Estimating the transmissibility of hepatitis C: A modelling study in Yichang City, China.

Yichang is a city in central China in the Hubei Province. This study aimed to estimate the dynamics of the transmissibility of hepatitis C using a mathematical model and predict the transmissibility of hepatitis C in 2030. Data of hepatitis C cases from 13 counties or districts (cities) in Yichang from 2008 to 2016 were collected. A susceptible-infectious-chronic-recovered (SICR) model was developed to fit the data. The transmissibility of hepatitis C at the counties or districts was calculated based on new infections (including infected or chronically infected cases) reported monthly in the city caused by one infectious individual (MNI). The trend of the MNI was fitted and predicted using 11 models, with the coefficient of determination (R2 ) was being used to test the goodness of fit of these models. A total of 3065 cases of hepatitis C were reported in Yichang from 2008 to 2016. The median MNI of Yichang was 0.0768. According to the fitting results and analysis, the trend of transmissibility of hepatitis C in Yichang City conforms with the logarithmic (R2  = 0.918, p < 0.001):MNI = 0.265-0.108 log(t) and exponential (R2  = 0.939, p < 0.001): MNI = 0.344e(-0.278t) models. Hence, the transmission of hepatitis C virus at the county level has a downward trend. In conclusion, the transmissibility of hepatitis C in Yichang has a downward trend. With the current preventive and control measures in place, the spread of hepatitis C can be controlled.

Evaluating the effectiveness of measures to control the novel coronavirus disease 2019 in Jilin Province, China.

BACKGROUND: Based on differences in populations and prevention and control measures, the spread of new coronary pneumonia in different countries and regions also differs. This study aimed to calculate the transmissibility of coronavirus disease 2019 (COVID-19), and to evaluate the effectiveness of measures to control the disease in Jilin Province, China. METHODS: The data of reported COVID-19 cases were collected, including imported and local cases from Jilin Province as of March 14, 2019. A Susceptible-Exposed-Infectious-Asymptomatic-Recovered/Removed (SEIAR) model was developed to fit the data, and the effective reproduction number (Reff) was calculated at different stages in the province. Finally, the effectiveness of the measures was assessed. RESULTS: A total of 97 COVID-19 infections were reported in Jilin Province, among which 45 were imported infections (including one asymptomatic infection) and 52 were local infections (including three asymptomatic infections). The model fit the reported data well (R2 = 0.593, P < 0.001). The Reff of COVID-19 before and after February 1, 2020 was 1.64 and 0.05, respectively. Without the intervention taken on February 1, 2020, the predicted cases would have reached a peak of 177,011 on October 22, 2020 (284 days from the first case). The projected number of cases until the end of the outbreak (on October 9, 2021) would have been 17,129,367, with a total attack rate of 63.66%. Based on the comparison between the predicted incidence of the model and the actual incidence, the comprehensive intervention measures implemented in Jilin Province on February 1 reduced the incidence of cases by 99.99%. Therefore, according to the current measures and implementation efforts, Jilin Province can achieve good control of the virus's spread. CONCLUSIONS: COVID-19 has a moderate transmissibility in Jilin Province, China. The interventions implemented in the province had proven effective; increasing social distancing and a rapid response by the prevention and control system will help control the spread of the disease.

The transmissibility of hepatitis C virus: a modelling study in Xiamen City, China.

This study aimed at estimating the transmissibility of hepatitis C. The data for hepatitis C cases were collected in six districts in Xiamen City, China from 2004 to 2018. A population-mixed susceptible-infectious-chronic-recovered (SICR) model was used to fit the data and the parameters of the model were calculated. The basic reproduction number (R0) and the number of newly transmitted cases by a primary case per month (MNI) were adopted to quantitatively assess the transmissibility of hepatitis C virus (HCV). Eleven curve estimation models were employed to predict the trends of R0 and MNI in the city. The SICR model fits the reported HCV data well (P < 0.01). The median R0 of each district in Xiamen is 0.4059. R0 follows the cubic model curve, the compound curve and the power function curve. The median MNI of each district in Xiamen is 0.0020. MNI follows the cubic model curve, the compound curve and the power function curve. The transmissibility of HCV follows a decreasing trend, which reveals that under the current policy for prevention and control, there would be a high feasibility to eliminate the transmission of HCV in the city.

