Floriana Bonura

Evidence for Recombination between Pandemic GII.4 Norovirus Strains New Orleans 2009 and Sydney 2012

ABSTRACT 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.

Recombinant norovirus GII.g/GII.12 gastroenteritis in children.

Recombinant GII.g/GII.12 norovirus (NoV) strains emerged in 2008 in Australia and subsequently have been associated with gastroenteritis outbreaks worldwide. In the winter season 2009-2010 GII.12 strains caused 16% of the NoV outbreaks in the United States. During 2009-2010 we also identified GII.g/GII.12 strains during surveillance of sporadic cases of gastroenteritis in Italian children. Severity scores were calculated for the GII.g/GII.12 NoV infections using the Vesikari scale and in two out of three paediatric cases they exceeded the median value calculated for concomitant GII.4 infections. Upon sequence analysis, the Italian strains were found to be recombinant viruses and displayed different patterns of nucleotide polymorphisms. Phylodynamic analysis with other GII.g/GII.12 recombinants showed a high rate of evolution, comparable to the rates observed for GII.4 viruses. The mechanisms leading to worldwide emergence of GII.12 NoV strains in 2008-2010 are not clear. Monitoring of GII.12 NoV circulation is necessary to understand these mechanisms of evolution.

Evolution of DS-1-like human G2P(4) rotaviruses assessed by complete genome analyses

Group A rotaviruses (RVAs) are a leading cause of viral gastroenteritis in children, with G2P[4] RVA being one of the most common human strains worldwide. The complete genome sequences of nine G2P[4] RVA strains, selected from a 26-year archival collection (1985-2011) established in Palermo, Italy, were determined. A strain associated with a peak of G2P[4] RVA activity in 1996 resembled a reassortant strain identified in Kenya in 1982 and differed completely in genomic make up from more recent strains that circulated during 2004-2011. Conversely, the 2004-2011 G2P[4] RVAs were genetically more similar to contemporary RVA strains circulating globally. Recent G2P[4] strains possessed either single or multiple genome segments (VP1, VP3 and/or NSP4) likely derived from ruminant viruses through intra-genotype reassortment. Amino acid substitutions were selected and maintained over time in the VP7 and VP8* antigenic proteins, allowing the circulation of two contemporary G2P[4] variants to be distinguished. Altogether, these findings suggest that major changes in the genomic composition of recent G2P[4] RVAs occurred in the early 2000s, leading to the appearance of a novel variant of the DS-1-like genotype constellation. Whether the modifications observed in the neutralizing antigens and in the genome composition of modern G2P[4] RVAs may affect the long-term effectiveness of the vaccination programmes remains to be explored.

Molecular characterization of genotype G6 human rotavirus strains detected in Italy from 1986 to 2009.

Group A human rotavirus (HRV) strains with a bovine-like (G6) major outer capsid protein VP7 were first detected in Palermo, Italy, in the late 1980s, and subsequently worldwide. During a 25-year rotavirus surveillance period, additional HRV G6 strains, associated with either a P[9] or P[14] VP4 genotype, have been detected sporadically, but repeatedly, in Palermo. Whether these G6 HRVs were transmitted to humans directly from an animal reservoir or could have circulated at low prevalence in susceptible individuals is uncertain. Upon sequence analyses of the VP7, VP4, VP6, NSP4 and NSP5 gene segments, all the Italian HRV strains displayed a conserved genotype constellation, G6-P[9]/[14]-I2-E2-H3. Intra-genotypic lineages and/or sub-lineages were observed among the various HRV strains, with some lineage/sublineage combinations being retained over time. Interestingly, two epidemiologically unrelated G6P[9] viruses, collected in the same rotavirus season, were found to have a clonal origin. In conclusion, our results indicate not only diverse origin of animal derived G6 HRVs in Palermo but also suggest human-to-human transmission of certain strains.

Genetic Heterogeneity and Recombination in Human Type 2 Astroviruses

ABSTRACT 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.

Analysis of early strains of the norovirus pandemic variant GII.4 Sydney 2012 identifies mutations in adaptive sites of the capsid protein.

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.

PREVALENCE OF ANTIBODIES ANTI-BARTONELLA HENSELAE IN WESTERN SICILY: CHILDREN, BLOOD DONORS, AND CATS

To evaluate seroprevalence of B. henselae infection both in Sicilian children and healthy blood donors. Furthermore, circulation of Bartonella in the natural reservoir was also studied. Two hundred forty-three children, living in Sicily (Palermo), affected by various diseases, without clinical features suggesting B. henselae infection, together with 122 healthy blood donors were serologically investigated for IgG and IgM antibodies by indirect fluorescent antibody test (IFAT). One hundred twenty stray and 62 pet cats were also analyzed only for IgG. Among children 25.1% had IgG antibodies to B. henselae; 18.5% showed a titer 1:64, 2.4% 1:128, 2.4% 1:256, 0.8% 1:512, 0.4% 1:1024, and 0.4% 1:5120. Among healthy blood donors 11.4% had IgG class antibodies to B. henselae; 9.8% showed a titer 1:64 and 1.6% 1:128. All the human serum samples did not show positive results for B. henselae IgM class antibodies. Stray cats (68.3%) and pet cats (35.4%) also had IgG class antibodies to B. henselae. We demonstrated high frequency of serologic evidence of past B. henselae infection, in young Italian children, affected by various diseases, apparently free of any clinical features suggesting B. henselae infection. This observation is supported by high circulation of Bartonella in cats.

Temporal variation in the distribution of type-1 human astrovirus lineages in a settled population over 14 years

Human astroviruses (HAstVs) are important enteric pathogens that are genetically and antigenically heterogeneous and can be classified into eight sero/genotypes (HAstV-1 to -8) and different lineages within each HAstV type. This study describes the genetic diversity of HAstVs circulating in southern Italy over 14 years. Molecular analysis of HAstV-1 strains showed that three different lineages (1a, 1b and 1d) of the predominant genotype were circulating during the study period. The study of an archival collection of HAstV strains offers a unique opportunity to evaluate the patterns of variation of HAstV infections over the years and to correlate the observed epidemiological changes to the genetic variability of HAstVs.

Identification of a multi-reassortant G12P[9] rotavirus with novel VP1, VP2, VP3 and NSP2 genotypes in a child with acute gastroenteritis

The G12 rotavirus genotype is globally emerging to cause severe gastroenteritis in children. Common G12 rotaviruses have either a Wa-like or DS-1-like genome constellation, while some G12 strains may have unusual genome composition. In this study, we determined the full-genome sequence of a G12P[9] strain (ME848/12) detected in a child hospitalized with acute gastroenteritis in Italy in 2012. Strain ME848/12 showed a complex genetic constellation (G12-P[9]-I17-R12-C12-M11-A12-N12-T7-E6-H2), likely derived from multiple reassortment events, with the VP1, VP2, VP3 and NSP2 genes being established as novel genotypes R12, C12, M11 and N12, respectively. Gathering sequence data on human and animal rotaviruses is important to trace the complex evolutionary history of atypical RVAs.

Norovirus GII.17 as major epidemic strain in Italy, winter 2015/16

In winter 2015–16, norovirus GII.17 Kawasaki 2014 emerged as a cause of sporadic gastroenteritis in children in Italy. Median patient age was higher for those with GII.17 than GII.4 infection (55 vs. 24 months), suggesting limited cross-protection for older children.