Visible-light-enabled cascade cross-dehydrogenative-coupling/cyclization to construct α-chromone substituted α-amino acid derivatives.

Organophotocatalytic cascade cross-dehydrogenative-coupling/cyclization reaction of o-hydroxyarylenaminones with α-amino acid derivatives for the construction of α-chromone substituted α-amino acid derivatives was developed. Various N-arylglycine esters, amides and dipeptides underwent the cascade cyclization reaction well with o-hydroxyarylenaminones to afford the corresponding 3-aminoalkyl chromones in good to excellent yields. This approach consists of visible-light-promoted oxidation of α-amino acid derivatives, the Mannich reaction, and intramolecular nucleophilic cyclization under acidic conditions, and features a wide reaction scope, a simple operation and mild reaction conditions, which may have the potential to be used for the synthesis of bioactive molecules.

Combining Enzyme and Photoredox Catalysis for the Construction of 3-Aminoalkyl Chromones.

Herein, we reported a practical and efficient strategy combining photoredox and enzyme catalysis for the construction of 3-aminoalkyl chromones from o-hydroxyaryl enaminones and N-arylglycine esters. A variety of 3-aminoalkyl chromones were synthesized with good yields under mild conditions in one pot. This synthetic protocol consists of sequential enzymatic hydrolysis and photoredox decarboxylation of N-arylglycine esters, oxidation of aminoalkyl radicals, Mannich reaction, and intramolecular nucleophilic cyclization, which affords a convenient pathway for the preparation of various 3-substituted chromones.

Associations of Abdominal Visceral Fat Content and Plasma Adiponectin Level With Intracranial Atherosclerotic Stenosis: A Cross-Sectional Study.

Background: Abdominal obesity and adipocytokines are closely related to atherosclerosis, and adiponectin level is considered one of the important clinical indicators. This study aimed to analyze the associations of abdominal visceral fat content and adiponectin level with intracranial atherosclerotic stenosis (ICAS). Methods: A total of 186 patients were enrolled in this study. Patients were distributed into ICAS and non-ICAS by the degree of artery stenosis. Plasma adiponectin levels and the ratio of visceral adipose tissue (VAT) to subcutaneous adipose tissue (SAT) were measured. The related factors of intracranial atherosclerotic stenosis were determined using multivariable logistic regression analysis. Results: The VAT/SAT ratio (OR, 26.08; 95% CI, 5.92-114.83; p < 0.001) and adiponectin (OR, 0.61; 95% CI, 0.44-0.84; p = 0.002) were found to be the independent predictors of ICAS in a multivariable logistic regression analysis. The prevalence of ICAS increased (T1: 27.4%; T2: 50.0%; T3: 75.8%) as the VAT/SAT ratio tertile increased (p < 0.001). The prevalence of ICAS decreased (T1: 72.6%; T2: 54.8%; T3: 25.8%) as the adiponectin tertile increased (p < 0.001). In ROC curves analysis, VAT/SAT ratio had a sensible accuracy for the prediction of ICAS. The optimal cut-off value of VAT/SAT ratio to predict ICAS in this study was 1.04 (AUC: 0.747; p < 0.001; sensitivity: 67.4%; specificity: 74.7%). The optimal adiponectin cutoff was 3.03 ug/ml (AUC: 0.716; p < 0.001; sensitivity:75.8%; specificity: 61.5%). Conclusion: Higher VAT/SAT ratio and lower plasma adiponectin levels were closely related to the increased risk of intracranial atherosclerotic stenosis.

Plastid phylogenomics provides novel insights into the infrafamilial relationship of Polypodiaceae.

The polygrammoids (Polypodiaceae) are the most species-rich and diversified epiphytic fern lineages, and hold an important role to understand the deep diverging events and rapid adaptation to changing environments in the plant tree of life. Despite progress in the phylogeny of this group of ferns in previous multilocus phylogenetic studies, uncertainty remains especially in backbone relationships among closely related clades, and the phylogenetic placement of recalcitrant species or lineages. Here, we investigated the deep phylogenetic relationships within Polypodiaceae by sampling all major lineages and using 81 plastid genomes (plastomes), of which 70 plastomes were newly sequenced with high-throughput sequencing technology. Based on parsimony, maximum-likelihood, Bayesian and multispecies coalescent analyses of genome skimming data, we achieved a better resolution of the backbone phylogeny of Polypodiaceae. Using simulated data matrices, we detected that potential phylogenetic artefacts, such as long-branch attraction and insufficient taxonomic sampling, may have a confounding impact on the incongruence of phylogenetic inferences. Furthermore, our phylogenetic analyses offer greater resolution than previous multilocus studies, providing a robust framework for future phylogenetic implications on the subfamilial taxonomy of Polypodiaceae. Our phylogenomic study not only demonstrates the advantage of a character-rich plastome dataset for resolving the recalcitrant lineages that have undergone rapid radiation, but also sheds new light on integrative explorations understanding the evolutionary history of large fern groups in the genomic era.

