Background Noroviruses (NoVs) are a leading cause of viral diarrhea in young children. Secretor status has been confirmed to be linked with Norwalk virus (NoV GI.1) infection but there is limited information about whether secretor genotypes are associated with pediatric NoV epidemic strains in vivo. Methods In this study, fecal specimens and serum samples were collected from 124 hospitalized children with acute diarrhea in Xi'an, China. TaqMan real-time RT-PCR was used to detect NoV in fecal samples and NoV positive samples were further verified using conventional RT-PCR and sequenced. DNA was extracted from sera and TaqMan single nucleotide polymorphism genotyping assay was applied to determine FUT2 A385T polymorphism. Results Only NoV GII.3 and GII.4 genotypes were found in NoV positive samples and NoV were detected in 25% (15/60), 40.5% (17/42), and 9.1% (2/22) of children with homozygous secretor genotype (Se385Se385), heterozygous secretor genotype (Se385se385), and homozygous weak secretor genotype (se385se385), respectively. Children with secretor genotypes (Se385Se385 and Se385se385) were significantly (P < 0.05) more susceptible to combined NoV GII.3 and GII.4 infections than children with weak secretor genotype (se385se385). Conclusions These findings indicate that secretor positive is significantly associated with GII.3 and GII.4 infections in Chinese pediatric diarrheal children and weak secretor is not a complete protection of children from GII.3 and GII.4 infections.

cHuman norovirus (NoV) outbreak investigations suggest that the hands of infected individuals play an important role in NoV transmission. However, there is no experimental evidence documenting the likelihood and degree of NoV contamination on hands. As part of a clinical trial designed to evaluate the efficacy of high-pressure processing for Norwalk virus (NV) inactivation in oysters, 159 hand rinse samples were collected from 6 infected and 6 uninfected subjects. NV was concentrated from the samples by polyethylene glycol precipitation, followed by RNA extraction using an automated guanidinium isothiocyanate-silica method. NV RNA was detected and quantified using multiple NV-specific reverse transcription-quantitative PCR (RT-qPCR) assays. A total of 25.4% (18/71) of the hand rinse samples collected from 6 infected volunteers were presumptively positive for NV, with an average of 3.86 log 10 genomic equivalent copies (GEC) per hand. Dot blot hybridization of PCR products obtained using a different primer set, and DNA sequencing of selected amplicons, provided further confirmation of the presence of NV in the hand rinses. NV contamination was also detected in two hand rinse samples obtained from one uninfected subject. These findings provide definitive evidence of NV contamination on the hands of infected subjects observed under controlled clinical research conditions. Such data support the need for better hand hygiene strategies to prevent NoV transmission. Human noroviruses (NoVs) are the most common cause of acute viral gastroenteritis worldwide (1) and a leading cause of food-borne disease (2, 3). They are spread primarily by the fecal-oral route but are also shed in vomitus. As such, NoV can be transmitted via consumption of fecally contaminated food or water or by contact with contaminated fomites and hands. The relative importance of each of these transmission routes is not well studied, but the potential for human hands to facilitate NoV transmission is widely recognized.A recent epidemiological study by the CDC (4) identified NoV as the predominant etiology of food-borne disease outbreaks, and the largest proportion of these outbreaks were associated with food handlers implicated as the source of contamination. Food handlers are of particular concern (5) because they may shed NoV at extremely high titers for days or weeks during a symptomatic or asymptomatic NoV infection and subsequently transfer viruses from their hands to food. Furthermore, both laboratory and epidemiological data (6-8) provide evidence that NoV may persist on hands and fomites for extended periods of time. For example, Malek et al. (9) described an outbreak of NoV infection in which the index case was an infected food handler who worked for a delicatessen meat supplier company and handled sliced delicatessen meat with bare hands 1 day after recovering from gastroenteritis symptoms. This investigation documented a clear association between the contaminated hands of the food handler and the subsequent NoV outbreak. Because of NoV-cont...