RESUMEN
The characteristics of norovirus outbreaks in children (0-5 years) in childcare centres in Victoria, Australia (2012-2015) were examined. The three most common open reading frame (ORF) 2 genotypes in childcare centre outbreaks were GII.4 (42%), GII.6 (21%) and GII.3 (14%); the remaining genotypes (GI.2, GI.3, GI.4, GI.8, GI.13, GII.1, GII.2, GII.7 and GII.13) each made up <10%. The GII.4 genotype was the only norovirus genotype seen in all 4 years of the study and was the most common genotype in 2012-2014 but in 2015 the most common genotype was GII.2. The GII.4 genotype was more common in children 0-2 years, whereas GII.2 and GII.7 were more common in children 4-5 years. ORF 1/ORF 2 recombinant forms identified were GII.P4_NewOrleans_2009/GII.4_Sydney_2012, GII.P12/GII.3, GII.Pb (GII.21)/GII.3, GII.Pe/GII.2, GII.Pe/GII.4_Sydney_2012 and GII.Pg/GII.1. The findings indicate that norovirus genotype prevalence patterns in children were influenced by the age of the children and the year in which the analysis was carried out. The majority of norovirus infections (84%) occurred after the first year of life so that vaccination before the age of one would appear to be the most efficacious.
Asunto(s)
Infecciones por Caliciviridae/epidemiología , Infecciones por Caliciviridae/virología , Guarderías Infantiles , Brotes de Enfermedades , Gastroenteritis/epidemiología , Gastroenteritis/virología , Norovirus/genética , Preescolar , Genotipo , Humanos , Lactante , Recién Nacido , Filogenia , ARN Viral/análisis , Análisis de Secuencia de ARN , Victoria/epidemiologíaRESUMEN
Noroviruses are a major cause of gastroenteritis. Vaccine strategies against norovirus are currently under consideration but depend on a detailed knowledge of the capsid genotypes. This study examined the incidence of norovirus outbreaks in residential aged-care facilities in Victoria, Australia over one year (2013) and documented the (capsid) norovirus genotypes associated with these outbreaks. It was found that 65·0% of 206 outbreaks tested were associated with norovirus infection, thereby showing norovirus to be the major cause of viral gastroenteritis in residential aged-care facilities. Fifteen capsid (open reading frame 2) genotypes were identified as follows: GI.2 (0·9%), GI.3 (1·8%), GI.4 (3·7%), GI.6 (0·9%), GI.7 (0·9%), GI.8 (0·9%), GII.1 (0·9%), GII.2 (0·9%), GII.3 (1·8%), GII.4 (2009-like) (0·9%), GII.4 (2012) (48·6%), GII.4 (2012-like) (16·5%), GII.4 (unknown) (9·2%), GII.5 (2·8%), GII.6 (0·9%), GII.7 (0·9%), GII.13 (6·4%) and an as yet unclassified GII genotype (0·9%). Although GII.4 was the most common norovirus capsid genotype detected, the great diversity of norovirus genotypes in the elderly indicates vaccination strategies for this demographic are not straightforward.
Asunto(s)
Infecciones por Caliciviridae/epidemiología , Infecciones por Caliciviridae/virología , Brotes de Enfermedades , Gastroenteritis/epidemiología , Gastroenteritis/virología , Hogares para Ancianos , Norovirus/clasificación , Anciano , Anciano de 80 o más Años , Proteínas de la Cápside/genética , Análisis por Conglomerados , Genotipo , Humanos , Masculino , Datos de Secuencia Molecular , Norovirus/genética , Norovirus/aislamiento & purificación , Filogenia , ARN Viral/genética , Análisis de Secuencia de ADN , Homología de Secuencia , Victoria/epidemiologíaRESUMEN
The current study examined the efficacy of the RIDAGENE norovirus (NoV) real-time polymerase chain reaction assay (R-Biopharm, Darmstadt, Germany) for use in a routine diagnostic laboratory. The RIDAGENE assay had an overall sensitivity of 98% but was more sensitive for GII than GI NoV. The assay had a specificity of 98%. The RIDAGENE assay could detect a variety of GI and GII open reading frame 2 genotypes including GI.1, GI.3, GI.8, GI.13, GII.2, GII.3, GII.4 (including the following variants: 2006b, 2009, 2012, and 3 others that have not been assigned), GII.6, GII.12, and GII.13. The assay did not cross react with a number of gastroenteritis viruses including adenovirus, astrovirus, rotavirus, and sapovirus. The assay was straightforward to perform, and for a run of 50 specimens, a result was obtainable in roughly 4 hours. The RIDAGENE assay can be recommended as a valuable detection method for NoV.