Clinical validation and utility of Chinese Eppendorf Itch Questionnaire in adults with chronic pruritus symptoms.

BACKGROUND: Pruritus, or itch, is a prevalent symptom causing profound health burden in many dermatological and non-dermatological disorders. Several itch questionnaires have been created to assess itch. Particularly, Eppendorf Itch Questionnaire (EIQ) is widely accepted since it encompasses various aspects of itch, including intensity, affects, coping behavior, and motivation to scratch. METHODS: In a cross-sectional survey, we examined the validity, reliability and clinical utility of Traditional Chinese EIQ. RESULTS: We administered the consensus version to 128 adults (median: 48.5 years, interquartile range [IQR]: 39-63) with active itch for more than 6 weeks at the Outpatient Clinics of three medical centers in Taiwan. Clinical diagnoses included psoriasis (N = 82), xerosis (N = 34), or other dermatitis (N = 12). Cronbach's alpha for each EIQ scale ranged 0.82-0.98, suggesting good to excellent internal consistency and reliability. Three EIQ scales significantly correlated with visual analogue scale (VAS) for itch intensity (P ≤ 0.001 for median test), supporting for its concurrent validity. None of EIQ scale was statistically correlated with Psoriasis Area Severity Index (PASI) scores in psoriasis patients, confirming its discriminant validity. Moreover, patients of different diagnoses had distinct responses to the multi-scale EIQ index, affording it a better clinical test (area-under-the-ROC curve [AUC]: 0.76, 95% CI: 0.63-0.90) than VAS alone (AUC: 0.42, 95%CI: 0.24-0.59) in distinguishing dermatitis/eczema-related itch from psoriasis or xerosis-related itch. CONCLUSION: We demonstrated the reliability and validity of Chinese EIQ in adult patients with chronic itch at the outpatient setting. The study also revealed the diversified aspects of itch across patients with various dermatoses.

Ag-Decorated MoSx Laminar-Film Electrocatalyst Made with Simple and Scalable Magnetron Sputtering Technique for Hydrogen Evolution: A Defect Model to Explain the Enhanced Electron Transport.

The active edge site, surface defect, and noble-metal nanoparticle have been engineered to improve the electrocatalytic activity of earth-abundant and layered MoS2, but there was no single and facile process to achieve all yet. Here, basal-plane-defected Ag/MoSx lamellae with different Ag contents were deposited by one-step, single-cermet target (ceramic + metal) magnetron sputtering for the electrocatalytic hydrogen evolution reaction (HER). Ag/MoSx (10 vol %) showed a current density of 10 mA/cm2 at an overpotential of 120 mV with a Tafel slope of 42 mV/dec in a 0.5 M H2SO4 solution. The HER performance of Ag-MoSx lamellae was higher than that of the Ag-free one due to the activated basal antisite defects and the decorated Ag for enhancing electron transport. The green magnetron sputtering technique together with the target design has achieved Ag/MoSx lamellae with the film grown using the advantages of active edge-up lamella, S vacancy-type basal sites, and electron transport-enhanced Ag interconnect for enhancing hydrogen evolution.

Changes of Vegetation Distribution in the East Dongting Lake After the Operation of the Three Gorges Dam, China.

