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With the development of neuroimaging technology, cerebral small vessel disease has become a hot research topic in recent years. It has been clearly related to cognitive decline, dementia and gait instability. However, recent studies have found that small cerebral vascular disease with white matter hyperintensities is the main cause of chronic dizziness in the elderly, but the pathogenesis is not completely clear, which may be related to brain neural network disconnection, visual dependence, eye movement disorder caused by abnormal brain tissue structure, oxidative stress regulation disorder, cerebral blood flow self-regulation disorder, and the interaction mechanism between vestibular system and emotional disorder.
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BackgroundIn early March 2022, a major outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant spread rapidly throughout Shanghai, China. Here we aimed to provide a description of the epidemiological characteristics and spatiotemporal transmission dynamics of the Omicron outbreak under the population-based screening and lockdown policies implemented in Shanghai. MethodsWe extracted individual information on SARS-CoV-2 infections reported between January 1 and May 31, 2022, and on the timeline of the adopted non-pharmacological interventions. The epidemic was divided into three phases: i) sporadic infections (January 1-February 28), ii) local transmission (March 1-March 31), and iii) city-wide lockdown (April 1 to May 31). We described the epidemic spread during these three phases and the subdistrict-level spatiotemporal distribution of the infections. To evaluate the impact on the transmission of SARS-CoV-2 of the adopted targeted interventions in Phase 2 and city-wide lockdown in Phase 3, we estimated the dynamics of the net reproduction number (Rt). FindingsA surge in imported infections in Phase 1 triggered cryptic local transmission of the Omicron variant in early March, resulting in the largest coronavirus disease 2019 (COVID-19) outbreak in mainland China since the original wave. A total of 626,000 SARS-CoV-2 infections were reported in 99.5% (215/216) of the subdistricts of Shanghai. The spatial distribution of the infections was highly heterogeneous, with 40% of the subdistricts accounting for 80% of all infections. A clear trend from the city center towards adjacent suburban and rural areas was observed, with a progressive slowdown of the epidemic spread (from 544 to 325 meters/day) prior to the citywide lockdown. During Phase 2, Rt remained well above 1 despite the implementation of multiple targeted interventions. The citywide lockdown imposed on April 1 led to a marked decrease in transmission, bringing Rt below the epidemic threshold in the entire city on April 14 and ultimately leading to containment of the outbreak. InterpretationOur results highlight the risk of widespread outbreaks in mainland China, particularly under the heightened pressure of imported infections. The targeted interventions adopted in March 2022 were not capable of halting transmission, and the implementation of a strict, prolonged city-wide lockdown was needed to successfully contain the outbreak, highlighting the challenges for successfully containing Omicron outbreaks. FundingKey Program of the National Natural Science Foundation of China (82130093). Research in contextO_ST_ABSEvidence before this studyC_ST_ABSOn May 24, 2022, we searched PubMed and Europe PMC for papers published or posted on preprint servers after January 1, 2022, using the following query: ("SARS-CoV-2" OR "Omicron" OR "BA.2") AND ("epidemiology" OR "epidemiological" OR "transmission dynamics") AND ("Shanghai"). A total of 26 studies were identified; among them, two aimed to describe or project the spread of the 2022 Omicron outbreak in Shanghai. One preprint described the epidemiological and clinical characteristics of 376 pediatric SARS-CoV-2 infections in March 2022, and the other preprint projected the epidemic progress in Shanghai, without providing an analysis of field data. In sum, none of these studies provided a comprehensive description of the epidemiological characteristics and spatiotemporal transmission dynamics of the outbreak. Added value of this studyWe collected individual information on SARS-CoV-2 infection and the timeline of the public health response. Population-based screenings were repeatedly implemented during the outbreak, which allowed us to investigate the spatiotemporal spread of the Omicron BA.2 variant as well as the impact of the implemented interventions, all without enduring significant amounts of underreporting from surveillance systems, as experienced in other areas. This study provides the first comprehensive assessment of the Omicron outbreak in Shanghai, China. Implications of all the available evidenceThis descriptive study provides a comprehensive understanding of the epidemiological features and transmission dynamics of the Omicron outbreak in Shanghai, China. The empirical evidence from Shanghai, which was ultimately able to curtail the outbreak, provides invaluable information to policymakers on the impact of the containment strategies adopted by the Shanghai public health officials to prepare for potential outbreaks caused by Omicron or novel variants.
