Emerging Novel GII.P16 Noroviruses Associated with Multiple Capsid Genotypes
Leslie Barclay,
Jennifer L. Cannon,
Mary E. Wikswo,
Annie R. Phillips,
Hannah Browne,
Anna M. Montmayeur,
Roman L. Tatusov,
Rachel M. Burke,
Aron J. Hall,
Jan Vinjé
Affiliations
Leslie Barclay
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Jennifer L. Cannon
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Mary E. Wikswo
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Annie R. Phillips
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Hannah Browne
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Anna M. Montmayeur
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Roman L. Tatusov
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Rachel M. Burke
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Aron J. Hall
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Jan Vinjé
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
Noroviruses evolve by antigenic drift and recombination, which occurs most frequently at the junction between the non-structural and structural protein coding genomic regions. In 2015, a novel GII.P16-GII.4 Sydney recombinant strain emerged, replacing the predominance of GII.Pe-GII.4 Sydney among US outbreaks. Distinct from GII.P16 polymerases detected since 2010, this novel GII.P16 was subsequently detected among GII.1, GII.2, GII.3, GII.10 and GII.12 viruses, prompting an investigation on the unique characteristics of these viruses. Norovirus positive samples (n = 1807) were dual-typed, of which a subset (n = 124) was sequenced to yield near-complete genomes. CaliciNet and National Outbreak Reporting System (NORS) records were matched to link outbreak characteristics and case outcomes to molecular data and GenBank was mined for contextualization. Recombination with the novel GII.P16 polymerase extended GII.4 Sydney predominance and increased the number of GII.2 outbreaks in the US. Introduction of the novel GII.P16 noroviruses occurred without unique amino acid changes in VP1, more severe case outcomes, or differences in affected population. However, unique changes were found among NS1/2, NS4 and VP2 proteins, which have immune antagonistic functions, and the RdRp. Multiple polymerase-capsid combinations were detected among GII viruses including 11 involving GII.P16. Molecular surveillance of protein sequences from norovirus genomes can inform the functional importance of amino acid changes in emerging recombinant viruses and aid in vaccine and antiviral formulation.