Water regime is regarded as the primary factor influencing the vegetation distribution in natural wetland ecosystems. However, the effect of water regime change induced by large-scale hydraulic engineering on vegetation distribution is still unclear. In this study, multi-temporal TM/ETM+/OLI images and hydrological data from 1995 to 2015 were used to elucidate how the change in water regime influenced the vegetation distribution in the East Dongting Lake (EDTL), especially after the operation of the Three Gorges Dam (TGD) in 2003. Using unsupervised and supervised classification methods, three types of land cover were identified in the study area: Water and Mudflat, Grass, and Reed and Forest. Results showed that the total vegetation area in EDTL increased by approximately 78 km2 during 1995-2015. The areas of Reed and Forest and Grass exhibited a contrasting trend, dramatic increase in Reed and Forest but sharp decrease in Grass, particularly after the operation of TGD. The lowest distribution elevations of Grass and Reed and Forest decreased by 0.61 and 0.52 m, respectively. As a result of water level variation, submergence duration increased at 20-21 m and 28 m elevations (1-13 days), but significantly decreased at 22-27 m and 29-30 m elevations (-3 to -31 days). The submergence duration of Grass and Reed and Forest was 246 and 177 days, respectively. This study indicated that wetland vegetation pattern significantly changed after the operation of TGD, mainly as a result of changes in submergence condition. Submergence duration might be an effective indicator to predict the shift of vegetation distribution in EDTL, and which could provide scientific guidance for vegetation restoration and wetland management in this lake.

Inhibition of litter decomposition of two emergent macrophytes by addition of aromatic plant powder.

Aromatic plants show antimicrobial activity due to their essential oils, but their effect on litter decomposition is unclear. In this study, we evaluated the biomass loss and nutrient dynamics in leaf litters of two macrophytes (Miscanthus sacchariflorus and Carex brevicuspis) with and without addition of powdered material of the aromatic plant Polygonum hydropiper or the non-aromatic plant C. brevicuspis. The two powders had similar basic chemical qualities but P. hydropiperi had a higher essential oils concentration. Leaf litters of M. sacchariflorus and C. brevicuspis were incubated with powdered P. hydropiper or C. brevicuspis (500 g m-3, 250 g m-3, and no addition) for 120 days in a mesocosm experiment. Compared with the control (no addition), P. hydropiperi addition decelerated nutrient release and litter decomposition, while C. brevicuspis addition accelerated those processes. The nitrogen concentrations in both leaf litters and the phosphorus concentration in C. brevicuspis leaf litter were increased by addition of both plant powders. The fungal biomass in both leaf litters decreased after P. hydropiperi addition, due to the antifungal activity of its essential oils. These data indicate that the aromatic plant P. hydropiperi inhibits litter decomposition via its essential oils and that such inhibition is not species-specific.

[Characteristics of Carex brevicuspis and its impact factors in Dingzidi, East Dongting Lake].

In recent 20 years, the area of lake grass has been drastically reduced and degraded. In order to search for reasonable recovery ways of the lake grass, the vegetational characteristics (plant height, coverage, density, biomass and biodiversity index) and soil physico-chemical characteristics (soil organic carbon, SOC; total nitrogen, TN; total phosphorus, TP; soil bulk density and moisture) were investigated in the Carex brevicuspis community from 63 sampling plots in 7 sampling belts along an elevation gradient in Dingzidi, East Dongting Lake. All biological characteristics showed an inverted "U" distribution pattern along with increasing elevation, except for diversity index, which showed a tendency of increasing at first and then decreasing. Plant growth was inhibited near water body (low elevation region) and levee (high elevation region). In contrast, the intermediate elevation region had a favorable condition for plant growth. For soil physical properties, soil water moisture decreased but soil bulk density increased along with increasing elevation. However, SOC and TN contents were higher in the intermediate elevation region and lower in both low and high elevation regions. TP content was fluctuant along with increasing elevation. The principal component analysis (PCA) showed that the key factors influencing biomass of C. brevicuspis were soil C and N contents, soil moisture and bulk density. These results indicated that increasing soil fertility and maintaining proper soil moisture might be efficient to recover the vegetation of C. brevicuspis.

Caregiver burden and its determinants among family members of patients with chronic viral hepatitis in Shanghai, China: a community-based survey.

