Dados do Trabalho

Título

Norovirus genotypes diversity and host HBGA susceptibility in the Northwestern Amazon region.

Introdução

Since the advent of the rotavirus vaccine, norovirus has become the main causative agent of viral acute gastroenteritis (VAGE) worldwide. These viruses affect young children, mainly living in low-income regions. The phenotype secretor (FUT2 gene) with respect to the antigens of the histo blood group (HBGA) is a strong susceptibility factor for norovirus infection.

Objetivo (s)

The objective of this study was to identify the molecular epidemiological profile of circulating noroviruses GII and GI in children under 5 years of age residing in the northwest region of the Brazilian Amazon.

Material e Métodos

The samples for this study (1,468 fecal and saliva samples collected in parallel) were obtained from 734 children (485/734 with AGE; 249/734 without AGE) aged up to 5 years during the period from 2016 to 2017 (Ethical Research Committee approved by the Federal University of Roraima; CEP No: 1,333,480 dated November 23, 2015). All fecal samples were previously tested for the presence of AGE-causing viruses, including norovirus GI and GII. Saliva samples were used for HBGA phenotyping assays, as previously described, to define the FUT2 secretor profile. RNA from 219 norovirus-positive samples was amplified using specific primers for norovirus GI and GII. For Sanger sequencing, the amplicons were sent to Macrogen Europe B.V. (Netherlands).

Resultados e Conclusão

A high diversity was identified. The total of 42% (92/219; GII) and 39% (7/18; GI) were successively genotyped. The GII genotypes detected were GII.1 (n=4); GII.2 (n=26); GII.4 (n=33); GII.6 (n=22); GII.7 (n=6); GII.14 (n=1); GI genotypes were GI.3 (n= 3); GI.7 (n=3) and GI.2 (n=1). GII and all 33 GII.4 noroviruses were associated with secretory status. Only genotypes GII.2 (n=2) and GII.6 (n=3) were observed in non-secretor children. Acute gastroenteritis (AGE) was associated with GII, all GII genotyped and not-GII.4 genotypes. This study is a large sampling collected in the years 2016-2017, involving 734 children living in isolated regions of the Amazon rainforest (Brazil, Venezuela, and Guyana). Most children are HBGA secretors (87%, 641/734), evidencing an impact to make noroviruses as an important viral agent causing AGE in the Northwest Amazon (Brazil and borders Venezuela and Guyana).

Palavras Chave

Norovírus; histo blood group antigens; FUT2; Acute gastroenteritis; Amazon region.