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White matter hyperintensity (WMH) is one of the major imaging markers of cerebral small vascular disease, which is prevalent in the elderly. At present, the pathogenesis of WMH is not clear, most of the previous studies focused on the arterial system, but the role of the venous system in WMH is attracting more and more attention. Small venous collagen hyperplasia, downstream intracranial venous dilatation and internal jugular venous reflux may be involved in the formation and development of white matter hyperintensity.
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Our manuscript was based on surveillance cases of COVID-19 identified before January 26, 2020. As of February 20, 2020, the total number of confirmed cases in mainland China has reached 18 times of the number in our manuscript. While the methods and the main conclusions in our original analyses remain solid, we decided to withdraw this preprint for the time being, and will replace it with a more up-to-date version shortly. Should you have any comments or suggestions, please feel free to contact the corresponding author.
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Objective@#To study the early dynamics of the epidemic of coronavirus disease (COVID-19) in China from 15 to 31 January, 2020, and estimate the corresponding epidemiological parameters (incubation period, generation interval and basic reproduction number) of the epidemic.@*Methods@#By means of Weibull, Gamma and Lognormal distributions methods, we estimated the probability distribution of the incubation period and generation interval data obtained from the reported COVID-19 cases. Moreover, the AIC criterion was used to determine the optimal distribution. Considering the epidemic is ongoing, the exponential growth model was used to fit the incidence data of COVID-19 from 10 to 31 January, 2020, and exponential growth method, maximum likelihood method and SEIR model were used to estimate the basic reproduction number.@*Results@#Early COVID-19 cases kept an increase in exponential growth manner before 26 January, 2020, then the increase trend became slower. The average incubation period was 5.01 (95%CI: 4.31-5.69) days; the average generation interval was 6.03 (95%CI: 5.20-6.91) days. The basic reproduction number was estimated to be 3.74 (95%CI: 3.63-3.87), 3.16 (95%CI: 2.90-3.43), and 3.91 (95%CI: 3.71-4.11) by three methods, respectively.@*Conclusions@#The Gamma distribution fits both the generation interval and incubation period best, and the mean value of generation interval is 1.02 day longer than that of incubation period. The relatively high basic reproduction number indicates that the epidemic is still serious; Based on our analysis, the turning point of the epidemic would be seen on 26 January, the growth rate would be lower afterwards.
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Objectives@#To establish a geographic information application system for analyzing the spatial and temporal distribution of major infectious diseases in various regions of the world and to assess the risk of importation of those diseases, to China.@*Methods@#We collected and integrated the following information on: 1) outbreaks and areas of epidemics of major infectious diseases in the world from 2000 to 2017, 2) cases of infectious diseases in arriving travelers through active surveillance at international entry-exit ports in mainland China from 2014 to 2016, 3) numbers of annual global international flights and travelers in the country. With the above information, a global space-time distribution database on major infectious diseases was then established, using the technology related to the system. Models regarding technologies on time-space analysis, probabilistic risk assessment and geographic information visualization, were applied to establish a geographic information system on risk assessment of infectious diseases that imported to China.@*Results@#Through integration of information on outbreaks and epidemic areas of 60 major infectious diseases in 220 countries and regions around the world, as well as 42 kinds of infectious diseases identified among the international arrivals in mainland China, a system was then developed. Information on the distribution of major infectious diseases and their potential risks in the worldwide various regions, characteristics of spectrum and disease burden of infectious diseases imported to each province of mainland China were displayed. Thus, risks on importing infectious diseases in each province via air way were able to be evaluated and simulated by the probabilistic risk assessment model, under the information on specific kind of infectious disease, outside China.@*Conclusion@#Geographic Information System on Risk Assessment Regarding Infectious Diseases Imported to China provides basic data for epidemiological reconnaissance and assessment on risks of importing infectious diseases outside China, thus would be helpful for the improvement of strategies on surveillance, prevention and control regarding the importing infectious diseases, in China.
