Rotavirus genotypes in children in the Basque Country (North of Spain): rapid and intense emergence of the G12[P8] genotype

Abstract

Between July 2009 and June 2011, rotavirus was detected in 507 of 4597 episodes of acute gastroenteritis in children aged <3 years in Gipuzkoa (Basque Country, Spain), of which the G-type was determined in 458 (90·3%). During the annual seasonal epidemic of 2010-2011, the unusual G-type 12 was predominant, causing 65% (145/223) of cases of rotavirus gastroenteritis. All the G12 strains were clustered in lineage III and were preferentially associated with P-type 8. This epidemic was characterized by broad geographical distribution (rural and urban) and, over 7 months, affected both infants and children, the most frequently affected being children between 4 and 24 months. Of children with rotavirus G12, 16% required hospital admission, the admission rate in children aged <2 years being 20·7 cases/10 000 children. The sudden emergence and predominance of G12 rotaviruses documented in this winter outbreak suggest that they may soon become a major human rotavirus genotype.

Fig. 1.

Monthly distribution and dominant genotype of episodes of acute rotavirus gastroenteritis in children aged <3 years between July 2006 and June 2011 in Gipuzkoa, Basque Country, Spain (counties of San Sebastián and Zumarraga). The data for the period July 2006 to June 2009 are from reference [13].

Fig. 2.

Phylogenetic analysis of 47 nucleotide sequences of G12 rotaviruses (region VP7, positions 48-870) from Gipuzkoa, Basque Country, Spain, July 2010–June 2011. A closed circle (•) indicates the rotavirus strains in this study and a triangle (▴) indicates G12 rotavirus strains detected in previous seasons (region VP7, positions 505-840). The sequences used for comparison were obtained from the GenBank database. The tree was constructed through the neighbour-joining method with 1000 bootstrap replications and shows bootstrap values higher than 70 in the branches. The distance is expressed as the number of the nucleotide substitutions per site.