Circulation profile of respiratory viruses in symptomatic and asymptomatic children from Midwest Brazil.

Acute respiratory infection (ARI) is a major cause of morbidity and mortality worldwide. Most of these infections are caused by viruses. Infections pose as important triggers of acute episodes of chronic respiratory diseases (CRD). This study sought to evaluate the frequency and circulation profile of respiratory viruses among ARI symptomatic patients and completely asymptomatic children in Midwest Brazil. The study enrolled symptomatic children with and without ARI symptoms. During 1 year, 225 nasal respiratory samples were obtained from patients aged 4-14 years old. The samples were screened by multiplex nested-PCR for 16 common respiratory viruses. From 225 samples, 42 had at least one virus detected. Samples from four different patients had multiple viruses detected. The viral detection rate in symptomatic (20.1%) and asymptomatic patients (14.8%) showed no significant difference. The most frequent viruses detected were rhinovirus (28.6%), FLUA (11.9%), adenovirus (11.9%), human bocavirus (HBoV) (11.9%), and respiratory syncytial virus (RSV) antigenic group A (9.5%). Monthly detection rate was higher during the rainy season. RSVs were detected during the months with higher rainfall indexes and higher air humidity, while FLU and HBoV were detected during the winter months. The obtained results reinforce the importance of viral pathogens in pediatric population, emphasizing similar viral occurrence in symptomatic and asymptomatic children.

Asthma exacerbations in a subtropical area and the role of respiratory viruses: a cross-sectional study.

BACKGROUND: Multiple factors are involved in asthma exacerbations, including environmental exposure and viral infections. We aimed to assess the association between severe asthma exacerbations, acute respiratory viral infections and other potential risk factors. METHODS: Asthmatic children aged 4-14 years were enrolled for a period of 12 months and divided into two groups: those with exacerbated asthma (group 1) and non-exacerbated asthma (group 2). Clinical data were obtained and nasopharyngeal samples were collected through nasopharyngeal aspirate or swab and analysed via indirect fluorescent immunoassays to detect influenza A and B viruses, parainfluenza 1-3, adenovirus and respiratory syncytial virus. Rhinovirus was detected via molecular assays. Potential risk factors for asthma exacerbation were identified in univariate and multivariate analyses. RESULTS: In 153 children (group 1: 92; group 2: 61), median age 7 and 8 years, respectively, the rate of virus detection was 87.7%. There was no difference between groups regarding the frequency of virus detection (p = 0.68); however, group 1 showed a lower frequency (19.2%) of inhaled corticosteroid use (91.4%, p < 0.01) and evidence of inadequate disease control. In the multivariate analysis, the occurrence of three or more visits to the emergency room in the past 12 months (IRR = 1.40; p = 0.04) and nonadherence to inhaled corticosteroid (IRR = 4.87; p < 0.01) were the only factors associated with exacerbation. CONCLUSION: Our results suggest an association between asthma exacerbations, poor disease control and nonadherence to asthma medication, suggesting that viruses may not be the only culprits for asthma exacerbations in this population.

Adenovirus infection among allogeneic stem cell transplant recipients.

The human adenovirus (HAdV) infection can cause severe disease in immunocompromised patients, such as those undergoing allogeneic hematopoietic stem cell transplant (ASCT). The main objective of this study was to prospectively monitor ASCT recipients for HAdV occurrence in a reference center in Brazil, and also to correlate viral positivity, viral load, molecular variant, clinical symptoms, and patients' prognosis. From October/2012 to October/2014, blood and feces of 21 ASCT recipients were screened for HAdV by Nested-PCR. Viral loads were determined by real-time PCR. In total, 57% of the patients had at least one positive sample (serum or feces) for HAdV. Patients presented significantly higher viral load in feces when compared to serum. Positive samples were characterized as HAdVs of species HAdV-C, -D, and -F. The main clinical symptom presented by infected patients was diarrhea, and Graft-versus-host disease (GVHD) was the main intercurrence. An association was observed between HAdV-positivity and diarrhea and also between HAdV-positivity and GVHD. Results from this study may contribute to a better understanding of the HAdV infection pattern in patients submitted to ASCT. Data therein highlight the importance of including HAdV testing during all routine laboratory exams performed on ASCT patients. J. Med. Virol. 89:298-303, 2017. © 2016 Wiley Periodicals, Inc.

Monitoring of Calicivirus among day-care children: evidence of asymptomatic viral excretion and first report of GI.7 Norovirus and GI.3 Sapovirus in Brazil.

Caliciviruses (Norovirus and Sapovirus) are important causes of acute gastroenteritis, with Norovirus (NoV) considered the leading cause of epidemic non-bacterial acute gastroenteritis; however, molecular and epidemiological data of the circulating Calicivirus (CV) strains among day-care children are still considered scarce. The role of asymptomatic CV excretion on viral transmission also remains poorly understood. The aim of the present study was to monitor the occurrence of NoV and Sapovirus (SaV) in a day-care center and to describe the molecular epidemiology of the circulating strains. Genomic sequencing and phylogenetic analysis of the capsid region were carried out in CV positive samples obtained from children younger than 5 years, with or without diarrhea, between October 2009 and October 2011. A total of 539 fecal samples were screened for CV. Forty-three (8%) were positive for NoV and 25 (4.6%) for SaV. Surprisingly, positivity rates for CV were significant in asymptomatic children, and virus circulation was detected in every month of the study. Great genomic diversity of CV was observed, and the circulating NoV strains were: GII.6, GII.2, GII.1, GI.7, GII.4, and GI.1. The SaV genotypes GI.1 and GI.3 were also detected. Five CV outbreaks caused by distinct viral strains were documented. This study provides an insight on the genetic diversity of CV in a day-care in Central West Brazil, highlighting the probable role of asymptomatic viral excretion and the significance of semi-closed settings in the dissemination of these agents.

Detection and genotyping of astroviruses from children with acute gastroenteritis from Goiânia, Goiás, Brazil.

BACKGROUND: The astroviruses constitute important agents of childhood diarrhea. The purpose of our research was to detect and genotype astroviruses in fecal samples from children with acute gastroenteritis from Goiânia- Goiás, Brazil. MATERIAL/METHODS: The samples were collected from children up to five years of age with acute gastroenteritis, hospitalized in two public hospitals in Goiânia- Goiás, a city located in the West Central region of Brazil. A total of 516 fecal samples were collected from March 1998 to March 2000. These samples were first screened for rotavirus and adenovirus by an enzyme immunoassay (EIARA) and by PAGE for the detection of rotaviruses. In all samples negative for both viruses (n=351) the presence of astrovirus was investigated by reverse-transcription-polymerase chain reaction (RT-PCR). RESULTS: 2.8% of the samples obtained from children up to two years of age were positive for astrovirus by RT-PCR, with an expected amplicon size of 449 bp. All positive samples, except one, were collected between October and December of 1998, which corresponds to the rainy season in the region (spring/early summer). Nested-PCR genotyping showed that all samples were genotyped and belonged to astrovirus genotype 1, presenting an amplicon band pattern of 212 bp. CONCLUSIONS: This study supports data from the literature about the occurrence of astrovirus in children with acute gastroenteritis. It also helps provide a better understanding of viral etiology in diarrhea.