Avaliação da ocorrência, caracterização molecular e determinação da carga viral de Norovírus em amostras de fezes e swab nasal provenientes de crianças atendidas em um hospital de Goiânia, Goiás

• Autor(a) principal: Silva, Nathânia Dábilla Alves
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/0013000009jr1
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/5995
• topic: Norovírus; Crianças; Ambiente nosocomial; Gastroenterite viral; Swab nasal; Carga viral; Norovirus; Children; Nosocomial environment; Viral gastroenteritis; Viral load; Nasal swab; CIENCIAS BIOLOGICAS::PARASITOLOGIA

The norovirus (NoVs) are important viral causative agents of acute gastroenteritis (AGE), affecting individuals of all ages in distinct parts of the word; however, the highest morbi-mortality rates occur mainly in children under five years of age and the elderly. The aim of this study was to to screening NoV by Polymerase Chain Reaction Post Reverse Transcription (RT-qPCR) and real-time (RT-qPCR) in fecal and nasal swab of children up to six years of age, with and without AGE symptoms. Samples were obtained at the Materno Infantil Hospital, from May/2014 to May/2015. Secretor status of children was also determined by enzyme immunoassay and genotyping (FUT2 gene) from the sediment of nasal swab epithelial cells. A global positivity index of 17% (37/219) for NoV in feces, and from these positive children, 48.6% (18/37) had AGE symptoms. Mean viral load in fecal samples was 2.59 x 1010 CG/g from symptomatic and 1.37 x 109 CG/g in asymptomatic. A higher positivity rate (70%) was observed GII NoV, compared to GI NoV (30%) and a higher positivity in children up to 24 month old (67.5%), although not statistically significant. As for the secretor status of children positive for NoV in fecal samples, 94.6% positive secretory status. The NoV were detected in practically every month of the study, and no particular pattern of circulation in relation to dry or rainy seasons was observed. Most children positive for NoV (70%) had the record they have received at least the first dose of the vaccine against Rotavirus, being the highest viral load detected among vaccinated children. The NoV RNA was detected in 8.7% of nasal swab samples of the children and of these, 58% had AGE symptoms. The mean viral load in swab samples from symptomatic children was 2.10 x 108 and in the asymptomatic children was 2.41 x 107 CG/mL. A high NoV genotype variability was found in the study (GI.2, GI.3, GI.5, GII.3, GII.4 and GII.6), with a predominance of GII.4 (28.6%), with this being the first report of NoV GI.5 in Brazil. The data obtained in this study reveal a high frequency, viral load, and genetic variability of NoVs among children attended in a hospital of Goiânia, Goiás. The results are important for a better understanding of NoV epidemiology in nosocomial environment, and may constitute useful information on the advent of the development of an effective vaccine. The viral load in nasal swab samples is a novel data that may contribute for the elucidation of a possible alternative rout of NoV transmission.