Global Trends in Norovirus Genotype Distribution among Children with Acute Gastroenteritis

Abstract

Noroviruses are a leading cause of acute gastroenteritis (AGE) among adults and children worldwide. NoroSurv is a global network for norovirus strain surveillance among children <5 years of age with AGE. Participants in 16 countries across 6 continents used standardized protocols for dual typing (genotype and polymerase type) and uploaded 1,325 dual-typed sequences to the NoroSurv web portal during 2016-2020. More than 50% of submitted sequences were GII.4 Sydney[P16] or GII.4 Sydney[P31] strains. Other common strains included GII.2[P16], GII.3[P12], GII.6[P7], and GI.3[P3] viruses. In total, 22 genotypes and 36 dual types, including GII.3 and GII.20 viruses with rarely reported polymerase types, were detected, reflecting high strain diversity. Surveillance data captured in NoroSurv enables the monitoring of trends in norovirus strains associated childhood AGE throughout the world on a near real-time basis.

Keywords: NoroSurv; P-types; acute gastroenteritis; capsids; children; dual typing; enteric infections; food safety; gastroenteritis; genotypes; norovirus; polymerase; surveillance; vaccines; viruses.

Figure 1

Countries participating in NoroSurv, December 2016–August 2020. Shades of blue and size of circles indicate the number of genetic sequences included from each country.

Figure 2

Global genotype distribution of norovirus sequences catalogued in NoroSurv during September 2016–August 2020. A) Dark blue line indicates all GII.4 Sydney viruses; light blue indicates GII.4 Sydney[P16] and pink indicates GII.4 Sydney[P31]); B) yellow indicates GII.2 viruses; C) red indicates GII.3 viruses; D) orange indicates GII.6 viruses; E) purple indicates other GII viruses; F) green indicates GI viruses. Gray lines overlay the distributions of other pictured genotypes to enable comparisons.

Figure 3

Distribution of dual typed sequences in NoroSurv, 2016–2020. Numbers to the right of bars indicate the number of sequences detected for each dual type.