Phylogenetic analysis of G1P[8] and G12P[8] rotavirus A samples obtained in the pre- and post-vaccine periods, and molecular modeling of VP4 and VP7 proteins.

Reduction in morbimortality rates for acute gastroenteritis (AGE) by Rotavirus A (RVA) has been observed after the introduction of vaccines, however the agent continues to circulate. The present study described the genomic characterization of the 11 dsRNA segments of two RVA samples G1P[8] obtained in the pre- and post-vaccination periods and one of G12P[8] sample (post-vaccine), compared to Rotarix™ vaccine. Analysis by molecular sequencing of the samples showed that the three samples belonged to genogroup I. In addition, the analysis of VP7 gene revealed that the samples G1 (pre-vaccine), G1 (post-vaccine) and G12 were characterized as lineages II, I and III, respectively. Regarding to VP4 and NSP4 gene it was observed that all samples belonged to lineage III, whereas for VP6 gene, the sample of the pre- and post-vaccine belonged to the lineage IV and I, respectively. Considering the VP7 gene, it was observed high nucleotide and amino acid identity for the two G1 samples when compared to Rotarix™ vaccine and lesser identity for the G12 sample. In relation to antigenic epitope of VP7 greater modifications were observed for the G12 sample in the 7-2 epitope that was confirmed by molecular modeling. On the other hand, for VP4, some changes in the 8-1 and 8-3 antigenic epitopes was observed for the three samples. This data could be interpreted as a low selective pressure exerted by vaccination in relation to G1P[8] samples and lesser protection in relation to G12P[8]. Thus, the continuous monitoring of RVA circulating samples remains important.

Norovirus in feces and nasopharyngeal swab of children with and without acute gastroenteritis symptoms: First report of GI.5 in Brazil and GI.3 in nasopharyngeal swab.

BACKGROUND: Noroviruses (NoVs) are an important cause of acute gastroenteritis (AGE), worldwide. OBJECTIVES: To evaluate the frequency, viral load and molecular profile of NoV in fecal and nasopharyngeal swab samples from hospitalized children, and to determine children's secretor status. STUDY DESIGN: From May 2014 to May 2015, 219 children were included in the study, 96 with gastroenteric symptoms and 123 without gastroenteric symptoms. All fecal and nasopharyngeal swab samples were screened by TaqMan RT-qPCR duplex (GI/GII NoV) and quality samples were characterized by genomic sequencing. RESULTS: Norovirus positivity rate in feces was 15.4% in asymptomatic and 18.8% in the symptomatic group. The median viral loads in feces were 2.69×108GC/g and 4.32×107GC/g from children with or without AGE symptoms, respectively. In nasopharyngeal swab samples, the NoV positivity was 11.4% in symptomatic children, with a median viral load of 2.20×107GC/mL and 6.5% in asymptomatic children, with an average viral load of 1.73×106GC/mL. In only two cases NoV was detected in both samples. A considerable genomic variability was observed in feces, with six genotypes being detected, as follows: GII.4, GII.6, GI.3 and GII.3, GI.2 and GI.5. Two GI.3 was detected in nasopharyngeal swab. CONCLUSIONS: Our data reveal considerable NoV frequencies in both nasopharyngeal and fecal samples from symptomatic and asymptomatic children. Higher viral loads were detected in samples from AGE symptomatic children, when compared to asymptomatic children. High genomic variability was observed, with this being the first report of GI.5 NoV in Brazil and of GI.3 in nasopharyngeal swab samples.

Phylodynamics of DENV-1 reveals the spatiotemporal co-circulation of two distinct lineages in 2013 and multiple introductions of dengue virus in Goiás, Brazil.

Dengue virus type 1 (DENV-1) was the first serotype introduced in Brazil, during in the 1980s. Since then, this virus has spread in the Brazilian territory, causing several outbreaks. In 2013 the highest number of dengue cases was notified, when compared to the previous years in Brazil, and the state of Goiás reported over 160 thousand cases. In this study, we aimed to present the Phylodynamics of DENV-1 isolates from the state of Goiás, Brazil, during 2013 outbreak, based on the envelope gene (E) sequences. Phylogenetic analysis revealed that Brazilian DENV-1 isolates are grouped together with viruses from genotype V in two distinct lineages (lineage I and lineage II) reflecting co-circulation. Phylogeographic analyses showed that these lineages were introduced in different moments in Goiás, Brazil, using distinct routes, likely originated from the Caribbean. Lineage I was first introduced coming from Rio de Janeiro (2007-2012), followed by the introduction from Argentina (2010-2013). Lineage II was introduced in a single moment from Rio de Janeiro and this clade has existed since 2007-2010. The different viral introduction events demonstrate the viral dispersion process with neighboring regions, which is essential for the maintenance of outbreaks and introduction of new emerging viruses. In conclusion, obtained data reveals the importance of continuous molecular surveillance of this virus in different regions, providing a better understanding of DENV-1 circulation, considering the evolutionary and virus spread patterns.

Identification of enterovirus serotypes by pyrosequencing using multiple sequencing primers.

Human enteroviruses (HEV) are considered as one of the major causes of central nervous system infections in pediatrics. They are currently classified into five species involving more than 60 officially recognized serotypes. This study describes a rapid molecular method, based on pyrosequencing of a VP1 fragment, for the identification of enterovirus serotypes. In order to do so, 200 isolates and clinical specimens that were first grouped into 62 different HEV serotypes using neutralization test, were analyzed by pyrosequencing. All serotypes were identified using the proposed method. Most of the isolates previously untypeable by classical procedures, as well as mixed enterovirus infections containing viruses belonging to different species, could also be determined using pyrosequencing. The present results give support to pyrosequencing as an efficient method of HEV genotyping.

Serological markers and risk factors related to hepatitis B virus in dentists in the Central West region of Brazil.

The hepatitis B virus (HBV) has been considered the major occupational risk agent for dentists. The Central West region of Brazil is considered an intermediate endemic pattern area, but currently there is no information about the HBV prevalence in dentists of Goiânia, Goiás. This study aimed at the detection of the HBV infection rate and risk factors for dentists of Goiânia and the comparison of the obtained data with the general population and other groups. A randomized sample of 680 professionals participated in this study. All dentists gave written consent for the procedure and filled out a questionnaire about risk factors. The HBV serological markers were analyzed using ELISA test and the presence of anti-HBc was observed in 41 (6.0%) of the dentists. None of them was HBsAg positive. Significant relationships with HBV positivity were observed with gender, the time working as a dentist and the use of incomplete personal protective equipment (PPE). The HBV prevalence found in this group of dentists was lower than the endemic pattern of the general population, other health care workers of the region and the dentists from other regions in Brazil. These results may indicate a positive impact of vaccination considering the high adherence of the dentists to the immunization program (98.4%). Finally, the use of complete PPE by the majority as well as other standard precautions recommended for health care workers could be responsible for the low HBV seroprevalence.