Asunto(s)
Infecciones por Caliciviridae/diagnóstico , Gastroenteritis/diagnóstico , Gastroenteritis/virología , Técnicas de Diagnóstico Molecular/métodos , Norovirus/genética , Norovirus/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Genotipo , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Norovirus/clasificación , Sensibilidad y Especificidad , Adulto JovenRESUMEN
The noroviruses are a major cause of outbreaks of gastroenteritis. The norovirus genotype "GII.e", identified by ORF (Open Reading Frame) 1 nucleotide sequencing, appears to be an obligatory recombinant, in that no unique GII.e ORF 2 genotype has been identified. In 2012 GII.e norovirus became the predominant ORF 1 genotype in norovirus outbreaks in Victoria, Australia, and the current study documents changes in the ORF 1 region of GII.e norovirus since it first emerged in 2008, as well as in the ORF 2 genotypes associated with GII.e norovirus. GII.e norovirus underwent significant genetic change in ORF 1 between 2010 and 2012 and this genetic change corresponded to a significant increase in the prevalence of the virus. Nucleotide sequencing of the ORF 2 region of GII.e specimens showed that in 2008-2009, all the ORF 2 sequences corresponded to the GII.4 (2007) variant, in 2010 all the ORF 2 sequences corresponded to the GII.4 (2012-like) variant and in 2012 all the ORF 2 sequences corresponded to the GII.4 (2012) variant, the GII.4 (2012-like) variant, or the GII.4 (2009-like) variant. The evidence indicated that the development of the 2012 GII.e epidemic strains was due to evolutionary change rather than a novel recombination event. The results also support the notion that ORF 1 is critical in determining the virulence of a norovirus strain.
Asunto(s)
Infecciones por Caliciviridae/virología , Norovirus/clasificación , Norovirus/genética , Sistemas de Lectura Abierta/genética , Secuencia de Aminoácidos , Brotes de Enfermedades , Heces/virología , Genotipo , Humanos , Datos de Secuencia Molecular , Norovirus/aislamiento & purificación , Filogenia , ARN Viral/análisis , ARN Viral/genética , Alineación de SecuenciaRESUMEN
GII.b norovirus is an obligatory recombinant with an open reading frame (ORF) 1 comprising the GII.b genotype and the ORF 2 region corresponding to one of a number of other norovirus genotypes. GII.b is the second most common genotype after GII.4 associated with gastroenteritis outbreaks in Victoria, Australia. The study involved norovirus testing of 14,186 specimens from 2,743 Victorian gastroenteritis outbreaks in the period 2002-2011. The noroviruses identified were further characterized by nucleotide sequencing and phylogenetic analysis. In the period 2002-2005, 21 GII.b norovirus outbreaks were identified, with the GII.b ORF 2 recombinant genotypes comprising GII.1 (47.6%), GII.3 (47.6%), and GII.13 (4.8%). For the period 2006-2011, 56 GII.b norovirus outbreaks were identified. In 51 of these, the ORF 2 genotype was identified, and comprised GII.1 (2.0%), GII.3 (94.1%), GII.13 (2.0%), and GII.21 (2.0%). GII.b norovirus outbreaks could occur in a range of settings involving individuals with a broad range of ages. However, GII.b/GII.3 norovirus tended to occur in a younger demographic and all outbreaks involving specifically children's settings had the GII.b/GII.3 genotype. Nucleotide sequencing studies demonstrated major changes in both the ORF 1 and ORF 2 regions of the GII.b/GII.3 noroviruses but not in the GII.b/GII.1 and GII.b/GII.13 noroviruses when the noroviruses for the two time periods 2002-2005 and 2006-2011 were compared. The findings suggest nucleotide changes in the pre-existing GII.b/GII.3 noroviruses resulted in a more virulent form.
