Retrospective molecular analysis of norovirus recombinant strains in the amazon region, Brazil
AnaCaroline Rodrigues Portela, Juliana Merces Hernandez, Renato Silva Bandeira, Edivaldo Costa Sousa, Taynah Cohen de Melo, Maria Silvia Sousa de Lucena, Dielle Monteiro Teixeira, Jones Anderson Monteiro Siqueira, Yvone Benchimol Gabbay, Luciana Damascena da Silva
Abstract
BACKGROUND: Noroviruses are enteric viruses that cause acute gastroenteritis worldwide. Over two decades, GII.4 genotype was responsible for most cases. However, recombinant strains have emerged and changed the epidemiological context of these infections. OBJECTIVES: The aim of this study was to identify the recombinant genetic strains of norovirus causing gastroenteritis in Brazilian children from the Amazon region. METHODS: We analyzed 534 cases of gastroenteritis between 2015 and 2016. Genotypic characterization was performed by partial sequencing of ORF1 and ORF2. Evolutionary history was inferred by Bayesian inference using MrBayes. Recombinant strains were confirmed by Simplot and RDP4 analysis. FINDINGS: We performed viral detection tests and identified a norovirus frequency of 31.8% (175/534). Based on viral RdRp and VP1 genes, nine genotypes were identified: GIIP31/GII.4, GII·P16/GII.4, GII·P7/GII.6, GII·P21/GII.13, GII·P33/GII.1, GII·P17/GII.17, GI·P7/GI.7, GII·P4/NT, and GII.7/NT. The phylogenetic tree showed evolutionary relationships among the genotypes, including the recombinant strains. This is the first description of GII·P33/GII.1 and GII·P21/GII.13 genotypes in Brazil. CONCLUSION: Norovirus evolution has been characterized by the continuous replacement of variants that have new antigenic properties. In recent years, recombinant strains have displaced GII.4, improving the viral fitness and influencing the viral transmissibility and pathogenicity.