Objective: To analyze the molecular epidemiology, genetic variations and evolution of enterovirus 71 (EV71) strains isolated in Jiangsu Province from 2009 to 2018. Methods: Statistical methods were used to analyze the data about epidemiological characteristics and results of pathogen detection in cases with EV71 infection in Jiangsu Province from 2009 to 2018. The complete VP1 sequences of 80 EV71 strains were amplified and sequenced for analysis of diversity and phylogenesis. Results: A total of 41 858 enterovirus-positive hand, foot and mouth disease cases were reported in Jiangsu Province from 2009 to 2018. EV71 was the predominant pathogen, accounting for 36.52%, and responsible for most of the severe cases. However, the percentage of EV71 among all pathogens gradually decreased over time. EV71 infection reached the peak in April to June and mainly occurred in children aged six months to five years old with higher incidence in males than in females. In terms of regional distribution, EV71 infections were characterized by area clustering in Jiangsu Province, mainly detected in Nanjing, Suzhou, Wuxi and Lianyungang. The 80 EV71 isolates belonged to C4a genotype. Nucleotide differences between them and three vaccine strains (H07, FY23 and FY7VP5)were 0.6%-5.5%, 0.8%-5.7% and 1.9%-6.9% and amino acid difference were 0-1.4%, 0.3%-2.0% and 0.3%-2.0%, respectively. Amino acid mutations in the epitopes of the 80 EV71 strains did not marked by years or regions. Conclusions EV71 strains showed obvious epidemiological characteristics in time, population and regional distribution in Jiangsu Province from 2009 to 2018.All of the 80 EV71 isolates belonged to C4a subgenotype. The nucleotide sequences between them and the vaccine strains varied greatly, but the homology of amino acids was relatively high, indicating the existence of some synonymous mutations and no risk of antigenic drift. This study would provide reference for EV71 vaccination in Jiangsu Province.

Objective:To investigate changes in the expression of Cosmc and T-synthase in peripheral B lymphocytes and in serum levels of galactose-deficient IgA1 (Gd-IgA1) in patients with Henoch-Sch?nlein purpura (HSP) .Methods:From January to August 2014, 56 patients with HSP were collected from outpatient or inpatient department of dermatology and venereology in the Second Hospital of Hebei Medical University, and were divided into 4 groups, including skin type group (22 cases) , joint type group (9 cases) , abdominal type group (12 cases) and renal type group (13 cases) . Twenty healthy volunteers served as healthy controls. Real-time fluorescence-based quantitative PCR was performed to determine the mRNA expression of Cosmc and T-synthase in peripheral B lymphocytes, and a lectin-based enzyme-linked immunosorbent assay (ELISA) to detect the serum level of Gd-IgA1. Comparisons among multiple groups were performed using one-way analysis of variance or Kruskal-Wallis H test, multiple comparisons were performed using least significant difference (LSD) - t test or Nemenyi test, and correlation analysis was performed using Spearman rank correlation analysis. Results:There was a significant difference in the duration from disease onset to the clinic visit ( χ2= 26.19, P < 0.05) among the skin type group (6.27 ± 3.09 d) , joint type group (5.56 ± 3.05 d) , abdominal type group (6.75 ± 3.75 d) , and renal type group (26.23 ± 14.12 d) , and the duration from disease onset to the clinic visit was significantly longer in the renal type group than in the other 3 groups (all P < 0.05) . The Cosmc mRNA expression significantly differed among the skin type group, joint type group, abdominal type group, renal type group and healthy control group (0.849 ± 0.239, 0.767 ± 0.181, 0.719 ± 0.183, 0.459 ± 0.121, 1.146 ± 0.232, F= 23.37, P < 0.05) , was significantly lower in the 4 patient groups than in the healthy control group ( P < 0.01) , and lower in the renal type group than in the other 3 patient groups (all P < 0.01) . There was no significant difference in the T-synthase mRNA expression in peripheral B lymphocytes among the patient groups and healthy control group ( F= 1.05, P > 0.05) . The serum level of Gd-IgA1 significantly differed among the skin type group, joint type group, abdominal type group, renal type group and healthy control group ( F= 7.06, P < 0.05) . Moreover, the Gd-IgA1 level was significantly higher in the patient groups than in the healthy control group (all P < 0.05) , and higher in the renal type group than in the other 3 patient groups (all P < 0.05) . The serum level of Gd-IgA1 in the HSP patients was significantly and negatively correlated with the mRNA expression of Cosmc ( rs=-0.50, P < 0.01) . Conclusion:Decreased mRNA expression of Cosmc and increased serum levels of Gd-IgA1 were observed in patients with HSP, and there was a negative correlation between the two indices.

Objective:To understand the relationship between the RNA shedding time of SARS-CoV-2 infected persons and the single nucleotide mutation of the virus, the population of infected persons, underlying diseases and other factors, so as to provide more clues for the study of SARS-CoV-2 infection dynamics.Methods:The data of epidemiology, clinical manifestations, and underlying diseases of infected persons in a cluster epidemic of COVID-19 in Jiangsu province from July to September 2021 were collected. Nasopharyngeal swab samples of cases were collected, and the whole genome of the virus was sequenced by second-generation sequencing technology. The online analysis platform was used to judge the virus type and analyze the mutation site, and Cox proportional risk model was used to analyze the relationship between the RNA shedding time of SARS-CoV-2 and various research factors.Results:There were 350 persons who finally obtained the whole genome sequence of the virus in this COVID-19 outbreak, of which 60.3% were female, the median age was 49 years old (interquartile range, IQR: 37-65 years old)), and the median time of virus shedding was 33 days ( IQR, 26-44 days). The whole-genome sequencing analysis showed that compared with the Wuhan reference strain sequence, the infected persons’ sequence had 34~41 nucleotide mutation sites, belonging to VOC/Delta variant (B.1.617.2 evolutionary branch), and C346T, C1060T, T2803C, T7513C, A29681C were the main single nucleotide polymorphisms (SNPs) of this epidemic. Cox regression analysis showed that age, underlying disease, clinical classification, vaccination, SNP T2803C and T7513C had an impact on the RNA shedding time of SARS-CoV-2. The adjusted multivariate Cox regression result showed that age [ HR=0.73, 95% CI (0.55, 0.95)] and T7513C [ HR=0.37, 95% CI (0.18, 0.77)] were still the risk factors for the extension of SARS-CoV-2 RNA shedding time. Conclusions:This study analyzed the effects of the individual factors and viral single nucleotide variations on the time of viral RNA shedding. Those who were older, suffered from hypertension, had more severe clinical symptoms, were not vaccinated or incompletely vaccinated, and had T7513C mutation in the infected virus, had a risk of a long RNA shedding time of SARS-CoV-2, which should be given special attention and follow-up after rehabilitation.