Epidemiological characteristics and transmissibility of shigellosis in Hubei Province, China, 2005 - 2017.

BACKGROUND: Shigellosis is one of the main diarrhea diseases in developing countries. However, the transmissibility of shigellosis remains unclear. METHODS: We used the dataset of shigellosis cases reported between January 2005 and December 2017, from Hubei Province, China. A mathematical model was developed based on the natural history and the transmission mechanism of the disease. By fitting the data using the model, transmission relative rate from person to person (b) and from reservoir to person (bw), and the effective reproduction number (Reff) were estimated. To simulate the contribution of b and bw during the transmission, we performed a "knock-out" simulation in four scenarios: A) b = 0 and bw = 0; B) b = 0; C) bw = 0; D) control (no intervention). RESULTS: A total of 130,770 shigellosis cases were reported in Hubei province, among which 13 cases were dead. The median annual incidence was 19.96 per 100,000 persons (range: 5.99 per 100,000 persons - 29.47 per 100,000 persons) with a decreased trend (trend χ2 = 25,470.27, P < 0.001). The mean values of b and bw were 0.0898 (95% confidence interval [CI]: 0.0851-0.0946) and 1.1264 × 10- 9 (95% CI: 4.1123 × 10- 10-1.8416 × 10- 9), respectively. The "knock-out" simulation showed that the number of cases simulated by scenario A was almost the same as scenario B, and scenario C was almost the same as scenario D. The mean value of Reff of shigellosis was 1.19 (95% CI: 1.13-1.25) and decreased slightly with a Linear model until it decreased to an epidemic threshold of 0.99 (95% CI: 0.65-1.34) in 2029. CONCLUSIONS: The incidence of shigellosis is still in high level. The transmissibility of the disease is low in Hubei Province. The transmission would be interrupted in the year of 2029.

Feasibility of containing shigellosis in Hubei Province, China: a modelling study.

BACKGROUND: The transmission features and the feasibility of containing shigellosis remain unclear among a population-based study in China. METHODS: A population-based Susceptible - Exposed - Infectious / Asymptomatic - Recovered (SEIAR) model was built including decreasing the infectious period (DIP) or isolation of shigellosis cases. We analyzed the distribution of the reported shigellosis cases in Hubei Province, China from January 2005 to December 2017, and divided the time series into several stages according to the heterogeneity of reported incidence during the period. In each stage, an epidemic season was selected for the modelling and assessing the effectiveness of DIP and case isolation. RESULTS: A total of 130,770 shigellosis cases were reported in Hubei Province. The median of Reff was 1.13 (range: 0.86-1.21), 1.10 (range: 0.91-1.13), 1.09 (range: 0.92-1.92), and 1.03 (range: 0.94-1.22) in 2005-2006 season, 2010-2011 season, 2013-2014 season, and 2016-2017 season, respectively. The reported incidence decreased significantly (trend χ2 = 8260.41, P <  0.001) among four stages. The incidence of shigellosis decreased sharply when DIP implemented in three scenarios (γ = 0.1, 0.1429, 0.3333) and when proportion of case isolation increased. CONCLUSIONS: Year heterogeneity of reported shigellosis incidence exists in Hubei Province. It is feasible to contain the transmission by implementing DIP and case isolation.

Relative transmissibility of hand, foot and mouth disease from male to female individuals.

