Abstract
Noroviruses (NoVs) are increasingly being recognized as important enteric pathogens. At a university-based hospital, we investigated a nosocomial outbreak of NoV infection that was originally attributed to Clostridium difficile. We describe here the unique challenges of the identification of NoVs as the true etiologic pathogen in an outbreak occurring in a health care setting, where C. difficile infection is endemic, as well as the important lessons learned.