BACKGROUND: In China, caregivers of chronic viral hepatitis patients experience considerable burdens, stress and disruption of their own well-being and social activities. Measurement of the effect on caregivers is an under-researched area. The Family Burden Interview Schedule (FBIS) was primarily devised for the caregivers of schizophrenia patients, and the adverse effect of the disease was similar to the effect of chronic viral hepatitis on family caregivers. In this study, we prospectively evaluated the psychometric properties of FBIS in the field of chronic viral hepatitis and used it to determine the factors affecting the caregiver burden on the family members of chronic viral hepatitis patients in Shanghai, China. METHODS: A representative sample of patients (n = 1478) and caregivers (n = 1478) was randomly obtained through a multi-stage cluster sampling in Shanghai, China. Reliability and validity tests were used to verify the psychometric properties of the instrument. The two-level random intercept model was applied to determine the factors of the caregiver burden between the household and the community level. RESULTS: Cronbach's alpha coefficient was 0.90 for the overall instrument with statistical significance. Factor analysis suggested a three-factor model for the FBIS and confirmed that the adjusted unidimensional model and the second-order multidimensional model had better fit statistics. The average score of the caregiver burden in Shanghai was 12.62 ± 10.74, and financial burden constituted the major effect. The two-level random intercept model demonstrated that the risk factors were hospitalisation (ß 1.69, 95%CI 0.48 to 2.90), elevated serum alanine aminotransferase levels (ß 1.05, 95%CI 0.15 to 1.95), HCV infection (ß 4.49, 95%CI 1.22 to 7.77), and acceptance of the hepatitis B vaccine (ß 2.20, 95%CI 0.56 to 3.85), whereas the protective factors were no consumption of alcohol (ß -2.69, 95%CI -5.19 to -0.19), average monthly costs for patients less than or equal to 100 US dollars (ß -2.96, 95%CI -5.83 to -0.09), and good health status of family caregivers (ß -9.91, 95%CI -12.76 to -7.05). CONCLUSIONS: FBIS can accurately measure the caregiver burden for chronic hepatitis. Targeting interventions toward the conditions associated with the caregiver burden is of great importance.

[Study on patients with Creutzfeldt-Jakob disease in Shanghai, 2006-2012].

OBJECTIVE: To describe the epidemiological characteristics of patients with Creutzfeldt-Jakob disease (CJD) in Shanghai from 2006 to 2012. METHODS: Clinical and epidemiological information on CJD patients from Shanghai CJD Surveillance Network was analyzed. Cerebral spinal fluid (CSF)and blood specimens from patients were collected and used for detecting the 14-3-3 protein, and polymorphism of 129 amino acid and mutation of PRNP genes. Data was processed by EpiData(V3.0)and analyzed by SPSS(V17.0). RESULTS: In totally, one definite CJD patient together with 56 probable and 17 possible sporadic CJD patients were identified. One E200K genetic CJD case was diagnosed and another one was clinically diagnosed. No period- or geographic-related events were observed for these cases, but the houses of the two genetic CJD cases were close to each other. The mean age of onset of the probable CJD patients was 62 years old which was significantly older than that of those possible CJD patients. CONCLUSION: Most of the CJD patients identified in Shanghai were sporadic and the number was stable from 2006 to 2012. The mean age of onset of those probable CJD patients was older than that of the possible CJD patients.

[Study on the epidemiological characteristics and incidence trend of scarlet fever in Shanghai, 2005-2012].

OBJECTIVE: To systemically analyze the epidemiological characteristics, molecular markers of circulating group A Streptococcus (GAS) isolates and the incidence trend of scarlet fever in Shanghai from 2005 to 2012 as well as to explore the practice of GAS isolates surveillance program and the combined mathematical model in the early warning of scarlet fever. METHODS: The morbidity series of scarlet fever were retrieved to analyze and fit the combined mathematical model which comprised an autoregressive integrated moving average (ARIMA) model and a neural network. GAS isolates surveillances programs were implemented on community healthy population, using the emm typing and superantigens detecting method in Shanghai during the epidemic period of scarlet fever in 2008, 2010 and 2012. The standardized prevalence of GAS isolates was estimated with the demographic data. RESULTS: From 2005 to 2012, there were a total of 9410 scarlet fever cases reported in Shanghai including local registered residents and immigrant population, showing that the distribution of patients as sporadic. The morbidity kept rising with seasonal and periodical variations and the peak was in 2011. The average morbidity was 6.012 per 100 000 persons. Morbidity in the the suburban was significantly higher than that in the urban areas. Children at 4 to 8 years old were easy to be involved. The mean error rate of single ARIMA model,ARIMA-GRNN and back propagation artificial neural network combined model were 0.268, 0.432 and 0.131 respectively. The predicted incidence of scarlet fever in 2013 would keep fluctuating within a narrow range from 0.446 to 3.467 per 100 000 persons. A total number of 4409 throat swab samples were collected through the GAS isolates surveillance programs in 2008, 2010 and 2012. The standardized prevalence of GAS isolates in each year were 0.000%, 0.000% and 1.092%. 18 GAS isolates were identified and 15 isolates (83.33%)belonged to emm 12.0. CONCLUSION: The morbidity of scarlet fever would continue to maintain an upward trend in Shanghai and the techniques used in GAS isolates surveillance program and in the combined mathematical model could be applied for the early warning system on scarlet fever.

