Dados do Trabalho

Título

Association between secretory status and infection by different genotypes of norovirus GI and GII in children residing in the Northwest Amazon region of Brazil.

Objetivos(s)

Noroviruses are the etiological agent most commonly associated with acute gastroenteritis (AG) in humans, with the GII.4 genotype being the most prevalent worldwide. These viruses affect young children, particularly those who live in low-income areas. The secretory phenotype (FUT2 gene) with respect to histo blood group antigens (HBGA) is a strong susceptibility factor for norovirus infection. This study aimed to investigate the molecular epidemiological profile of circulating noroviruses GI and GII in children under 5 years of age residing in the Northwest Amazon region of Brazil.

Relato do Caso

An epidemiological investigation study in the Amazon region was carried out to identify viral etiological agents causing AG and the association with HBGA host susceptibility in 734 children ≤ 5 years old during 1 year (October 2016 to October 2017). Children were divided into groups with AG 485 (66%, 485/734) and without AG (34%, 249/734) and feces and saliva were collected in parallel. Norovirus in stool was detected using real-time PCR and positive GI and GII samples with a cycle threshold (Ct) below 37 were VP1 genotyped by Sanger sequencing. The salivas were used to define the HBGA profile and secretory status by enzyme immunoassay (EIA) for the detection of αA, αB, Lea, Leb and Fucα1-2Gal-R. Results: A high diversity was identified. A total of 42% (92/219; GII) and 39% (7/18; GI) were successively genotyped. The detected GII genotypes 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 noroviruses GII.4 were associated with secretory status. Only the GII.2 (n=2) and GII.6 (n=3) genotypes were observed in non-secretory children. AG was associated with GII, all genotyped GII and non-GII genotypes.4.

Conclusão

To our knowledge, this is the first study with a large sample involving 734 children living in isolated regions of the Amazon rainforest (Brazil, Venezuela and Guyana) that secrete more HBGA (87%, 641/734), and which portrays the impact of norovirus as an important viral agent causing AG.

Keywords: Norovirus, histo blood group antigens, FUT 2, acute gastroenteritis, Amazon.

Agradecimentos

1. Comparative and Environmental Virology Laboratory, Instituto Oswaldo Cruz (IOC).
2. Graduate Program in Tropical Medicine, IOC.
3. Roraima State Health Secretariat.
4. State University of Roraima.
5. Department of Biomedical and Clinical Sciences, Linköping University.
6. Department of Medicine, Stockholm.