Norovirus spreads swiftly wherever there are many people in a small area, including nursing homes, restaurants, hotels, dormitories ... and cruise ships.
The common cold is the only illness more common, and the Centers for Disease Control and Prevention in Atlanta estimates that there are 23 million cases of Norovirus annually.
Though Norovirus can be passed via contaminated food and water, when it comes to cruise ships it is typically spread through physical contact with ill people or surfaces/objects they may have touched. This includes shaking hands, caring for a sick friend or family member, sharing food or eating from the same utensils. . . .
Though generally moderate, symptoms are often flu-like (in fact, Norovirus is often called the "stomach flu," even though it is not related to influenza). Symptoms include nausea, vomiting, diarrhea and abdominal cramps; children often vomit more than adults. A low-grade fever and headache are also possible.
Once you have been exposed to Norovirus, it takes anywhere from one to three days for its symptoms to appear; symptoms typically last only 24 to 48 hours but keep up the good hygiene -- people may be contagious for as long as two weeks after recovery.