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. The findings are published in a new study in Clinical Infectious Diseases and available online (http://www.oxfordjournals.org/our_journals/cid/cir144.pdf).