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This article provides an overview of the severe acute respiratory syndrome (SARS) epidemics in mainland China and of what we have learned since the outbreak.The epidemics spanned a large geographical extent but clustered in two regions:first in Guangdong Province,and about 3 months later in Beijing and its surrounding areas.The resulting case fatality ratio of 6.4％ was less than half of that in other SARS-affected countries and regions,partly due to younger-aged patients and a higher proportion of community-acquired infections.Strong political commitment and a centrally coordinated response were most important for controlling SARS.The long-term economic consequence of the epidemic was limited.Many recovered patients suffered from avascular osteonecrosis,as a consequence of corticosteroid usage during their infection.The SARS epidemic provided valuable experience and lessons relevant in controlling outbreaks of emerging infectious diseases,and has led to fundamental reforms of the Chinese health system.Additionally,the epidemic has substantially improved infrastructures,surveillance systems,and capacity to response to health emergencies.In particular,a comprehensive nationwide internet-based disease reporting system was established.
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Objective To understand the epidemiological characteristics of scrub typhus and influencing factors in Yunnan province,and provide further information for the prevention and control of scrub typhus.Methods Based on the incidence data of scrub typhus reported in Yunnan from 2006 to 2013,the epidemiological characteristics of scrub typhus were analyzed and related environmental factors were identified with panel negative binomial regression model.Results A total of 8 980 scrub typhus cases were reported during 2006-2013 in Yunnan.The average annual incidence was 2.46/100 000,with an uptrend observed.Natural focus expansion was found,affecting 71.3％ of the counties in 2013.The epidemic mainly occurred in summer and autumn with the incidence peak during July-October.The annual incidence was higher in females than in males.More cases occurred in children and farmers,the proportions of cases in farmers and pre-school aged children showed an obvious increase.Panel negative binomial regression model indicated that the transmission risk of scrub typhus was positive associated with monthly temperature and monthly relative humidity.Furthermore,an "U" pattern between the risk and the increased coverage of cropland and grassland as well as an "inverted-U" pattern between the risk and increased coverage of shrub were observed.Conclusion It is necessary to strengthen the scrub typhus surveillance in warm and moist areas as well as the areas with high coverage of cropland and grassland in Yunnan,and the health education in children and farmers who are at high risk.
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Objective: To understand the epidemiological characteristics of scrub typhus and influencing factors in Yunnan province, and provide further information for the prevention and control of scrub typhus. Methods: Based on the incidence data of scrub typhus reported in Yunnan from 2006 to 2013, the epidemiological characteristics of scrub typhus were analyzed and related environmental factors were identified with panel negative binomial regression model. Results: A total of 8 980 scrub typhus cases were reported during 2006-2013 in Yunnan. The average annual incidence was 2.46/100 000, with an uptrend observed. Natural focus expansion was found, affecting 71.3% of the counties in 2013. The epidemic mainly occurred in summer and autumn with the incidence peak during July-October. The annual incidence was higher in females than in males. More cases occurred in children and farmers, the proportions of cases in farmers and pre-school aged children showed an obvious increase. Panel negative binomial regression model indicated that the transmission risk of scrub typhus was positive associated with monthly temperature and monthly relative humidity. Furthermore, an "U" pattern between the risk and the increased coverage of cropland and grassland as well as an "inverted-U" pattern between the risk and increased coverage of shrub were observed. Conclusion: It is necessary to strengthen the scrub typhus surveillance in warm and moist areas as well as the areas with high coverage of cropland and grassland in Yunnan, and the health education in children and farmers who are at high risk.
