Molecular epidemiology of G12 rotavirus strains during eight consecutive epidemic seasons in the Basque Country (North of Spain), 2010-2018

Abstract

G12 rotaviruses were first detected in Spain (Gipuzkoa province) in December 2004. After four years with no detections, G12 strains re-emerged in the 2010-2011 epidemic season, when the first European epidemic circulation of this genotype was observed in Gipuzkoa. G12 rotaviruses were also the dominant strains in 2011-2012, 2014-2015 and 2015-2016 epidemic seasons and were sporadically detected in the remaining periods (2012-2014 and 2016-2018). The most frequently detected G-type between 2010 and 2018 was G12 (29.9%) rather than G1 rotavirus (17.8%), which historically had been the dominant genotype in our setting (1989-2009 period) and globally. Phylogenetic analysis of the VP4 and VP7 genome segments showed chronologically ordered clades, which spanned between two to four consecutive seasons. Overall, the circulating G12 rotavirus strains in Gipuzkoa between 2010 and 2018 belonged to four clades, which emerged in early 2009 potentially due to at least four importations from other regions followed by local evolution. Whole genome analysis of 16 G12 strains detected from 2010 to 2018 revealed a Wa-like genotype constellation, G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1, and also showed that G12 strains from Gipuzkoa were similar to those identified in other countries. These findings suggest circulation of G12 rotavirus strains in different parts of the world leading to high genetic diversity.

Keywords: Acute gastroenteritis; G12 rotavirus; Rotavirus phylodynamics; Wa-like genetic backbone; Whole genome sequencing.