[Assessment and application of a molecular diagnostic method on the detection of four types of diarrheagenic Escherichia coli].

OBJECTIVE: To establish and evaluate a molecular diagnostic method for routine monitoring of four types of diarrheagenic Escherichia (E.) coli (DEC)and to study the distribution of four types of DEC isolated from diarrheal patients in Shanghai. METHODS: DEC-PCR standard operation procedure(SOP)had been developed for DEC detection and isolation, using the Statens Serum Institute (SSI) DEC PCR kits with multiplex PCR technique after verification tests on reference strains. Diarrhea specimens from 3 clinical hospitals in Shanghai were tested from June to September, 2012. RESULTS: Specificity of the PCR kit was 100% by verification on the 26 DEC reference strains. A total number of 218 DEC isolates, including 181 fermented lactose and 37 unfermented lactose were identified from the 1887 stool specimens of diarrhea patients, with positive rate as 11.6%. The most common pathogen(54.1%, 118/218)was enteropathogenic E. coli(EPEC), followed by enterotoxigenic E. coli(ETEC, 41.3%, 90/218), enteroinvasive E. coli (EIEC, 4.1%, 9/ 218) and Shigatoxin-producing E. coli(STEC, 0.5%, 1/218)in addition to 18 Shigella isolates. ETEC dominated in diarrhea patients with foreign residency, as well as 1/3 were perinatal stage of neonatal ETEC of all diarrhea cases under the age of 5, while EPEC dominated in the Chinese diarrhea patients especially among young kids under the age of 2. CONCLUSION: Data was reliable after assessment on this molecular diagnostics and seperation procedures used for the routine monitoring on four types of DEC, while the diagnosis and reference ability of DEC regarding the laboratories net-working on food-borne pathogens need to be built up and improved.

The development of a combined mathematical model to forecast the incidence of hepatitis E in Shanghai, China.

BACKGROUND: Sporadic hepatitis E has become an important public health concern in China. Accurate forecasting of the incidence of hepatitis E is needed to better plan future medical needs. Few mathematical models can be used because hepatitis E morbidity data has both linear and nonlinear patterns. We developed a combined mathematical model using an autoregressive integrated moving average model (ARIMA) and a back propagation neural network (BPNN) to forecast the incidence of hepatitis E. METHODS: The morbidity data of hepatitis E in Shanghai from 2000 to 2012 were retrieved from the China Information System for Disease Control and Prevention. The ARIMA-BPNN combined model was trained with 144 months of morbidity data from January 2000 to December 2011, validated with 12 months of data January 2012 to December 2012, and then employed to forecast hepatitis E incidence January 2013 to December 2013 in Shanghai. Residual analysis, Root Mean Square Error (RMSE), normalized Bayesian Information Criterion (BIC), and stationary R square methods were used to compare the goodness-of-fit among ARIMA models. The Bayesian regularization back-propagation algorithm was used to train the network. The mean error rate (MER) was used to assess the validity of the combined model. RESULTS: A total of 7,489 hepatitis E cases was reported in Shanghai from 2000 to 2012. Goodness-of-fit (stationary R2=0.531, BIC= -4.768, Ljung-Box Q statistics=15.59, P=0.482) and parameter estimates were used to determine the best-fitting model as ARIMA (0,1,1)×(0,1,1)12. Predicted morbidity values in 2012 from best-fitting ARIMA model and actual morbidity data from 2000 to 2011 were used to further construct the combined model. The MER of the ARIMA model and the ARIMA-BPNN combined model were 0.250 and 0.176, respectively. The forecasted incidence of hepatitis E in 2013 was 0.095 to 0.372 per 100,000 population. There was a seasonal variation with a peak during January-March and a nadir during August-October. CONCLUSIONS: Time series analysis suggested a seasonal pattern of hepatitis E morbidity in Shanghai, China. An ARIMA-BPNN combined model was used to fit the linear and nonlinear patterns of time series data, and accurately forecast hepatitis E infections.

[Prediction of influenza-like illness in Shanghai based on the generalized additive method].

