ABSTRACT
During a 5-year (2007-2011) surveillance period a total of 435 (15·34%) of 2834 stool specimens from children aged <14 years with acute gastroenteritis tested positive for norovirus and 217 strains were characterized upon partial sequence analysis of the polymerase gene as either genogroup (G)I or GII. Of the noroviruses, 99·2% were GII with the GII.P4 genotype being predominant (80%). GII.P4 variants (Yerseke 2006a, Den Haag 2006b, Apeldoorn 2008, New Orleans 2009) emerged sequentially during the study period. Sequence analysis of the capsid gene of 57 noroviruses revealed that 7·8% were recombinant (ORF1/ORF2) viruses including GII.P7_GII.6, GII.P16_GII.3, GII.P16_GII.13, GII.Pe_GII.2, and GII.Pe_GII.4, never identified before in Italy. GII.P1_GII.1, GII.P2_GII.1, GII.P3_GII.3 and GII.P6_GII.6 strains were also detected. Starting in 2011 a novel GII.4 norovirus with 3-4% nucleotide difference in the polymerase and capsid genes from variant GII.4 New Orleans 2009 was monitored in the local population. Since the epidemiology of norovirus changes rapidly, continuous surveillance is necessary to promptly identify the onset of novel types/variants.
Subject(s)
Caliciviridae Infections/epidemiology , Gastroenteritis/epidemiology , Norovirus/genetics , Norovirus/isolation & purification , Acute Disease , Age Distribution , Caliciviridae Infections/diagnosis , Capsid Proteins/genetics , Child , Child, Preschool , Feces/virology , Female , Gastroenteritis/virology , Genotype , Humans , Incidence , Infant , Italy/epidemiology , Male , Molecular Epidemiology , Phylogeny , Polymerase Chain Reaction/methods , RNA, Viral/genetics , Risk Assessment , Severity of Illness Index , Sex DistributionABSTRACT
Global surveillance for norovirus identified in 2012 the emergence of a novel pandemic GII.4 variant, termed Sydney 2012. In Italy, the novel pandemic variant was identified as early as November 2011 but became predominant only in the winter season 2012-2013. Upon sequencing and comparison with strains of global origin, the early Sydney 2012 strains were found to differ from those spreading in 2012-2013 in the capsid (ORF2) putative epitopes B, C and D, segregating into a distinct phylogenetic clade. At least three residues (333, 340 and 393, in epitopes B, C and D, respectively) of the VP1 varied among Sydney 2012 strains of different clades. These findings suggest that the spread of the pandemic variant in Italy during the winter season 2012-2013 was due to the introduction of strains distinct from those circulating at low frequency in the former winter season and that similar strains were also circulating elsewhere worldwide.
Subject(s)
Capsid Proteins/genetics , Gastroenteritis/virology , Mutation , Norovirus/genetics , Amino Acid Sequence , Capsid Proteins/metabolism , Gastroenteritis/epidemiology , Humans , Italy/epidemiology , Molecular Sequence Data , Norovirus/classification , Norovirus/isolation & purification , Norovirus/physiology , Pandemics , Phylogeny , SeasonsABSTRACT
During 2012, a novel pandemic GII.4 norovirus variant, Sydney 2012, emerged worldwide. A signature of the variant was a GII.Pe ORF1, in association with GII.4 Apeldoorn 2008-like ORF2-ORF3 genes. We report the detection of recombinant GII.4 Sydney 2012 strains, possessing the ORF1 gene of the former pandemic variant New Orleans 2009.
Subject(s)
Caliciviridae Infections/virology , Norovirus/classification , Norovirus/genetics , Recombination, Genetic , Caliciviridae Infections/epidemiology , Child , Child, Preschool , Humans , Molecular Sequence Data , Norovirus/isolation & purification , Open Reading Frames , Pandemics , RNA, Viral/genetics , Sequence Analysis, DNAABSTRACT
The study investigated the genetic diversity of human astroviruses (HAstVs) detected in children hospitalized with gastroenteritis in Italy in 2008-2009. A total of 1321 faecal samples were collected in Parma (northern Italy), Bari (southern Italy), and Palermo (Sicily) and screened for the presence of HAstVs. RT-PCR amplification of a portion at the 5'-end of ORF2 allowed the detection of HAstVs in 3·95% of the patients. Four different genotypes (HAstV-1, HAstV-2, HAstV-4, HAstV-5) were found to be circulating during the study period, with HAstV-1 being the predominant type. Interestingly, a novel lineage, proposed as HAstV-2d, was found to have emerged in Parma in 2009. Investigating the genetic variability of HAstVs will be important for understanding the epidemiological trends and evolution of these viruses.
Subject(s)
Astroviridae Infections/epidemiology , Astroviridae Infections/virology , Mamastrovirus/genetics , Population Surveillance , Child, Preschool , Feces/virology , Genotype , Humans , Infant , Italy/epidemiology , Mamastrovirus/isolation & purification , PrevalenceABSTRACT
Novel lineages of human astrovirus (HAstV) types 2, 2c, and 2d have been identified. Upon sequencing of the 3' end of the genome, the type 2c and 2d HAstVs were found to be open reading frame 1b (ORF1b)-ORF2 recombinant, with ORF1b being derived from type 3 and type 1 HAstVs, respectively. An ORF2 interlineage recombinant strain, 2c/2b, was also identified.
