Loading...
Noroviruses, which belong to the family Caliciviridae, are the most common cause of epidemic gastroenteritis in the U.S. Norovirus strains associated with outbreaks in this country are tracked by a surveillance network called CaliciNet. Of the five known genogroups of norovirus, GI and GII predominate in human disease, with GII.4 strains the most common cause of outbreaks.
Recently, GII.4 Sydney — a new strain named for the place in Australia where it was first isolated — has replaced GII.4 New Orleans as the predominant strain in the U.S. The proportion of outbreaks attributed to this new strain increased from 19% in September 2012 to 58% in November and December 2012. Most of the outbreaks resulted from person-to-person spread (JW Infect D…