Asunto(s)
Infecciones por Caliciviridae/epidemiología , Brotes de Enfermedades , Gastroenteritis/epidemiología , Norovirus/clasificación , Norovirus/genética , Recombinación Genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Infecciones por Caliciviridae/virología , Niño , Preescolar , Análisis por Conglomerados , Femenino , Gastroenteritis/virología , Genotipo , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Norovirus/aislamiento & purificación , Filogenia , ARN Viral/genética , Análisis de Secuencia de ADN , Homología de Secuencia , Victoria/epidemiología , Adulto JovenRESUMEN
The epidemiology of GIIb norovirus outbreaks and the characteristics of GIIb open reading frame (ORF) 2 recombinant forms are poorly understood and this study examined these questions using norovirus-associated gastroenteritis outbreaks in Victoria, Australia, during 2002-2005. Twenty-one GIIb outbreaks were detected and were the second most common ORF 1 norovirus outbreak genotype (5%) after GII.4 (90%). Both GIIb and GII.4 outbreaks peaked in warmer months of the year but their periodicity was different. ORF 2 sequencing analysis was carried out in the two regions previously designated C and D. RT-PCR region D primers were less sensitive than region C primers. No evidence of recombination between regions C and D was found. ORF 2 genotypes for the 21 GIIb outbreaks were: GII.1 (10 outbreaks), GII.3 (10 outbreaks) and, apparently for the first time, GII.13 (1 outbreak). GIIb outbreaks could occur in a broad range of settings and there was no correlation between ORF 2 genotype and setting except that all 5 outbreaks involving mainly young children were associated with GIIb/GII.3.
Asunto(s)
Infecciones por Caliciviridae/epidemiología , Infecciones por Caliciviridae/virología , Brotes de Enfermedades , Norovirus/clasificación , Norovirus/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Genotipo , Humanos , Lactante , Persona de Mediana Edad , Epidemiología Molecular , Datos de Secuencia Molecular , Norovirus/aislamiento & purificación , Filogenia , Estaciones del Año , Análisis de Secuencia de ADN , Homología de Secuencia , Victoria/epidemiología , Proteínas Virales/genéticaRESUMEN
Noroviruses are considered the most common cause of outbreaks of non-bacterial gastroenteritis in humans and the GII.4 genotype the most common norovirus genotype. Previous studies have shown that two adjacent codons acted as markers of the severity of GII.4 norovirus outbreak epidemics. In this study, a further such codon was identified at nucleotide position 4670-4672 relative to the norovirus strain Lordsdale virus (GenBank accession no. X86557). Taken together, the data indicate these epidemic marker sites occur, on average, about once in 30 amino acids (aa) in the polymerase region. None of the variant forms associated with the three codons resulted in an aa change. The three codons were not associated with the active sites of the polymerase gene. It is possible changes in these marker sites may influence norovirus virulence by altering the timing of co-translational folding in the norovirus genome.
Asunto(s)
Biomarcadores/análisis , Infecciones por Caliciviridae/virología , Gastroenteritis/virología , Norovirus/genética , ARN Polimerasa Dependiente del ARN/genética , Proteínas Virales/genética , Infecciones por Caliciviridae/epidemiología , Codón/genética , Brotes de Enfermedades , Gastroenteritis/epidemiología , Genotipo , Humanos , Norovirus/clasificaciónRESUMEN
The aim of the study was to compare the sensitivity of a norovirus RT-PCR method using two manual RNA extraction methods (Qiagen and Roche) and two automated RNA extraction methods (Qiagen and Corbett). All four RNA extraction methods gave similar sensitivities although the automated methods, especially the Corbett, required significantly less labour than the manual methods. The automated methods also enabled RNA extraction of approximately two to three times the number of specimens in a given time period compared to manual methods.
Asunto(s)
Norovirus/aislamiento & purificación , ARN Viral/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Humanos , Norovirus/genética , ARN Viral/genética , Sensibilidad y EspecificidadRESUMEN
The study presented here was conducted in order to gain a better understanding of the role of astroviruses (AsVs) in outbreaks of gastroenteritis among the elderly. This report is the first to provide detailed information on the molecular characteristics of an AsV causing an outbreak in an aged-care centre and is the first to clearly establish that individuals infected in such an outbreak were, in fact, elderly. The outbreak under investigation took place in Victoria, Australia, in October 2005. Twelve individuals (mean age +/- standard deviation [SD] 85.5 +/- 12.3 years) became ill during the outbreak from a total population of 86 susceptible residents. The mean duration (+/-SD) of illness was 2.3 +/- 1.6 days; symptoms included diarrhoea, abdominal pain, nausea and headache. No bacterial pathogens were detected. AsV was identified in five faecal specimens using electron microscopy and reverse transcription-polymerase chain reaction methodologies; no other gastroenteritis virus was detected. Nucleotide sequence analysis indicated the AsV identified could be assigned to the 1d lineage of AsV serotype 1 and that the AsV was not a recombinant form. The findings, taken together with previous work, indicate the AsV serotype most commonly associated with gastroenteritis outbreaks among the elderly is serotype 1 AsV.