Temporal Dynamics of Norovirus GII.4 Variants in Brazil between 2004 and 2012

Abstract

Noroviruses (NoVs) are the major cause of acute gastroenteritis outbreaks, and, despite a wide genetic diversity, genotype II.4 is the most prevalent strain worldwide. Mutations and homologous recombination have been proposed as mechanisms driving the epochal evolution of the GII.4, with the emergence of new variants in 1–3-year intervals causing global epidemics. There are no data reporting the dynamics of GII.4 variants along a specific period in Brazil. Therefore, to improve the understanding of the comportment of these variants in the country, the aim of this study was to evaluate the circulation of NoV GII.4 variants during a 9-year period in 3 out of 5 Brazilian regions. A total of 147 samples were sequenced, and a phylogenetic analysis of subdomain P2 demonstrated the circulation of six GII.4 variants, Asia_2003, Hunter_2004, Den Haag_2006b, Yerseke_2006a, New Orleans_2009, and Sydney_2012, during this period. The most prevalent variant was Den Haag_2006b, circulating in different Brazilian regions from 2006 to 2011. A Bayesian coalescent analysis was used to calculate the mean evolutionary rate of subdomain P2 as 7.3×10−3 (5.85×10−3–8.82×10−3) subst./site/year. These analyses also demonstrated that clade Den Haag_2006b experienced a rapid expansion in 2005 and another in 2008 after a period of decay. The evaluation of the temporal dynamics of NoV GII.4 in Brazil revealed a similar pattern, with few exceptions, to the worldwide observation. These data highlight the importance of surveillance for monitoring the emergence of new strains of NoV GII.4 and its impact on cases of acute gastroenteritis.

Genotype diversity and molecular evolution of noroviruses: A 30-year (1982-2011) comprehensive study with children from Northern Brazil

“…Previous reports [67] have indicated the suitability of region D for evolutionary studies; however, when working with GII.4 species, the analysis of the P2 region of the VP1 gene is more appropriate due to its greater selective pressure. Moreover, the P2 region may reflect the subs./site/year of the entire VP1 gene, as has been previously asserted [74]. Unfortunately, the primers used in this study [32] to amplify the P2 region were designed exclusively for GII.4 strains, and it is not possible to characterize other clusters according to this genomic region.…”

Acute norovirus gastroenteritis in children in a highly rotavirus-vaccinated population in Northeast Brazil

“…In Brazil, GII.4 NoV is most frequently reported from emergency departments [5,6,29,30]. The presence of a variety of genotypes in Sergipe and the periodic shift of GII.4 variants (i.e., GII.4 New-Orleans_2009 and GII.4 Sydney_2012) reflects the emergence worldwide of GII.4 variants [29,[31][32][33][34][35][36], confirming that the NoV genotypes have a wide geographical distribution.…”

“…Although NoV has become the most common cause of severe diarrhoea in industrialized countries with high rotavirus immunization [1,2], few studies have described NoV epidemiology since the introduction of rotavirus vaccines in other settings [5][6][7][8]. Brazil was one of the first countries to introduce a monovalent rotavirus vaccine (Rotarix) on a large scale in March 2006 [9], reaching high vaccine coverage levels (>80%) within a year of vaccine introduction and rapidly reducing the incidence of rotavirus-related hospitalizations [10,11].…”

Epidemiological and molecular investigation of norovirus and astrovirus infections in Rio Branco, Acre, Northern Brazil: A retrospective study

“…Worldwide, New Orleans_2009 was the most prevalent in NoV infections among 2009 to 2010, until being replaced by Sydney_2012 . Both were already described in four geographic regions of Brazil (Northern, Southern, Northeast, and Southeast), with the first detection of Sydney_2012 in the country made in Rio Branco, Acre in 2012 . Regarding Deen Haag_2006b, a high frequency was observed between 2007 and 2008, being observed a posteriori to cause gastroenteritis in Portugal, Australia, and Brazil .…”