Navegando por Autor "OLIVEIRA, Alessilva do Socorro Lima de"

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Avaliação temporal e genética do rotavírus genótipo G2 circulante na Região Norte do Brasil antes e após a introdução da vacina contra rotavírus
(Universidade Federal do Pará, 2016-10-31) OLIVEIRA, Alessilva do Socorro Lima de; MASCARENHAS, Joana D'Arc Pereira; http://lattes.cnpq.br/5156164089432435
Rotavirus group A (RVA) is the most important cause of diarrhea, accounting for about 40% of morbidity and mortality related to this disease in children around the world before the introduction of the vaccine. After the introduction of the vaccine against the RVA in Brazil in 2006 genotype G2RVA he rose again, being detected in up to 82% of children under five years of age performed post vaccination studies, leading to questions about the protection afforded by the vaccine facing the G2 type, as well as the occurrence of a selective pressure vaccine. Little is known about the evolution and diversity of G2 genotype and the possible influence of the vaccine on this. To provide a better understanding of the flow and genetic diversity of RVA genotype G2, we perform the time of circulation analysis of genotype over 31 years and analysis of structural and non-structural genes from samples that have circulated over 20 years in northern region of Brazil. The temporal assessment of movement of different genotype circulating in this region has observed that the G2 type RVA presented over the years a cyclical pattern of occurrence that did emerge in a post deployment of the vaccine scenario, suggesting a natural fluctuation due to variations natural occurring over time. Phylogenetic analyzes showed that for VP7 lines G2 there is a continuous, responsible for a movement of rotation in the lines being detected two lines and three sublineages over 20 years. Three important substitutions in antigenic regions of VP7 (A87T, D96N and S213D) were identified in samples that circulated from the 90. These changes may have increased the capacity of the circulating strains in environments where there is vaccine coverage for RVA. All G2P[4] strains analyzed revealed a DS-1-like genome constellation: I2-R2-C2-M2-A2-N2-T2-E2-H2. However, several viral variants circulated during the study period. No differences were observed in the antigenic sites of the VP8 * and VP7 proteins between samples that circulated in the period before and after the introduction of the vaccine. For VP2 and VP3 genes was evident in some samples a strong correlation with animal genes. This study provides evidence of genetic diversity in G2 genotype RVA, suggesting that this type has natural characteristics fluctuation and its emergence after the implementation period of the vaccine is more directly associated with ecological characteristics of the virus than a vaccine pressure.
Acesso aberto (Open Access)
Epidemiologia molecular das infecções por rotavírus G2 ao longo de 16 anos (1992 a 2008) na região amazônica, Brasil
(Universidade Federal do Pará, 2010-07-05) OLIVEIRA, Alessilva do Socorro Lima de; LINHARES, Alexandre da Costa; http://lattes.cnpq.br/3316632173870389
In Brazil it is estimated that rotavirus causes 3,352,053 episodes of diarrhea, 655 853 visits to emergency rooms, 92,453 hospitalizations and 850 deaths involving children under 5 years of age. Rotavirus belongs to the family Reoviridae, genus Rotavirus. The viral particle consists of three concentric layers of protein and the viral genome of 11 segments making up a double-stranded RNA. Currently, 23 G genotypes and 31 P genotypes. have been recognized. Among the G genotypes detected so far, G2 represents one of the most important and it is usually associated with the genotype P [4]. Over the past three years it has been observed on a continental scale the reemergence of genotype G2, throughout the years following the introduction of universal rotavirus vaccination, particularly in Brazil. This study aimed at the molecular characterization of samples of G2 strains obtained from children participating in several studies on rotavirus gastroenteritis in the Amazon region, Brazil, from 1992 to 2008. We selected 53 rotavirus G2 samples which were sequenced for VP4 and 38 samples for VP7. These samples were genotyped by RTPCR and its products being purified, quantified and sequenced. Samples were also subjected to electrophoresis of RNA segments. The obtained sequences of VP4 and VP7 genes were aligned and edited using the program Bioedit (v.6.05) and compared with other sequences registered in the RV gene bank using the BLAST program. The phylogenetic tree was made using the program Mega 2.1. Of the total 53 samples sequenced for the VP7 gene, phylogenetic analysis revealed two lineages (II and III) and three sublineages (IIa, IIc, IId) that circulated in different periods in the population. Samples of sub-lineages IIa and IIc showed mutation at amino acid position 96(Asp/Asn). This modification may result in a conformational change of epitopes recognized by neutralizing antibodies. The G2 strains that circulated in Belém were identical to those circulating in other states in the Amazon region which were included in the study. The VP[4] gene was sequenced in the region of VP8*, yielding 36 which-belonged to genotype P[4] and tree to P[6] we could identify two strains: P[4]-4, occurring during 1998-2000 and the P[4]-5 during 1993-1994 and 2006-2008 periods. Our findings sustain recent findings indicating a worldwide reemergence of G2 genotypes of variant IIc, which were established in the population in combination with genotype P[4]-5. In our study, the high homology among G2 strains in various states suggests that detected mutations have even surpassed geographical and temporal barriers.