Hand, foot and mouth disease (HFMD) has spread widely and leads to high disease burden in many countries. However, relative transmissibility from male to female individuals remains unclear. HFMD surveillance database was built in Shenzhen City from 2013 to 2017. An intersex transmission susceptible-infectious-recovered model was developed to calculate the transmission relative rate among male individuals, among female individuals, from male to female and from female to male. Two indicators, ratio of transmission relative rate (Rß) and relative transmissibility index (RTI), were developed to assess the relative transmissibility of male vs. female. During the study period, 270 347 HFMD cases were reported in the city, among which 16 were death cases with a fatality of 0.0059%. Reported incidence of total cases, male cases and female cases was 0.0057 (range: 0.0036-0.0058), 0.0052 (range: 0.0032-0.0053) and 0.0044 (range: 0.0026-0.0047), respectively. The difference was statistically significant between male and female (t = 3.046, P = 0.002). Rß of male vs. female, female vs. female, from female to male vs. female and from male to female vs. female was 7.69, 1.00, 1.74 and 7.13, respectively. RTI of male vs. female, female vs. female, from female to male vs. female and from male to female vs. female was 3.08, 1.00, 1.88 and 1.43, respectively. Transmissibility of HFMD is different between male and female individuals. Male cases seem to be more transmissible than female.

Detecting influenza and emerging avian influenza virus by influenza and pneumonia surveillance systems in a large city in China, 2005 to 2016.

BACKGROUND: Detecting avian influenza virus has become an important public health strategy for controlling the emerging infectious disease. METHODS: The HIS (hospital information system) modified influenza surveillance system (ISS) and a newly built pneumonia surveillance system (PSS) were used to monitor the influenza viruses in Changsha City, China. The ISS was used to monitor outpatients in two sentinel hospitals and to detect mild influenza and avian influenza cases, and PSS was used to monitor inpatients in 49 hospitals and to detect severe and death influenza cases. RESULTS: From 2005 to 2016, there were 3,551,917 outpatients monitored by the ISS system, among whom 126,076 were influenza-like illness (ILI) cases, with the ILI proportion (ILI%) of 3.55%. After the HIS was used, the reported incident cases of ILI and ILI% were increased significantly. From March, 2009 to September, 2016, there were 5,491,560 inpatient cases monitored by the PSS system, among which 362,743 were pneumonia cases, with a proportion of 6.61%. Among pneumonia cases, about 10.55% (38,260/362,743) of cases were severe or death cases. The pneumonia incidence increased each year in the city. Among 15 avian influenza cases reported from January, 2005 to September, 2016, there were 26.7% (4/15) mild cases detected by the HIS-modified ISS system, while 60.0% (9/15) were severe or death cases detected by the PSS system. Two H5N1 severe cases were missed by the ISS system in January, 2009 when the PSS system was not available. CONCLUSIONS: The HIS was able to improve the efficiency of the ISS for monitoring ILI and emerging avian influenza virus. However, the efficiency of the system needs to be verified in a wider area for a longer time span in China.

Seasonality of the transmissibility of hand, foot and mouth disease: a modelling study in Xiamen City, China.

This study attempts to figure out the seasonality of the transmissibility of hand, foot and mouth disease (HFMD). A mathematical model was established to calculate the transmissibility based on the reported data for HFMD in Xiamen City, China from 2014 to 2018. The transmissibility was measured by effective reproduction number (Reff) in order to evaluate the seasonal characteristics of HFMD. A total of 43 659 HFMD cases were reported in Xiamen, for the period 2014 to 2018. The median of annual incidence was 221.87 per 100 000 persons (range: 167.98/100,000-283.34/100 000). The reported data had a great fitting effect with the model (R2 = 0.9212, P < 0.0001), it has been shown that there are two epidemic peaks of HFMD in Xiamen every year. Both incidence and effective reproduction number had seasonal characteristics. The peak of incidence, 1-2 months later than the effective reproduction number, occurred in Summer and Autumn, that is, June and October each year. Both the incidence and transmissibility of HFMD have obvious seasonal characteristics, and two annual epidemic peaks as well. The peak of incidence is 1-2 months later than Reff.

