Small round-structured (Norwalk-like) viruses and classical human caliciviruses in Southeastern Australia

Abstract

A total of 6,226 fecal samples collected from 1980 to 1996 in the Australian states of Victoria, New South Wales, and Tasmania from individuals with gastroenteritis were tested for small round-structured viruses (SRSVs) and classical human caliciviruses (ClHuCVs) by electron microscopy. There were 223 samples positive for SRSVs, and nine positive for ClHuCVs. SRSVs were detected in individuals of all ages and were commonly associated with gastroenteritis outbreaks in nursing homes and hospitals. SRSVs were detected throughout the year, but were more common in the period from late winter to early summer in Australia (August to December). There were peaks of virus activity in the early 1980s and more recently in 1995 and 1996. Analyses by RT-PCR and sequencing of a segment of ORF1 encoding the putative RNA polymerase for SRSVs and ClHuCVs showed the presence of viruses belonging to several genogroups. Viruses of genogroup 1 (Norwalk/Southampton-like) and genogroup 3 (ClHuCVs) were relatively rare. Viruses of genogroup 2 (Snow Mountain-like) were common, and could be divided into two subgroups, one containing Toronto/Mexico-like viruses, the other Lordsdale/Camberwell-like viruses. The majority of viruses detected belonged to this latter subgroup.

The Importance of Intergenic Recombination in Norovirus GII.3 Evolution

“…A single study conducted in the United States on norovirus strains collected in the 1970s showed that norovirus strains possessing a GII.3 VP1 gene and ancestral RdRp gene were the most prevalent genotype circulating in children at that time (22). Genotype GII.3/GII.3 (capsid/RdRp) noroviruses were prevalent in children globally from the late 1980s to the late 1990s (22,23,26,27) before being succeeded by GII.3/GII.b recombinant strains, which were a major cause of pediatric disease worldwide from 2000 to 2009 (29,30,33,34,37,54). In contrast, GII.3/GII.a recombinant strains were not as prevalent, causing isolated outbreaks and sporadic disease in Australia, Argentina, and Japan during 1998 and 2002 (55)(56)(57).…”

“…GII.4 is the most common genotype circulating worldwide, having caused at least four global epidemics since 1995, each caused by a distinct GII.4 antigenic variant (18)(19)(20)(21). Genotype II.3 is a common cause of sporadic infection in children (22)(23)(24)(25). In infants and young children, GII.3 strains often predominate and were particularly prevalent in various countries throughout the late 1970s and 1980s (22), the early 1990s (26)(27)(28), and in the early and late 2000s (25,(29)(30)(31).…”

Detection of calicivirus from fecal samples from children with acute gastroenteritis in the West Central region of Brazil

“…Several studies show the occurrence of calicivirus, mainly NoV, during the colder months of the year (Xi et al 1990, Inouye et al 2000, Mounts et al 2000, while other show the circulation of these agents at different periods (Wright et al 1998, Greening et al 2001. The climate in the West Central region is sub-tropical and in Goiânia, temperatures are almost invariable throughout the year.…”

Genetic classification of "Sapporo-like viruses"

“…The members of the genera "Sapporo-like viruses" (SLVs) and "Norwalk-like viruses" (NLVs) in the family Caliciviridae [14,32] are an important cause of gastroenteritis in humans [4,8,10,12,21,28,30,39,40,43] and animals [7,15,26,38]. In humans, the illnesses caused by SLVs and NLVs differ in epidemiological features and clinical symptoms.…”