The aim of the current research topic was to test the generalized additive method (GAM), using data from the analysis and prediction on influenza-like illness (ILI) in Shanghai. Through collecting the meteorological data as well as the ILI from 2006 to 2010, we established several nonlinear regression candidate models based on the GAM. These models considered factors as: the nonlinear dependence on the meteorological data, i.e. weekly average temperature and weekly average (maximum) temperature differences and the ILI. The AIC (Akaike information criterion) involved two simplified models which were implemented for further analysis and prediction. Finally, numerical examples showed that the proposed models could shed light on the connection between the meteorological data and the ILI. GAM could be used to fit the frequencies of ILI and meteorological factors in Shanghai. The proposed models were able to accurately analyze the onset of ILI, implying that GAM might be suitable for the prediction and analysis of those meteorological correlative diseases.

[Study on the status of HBV infection and its determinants among family members with HBV infected persons in Shanghai].

OBJECTIVE: To understand the status of HBV infection among family members with HBV infected persons in Shanghai and to probe the determinants of HBV infection so as to provide evidence for improving the related strategies on hepatitis B prevention and control. METHODS: Three hundred and four hepatitis B patients together with 288 HBsAg carriers from 6 districts in Shanghai were randomly sampled in 2010. All the said persons and their families members were asked to fill in questionnaires and to be drawn 5 ml venous blood for HBV serologic indicators detection. The subjects were divided into case group and control group according to their status of HBV infection. Univariate analysis and multivariate logistic regression analysis were carried out to identify the determinants of HBV infection among family members. RESULTS: Among 1485 subjects from 592 households, a total of 1137 persons were infected by HBV, with the overall infection rate as 76.57%. Fifteen infection modes were noticed, in which double positive of anti-HBs and anti-HBc, triple positive of HBsAg, anti-HBe and anti-HBc, together with triple positive of anti-HBs, anti-HBe and anti-HBc accounted for the top three, with the proportions as 30.69%, 26.65% and 10.03% respectively. The differences between the years of carrying HBV and the proportions of numbers that carrying HBV in families, were not statistically significant. The infection rate among children (42.86%) was significantly lower than that of their parents (87.54%) (P < 0.001). Results from both univariate and multivariate analysis showed that gender, age, utensil sharing, histories of receiving hepatitis B vaccines and dental outpatient service were determinants of HBV infection among families members (P < 0.05), with OR values being 9.009 for persons without immunization history of hepatitis B vaccines, 3.817 for persons above 40 years old and 2.283 for persons of 21 - 40 years old, 2.222 for families members who sharing utensil, 2.124 for persons with history of dental outpatient service and 1.339 for male members, respectively. CONCLUSION: Family clustering of HBV infection in was seen in Shanghai. In order to reduce the number of HBV infection in families, hepatitis B vaccination program need to be carried out. Healthy lifestyle should be emphasized to prevent HBV infection due to close contact. The risk of iatrogenic HBV transmission should also be prevented.

[Study and application of transmission tracking analysis technique during incubation period of respiratory infectious diseases].

OBJECTIVE: To develop a new transmission tracking analysis technique during incubation period of respiratory infectious diseases, and to discuss its practical value in the field survey of infectious diseases. METHODS: The classical epidemiological theory was integrated with geographic information system. The transmission tracking analysis technique was established based on the modeling platform ArcGIS Engine Developer Kit 9.3, using the techniques of address matching, shortest path analysis and buffer analysis, and programming by Visual C++. Eight serious sever acute respiratory syndrome (SARS) cases in Shanghai in year 2003 were then chose as prototype to set up the test cases A-H. The electronic map and population density data were separately collected from Institute of Surveying and Mapping in Shanghai and Shanghai statistical yearbook 2003, to calculate and explore the parameters as length of transmission path, area of buffer zone and key departments by single and multi case analysis module. RESULTS: The single case transmission tracking analysis showed that the length of transmission track of case A was 129.89 km during April 25th to 29th in 2003, including 12 tracing point and 108 intimate contacts, and the total area of buffer zone was 7.11 km(2) including 81 important institutes, naming 72 schools, 6 kindergartens and 3 gerocomiums. The multi-case transmission tracking analysis showed that the 8 cases shared 5 tracks without any temporal communication. However, there was a spatial communication whose length was 1.42 km and area was 0.60 km(2). There were no important institutes found in this communication area. CONCLUSION: Transmission tracking technique is practicable and efficient to trace the source of infection, analyze the transmission tracks, establish the isolation buffer area and explore the important geographic positions in epidemiological investigation.