[Relationship Between LEP G2548A Polymorphism and Cholesterol Gallstone].

OBJECTIVES: To determine the associations of single nucleotide polymorphism (SNP) in leptin (LEP) genes and environmental factors with cholesterol gallstone in southeast Han populations. METHODS: A 1:2 matched case-control study was conducted involving 200 patients with cholesterol gallstone. Genotyping of the SNP was examined on the LightCycler480 PCR platform using in-house high resolution melting (HRM) approaches. Detection correctness was validated through direct sequencing. Multifactor dimensionality reduction (MDR) analysis was applied to examine the effects of potential gene-environment interactions. RESULTS: Three genotypes of LEP G2548A were obtained by HRM genotyping, including 52 cases of GG wild type, 192 cases of GA mutant heterozygosity and 356 cases of AA mutation homozygous type. The genotype distribution of the SNP locus in the control group was in line with the Hardy-Weinberg genetic balance (P>0.05). The AA genotype carriers of LEP G2548A had significantly higher serum leptin than the GA/GG genotype carriers (H=6.83, P<0.05). The conditional logistic regression revealed that high serum leptin [odds ratio (OR)=5.012, 95% confidence interval (CI): 3.248-7.734], AA genotype of LEP G2548A site (OR=2.292, 95%CI: 1.012-5.193), family history of gallstones (OR=2.984, 95%CI: 1.329-6.700), high SBP (OR=1.927, 95%CI: 1.140-3.255) and smoking (OR=1.717, 95%CI: 1.006-2.928) were predictors of cholesterol gallstone. However, regular drinking of strong tea (OR=0.552, 95%CI: 0.336-0.907) and exercise (OR=0.591, 95%CI: 0.395-0.882) were protecting factors for cholesterol gallstone. The results of MDR analysis indicated that tea drinking, genotype of LEP G2548A site and serum leptin formed the optimal gene-environment interaction model. CONCLUSIONS: Individuals who drink less tea, carry AA genotype and have high serum leptin are more susceptible to cholesterol gallstone.

[Levels of phthalate internal exposure levels in pregnant women and influencing factors].

OBJECTIVE: To investigate the levels and influencing factors of phthalate internal exposure in pregnant women (gestation age ≤ 16 weeks). METHODS: During April to June in 2013, 1 020 pregnant women (gestation age ≤ 16 weeks) who had established the maternal care manual were recruited in maternal and child health hospital of Siming District, Xiamen city. Participators were asked to complete a questionnaire to obtain information on socio-demographic characteristics, lifestyle behaviors, and antenatal examination and to provide a urine sample. Finally, 998 pregnant women who provided a urine sample and completed the questionnaire were enrolled. Adopting systematic sampling method, 100 ones were selected randomly among 998 pregnant women. High performance liquid chromatography-electrospray ionization-tandern mass was used to determine the concentration of five phthalate monoesters in each urine, including mono-n-methyl phthalate (MMP), mono-ethyl phthalate (MEP), mono-butyl phthalate (MBP), mono-benzyl phthalate (MBzP), mono-ethylhexyl phthalate (MEHP). Based on the measurements and questionnaire data, multivariate logistic regression was used to analyze the association between the phthalate monoester levels and potential influential factors. RESULTS: The detection rates of MMP, MEP, MBP, MBzP and MEHP in 100 pregnant urine samples were 94%, 93%, 87%, 83%, 99%, respectively. And the urinary median uncorrected concentrations of MMP, MEP, MBP, MBzP and MEHP in 100 urine samples were 20.56, 17.62, 10.15, 2.03, and 5.12 ng/ml, respectively. Specific gravity-corrected concentration were 20.81, 20.36, 12.88, 2.58, 5.00 ng/ml, respectively. The results of multivariate logistic regression analysis indicated that: education degree was negatively associated with urinary concentration of MMP, MEP, MBP, MBzP and MEHP, OR (95% CI) were 0.495 (0.253-0.966), 0.380 (0.191-0.755), 0.379 (0.186-0.774), 0.401 (0.196-0.819), 0.373(0.183-0.762), respectively. Participants who had hair permed and dyed during pregnancy had higher urinary level of MBP and MBzP, OR (95% CI) were 12.867 (1.240-133.525), 15.982 (1.367-186.911), respectively; Participants who use cosmetics during pregnancy had higher urinary level of MEP and MBP, OR (95% CI) were 2.977 (1.012-8.757), 4.440 (1.485-13.272), respectively; plastic bottled water consumption was positively associated with urinary concentrations of MEP and MEHP, OR (95% CI) were 3.780 (1.417-10.083), 2.699 (1.039-7.010), respectively; annual household income was negatively associated with urinary concentration of MMP, OR (95% CI) was 0.597 (0.372-0.959); individuals who took medications during pregnancy had higher urinary level of MEHP than non-takers, OR (95% CI) was 4.853 (1.084-21.732). CONCLUSION: Pregnant women whose gestation age was less than 16 weeks are generally exposed to phthalate. Phthalate internal exposure levels are significantly associated with most measured factors and the influencing factors with different phthalates internal exposure levels are different.

