Genetic Diversity of Norovirus and Sapovirus Outbreaks in Long-Term Care Facilities in Quebec, Canada, 2011–2016

Norovirus (NoV) and sapovirus (SaV) are major viral pathogens causing acute gastroenteritis (AGE) in both children and adults in developed countries and are also responsible for large-scale outbreaks. However, in Quebec, Canada, there are limited and updated data with respect to the genotypes circulating and implicated in outbreaks, particularly for SaV. This study aimed to investigate the genetic diversity and genotype predominance of NoVs and SaVs associated with AGE outbreaks in Quebec, Canada. Confirmed NoV and SaV outbreaks from long-term care facilities and hospital settings between September 2011 and April 2016 were investigated (<i>n</i> = 252). NoVs and SaVs were genetically diverse: 21 RdRp-capsid combinations were identified, of which 10 are recombinants. NoV GII.4 New Orleans[P4 NewOrleans] was the predominant genotype from 2011 to 2013, and GII.4 Sydney[P31] was the predominant genotype from 2013 to 2015. In 2015-2016, no single genotype predominated; instead, GII.17[P17], GII.4 Sydney[P16], GII.4 Sydney[P31], and SaV GI.2 strains were co-circulating at similar frequencies. Notably, emerging global genotypes including GII.17[P17], GII.4 Sydney[P16], GII.2[P16], and GII.4 San Francisco[P31] were detected for the first time in Quebec. These findings may contribute to an enhanced understanding of NoV and SaV infection and spread, and to the development of candidate vaccines.