Short communication Surveillance of norovirus in Portugal and the emergence of the Sydney variant, 2011-2013

This report presents the results of the national surveillance system of diarrhea etiology of the National Institute of Health of Portugal concerning norovirus (NoV) during a two-year period, May 2011–2013. Of the total 580 stool samples collected from patients hospitalized for acute diarrhea in 13 Hospitals of Portugal, 67 (11.6%) tested positive for NoV. From May 2011 to March 2012 the GII.4 variant New Orleans