RESUMO
Group A human rotaviruses (HuRVA) are causative agents of acute gastroenteritis. Six viral structural proteins (VPs) and six nonstructural proteins (NSPs) are produced in RV-infected cells. NSP4 is a diarrhoea-inducing viral enterotoxin and NSP4 gene analysis revealed at least 15 (E1-E15) genotypes. This study analysed the NSP4 genetic diversity of HuRVA G2P[4] strains collected in the state of São Paulo (SP) from 1994 and 2006-2010 using reverse transcription-polymerase chain reaction, sequencing and phylogenetic analysis. Forty (97.6%) G2P[4] strains displayed genotype E2; one strain (2.4%) displayed genotype E1. These results are consistent with the proposed linkage between VP4/VP7 (G2P[4]) and the NSP4 (E2) genotype of HuRVA. NSP4 phylogenetic analysis showed distinct clusters, with grouping of most strains by their genotype and collection year, and most strains from SP were clustered together with strains from other Brazilian states. A deduced amino acid sequence alignment for E2 showed many variations in the C-terminal region, including the VP4-binding domain. Considering the ability of NSP4 to generate host immunity, monitoring NSP4 variations, along with those in the VP4 or VP7 protein, is important for evaluating the circulation and pathogenesis of RV. Finally, the presence of one G2P[4]E1 strain reinforces the idea that new genotype combinations emerge through reassortment and independent segregation.
Assuntos
Antígenos Virais/isolamento & purificação , Glicoproteínas/genética , RNA Viral/genética , Rotavirus/genética , Toxinas Biológicas/genética , Proteínas não Estruturais Virais/genética , Adulto , Sequência de Aminoácidos , Sequência de Bases , Brasil , Criança , Fezes/virologia , Ligação Genética/genética , Variação Genética , Genótipo , Humanos , Técnicas Imunoenzimáticas , Dados de Sequência Molecular , Filogenia , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Rotavirus/classificação , Rotavirus/imunologia , Alinhamento de SequênciaRESUMO
Group A human rotaviruses (HuRVA) are causative agents of acute gastroenteritis. Six viral structural proteins (VPs) and six nonstructural proteins (NSPs) are produced in RV-infected cells. NSP4 is a diarrhoea-inducing viral enterotoxin and NSP4 gene analysis revealed at least 15 (E1-E15) genotypes. This study analysed the NSP4 genetic diversity of HuRVA G2P[4] strains collected in the state of São Paulo (SP) from 1994 and 2006-2010 using reverse transcription-polymerase chain reaction, sequencing and phylogenetic analysis. Forty (97.6%) G2P[4] strains displayed genotype E2; one strain (2.4%) displayed genotype E1. These results are consistent with the proposed linkage between VP4/VP7 (G2P[4]) and the NSP4 (E2) genotype of HuRVA. NSP4 phylogenetic analysis showed distinct clusters, with grouping of most strains by their genotype and collection year, and most strains from SP were clustered together with strains from other Brazilian states. A deduced amino acid sequence alignment for E2 showed many variations in the C-terminal region, including the VP4-binding domain. Considering the ability of NSP4 to generate host immunity, monitoring NSP4 variations, along with those in the VP4 or VP7 protein, is important for evaluating the circulation and pathogenesis of RV. Finally, the presence of one G2P[4]E1 strain reinforces the idea that new genotype combinations emerge through reassortment and independent segregation.
Assuntos
Adulto , Criança , Humanos , Antígenos Virais/isolamento & purificação , Glicoproteínas/genética , RNA Viral/genética , Rotavirus/genética , Toxinas Biológicas/genética , Proteínas não Estruturais Virais/genética , Sequência de Aminoácidos , Sequência de Bases , Brasil , Fezes/virologia , Variação Genética , Genótipo , Ligação Genética/genética , Técnicas Imunoenzimáticas , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , RNA Viral/isolamento & purificação , Rotavirus/classificação , Rotavirus/imunologia , Alinhamento de SequênciaRESUMO
INTRODUCTION: The diarrhea associated with gastroenteritis is a major cause of morbidity and mortality worldwide, affecting mainly infants. The characterization of both viral and bacterial agents associated with gastroenteritis can establish policies for surveillance, prevention and treatment of infections. Group A rotaviruses are the major infectious agent associated with dehydration in children, followed by pathotypes of Escherichia coli. There are three main types of clinical infections caused by E. coli strains that have acquired virulence genes: (i) enteric and diarrheal diseases, (ii) urinary tract infections, and (iii) sepsis and meningitis. METHODOLOGY: In this study, the objective was to identify the presence of rotavirus and diarrhogenic E. coli in the feces of children 4 to 14 months of age who displayed no gastroenteritis symptoms and stayed all day in a day-care center. We analyzed 188 samples using PAGE and PCR to identify rotaviruses and E. coli virulence genes, respectively. RESULTS: Thirty-six samples (19.1%) were positive for at least one pathotype of E. coli. Nineteen were identified to be of the EPEC group and fifteen of the EAEC group. Rotaviruses were not identified. CONCLUSIONS: As EPEC and EAEC are potential pathogens for children less than one year of age or immunocompromised individuals, our results show the importance of appropriate monitoring by public health agencies. In the situation that we have studied, children can be considered asymptomatic carriers of these pathogens and can transmit them to other susceptible children.
Assuntos
Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Escherichia coli/isolamento & purificação , Fezes/microbiologia , Rotavirus/isolamento & purificação , Brasil , Creches , Feminino , Humanos , Lactente , Masculino , PrevalênciaRESUMO
Picobirnaviruses have been identified in the feces of a broad range of hosts by several international research groups. Because there is no standard nomenclature for these viruses, we propose a clear and unique name for each strain.
Assuntos
Picobirnavirus/classificação , Terminologia como Assunto , Animais , Primers do DNA , Fezes/virologia , Interações Hospedeiro-Patógeno , Humanos , Picobirnavirus/genética , Infecções por Vírus de RNA/veterinária , Infecções por Vírus de RNA/virologia , Coelhos , Especificidade da EspécieRESUMO
Picobirnaviruses (PBVs) have recently been classified into the Picobirnaviridae family. They are small, non-enveloped viruses with bisegmented, double-stranded (ds) RNA genomes. Although they are found in the feces of a broad range of hosts, information regarding their genomes is limited to viruses detected from humans, rabbits, and porcine. Identification of PBVs has been done using PAGE and reverse transcription PCR (RT-PCR). In this study, we present a phylogenetic analysis of PBVs detected in the feces of dogs, snakes, and rats. In addition, we compare these strains to those from human and porcine hosts. To do so, 487 fecal specimens from dogs, snakes and rats were analyzed by PAGE. The positive specimens for PBV were tested by RT-PCR using primers for genogroup I of the PBVs. From the 11 genogroup I PBV samples, at least one from each host was sequenced and submitted for phylogenetic analysis. All of the sequences showed high homology with the human and porcine genogroup I PBV sequences. In this study we report the first detection of PBVs in snakes (8.5%). We also report a phylogenetic analysis that goes beyond humans and pigs to include dogs, rats, and snakes. However, more hosts must be included in the analysis so that we may reach better conclusions regarding the spread of these viruses.
