Search results for "Norovirus"
showing 10 items of 132 documents
Identification of the novel Kawasaki 2014 GII.17 human norovirus strain in Italy, 2015
2015
Surveillance of noroviruses in Italy identified the novel GII.17 human norovirus strain, Kawasaki 2014, in February 2015. This novel strain emerged as a major cause of gastroenteritis in Asia during 2014/15, replacing the pandemic GII.4 norovirus strain Sydney 2012, but being reported only sporadically elsewhere. This novel strain is undergoing fast diversification and continuous monitoring is important to understand the evolution of noroviruses and to implement the future strategies on norovirus vaccines.
Epidemiological dynamics of norovirus GII.4 variant New Orleans 2009.
2015
Norovirus (NoV) is one of the major causes of diarrhoeal disease with epidemic, outbreak and sporadic patterns in humans of all ages worldwide. NoVs of genotype GII.4 cause nearly 80–90 % of all NoV infections in humans. Periodically, some GII.4 strains become predominant, generating major pandemic variants. Retrospective analysis of the GII.4 NoV strains detected in Italy between 2007 and 2013 indicated that the pandemic variant New Orleans 2009 emerged in Italy in the late 2009, became predominant in 2010–2011 and continued to circulate in a sporadic fashion until April 2013. Upon phylogenetic analysis based on the small diagnostic regions A and C, the late New Orleans 2009 NoVs circulati…
Genotyping of GII.4 and GIIb norovirus RT-PCR amplicons by RFLP analysis
2007
GII.4 and GIIb/Hilversum norovirus (NoV) strains appear to have a prominent epidemiological role in outbreaks or sporadic cases of human gastroenteritis. Sequence analysis, although laborious, is the reference method used for characterization of noroviruses. In this study a screening test is proposed to characterize GIIb and GII.4 NoVs based on restriction fragment length polymorphism (RFLP) analysis of amplicons obtained from the RNA-dependent RNA polymerase (RdRp) region. Virtual analysis of 793 RdRp sequences of GGI and GGII NoVs, retrieved from GenBank, and representative of global geographical origins on a long-time period, permitted the selection of four restriction enzymes, XmnI, Ahd…
Detection of the norovirus variants GGII.4 hunter and GGIIb/hilversum in Italian children with gastroenteritis.
2006
Noroviruses (NoVs) are important enteric pathogens of humans. Although they exhibit an impressive genetic diversity, few NoV strains appear to predominate worldwide. Limited epidemiological data are available on NoV gastroenteritis in Italy. In this study, we assessed the prevalence of human NoV in Italian children with gastroenteritis by using a reverse-transcription nested polymerase chain reaction (RT-PCR) assay specific for the RNA-dependent RNA polymerase (RdRp) on faecal samples collected throughout the 2004 surveillance activity in Palermo, Italy. NoVs were detected in 47% of the stool samples obtained from children <5 years age, admitted to hospital with acute non-bacterial gastroen…
Surveillance of enteric virus infections in a neonatal intensive care unit.
2005
Objective. To investigate the epidemiology of neonatal viral gastroenteritis compared to the circulation of enteric viruses in children, 109 newborns in the NICU of Mother and Child Department and 214 children with enteritis admitted to the “G. Di Cristina” Children’s Hospital in Palermo were monitored for Rotavirus, Adenovirus, Astrovirus and Norovirus infections. Methods. Stool samples were examined by EIA to detect viral antigens. Rotavirus strains were subjected to P- and G-typing. Results. A Norovirus strain was detected in one neonatal stool specimen whereas an astrovirus strain was dectected in two neonatal specimens. No Rotavirus or Adenovirus infection was identified among the newb…
Sorveglianza delle gastroenteriti da Norovirus in Italia: comparsa e diffusione della nuova variante GII.4 Sydney 2012
2013
In the 2012-2013 winter season, global surveillance for norovirus circulation evidenced the onset of a new norovirus GII.4 variant, termed Sydney 2012. In Italy, ISGEV hospital-based surveillance revealed that this variant already circulated at low frequency in the winter season 2011-2012 and emerged definitively only in the late 2012. This lag-time pattern mirrors the findings reported elsewhere and suggests that the novel variant circulated at low prevalence before spreading globally.
Study of the dynamics of biomolecules by high speed atomic force microscopy and surface enhanced Raman spectroscopy
2015
This thesis focuses on the coupling of High–Speed Atomic Force Microscopy (HS-AFM) and Surface Enhanced Raman Spectroscopy (SERS) for biomolecule analysis. We have designed a fabrication protocol to manufacture “SERS-active” substrates. The efficacy of gold, silver and gold-silver bimetallic crystalline nanoparticle substrates were evaluated. We have investigated the impact of optical and morphological features of the substrates on Raman signal intensity by analyzing well-known samples such as bipyridine ethylene and methylene blue molecules. We took an interest in three distinct biological problematics with HS-AFM and SERS analyses. First, we have detected the chemical signature of cytochr…
Quasispecies dynamics and molecular evolution of human norovirus capsid P region during chronic infection.
2009
In this novel study, we have for the first time identified evolutionarily conserved capsid residues in an individual chronically infected with norovirus (GGII.3). From 2000 to 2003, a total of 147 P1-1 and P2 capsid sequences were sequenced and investigated for evolutionarily conserved and functionally important residues by the evolutionary trace (ET) algorithm. The ET algorithm revealed more absolutely conserved residues (ACR) in the P1-1 domain (47/53, 88 %) as compared with the P2 domain (86/133, 64 %). The capsid P1-1 and P2 domains evolved in time-dependent manner, with a distinct break point observed between autumn/winter of year 2000 (isolates P1, P3 and P5) and spring to autumn of y…
Analysis of integrated virological and epidemiological reports of norovirus outbreaks collected within the Foodborne Viruses in Europe network from 1…
2008
ABSTRACT The Foodborne Viruses in Europe network has developed integrated epidemiological and virological outbreak reporting with aggregation and sharing of data through a joint database. We analyzed data from reported outbreaks of norovirus (NoV)-caused gastroenteritis from 13 European countries (July 2001 to July 2006) for trends in time and indications of different epidemiology of genotypes and variants. Of the 13 countries participating in this surveillance network, 11 were capable of collecting integrated epidemiological and virological surveillance data and 10 countries reported outbreaks throughout the entire period. Large differences in the numbers and rates of reported outbreaks pe…
Absolute Humidity Influences the Seasonal Persistence and Infectivity of Human Norovirus
2014
ABSTRACT Norovirus (NoV) is one of the main causative agents of acute gastroenteritis worldwide. In temperate climates, outbreaks peak during the winter season. The mechanism by which climatic factors influence the occurrence of NoV outbreaks is unknown. We hypothesized that humidity is linked to NoV seasonality. Human NoV is not cultivatable, so we used cultivatable murine norovirus (MNV) as a surrogate to study its persistence when exposed to various levels of relative humidity (RH) from low (10% RH) to saturated (100% RH) conditions at 9 and 25°C. In addition, we conducted similar experiments with virus-like particles (VLPs) from the predominant GII-4 norovirus and studied changes in bin…