Outbreaks of Norwalk-like viral gastroenteritis--Alaska and Wisconsin, 1999.

Norwalk-like viruses (NLVs) are the most common cause of epidemic gastroenteritis in the United States, resulting in illness in approximately 23 million persons each year . Persons of all ages are affected because previous infection confers only short-term immunity. Most NLV gastroenteritis outbreaks involve foodborne or person-to-person transmission. This report presents investigations of a foodborne NLV outbreak in Alaska and person-to-person transmission in Wisconsin.