Molecular and Epidemiological Characteristics of Norovirus Associated with Community-Based Sporadic Gastroenteritis Incidents and Norovirus Outbreaks in Victoria, Australia, 2002-2007

Objectives: The molecular and epidemiological features of community-based norovirus-associated sporadic gastroenteritis incidents (NASGIs) are poorly understood. This study examined these features and compared the findings with studies of community-based and institutional norovirus-associated gastroenteritis outbreaks (NAGOs). Methods: Fecal specimens from NASGIs and NAGOs that occurred in Victoria, Australia (2002-2007) were tested for norovirus by reverse transcription-polymerase chain reaction methodology. Norovirus genotype was determined by nucleotide sequence analysis. Results: 106 community-based NASGIs, 116 community-based NAGOs and 902 institutional NAGOs were identified. The mean age and gender ratio of individuals associated with community-based NASGIs and community-based NAGOs were similar but differed from that found for institutional NAGOs. Although GII. 4 was the predominant genotype associated with all three incident types, the mix of genotypes was similar for community-based NASGIs and community-based NAGOs but that for institutional NAGOs was different. All three incident types had a similar seasonal periodicity due to the pronounced seasonal periodicity of GII. 4 incidents. Conclusions: The molecular and epidemiological features of noroviruses associated with community-based NASGIs and community-based NAGOs are similar but are different from those found for institutional NAGOs. Copyright (C) 2010 S. Karger AG, Basel