Investigation suggests preventive steps passengers and crew can take. Norovirus is the leading cause of acute gastroenteritis in the United States and is estimated to cause nearly 21 million cases annually. It is highly transmissible through person-to-person contact and contaminated food, water, and environmental surfaces. The results of an investigation of a 2009 outbreak on a cruise ship shed light on how the infections can spread and the steps both passengers and crew can take to prevent them.


