Résumé
ABSTRACT Noroviruses are highly infectious, genetically diverse viruses. Global outbreaks occur frequently, making molecular surveillance important for infection monitoring. This cross-sectional descriptive study aimed to monitor cases of norovirus gastroenteritis in the Brazilian Amazon. Fecal samples were tested by immunoenzymatic assay, RT-PCR and genetic sequencing for the ORF1/ORF2 and protease regions. Bayesian inference with a molecular clock was employed to construct the phylogeny. The norovirus prevalence was 25.8%, with a higher positivity rate among children aged 0-24 months. Genogroup GII accounted for 98.1% of the sequenced samples, while GI accounted for 1.9% of them. The GII.P16/GII.4 genotype was the most prevalent, with an evolution rate of 2.87x10−3 and TMRCA estimated in 2012. This study demonstrates that norovirus is a primary causative agent of gastroenteritis and provides data on viral genetic diversity that may facilitate infection surveillance and vaccine development.
Résumé
Introduction: The objective of this study was to determine the prevalence and etiological profile of enteropathogens in children from a daycare center. Methods: From October 2010 to February 2011 stool samples from 100 children enrolled in a government daycare center in the municipality of São José do Rio Preto, in the state of São Paulo, were collected and analyzed. Results: A total of 246 bacteria were isolated in 99% of the fecal samples; 129 were in the diarrheal group and 117 in the non-diarrheal group. Seventy-three strains of Escherichia coli were isolated, 19 of Enterobacter, one of Alcaligenes and one of Proteus. There were 14 cases of mixed colonization with Enterobacter and E. coli. Norovirus and Astrovirus were detected in children with clinical signs suggestive of diarrhea. These viruses were detected exclusively among children residing in urban areas. All fecal samples were negative for the presence of the rotavirus species A and C. The presence of Giardia lamblia, Entamoeba coli, Endolimax nana and hookworm was observed. A significant association was found between food consumption outside home and daycare center and the presence of intestinal parasites. Conclusions: For children of this daycare center, intestinal infection due to pathogens does not seem to have contributed to the occurrence of diarrhea or other intestinal symptoms. The observed differences may be due to the wide diversity of geographical, social and economic characteristics and the climate of Brazil, all of which have been reported as critical factors in the modulation of the frequency of different enteropathogens.
Introdução: O objetivo deste estudo foi determinar a prevalência e o perfil etiológico de enteropatógenos em crianças de uma creche. Métodos: No período de outubro de 2010 a fevereiro de 2011 foram coletadas e analisadas amostras de fezes de 100 crianças matriculadas em creche do governo no município de São José do Rio Preto, Estado de São Paulo. Resultados: Um total de 246 bactérias foram isoladas em 99% das amostras de fezes; 129 eram diarreicas e 117 não-diarreicas. Foram isoladas setenta e três cepas de Escherichia coli, 19 de Enterobacter, uma de Alcaligenes e uma de Proteus. Foram detectados 14 casos de colonização mista com Enterobacter e de E. coli. Norovírus e Astrovirus foram detectados em crianças com sinais clínicos sugestivos de diarréia. Estes vírus foram detectados exclusivamente entre as crianças residentes em áreas urbanas. Todas as amostras fecais foram negativas para a presença das espécies de rotavírus A e C. Foi observada a presença de Giardia lamblia, Entamoeba coli, Endolimax nana e ancilostomídeos. Foi encontrada associação significativa entre o consumo de alimentos fora do centro da casa e creche e a presença de parasitos intestinais. Conclusões: Para as crianças desta creche, a infecção intestinal por patógenos não parece ter contribuido para a ocorrência de diarreia ou outros sintomas intestinais. As diferenças observadas podem ser atribuídas à grande diversidade de características geográficas, sociais e econômicas e o clima do Brasil, as quais tem sido relatadas como fatores críticos para a modulação da frequência de diferentes enteropatógenos.