Asunto(s)
Gastroenteritis/epidemiología , Gastroenteritis/virología , Virosis/epidemiología , Virosis/virología , Adenovirus Humanos/aislamiento & purificación , Niño Hospitalizado , Preescolar , Humanos , Hungría/epidemiología , Lactante , Mamastrovirus/aislamiento & purificación , Rotavirus/aislamiento & purificaciónRESUMEN
Human astroviruses (HAstV) can, on the basis of immunoassays using type-specific rabbit antisera, be classified into eight serotypes that correlate with genotypes. Very few isolates of HAstV type 8 have been described and there is a paucity of data available with regard to the antigenic and genetic relationships between HAstV type 8 (HAstV-8) and HAstV types 1 (HAstV-1) to 7 (HAstV-7). A wild-type HAstV from a South African paediatric patient with diarrhoea was analysed antigenically, by immune electron microscopy and enzyme immunoassay, and genetically in selected regions of the ORF1a, ORF1b and ORF2 and characterised as a HAstV-8. This HAstV-8 strain exhibited greatest homology with HAstV-4 in the 5' end of the capsid gene and ORF1a and 1b, and greatest homology with HAstV-5 in the 3' end of the capsid region. This study confirms, by both antigenic and genetic analyses, that HAstV-8 represents a distinct antigenic and genotype and is the first report of a HAstV-8 from a hospitalised paediatric patient with diarrhoea in southern Africa.
Asunto(s)
Antígenos Virales/inmunología , Mamastrovirus/clasificación , Mamastrovirus/genética , Mamastrovirus/inmunología , Sistemas de Lectura Abierta/genética , ARN Viral/química , Secuencia de Aminoácidos , Animales , Antígenos Virales/genética , Infecciones por Astroviridae/virología , Secuencia de Bases , Aves , Cápside/genética , Gatos , Preescolar , Epítopos , Genotipo , Humanos , Técnicas para Inmunoenzimas , Funciones de Verosimilitud , Mamastrovirus/ultraestructura , Microscopía Electrónica , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico , Serotipificación , SudáfricaRESUMEN
Human astroviruses (HAstVs) were detected in 23 stool samples from 365 diarrhea episodes among 214 children (<18 months old) prospectively monitored for diarrhea in Mexico City. Stool samples were tested by EIA and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. EIA was less sensitive (74%) and equally specific, compared with RT-PCR analysis using type-common primers for HAstV detection. Of 31 HAstV isolates, EIA typed 18 (69%) of 26 EIA-positive samples, and RT-PCR analysis typed 26 (84%) of 31 RT-PCR-positive samples. Phylogenetic analysis of the 3' end of the capsid region (363 nucleotides) confirmed the type assignment by EIA and RT-PCR analysis and determined the type for 5 previously untyped samples. Six HAstV antigenic types cocirculated in the community: HAstV-2 (42%), HAstV-4 (23%), HAstV-3 (13%), HAstV-1 (10%), HAstV-5 (6%), and HAstV-7 (6%). RT-PCR and sequence analysis provided more detailed epidemiology of HAstV in the community than did antigenic detection methods.
Asunto(s)
Infecciones por Astroviridae/epidemiología , Diarrea Infantil/epidemiología , Mamastrovirus/clasificación , Infecciones por Astroviridae/virología , Secuencia de Bases , Células CACO-2 , Cartilla de ADN , Diarrea Infantil/virología , Brotes de Enfermedades , Heces/virología , Femenino , Humanos , Técnicas para Inmunoenzimas , Lactante , Recién Nacido , Masculino , Mamastrovirus/genética , Mamastrovirus/aislamiento & purificación , México/epidemiología , Epidemiología Molecular , Datos de Secuencia Molecular , Filogenia , Estudios Prospectivos , ARN Viral/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sensibilidad y Especificidad , Estudios Seroepidemiológicos , Población Urbana/estadística & datos numéricosRESUMEN
We identified a primate calicivirus (Pan-1) VPg in Pan-1-infected cells. The Pan-1 VPg was associated with both genomic and subgenomic RNAs. RNase digestion of Pan-1 RNA yielded a residual protein of 16 kDa. The N-terminal sequence of Pan-1 VPg was determined by direct amino acid sequencing and mapped to a region of the genome equivalent to picornavirus VPgs. Alignment of this protein sequence with similar regions of other calicivirus genomes allowed identification of conserved amino acid motifs and potential boundaries of the calicivirus VPg genes. Proteinase K treatment abolished the infectivity of Pan-1 RNA, suggesting that Pan-1 VPg is required for RNA infectivity.