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Niño , Femenino , Humanos , Masculino , China/epidemiología , Ambiente , Epidemias , Agricultores , Incidencia , Modelos Estadísticos , Orientia tsutsugamushi , Factores de Riesgo , Tifus por Ácaros/transmisión , TemperaturaRESUMEN
Objective To investigate the spatiotemporal expansion and risk factors of scrub typhus (ST) in Shandong,Jiangsu and Anhui provinces.Methods Based on the reported cases in Shandong and Jiangsu from 2006 to 2013,and Anhui from 2008 to 2013 epidemiological characteristics of ST and associated environmental factors were analyzed,using the panel negative binomial regression model.Results A total of 2 968,2 331 and 3 447 ST cases were respectively reported in Shandong,Jiangsu and Anhui during 2006-2013,with the average annual incidence rates as 0.39,0.38 and 0.94 per 100 000 population.Uptrend in Shandong and Jiangsu,but a slight rollback seen in Anhui were observed.Expansion of natural foci was found in the 3 provinces,with affected counties accounted for 38.0％,48.2％ and 46.5％ in Shandong,Jiangsu and Anhui,respectively in 2013.Cases were clustered in autumn but with a peak of single epidemic appeared in October or November,in all the 3 provinces.More female and elderly patients were seen,than in the other age groups,in all the 3 provinces.Majority of the cases were farmers,with an increasing trend in incidence,in all these provinces,followed by housekeepers in Shandong and preschool children in Anhui.The risk factors of transmission in all the 3 provinces were negatively associated with the monthly precipitation,and showing an "inverted-U" pattern in association with monthly temperature.A positive relationship between the risk of transmission and monthly relative humidity was found in Shandong and Jiangsu provinces.However,an "inverted-U" pattern between the risk of transmission and the monthly sunshine hour,appeared in Shandong and Anhui provinces.The incidence of Scrub typhus in Shandong was also positively related to the coverage of forest.Conclusion Surveillance programs and health education measures should focus on the warm and moist areas in all the 3 provinces,and also on forestry areas in Shandong.Health education and prevention on mite-bite should be targeted,especially on high-risk populations as the elderly and farmers,in the 3 provinces.Housekeepers in Shandong and children in Anhui should also be under special concern.
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Objective To investigate the spatiotemporal expansion and risk factors of scrub typhus (ST) in Shandong,Jiangsu and Anhui provinces.Methods Based on the reported cases in Shandong and Jiangsu from 2006 to 2013,and Anhui from 2008 to 2013 epidemiological characteristics of ST and associated environmental factors were analyzed,using the panel negative binomial regression model.Results A total of 2 968,2 331 and 3 447 ST cases were respectively reported in Shandong,Jiangsu and Anhui during 2006-2013,with the average annual incidence rates as 0.39,0.38 and 0.94 per 100 000 population.Uptrend in Shandong and Jiangsu,but a slight rollback seen in Anhui were observed.Expansion of natural foci was found in the 3 provinces,with affected counties accounted for 38.0％,48.2％ and 46.5％ in Shandong,Jiangsu and Anhui,respectively in 2013.Cases were clustered in autumn but with a peak of single epidemic appeared in October or November,in all the 3 provinces.More female and elderly patients were seen,than in the other age groups,in all the 3 provinces.Majority of the cases were farmers,with an increasing trend in incidence,in all these provinces,followed by housekeepers in Shandong and preschool children in Anhui.The risk factors of transmission in all the 3 provinces were negatively associated with the monthly precipitation,and showing an "inverted-U" pattern in association with monthly temperature.A positive relationship between the risk of transmission and monthly relative humidity was found in Shandong and Jiangsu provinces.However,an "inverted-U" pattern between the risk of transmission and the monthly sunshine hour,appeared in Shandong and Anhui provinces.The incidence of Scrub typhus in Shandong was also positively related to the coverage of forest.Conclusion Surveillance programs and health education measures should focus on the warm and moist areas in all the 3 provinces,and also on forestry areas in Shandong.Health education and prevention on mite-bite should be targeted,especially on high-risk populations as the elderly and farmers,in the 3 provinces.Housekeepers in Shandong and children in Anhui should also be under special concern.
