Distinct epidemiological patterns of Norwalk-like virus infection

Abstract

Norwalk-like viruses (NLV) are important economically as a cause of both sporadic gastroenteritis in the community and large outbreaks in hospitals and other institutional settings. Despite the description of several antigenic types relatively little is known about the epidemiology of these individual types. NLVs were detected by electron microscopy in faecal specimens from 706 outbreaks of gastroenteritis that represented 68% of all outbreaks of non-bacterial gastroenteritis. These outbreaks took place in the counties of West and North Yorkshire and Humberside during six winter seasons between July 1992 and June 1998. NLV strains from 671 outbreaks were typed by antigen capture enzyme linked immunosorbent assays (ELISA) based on antisera made to recombinant virus-like particles of three antigenically distinct NLVs; Norwalk (NV), Mexico (MXV) and Grimsby (GRV) viruses. GRV was the predominant strain for five of the six winter seasons and overall was associated with 61% of NLV outbreaks. MXV was responsible for a single epidemic peak in the winter of 1993/94 but was also observed at other times throughout the study period. NV was only associated with two outbreaks in 1994 that were epidemiologically linked. Strains from the remaining 32% of outbreaks were non-reactive in all three ELISA. Thus, a single NLV antigenic type seems to have predominated during the period 1992 to 1998 in the UK.

Laboratory efforts to cultivate noroviruses

“…HECVs are divided into two genera, the genus Norovirus (NoV, formerly known as 'Norwalk-like viruses') and the genus Sapovirus (SaV, formerly known as 'Sapporo-like viruses'). Recent studies have determined that NoVs are among the leading causes of food-and waterborne gastroenteritis in Western countries, such as The Netherlands, the UK and the USA (de Wit et al, 2001;Hale et al, 2000;Fankhauser et al, 2002). The genus Norovirus is currently subdivided into two genogroups, GGI and GGII, on the basis of sequence homologies of the capsid gene RNA, although subdivision into five genogroups has been proposed recently (Karst et al, 2003).…”

Asymptomatic and Symptomatic Excretion of Noroviruses during a Hospital Outbreak of Gastroenteritis

“…Representatives of genogroup I genotypes include GI-1 (Norwalk/1968/ US), GI-2 (Southampton/1991/UK), GI-3 (Desert Shield/ 1990/SA), and GI-4 (Valetta/1995/MA), while genogroup II genotypes include GII-1 (Hawaii/1971/US), GII-2 (Melksham/ 1994/UK), GII-3 (Mexico/1989/MX), and GII-4 (Grimsby/ 1995/UK). Globally, norovirus outbreaks are caused by different strains of norovirus from genogroups I and II, with the genogroup II strains predominating worldwide (3,11,19). GII-4 has been the predominant norovirus genotype circulating worldwide in recent years (8,9,11,17).…”

“…Globally, norovirus outbreaks are caused by different strains of norovirus from genogroups I and II, with the genogroup II strains predominating worldwide (3,11,19). GII-4 has been the predominant norovirus genotype circulating worldwide in recent years (8,9,11,17).…”

Molecular Epidemiology of Caliciviruses Causing Outbreaks and Sporadic Cases of Acute Gastroenteritis in Spain

“…Human caliciviruses (HuCVs) are considered the most common cause of nonbacterial gastroenteritis outbreaks in persons of all ages worldwide (14,17). These viruses can phylogenetically be divided into two genera, Norwalk-like viruses (NLVs), with genogroups I and II, and Sapporo-like viruses (SLVs), a group of typical human caliciviruses with distinctive morphology by electron microscopy.…”