Background Norovirus (NoV) is a major cause of viral acute gastroenteritis (AGE) in children worldwide. Epidemiological analysis with respect to the virus strains is limited in China. This study aimed to investigate the prevalence, patterns, and molecular characteristics of NoV infection among children with AGE in China. Methods A total 4848 stool samples were collected from children who were admitted with AGE in Tianjin Children’s Hospital from August 2018 to July 2020. NoV was preliminarily detected using real-time reverse transcription polymerase chain reaction (RT-PCR). Partial sequences of the RNA-dependent RNA polymerase (RdRp) and capsid genes of positive samples were amplified by conventional RT-PCR and then sequenced. The NoV genotype was determined by online Norovirus Typing Tool Version 2.0, and phylogenetic analysis was conducted using MEGA 6.0. Results The prevalence of NoV was 26.4% (1280/4848). NoV was detected in all age groups, with the 7–12 months group having the highest detection rate (655/2014, 32.5%). NoV was detected during most part of the year with higher frequency in winter than other seasons. Based on the genetic analysis of RdRp, GII. Pe was the most predominant genotype detected at 70.7% (381/539) followed by GII.P12 at 25.4% (137/539). GII.4 was the most predominant capsid genotype detected at 65.3% (338/518) followed by GII.3 at 26.8% (139/518). Based on the genetic analysis of RdRp and capsid sequences, the strains were clustered into 10 RdRp–capsid genotypes: GII.Pe-GII.4 Sydney 2012 (65.5%), GII.P12-GII.3 (27.2%), GII.P16-GII.2 (1.8%), GII.P12-GII.2 (0.2%), GII.P17-GII.17 (1.1%), GII.Pe-GII.3 (1.8%), GII.Pe-GII.2 (1.1%), GII.Pe-GII.1 (0.4%), GII.16-GII.4 Sydney 2012 (0.7%), and GII.P7-GII.6 (0.2%). The predominant NoV genotypes changed from GII.Pe-GII.4 Sydney 2012 and GII.P12-GII.3 between August 2018 and July 2019 to GII.Pe-GII.4 Sydney 2012 and GII.P16-GII.2 between August 2019 and July 2020. The patients with GII.Pe-GII.4 Sydney 2012 genotype were more likely to suffer from vomiting symptom than those with GII.P12-GII.3. Conclusions NoV is an important pathogen responsible for viral AGE among children in China. GII.Pe-GII.4 Sydney 2012 and GII.P12-GII.3 were major recombinant genotypes. Knowledge of circulating genotypes and seasonal trends is of great importance for disease prevention and surveillance.

BackgroundNeural tube defects (NTDs) are birth defects of the brain, spine, or spinal cord invoked by the insufficient intake of folic acid in the early stages of pregnancy and have a complex etiology involving both genetic and environmental factors. So the study aimed to explore the association between alterations in maternal one-carbon metabolism and NTDs in the offspring.MethodsWe conducted a case-control study to get a deeper insight into this association, as well as into the role of genetic polymorphisms. Plasma concentrations of folate, homocysteine (Hcy), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) and genotypes and alleles distributions of 52 SNPs in 8 genes were compared for 61 women with NTDs-affected offspring and 61 women with healthy ones.ResultsThere were significant differences between groups with regard to plasma folate, SAM, SAH and SAM/SAH levels. Logistic regression results revealed a significant association between maternal plasma folate level and risk of NTDs in the offspring. For MTHFD1 rs2236225 polymorphism, mothers having GA genotype and A allele exhibited an increased risk of NTDs in the offspring (OR = 2.600, 95%CI: 1.227–5.529; OR = 1.847, 95%CI: 1.047–3.259). For MTHFR rs1801133 polymorphism, mothers having TT and CT genotypes were more likely to affect NTDs in the offspring (OR = 4.105, 95%CI: 1.271–13.258; OR = 3.333, 95%CI: 1.068–10.400). Moreover, mothers carrying T allele had a higher risk of NTDs in the offspring (OR = 1.798, 95%CI: 1.070–3.021). For MTRR rs1801394 polymorphism, the frequency of G allele was significantly higher in cases than in controls (OR = 1.763, 95%CI: 1.023–3.036). Mothers with NTDs-affected children had higher AG genotype in RFC1 rs1051226 polymorphism than controls, manifesting an increased risk for NTDs (OR = 3.923, 95%CI: 1.361–11.308).ConclusionFolic acid deficiency, MTHFD1 rs2236225, MTHFR rs1801133, MTRR rs1801349 and RFC1 rs1051226 polymorphisms may be maternal risk factors of NTDs.

The BHMT gene rs3733890, RFC1 gene rs1051266 and MTR gene rs1805087 were associated with the occurrence of NTDs in Han population of Northern China. It was confirmed that the gene variation related to OCM was one of the susceptibility factors for NTDs.

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