Characterisation of a household norovirus outbreak occurred in Valencia (Spain).

Noelia Carmona-Vicente,Susana Vila-Vicent,Jesús Rodríguez-Díaz,Manuel Fernández-Jiménez,Javier Buesa

doi:10.1186/s12879-016-1455-9

Noelia Carmona-Vicente, Susana Vila-Vicent + Show 3 more

Open Access

https://doi.org/10.1186/s12879-016-1455-9

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Journal: BMC infectious diseases	Publication Date: Mar 12, 2016
Citations: 37	License type: cc-by

Affiliation: University of Valencia

Abstract

BackgroundHuman noroviruses (NoVs) are the main cause of non-bacterial gastroenteritis worldwide. Several studies have linked human susceptibility to NoVs with the expression of histo-blood group antigens (HBGAs). In January 2012, a NoV gastroenteritis outbreak affected a household in Valencia, Spain, and the personal susceptibility to NoV was investigated.MethodsTo reach this aim 8 members of the affected household were recruited for this study and their secretor status, ABO and Lewis antigens were determined. NoV-specific saliva IgA and serum IgG antibody titers were analyzed. Their capacity to block viral binding to saliva receptors was analyzed, using virus-like particles (VLPs) of the NoV GII.4 genotype, 2006b variant, and saliva from a secretor O blood type donor.ResultsThe most relevant finding was that an asymptomatic non-secretor individual shed NoVs in his stools. Interestingly, anti-NoV IgA antibody titers in saliva from secretor and non-secretor individuals showed no differences. On the contrary, high titers of NoV-specific IgG antibody were found in both convalescent sera and in sera collected 1 year post-infection, but only from secretor individuals. NoV GII.4-2006b VLP binding to receptors present in the saliva was efficiently blocked only by sera from secretor positive individuals.ConclusionsDespite the small number of individuals involved in this outbreak, this study reinforces the idea that susceptibility to human NoV is both dependent on the HBGA profile of the individuals as well as on the viral genotype and variant. We also show that the immunity to NoV lasts for at least 1 year after infection, demonstrating that symptomatic infections strongly stimulate immune responses.

Highlights

Human noroviruses (NoVs) are the main cause of non-bacterial gastroenteritis worldwide
Gastroenteritis outbreak was caused by norovirus GII.4-New Orleans_2009 variant In January 2012 three members of a household in Valencia showed typical symptoms of acute gastroenteritis caused by NoV 24 h after having been in contact with the index case
Reverse transcriptase-polymerase chain reaction (RT-PCR) assay performed on stool samples collected (n = 3) from two symptomatic patients and from one asymptomatic individual revealed the presence of NoV GII.4, the GII.4-New Orleans_2009 variant

Summary

Introduction

Human noroviruses (NoVs) are the main cause of non-bacterial gastroenteritis worldwide. Noroviruses (NoVs), members of the Caliciviridae family, are small, positive-polarity RNA viruses and the most important cause of human viral gastroenteritis worldwide [1]. They are classified into 7 genogroups, genogroups I (GI) and GII cause most human NoV infections [2]. These two genogroups are subdivided into 9 and 22 different genotypes, respectively. Several genotype GII. variants have emerged and caused the majority of all NoV-associated gastroenteritis outbreaks and sporadic infections over the past 2 decades [3]. This different susceptibility is associated blood group, the Lewis phenotype and the secretor status)

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