Objective To determine the persistence time of genotype 4 hepatitis E (HE) viremia after the onset of clinical symptoms in HE patients and provide essential data for study on HE epidemiologieal transmission, so that to evaluate potential contagiousness of HE patients after clinical stage. Methods The first serum samples from 162 HE patients after hospitalized in Eastern China were collected and tested for hepatitis E virus (HEV) RNA by nested reversed transcription- polymerase chain reaction (RT-PCR). The persistence time of HEV viremia after the onset of clinical symptoms was estimated with Kaplan-Meier survival analysis. Results HEV RNA was detectable in 101 out of 162 serum samples with positive rate of 62.35%, which was all grouped to genotype 4 by homology analysis. Furthermore, HEV RNA was detectable in 74 (64.91%) out of 114 male and 27 (56.25%) out of 48 female, which was not significantly different (χ2 = 1.08, P=0. 30). Kaplan-Meier survival analysis showed that the median persistence time of HEV genotype 4 viremia was 24 days after the onset of clinical symptoms (95% CI: 18-30 days), which meant that the viremia of 50% HE patients remaining detectable up to 24 days after the onset. The 75% and 25% percentiles were 14 days and 31 days, respectively. There was no significant difference of viremia persistence time between male and female (Breslow test: P=0.98, Tarone-Ware test: P=0.91). Conclusions The viremia of 75% patients with HEV genotype 4 infection could persistent until 2 weeks after the onset of clinical symptoms and that of some patients could persistent over 1 month. It is indicated that the viremia is still persistent and HE patient could be a reservoir even after the clinical symptoms disappeared and biochemical marks normalized.

Objective To investigate awareness and influencing factors of human papilloma virus (HPV)self-sampling for cervical cancer screening of female in Shenzhen.Methods A total of 544 female,who during July 2014 to June 2015,participated in live and online HPV self-sampling detection organized by our hospital,were surveyed by self-designed questionnaire.Their epidemiological data,HPV and cervical cancer related knowledge,awareness of HPV self-sampling for cervical cancer screening,their attitude,willingness and acceptance to HPV self-sampling for cervical cancer screening were investigated.Effects of awareness of HPV self-sampling to the cervical cancer screening and main influencing factors were analyzed.Results Among the 544 women,47.1% were aware of HPV;22.8% were aware of what diseases could be caused by HPV;12.5%had heard of and done by themselves self-sampling for cervical cancer screening;only 6.3% had heard of and participated in online self-sampling for cervical cancer screening.Women,who were enterprise /corporate white collar/independent enterprise manager or whose monthly income was over 30,000 yuan,were less aware of HPV self-sampling than other women (χ2 =13.058,12.626;P <0.05).81.6% of the female were apparently inclined to be sampled by doctors,and only 7.0% of the female believed that credibility of self-sampling screening was above 80%.The biggest concern about online self-sampling was mainly metamorphic specimens during transport,pollution,etc.Conclusions Awareness of female in Shenzhen about HPV and HPV self-sampling cervical cancer screening are relatively low.Intervention should be emphasized in reliability degree of self-sampling result,discomfort degree of sampling,complexity,specimen preservation,transport and result feedback.

Objective:To evaluate the characteristics of vaginal flora between normal and abnormal pregnant women throughout pregnancy.Methods:Vaginal swab specimens were collected from pregnant women in the first (<14 gestation weeks, GW), second (14~28 GW) and third trimester (>28 GW) in Anqing, Anhui Province from February 2018 to February 2020. Pregnant women were divided into normal and abnormal groups according to all clinical diagnosis. The sequences of 16S rRNA gene (V3-V4) from vaginal swabs were analyzed using QIIME2 platform. The differences in the dominance of Lactobacillus, community state type (CST) transition, Alpha diversity and Beta diversity were analyzed. Diversity data after log transition were used in the analysis of linear mixed model. Results:A total of 34 pregnant women (10 normal and 24 abnormal) with 102 samples were included for analysis. The composition of vaginal flora between two groups: the relative abundance of Lactobacillus was the highest at the genus level and Lactobacillus crispatus and Lactobacillus iners was the top two species with high relative abundance. The dominance of Lactobacillus, Alpha diversity and transition of CST were also similar. Both groups had a gradually decreased trend of Alpha diversity with GW, and the Chao1, Observed species and Faith′s PD indexes′ were different in different GW ( P<0.05). All Beta diversity metrics in normal group had descending trend, with lower value of the index of first distance which implied a higher microbiota stability, while Bray-Curtis, Weighted UniFrac distance had ascending trend in abnormal group, indicating lower stability. Jaccard distance′s first distance was statistically differed among GW and Unweighted UniFrac distance′s differed between normal and abnormal groups. Conclusions:The first distance of Unweighte UniFrac distance in abnormal pregnant women is higher than that of normal pregnant women and the vaginal flora in abnormal group has lower stability.

