Molecular epidemiology of norovirus infections in sporadic cases of viral gastroenteritis among children in Northern Italy

Abstract

Surveillance of norovirus infections in sporadic cases of pediatric gastroenteritis admitted to a main hospital in Northern Italy during a full-year period (2002) showed that noroviruses (10.4%) were the second most common causative viral agent, following rotaviruses (21.1%), and noroviruses (81%) were mostly implicated in mixed infections. The epidemic period of norovirus was September-December, with September and November as months of major prevalence (33.3 and 38.5%, respectively). Six distinct norovirus genotypes were detected (GI.7, GII.1, GII.2, GII.4, GII.7, GII, not assigned named GIIb), and the predominant genotype was GII.4. A "new GII.4 2002 variant" accounted for 82.9% of total strains. Since the severity of norovirus symptoms does not usually require admission to hospital, the burden of norovirus disease in the general children population may be much higher than that suggested by the present hospital-based investigation.

Epidemiology and clinical features of gastroenteritis in hospitalised children: prospective survey during a 2-year period in a Parisian hospital, France

“…The literature concerning symptom severity in norovirus and rotavirus gastroenteritis is heterogeneous [42]. A number of previous studies found lower levels of disease severity in norovirus than in rotavirus gastroenteritis, and most of these were carried out in developed countries [7,[43][44][45][46][47]. In contrast, other studies found no significant differences between the severity of rotavirus and norovirus infections [48][49][50][51].…”

Murine Noroviruses Comprising a Single Genogroup Exhibit Biological Diversity despite Limited Sequence Divergence

“…Noroviruses cause most outbreaks of gastroenteritis, as well as a significant proportion of sporadic cases of gastroenteritis in children and adults (7,9,16,20,37,54). Symptoms of norovirus infection, which include vomiting, diarrhea, lowgrade fever, malaise, and abdominal cramping or pain, usually resolve within 48 h, although noroviruses can be shed for 3 weeks after infection in adults and at least 6 weeks after infection in children of less than 6 weeks of age (13,21,57,68).…”

Norovirus GII.4 Strain Antigenic Variation

“…In 2002, the US95/96 strain was replaced by the Farmington Hills strain (66), which was associated with ϳ80% of norovirus outbreaks (17) in the United States. Simultaneously in Europe, the GII.4b variant emerged and caused outbreaks during the winter, spring, and summer (42,44,51). In 2004, the Hunter GII.4 variant was detected in Australia, Europe, and Asia (7,33,51).…”