[Diagnostic value of serum Golgi protein-73 (GP73) combined with AFP-L3% in hepatocellular carcinoma: a meta-analysis].

OBJECTIVE: To investigate the diagnostic value of serum Golgi protein-73 (GP73) combined with the AFP-L3% test for hepatocellular carcinoma. METHODS: Comprehensive electronic and manual searches were performed to retrieve relevant studies on GP73 combined with AFP-L3% for diagnosis of hepatocellular carcinoma. After screening of the studies according to inclusion criteria and extraction of the data,meta-analysis was performed in Meta-disc 1.4 and Stata 12.0. RESULTS: Eleven studies that met the inclusion criteria were selected from the total 138 references with potential relevance.The threshold effect was not found in the GP73 combined with AFP-L3% for the diagnosis of liver cancer.However,heterogeneity was found in this meta-analysis. The pooled sensitivity and specificity of GP73 combined with AFP-L3% was 0.853 and 0.960 respectively. The area under summary receiver operating characteristics curve was 0.948, and the Q index was 0.888. CONCLUSION: GP73 combined with AFP-L3% can significantly improve the diagnostic sensitivity and specificity to a high level, and can improve the diagnosis rate of hepatocellular carcinoma.

[Exposure risk assessment of plasticizer in dietary food in Xiamen].