Objective:To study the characteristics of vaginal microbiota in pregnant women with premature rupture of membranes (PROM) and to establish prediction models for PROM.Methods:This study involved 35 women with preterm premature rupture of membranes (PPROM), 180 with term premature rupture of membranes (TPROM) and 255 term birth cases without premature rupture of membranes (TBWPROM, control group). The V3-V4 hypervariable region sequences in the vaginal samples collected at 16-28 weeks of gestation were detected by 16S rRNA gene next-generation sequencing. The differences in Alpha and Beta diversity, and the attributes and metabolic function prediction of each recognized species among the three groups were analyzed. Subsequently, a random forest model was used to establish the prediction models for PROM using vaginal microbiota species and environmental risk factors.Results:Compared with the control group, the Alpha diversity of the PPROM group was higher (Observed features, P=0.022; Faith_pd index, P=0.024) and Beta diversity was also significantly different (Unweighted UniFrac, P=0.010; Jaccard index, P=0.008). In PPROM cases, Megasphaera genomosp. typeⅠ was significantly increased ( P=0.017) and Lactobacillus mulieris was significantly decreased ( P=0.003). In the patients with TPROM, Megasphaera was significantly increased ( P=0.009) and Lactobacillus mulieris was significantly decreased ( P=0.002). In terms of functional pathways, sulfur oxidation ( P=0.021), methanogenesis from acetate ( P=0.036), L-histidine biosynthesis ( P=0.009), adenosylcobalamin biosynthesis ( P=0.041) and fucose degradation ( P=0.001) were significantly increased in patients with PPROM; L-histidine biosynthesis ( P<0.001) and fucose degradation ( P=0.030) were significantly increased in patients with TPROM. The prediction models were established using the random forest model with vaginal microbiota species and environmental risk factors and the prediction model for PPROM performed well [AUC: 0.739 (95%CI: 0.609-0.869), sensitivity: 0.928, specificity: 0.659, positive predictive value: 0.750, negative predictive value: 0.906], which had a certain reference value. Conclusions:Vaginal microbiota might be related to the development and progression of PROM. Studying the differences in vaginal microbiota might provide a new idea for the prevention and treatment of PROM. Functional prediction provided a direction for further research on the mechanism of PROM. The established prediction model could prevent the occurrence of PPROM and promote maternal and infant health.

Objective Intrahepatic cholestasis during pregnancy (ICP) and its relation to incidence of preterm birth (PTB) were under study.Methods A prospective cohort study was carried out that including all the hospitalized pregnant women with live singleton births,from January 2014 to March 2015 in Anqing Municipal Hospitals.Informed consent was followed in every pregnant woman with related demographic information collected through questionnaire and hospital electronic medical record system.Both univariate and multi-variate statistical methods were used to analyze the relations between ICP and incidence of PTB.Results A total of 2 758 pregnant women were included in this study.The incidence proportions of ICP and PTB appeared as 7.25％ and 16.28％ respectively.Results from the logistic regression analysis showed that ICP increased the risk of both overall PTB (RR=2.33,95％CI:1.67-3.25) and medically indicated PTB (RR=8.46,95％CI:5.45-13.12),but not the spontaneous PTB (RR=0.94,95％CI:0.57-1.54).Conclusion ICP seemed to have increased the risk on medically indicated PTB but not the spontaneous PTB.

