Detection of the norovirus variants GGII.4 hunter and GGIIb/hilversum in Italian children with gastroenteritis

Abstract

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 gastroenteritis. A selection of strains was further analyzed by partial sequence analysis of the RdRp gene. The strains were characterized as genogroup (GG) II and clustered into two distinct virus populations that resembled the emerging European GGIIb/Hilversum strains and the Australian Hunter GGII.4 strains. A temporal pattern of distribution of the two NoV strains was observed which was consistent with an independent circulation of two separate strains in the local population. Based on this 1-year study we concluded that NoVs were a diffuse cause of sporadic cases of acute childhood gastroenteritis and that strains of global epidemiological relevance were circulating in Palermo, Italy in 2004.

Molecular Identification and Genetic Analysis of Norovirus Genogroups I and II in Water Environments: Comparative Analysis of Different Reverse Transcription-PCR Assays

“…In fact, it is well known that sequence data generated from small regions should be interpreted with caution. To our knowledge, to date, published nested assays (required when analyzing environmental samples) produce fragments of no more than 158 bp (15,21,37,38,43,50,57). The newly designed assays for GI and GII provided more extensive regions of the polymerase gene, which allows high-confidence BLAST searches of the public database.…”

“…Italy, unlike other countries, has no specific surveillance system for viral gastroenteritis, and laboratory diagnosis is rarely performed; therefore, few epidemiological data are available regarding NoV gastroenteritis (34,39,43).…”

Genogroup IIb Norovirus Infections and Association with Enteric Symptoms in a Neonatal Nursery in Southern India

“…These strains showed a high degree of identity of the GIIb strains from children with gastroenteritis in India (6). There are several recent reports of GIIb infection among children worldwide, resulting in speculation that this strain may preferentially cause infections in children (3,10,15). It is important to note that no GIIb strains were described in previous concomitant community-and hospital-based epidemiological studies of NoV infections in children from this region (12).…”

Emerging GII.4 norovirus variants affect children with diarrhea in Palermo, Italy in 2006

“…When in the RT-PCR no specific PCR product (327 bp in length) was obtained, a hemi-nested PCR with primer pair JV13/Ni was carried out, that amplifies a 110-bp fragment [Ramirez et al, 2006]. The PCR products were visualized by gel electrophoresis on ethidium bromide-stained 2% agarose.…”

“…Human NoVs have been classified into three separate genetic groups (GGI, GGII, and GGIV), and in at least 30 genotypes by analysis of the capsid gene (ORF2) [Green, 2007]. GGII NoVs account for at least 90% of the NoV isolates, with GII.4 strains being responsible for the majority of episodes of diarrhea [Bull et al, 2006;Ramirez et al, 2006;Siebenga et al, 2007a]. The high incidence of NoV infections seems to be related to the sequential appearance and rapid spread of new variants and/or of recombinant NoV strains.…”