OBJECTIVE: To understand the dietary consumption of residents in Xiamen and the content of phthalic acid esters (PAEs) in food, and to assess the plasticizer exposure risk of diet in Xiamen. METHODS: The survey was conducted by stratified cluster random sampling method in Xiamen from September to October in 2010. According to the Xiamen administrative division, six neighborhood communities were selected as sampling units, then 25 families were randomly chosen from each sampling units.From the above 150 families, the permanent residents over the age of six were permitted to our study. The survey included 495 residents totally. These participants' information, such as basic personal information, physical activity levels, meal frequency and the average consumption of 33 kinds of food in 13 categories were collected using questionnaires. Thirteen categories included cereal and tubers, beans, vegetables, fungi and algae, fruits, dairy products, meat, seafood, eggs, snacks, beverages, cooking oil and spices. The height and weight of residents were measured and the average daily dietary intake was calculated. Thirty-three kinds of food in 13 categories were collected in supermarkets in Xiamen. According to the annual sales ranking, the top three-five brands of each kinds of food were selected and numbered, then two or three brands were chosen by random number table method from them; three completely individual packed samples in the same batch of each brand were detected; 243 samples were included in our study.100-500 g solid samples or 100-500 ml liquid samples were collected. The content of diethyl phthalate (DEP), dibutyl phthalate (DBP), di (2-ethylhexyl) phthalate (DEHP) in food were detected by liquid chromatography mass spectrometry, which expressed by median (minimum-maximum). The exposure dose, contribution rate and risk index of PAEs were calculated by point estimation method. RESULTS: According to the average daily dietary intake of residents in Xiamen, the top three ones in 13 categories of food were cereal and tubers (337.16 g/d, 18.21%), vegetables (309.12 g/d, 16.69%) and fruits (213.20 g/d, 11.51%). The content of DEP, DBP or DEHP among different categories of food was significantly different (χ² values were 58.05, 50.19 and 102.10, P < 0.01). Among 13 categories of food, seafood contained the most DEP (0.090 (0.000-0.324)mg/kg); cooking oil had the most DBP (0.700(0.000-2.980) mg/kg) and DEHP (5.115(0.000-24.160) mg/kg). DEP, DBP and DEHP exposure(0.19, 4.20, 18.10 µg × kg⁻¹ ×d ⁻¹)in dietary food in Xiamen were less than the reference dose(RfD) (800, 100, 20 µg × kg⁻¹ × d⁻¹) proposed by the United States Environmental Protection Agency (EPA), and the risk indexes were 0.02%, 4.20% and 90.50%, respectively. Among 13 categories of foods, seafood was the main source of DEP dietary exposure. The exposure dose and contribution rate of DEP in seafood were 0.18 µg × kg⁻¹ × d⁻¹ and 94.74%, respectively.Vegetables were the main source of DBP and DEHP dietary exposure. The exposure dose and contribution rate of DBP and DEHP were 1.48 µg × kg⁻¹ × d⁻¹, 35.24% and 6.07 µg × kg⁻¹ × d⁻¹, 33.54%, respectively. CONCLUSION: The food consumed by residents in Xiamen was overall in a safe state, but to some extent, there still exists DEHP exposure risk in foods.

Simulating potential outbreaks of Delta and Omicron variants based on contact-tracing data: A modelling study in Fujian Province, China.

Although studies have compared the relative severity of Omicron and Delta variants by assessing the relative risks, there are still gaps in the knowledge of the potential COVID-19 burden these variations may cause. And the contact patterns in Fujian Province, China, have not been described. We identified 8969 transmission pairs in Fujian, China, by analyzing a contact-tracing database that recorded a SARS-CoV-2 outbreak in September 2021. We estimated the waning vaccine effectiveness against Delta variant infection, contact patterns, and epidemiology distributions, then simulated potential outbreaks of Delta and Omicron variants using a multi-group mathematical model. For instance, in the contact setting without stringent lockdowns, we estimated that in a potential Omicron wave, only 4.7% of infections would occur in Fujian Province among individuals aged >60 years. In comparison, 58.75% of the death toll would occur in unvaccinated individuals aged >60 years. Compared with no strict lockdowns, combining school or factory closure alone reduced cumulative deaths of Delta and Omicron by 28.5% and 6.1%, respectively. In conclusion, this study validates the need for continuous mass immunization, especially among elderly aged over 60 years old. And it confirms that the effect of lockdowns alone in reducing infections or deaths is minimal. However, these measurements will still contribute to lowering peak daily incidence and delaying the epidemic, easing the healthcare system's burden.

A comparative study on epidemiological characteristics, transmissibility, and pathogenicity of three COVID-19 outbreaks caused by different variants.

