The Global Seasonality of Norovirus Gastroenteritis Open Access

Ahmed, Sharia Marie (2012)

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The Global Seasonality of Norovirus Gastroenteritis

Background: Norovirus is the leading cause of epidemic, acute gastroenteritis in industrialized countries, and may be a cause of severe disease in certain populations (e.g. children, elderly, and hospitalized patients). Norovirus is generally recognized to have an irregular wintertime seasonality in temperate climates, but these patterns have not been systematically described across geographic areas in the era of modern diagnostics.
Methods: We present the results of a systematic review and meta-analysis of norovirus gastroenteritis across various geographic regions. In the systematic review we searched for publications that reported at least one full year of monthly data on norovirus outbreaks or cases in a specified geographic region. The initial literature search identified 287 potential publications, with 78 meeting the inclusion criteria. Data were then extracted from each publication using Plot Digitizer software.
Results: The proportion of cases/outbreaks of norovirus per calendar month was calculated from studies representing twenty-six countries on six continents (37 case-based studies, 32 outbreak-based studies, representing a total of 12 years of data).
Conclusions: There is a clear seasonality of norovirus across the six continents included in this study, with disease burden peaking in winter months in the northern hemisphere.

Table of Contents

Table of Contents



Background on Norovirus 1

Seasonality of Norovirus 1

Seasonality of Infectious Diseases 3

Climate Change and Infectious Disease 6

Systematic Reviews 8

Motivation for this study 9


Literature Review 10

Methods to Summarize Data 11

Predictors and Independent Variables 12

Statistical Methods 13

Results 15

Discussion 18

References 21

Tables/Figures 31


Detailed Search Protocol 39

Regression Results 43

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