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Objective To understand the impact of meteorological factors on the incidence of hand,foot and mouth disease (HFMD) and the epidemiological characteristics of HFMD in China.Methods Bayesian hierarchical model[Besag,York,and Mollie' (BYM) model] was used to fit the data.The fitting effects of uncorrelated heterogeneity (UH) model,correlated heterogeneity (CH) model and spatial and temporal interaction model were compared and the best model was selected to analyze the meteorological factors influencing the incidence of HFMD.Results The UH +CH model with spatial and temporal interaction had best fitting effect (DIC=35 507.2).Rainfall(RR=1.051 7,95％ CI:1.050 4-1.052 5),average temperature (RR=1.089 6,95％ CI:1.078 1-1.106 9),average relative humidity (RR=l.089 0,95％CI:1.082 1-1.091 2),average air pressure (RR=l.076 4,95％ CI:1.074 8-1.077 9) and hours of sunshine (RR=1.0851,95％ CI:1.0798-1.0875) were the meteorological factors influencing the incidence of HFMD.Conclusion The incidence of HFMD had spatial and temporal clustering characteristics.The meteorological factors were closely related with the incidence of HFMD.
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Objective To explore the effect of GAS MAN assisted instruction on theory learning of volatile anesthetics in anesthesiology residency training.Methods A total of 32 residents in the first stage of anesthesiology training were enrolled and randomly assigned to either study(S) or control (C) group.Theory-test l(Test-1) was conducted for all residents after the lecture-based learning (LBL).Next,reference book self-reading strategy was used in both groups while computer-based simulation(CBS) using GAS MAN was only developed in S group.Then,theory-test 2(Test-2)was conducted for residents in both groups and residents in S group completed the questionnaire smvey.In addition,thirty-four resident teachers observed the CBS courses and completed the questionnaire smvey.Results The mean scores of Test-1 did not differ significantly between the two groups(P=0.64).However,the mean Test-2 score of S group(81.3 ± 13.6) was significantly higher than that of C group(61.3 ± 15.4) (P=0.001).100％(16/16) residents believed that CBS was beneficial to the theoretical study of volatile anesthetics,93.8％(15/16) residents considered GAS MAN could help understand the concepts and improve efficiency during self-learning.97.1％ (33/34) and 91.2％ (31/34)resident teachers agreed that CBS was helpful for analyzing complex concepts and improving study effectiveness,respectively.Conclusions CBS using GAS MAN improves theory knowledge and study effectiveness for anesthesia residents.Both residents and resident teachers find GAS MAN highly ac ceptable.Therefore,GAS MAN has the potential to be the assistant teaching tool for LBL in anesthesiology residency-training program.
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Objective To investigate the effect of formative assessment on skill acquisition of basic life support (BLS) among medical students. Methods Totally 206 undergraduates were ran-domized into control group (C group) and interventional group (F group). A BLS lecture was given in both groups. And then, 45 min BLS training and BLS skill assessment (after training) were given in C group. Undergraduates in F group received BLS skill assessment (formative assessment) before training, and 15 min feedback was delivered based on the assessment, then 30 min BLS training was conducted. Skills assessment was conducted again in F group after the training. Student's-t-test was used to compare the difference of skills between the two groups and P<0.05 signifies statistically sig-nificant differences. Results Score of F group (85.2±7.3) were higher than that in C group (68.2± 13.2), with statistical difference. Conclusion A formative assessment could significantly improve skill acquisition of BLS among medical students.
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One hundred forty-four residents registered at department of anesthesia of West China Hospital from 1999 to 2010.The duration of residency training is 5 years (3 + 2).The residents enrolled during 1999-2002 were on the staff.They were assigned to work at this hospital after graduation from medical school and became staff anesthesiologist of this hospital after 5 year training.The residents enrolled during 2003-2010 were trainees and not on the staff.They had to apply for a job as anesthesiologist somewhere after 5 year training.After 3 year training the residents are qualified to undergo subspecialty training.Thirty-nine of the 144 residents dropped out of the training program.The reasons for their withdrawing from the program included finding a regular job,failing the qualifying examination,changing profession studying abroad and death.In order to reduce dropout rate,correct public opinion on the importance of residency training,raising the quality of the residents and improving income of the residents are needed.