OBJECTIVES: The Omicron BA.2 variant is probably the main epidemic strain worldwide at present. Comparing the epidemiological characteristics, transmissibility, and influencing factors of SARS-CoV-2, the results obtained in this paper will help to provide theoretical support for disease control. METHODS: This study was a historical information analysis, using the R programming language and SPSS 24.0 for statistical analysis. The Geoda and Arc GIS were used for spatial autocorrelation analysis. RESULTS: Local spatial autocorrelations of the incidence rate were observed in Delta and Omicron BA.1 outbreaks, whereas Omicron BA.2 outbreaks showed a random distribution in incidence rate. The time-dependent reproduction number of Delta, Omicron BA.1, and Omicron BA.2 were 3.21, 4.29, and 2.96, respectively, and correspondingly, the mean serial interval were 4.29 days (95% confidence interval [CI]: 0.37-8.21), 3.84 days (95% CI: 0-8.37), and 2.77 days (95% CI: 0-5.83). The asymptomatic infection rate of cases in Delta, Omicron BA.1, and Omicron BA.2 outbreaks were 21.71%, 6.25%, and 4.35%, respectively. CONCLUSION: The Omicron BA.2 variant had the greatest serial interval, transmissibility, and transmission speed, followed by BA.1, and then Delta. Compared with Delta and Omicron BA.1 variants, the Omicron BA.2 variant may be less pathogenic and more difficult to control than Omicron BA.1 and Delta.

Evaluation of the transmissibility of norovirus and the effectiveness of prevention and control measures for schools in Jiangsu Province.

OBJECTIVE: This study aims to estimate the transmissibility of norovirus outbreaks in schools by different transmission routes, and to evaluate the effects of isolation, school-closure and disinfection measures under different intervention intensities, finally, scientific prevention and control suggestions are proposed. METHOD: 23 outbreaks of norovirus infectious diarrhea occurring in Jiangsu Province's school from 2012-2018 were selected and fitted to the model. The data includes various types of school places and pathogen genotype. A 'SEIAQRW' model with two transmission routes was established. The transmissibility of each outbreak was assessed using effective reproduction number, the efficacy of different intervention measures and intensities were evaluated by calculating the total attack rate and peak incidence. RESULTS: The mean effective reproduction number of noroviruses was estimated to be 8.92 for the human-to-human route of transmission and 2.19 for the water or food-to-human route of transmission. When all symptomatic cases were isolated, the median peak incidence for both transmission routes both being less than 1.8%. There was a smaller reduction in total attack rate compared to peak incidence, the median total attack rate for the two transmission routes decreased by 17.59% and 42.09%, respectively. When the effect of school-closure or disinfection is more than 90%, the total attack rate and peak incidence in the human-to-human route are reduced by more than 90% compared to no intervention, and the peak incidence in the water or food-to-human routes can be reduced to less than 1.4%, but the reduction in the total attack rate is only 50% or so. CONCLUSION: Norovirus outbreaks have a high rate of transmission in schools. In the case of norovirus outbreaks, isolation should be complemented by other interventions, and the implementation of high-intensity school closures or disinfection of the external environment can be effective in reducing the spread of the virus.

Epidemiological characteristics and transmissibility of HPV infection: A long-term retrospective study in Hokkien Golden Triangle, China, 2013-2021.

OBJECTIVE: Multiple human papillomavirus (HPV)-associated diseases have put a significant disease burden on the world. Therefore, we conducted a study to explore the epidemiological characteristics of HPV and the transmissibility of its genotypes. METHODS: HPV testing data was collected from Hospital. A transmission dynamics model of HPV was constructed to simulate and compare the transmissibility of different HPV genotypes, which was quantitatively described by the basic reproduction number (R0). RESULTS: The collected HPV subjects were mainly from Xiamen City, Zhangzhou City and Quanzhou City, together, they are known as the Hokkien golden triangle. There were variations in the distribution of HPV infections by age groups. Among all HPV genotypes, 13 of them had R0 > 1, with 10 of them being high-risk types. The top five were HPV56, 18, 58, 52 and 53, among which, HPV56, 18, 58 and 42 were of high risk, whereas HPV53 was not, and the R0 values for the five were 3.35 (CI: 0.00-9.99), 3.20 (CI: 0.00-6.46), 3.19 (CI: 1.27-6.94), 3.19 (CI: 1.01-8.42) and 2.99 (CI: 0.00-9.39), respectively. In addition, HPV52 had R0 > 1 for about 51 months, which had the longest duration. CONCLUSION: Most high-risk HPV types in the Hokkien golden triangle could transmit among the population. Therefore, there is a need of further optimization for developing HPV vaccines and better detection methods in the region.

