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.

The aim of this study was to determine the levels of selenium, T-2 toxin, and deoxynivalenol (DON) contamination in Kashin-Beck disease (KBD) areas and provide information for understanding the high prevalence of KBD in Qinghai Province. A total of 183 subjects were chosen in a KBD-prevalent county (Guide County) and a non-KBD county (Huangzhong County) in Qinghai Province, northwestern China, and the samples of wheat flour, soil, drinking water and blood, urine, and hair of children were collected from these residents. The selenium concentrations from all these sources were determined using atomic fluorescence spectrophotometry. The levels of T-2 toxin and DON contamination in the wheat flour samples were assayed using HPLC-MS/MS. The average selenium content in the soil, drinking water, and wheat flour samples from KBD areas were 26.93 ± 10.06 μg/kg, 0.097 ± 0.038 μg/L, and 9.50 ± 7.17 μg/kg, respectively. Among these, the selenium levels in the drinking water and wheat flour samples from the KBD endemic county were significantly lower than those from the non-KBD county. For the selenium nutrient status, only the hair selenium concentration of children from the KBD endemic county was significantly lower than that from the non-KBD county. The contents of T-2 toxin in all wheat samples were below the detection limit (0.4 μg/kg). The levels of DON contamination in wheat flour samples from KBD and non-KBD children's households within the KBD endemic county were relatively higher, with average levels of 302 ± 49 and 280 ± 48 μg/kg, respectively. The DON level of wheat flour samples from the children's households in the non-KBD county was significantly lower than that from the KBD endemic county. These results suggest that the lower selenium status in Guide County still remains. While the selenium nutritional status of the local children has improved to some extent, partly due to the introduction of food produce from nonlocal areas. DON contamination in the wheat flour may be involved in the fluctuating high prevalence rates of KBD in children in the KBD endemic Guide County in Qinghai Province.

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