stomach pain, nausea, vomiting and/or diarrhea. This illness can lead to dehydration in older adults and children. Norovirus activity tends to be higher in the late fall and early spring. It is the virus that you may read about affecting cruise ship passengers. Please see the video and links below for information from the Centers for Disease Control (CDC):