Identification of Human Bocavirus type 4 in a child asymptomatic for respiratory tract infection and acute gastroenteritis - Goiânia, Goiás, Brazil

Abstract Human Bocavirus (HBoV) has been identified from feces and respiratory samples from cases of both acute gastroenteritis and respiratory illness as well as in asymptomatic individuals. The aim of this study was to detect and characterize HBoV from fecal samples collected from hospitalized children aged less than five years old with no symptoms of respiratory tract infection (RTI) or acute gastroenteritis (AGE). The study involved 119 children and one fecal sample was collected from each participant between 2014 and 2015. HBoV was detected using Nested-PCR, and the viral type identified by genomic sequencing. HBoV-4 was identified from one sample obtained from a hospitalized child with soft tissue tumor of the submandibular region. This is the first report of HBoV-4 identification in Brazil, but we consider that this type may be circulating in the country similar to the other types and new investigations are necessary.

Screening of fecal samples from asymptomatic children, for norovirus detection, using a third generation enzyme immunoassay commercial kit

Norovirus is the leading cause of non-bacterial acute gastroenteritis outbreaks worldwide. Recently, third generation Enzyme Immunoassay (EIA) commercial kits have been developed, and controversial results have been obtained by different studies regarding the sensitivity and specificity of these assays. Therefore, the aim of this study was to test 60 fecal samples, previously tested as positive by RT-PCR for caliciviruses (40 norovirus-positive and 20 sapovirus-positive samples), for qualitative determination of genogroup I and II noroviruses by a commercial EIA kit (RIDASCREEN® Norovirus (C1401) 3rd Generation, R-Biopharm, Darmstadt, Germany). The samples were obtained from 30 children aged less than five years, mostly asymptomatic, who attend a day-care center in Goiânia, Goiás, Brazil. The results conferred a positivity rate for NoV of 35 percentand a specificity rate of 100 percent for the EIA, when compared to the RT-PCR. The test also failed to detect samples that were positive for GI.1 and GI.4 norovirus. The presumably lower viral load of asymptomatic children might be related to the poor sensitivity. Our results reinforce the notion that screening of samples by molecular assays, especially of samples that might have a low number of viral particles such as those obtained from asymptomatic patients, should not be replaced by the use of EIA kits...

Triagem de amostras fecais de crianças assintomáticas utilizando-se um kit comercial de Elisa 3a geração determinação qualitativa de norovírus dos genogrupos I e II por meio de kit comercial de EIE (RIDASCREEN® Norovirus (C1401) 3rd Generation, R-Biopharm, Darmstadt, Germany). Previamente testadas, elas se mostraram positivas para calicivírus por RT-PCR (40 positivas para norovirus e 20 positivas para sapovirus). As amostras foram obtidas de 30 crianças menores de 5 anos de idade, predominantemente assintomáticas, que frequentavam uma creche em Goiânia, Goiás, Brasil. Os resultados revelaram índices de 35 porcento de positividade para os norovírus e de 100 porcento de especificidade para o EIE quando comparado a RT-PCR. O teste também falhou em detectar amostras que eram positivas para norovírus GI.1 e GI.4. A carga viral, presumidamente mais baixa, das crianças assintomáticas pode estar relacionada com a baixa sensibilidade. Os resultados reforçam o entendimento de que a triagem de amostras por ensaios moleculares não deve ser substituída pelo uso de kits de EIE, especialmente quando se tratar de amostras que, presumidamente, apresentem um baixo número de partículas virais como as obtidas de pacientes assintomáticos...