Long-term ozone exposure is negatively associated with estimated glomerular filtration rate in Chinese middle-aged and elderly adults.

Chronic kidney disease (CKD) is an inflammatory disease characterized by the deterioration of renal function, which imposes a significant burden on the healthcare system. In the recent decades, the ageing of the population and the increase of ozone pollution have accelerated. However, epidemiological associations between long-term ozone exposure and renal function in susceptible populations are understudied. In this study, we aimed to investigate the association of 1 y ozone exposure with renal function among the older adults in Xiamen City, China. We recruited 6024 eligible participants with a median age of 65.00 years, estimated their ozone exposure data, and collected questionnaires on demographic status and lifestyle factors as well as information on healthcare access. A generalized linear model was used to assess the association. An increase of 10 µg/m3 of 1 y ozone exposure was negatively associated with the estimated glomerular filtration rate (eGFR) [-3.12 (95% CI: -4.76, -1.48)]. The associations were stronger in men, non-smokers, and those with hypertension or T2DM. Clinical indicators of high-density lipoprotein, low-density lipoprotein, triglycerides, and total cholesterol were the main mediators to regulate the ozone-renal function association. Our results suggested that long-term ozone exposure is a potential risk factor for renal function in Chinese middle-aged and elderly adults.

Design of a Variable Stiffness Gecko-Inspired Foot and Adhesion Performance Test on Flexible Surface.

Adhesion robots have broad application prospects in the field of spacecraft inspection, repair, and maintenance, but the stable adhesion and climbing on the flexible surface covering the spacecraft has not been achieved. The flexible surface is easily deformed when subjected to external force, which makes it difficult to ensure a sufficient contact area and then detach from it. To achieve stable attachment and easy detachment on the flexible surface under microgravity, an adhesion model is established based on the applied adhesive material, and the relationship between peeling force and the rigidity of the base material, peeling angle, and working surface stiffness is obtained. Combined with the characteristics of variable stiffness structure, the adhesion and detachment force of the foot is asymmetric. Inspired by the adhesion-detachment mechanism of the foot of the gecko, an active adhesion-detachment control compliant mechanism is designed to achieve the stable attachment and safe detachment of the foot on the flexible surface and to adapt to surfaces with different rigidity. The experimental results indicate that a maximum normal adhesion force of 7.66 N can be generated when fully extended, and the safe detachment is achieved without external force on a flexible surface. Finally, an air floating platform is used to build a microgravity environment, and the crawling experiment of a gecko-inspired robot on a flexible surface under microgravity is completed. The experimental results show that the gecko-inspired foot with variable stiffness can satisfy the requirements of stable crawling on flexible surfaces.

Computing R 0 of dynamic models by a definition-based method.

Objectives: Computing the basic reproduction number (R 0) in deterministic dynamical models is a hot topic and is frequently demanded by researchers in public health. The next-generation methods (NGM) are widely used for such computation, however, the results of NGM are usually not to be the true R 0 but only a threshold quantity with little interpretation. In this paper, a definition-based method (DBM) is proposed to solve such a problem. Methods: Start with the definition of R 0, consider different states that one infected individual may develop into, and take expectations. A comparison with NGM has proceeded. Numerical verification is performed using parameters fitted by data of COVID-19 in Hunan Province. Results: DBM and NGM give identical expressions for single-host models with single-group and interactive R ij of single-host models with multi-groups, while difference arises for models partitioned into subgroups. Numerical verification showed the consistencies and differences between DBM and NGM, which supports the conclusion that R 0 derived by DBM with true epidemiological interpretations are better. Conclusions: DBM is more suitable for single-host models, especially for models partitioned into subgroups. However, for multi-host dynamic models where the true R 0 is failed to define, we may turn to the NGM for the threshold R 0.