ISTANBUL Norovirus cases appear to be increasing in various parts of the US, ABC News reported, citing data from the Centers for Disease Control and Prevention (CDC). More than 90 norovirus outbreaks were reported during the week of December 5, the most recent week for which data is available. Previous years' data for the same December week shows a maximum of 65 outbreaks, according to the CDC. The number of norovirus outbreaks reported by state health departments within a week of illness onset