Emergence in Taiwan of Novel Norovirus GII.4 Variants Causing Acute Gastroenteritis and Intestinal Hemorrhage in Children.

The objective of the study was to delineate the clinical manifestations and complications associated with these new norovirus GII.4 variants in children. We investigated norovirus infections from the community outbreak in October 2011-September 2012 and an earlier outbreak in 2006-2007 in northern Taiwan. Norovirus genotypes and their variants were validated using molecular methods. A norovirus outbreak started in mid-2011 and continued through 2012 in northern Taiwan. Hospitalized children infected by norovirus in 2012 showed a significantly higher incidence of intestinal hemorrhage, as indicated by grossly bloody feces (P=0.012) and occult blood in feces (P<0.001), and also presented with more high fever >39℃ (P<0.001), fever >38.5℃ (P<0.001), and fever of any temperature >38℃ (P<0.001), compared to children hospitalized in 2006-2007. Analysis of 20 near-full-length genome sequences indicated an emergence of GII.4 2012 variants in 2011-2012. Circulating noroviruses can be divided into two clusters: GII.4 2012a, which is identical to the newly reported strain GII.4 Sydney 2012; and GII.4 2012b, which is close to GII.4 2006b, the earlier predominant strain. The emerging new variants of norovirus GII.4 caused a distinct clinical syndrome of acute gastroenteritis with severe fever and a high rate of intestinal hemorrhage in children. The genetic diversity associated with changing clinical manifestations poses major obstacles to norovirus control. ...
Source: Journal of Medical Microbiology - Category: Microbiology Authors: Tags: J Med Microbiol Source Type: research