Molecular epidemiology of norovirus in Edinburgh healthcare facilities, Scotland 2007-2011

Norovirus (NoV) is a leading cause of outbreaks of gastroenteritis worldwide, and a major burden for healthcare facilities. This study investigated the NoV genotypes responsible for outbreaks in Edinburgh healthcare facilities between June 2008 and July 2011, and studied their temporal distribution to enable a better understanding of the epidemiology of the outbreaks. A total of 287 samples positive for NoV genogroup II (GII) RNA by reverse transcription-polymerase chain reaction (RT-PCR) during routine diagnostic testing were investigated. Nested RT-PCR (nRT-PCR) and sequencing was used to genotype the NoV strains. Overall, a total of 69 NoV strains belonging to six different genoclusters (GII. 1, GII. 2, GII. 3, GII. 4, GII. 6, GII. 13) were detected. The predominant genotype was GII. 4 that included four variants, GII. 4 2006a, GII. 4 2006b, GII. 4 2007 and GII. 4 2010. Importantly, increases in NoV activity coincided with the emergence of new GII. 4 strains, highlighting the need for an active surveillance system to allow the rapid identification of new strains.