Objective:To study the characteristics and influencing factors of vaginal microbiota in normal pregnant women.Methods:This study was based on a cohort of pregnant women established in Anqing Municipal Hospital Affiliated to Anhui Medical University from February 2018 to February 2020. Vaginal samples of normal pregnant women who met the inclusion and exclusion criteria were ordered by the gestational weeks at sampling. Five samples were randomly selected from each gestational week group and if the samples were less than five, all samples were included. Sequencing of the V3-V4 region of the 16S rRNA gene was performed. Dominant species were analyzed by MicrobiomeAnalyst. Alpha diversity was measured with Chao1, Observed Features, Shannon diversity, Simpson diversity, Faith_pd and Pielou′s Evenness. The dominant status of Lactobacillus was also described and compared. Multiple linear regression and logistic regression were used to analyze the factors influencing vaginal microbiota. Analysis of variance and Kruskal Wallis test were used for statistical analysis of continuous variables, and Chi-square test and Fisher′s exact test were used for categorical data. The differences were considered statistically significant when the P value was less than 0.05. Results:This study enrolled 91 pregnant women (91 vaginal samples) with an average age of (27.37±3.60) years. There were 18, 56 and 17 vaginal samples collected at the median gestational age of 11.93 weeks (the first trimester), 19.43 weeks (the second trimester) and 38.29 weeks (the third trimester), respectively. The relative abundance of Firmicutes and Lactobacillus was 91.30% and 87.67%, respectively. Lactobacillus iners and Lactobacillus crispatus had a relative abundance of 43.95% and 36.33%, respectively. Moreover, Lactobacillus iners-dominated vaginal microbiota was detected in all trimesters. The number of samples with high relative abundance of Lactobacillus iners gradually decreased with gestational age. Lactobacillus crispatus-dominated vaginal microbiota was found in the second and third trimesters and the number of samples with high relative abundance gradually increased during pregnancy. The Alpha diversity of vaginal microbiota had a decreasing trend during the gestation. There were significant differences in Pielou′s Evenness diversity index of vaginal microbiota between different smoking groups ( P<0.05) and in Shannon diversity index between different drinking groups ( P<0.05). There were significant differences in Chao1, Observed Features and Faith_pd diversity index of vaginal microbiota between pregnant women with different education ( P<0.05) and in Shannon and Simpson diversity index between different income groups ( P<0.05). Conclusions:Vaginal microbiota was dominated by Lactobacillus in normal pregnant women. The dominance of Lactobacillus iners gradually decreased, while that of Lactobacillus crispatus increased during gestation. In normal pregnant women, the Alpha diversity of vaginal microbiota was correlated with smoking, drinking, education and family annual income. Smoking cessation and drinking before pregnancy were related to lower Alpha diversity of vaginal microbiota in pregnant women, while lower education and higher family income were associated with higher Alpha diversity.

Observation and experiment and their related connotations and concepts remain vague, which affects the correct understanding of research design and the judgment of the validity of causal inference. This article borrows the concept of phase transition in physics, combines causal thinking and causal diagrams, firstly establishes the relationships among the attribute, state, event, and phenomenon, and then identifies two ways with the opposite causal structures to acquire phenomena—human observations and human manipulated experiments. In causal inference, the ways mentioned above, intervention and assignment of exposure are affected by their own causal mechanisms. Finally, intervention is a causal concept, a core link among known phenomena, unknown phenomena available for measurement, and natural causality. Based on this, the two strategies in classifying research design are analyzed, and intervention method and non-intervention method are proposed, as is comprehensive and concise. Observations and experiments provide the basis for all scientific knowledge and should be viewed as concepts with a unified connotation. The accurate classification of research designs based on the law of causality and measurement process may be one of the best options worthy of in-depth study.

Objective To evaluate and compare the detection consistency of hepatitis B surface antigen (HBsAg) by two immunoassays: enzyme-linked immunosorbent assay (ELISA) and electrochemiluminescent immunoassay (ECLIA). Methods A prospective study was conducted among 2296 pregnant women recruited consecutively from January 1, 2014 to January 31, 2015 in a hospital. Blood samples were collected from them for the detection of HBsAg by using ELISA and ECLIA, Ka ppa test was performed on the results. Nested polymerase chain reaction and sequencing of HBV S gene were also performed in all samples. Phylogenetic analysis was performed using Mega 6.0 software. Results The two methods had high detection consistence of HBsAg ( Ka ppa=0.71). There were significant differences in detection result of B genotype and adw2 serotype HBV strains between two methods. Among 123 identified HBV strains, 113 belonged to genotype B and available for further analysis. The difference in detection of substitution rates between two methods or different positive groups were not significant. Compared with ELISA single positive group, the ECLIA single positive group had completely different substitution sites. Conclusion The two methods had high detection consistence of HBsAg, but there were still 32.4% HBV DNA positive cases in ELISA/ECLIA single positive group, and complete complementary substitution sites between ELISA single positive group and ECLIA single positive group. Our results suggested that more effective detection procedure should be considered for the possible impact of the HBV silent transmission and infection.