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RationaleSeveral studies have estimated basic production number of novel coronavirus pneumonia (NCP). However, the time-varying transmission dynamics of NCP during the outbreak remain unclear. ObjectivesWe aimed to estimate the basic and time-varying transmission dynamics of NCP across China, and compared them with SARS. MethodsData on NCP cases by February 7, 2020 were collected from epidemiological investigations or official websites. Data on severe acute respiratory syndrome (SARS) cases in Guangdong Province, Beijing and Hong Kong during 2002-2003 were also obtained. We estimated the doubling time, basic reproduction number (R0) and time-varying reproduction number (Rt) of NCP and SARS. Measurements and main resultsAs of February 7, 2020, 34,598 NCP cases were identified in China, and daily confirmed cases decreased after February 4. The doubling time of NCP nationwide was 2.4 days which was shorter than that of SARS in Guangdong (14.3 days), Hong Kong (5.7 days) and Beijing (12.4 days). The R0 of NCP cases nationwide and in Wuhan were 4.5 and 4.4 respectively, which were higher than R0 of SARS in Guangdong (R0=2.3), Hongkong (R0=2.3), and Beijing (R0=2.6). The Rt for NCP continuously decreased especially after January 16 nationwide and in Wuhan. The R0 for secondary NCP cases in Guangdong was 0.6, and the Rt values were less than 1 during the epidemic. ConclusionsNCP may have a higher transmissibility than SARS, and the efforts of containing the outbreak are effective. However, the efforts are needed to persist in for reducing time-varying reproduction number below one. At a Glance CommentaryO_ST_ABSScientific Knowledge on the SubjectC_ST_ABSSince December 29, 2019, pneumonia infection with 2019-nCoV, now named as Novel Coronavirus Pneumonia (NCP), occurred in Wuhan, Hubei Province, China. The disease has rapidly spread from Wuhan to other areas. As a novel virus, the time-varying transmission dynamics of NCP remain unclear, and it is also important to compare it with SARS. What This Study Adds to the FieldWe compared the transmission dynamics of NCP with SARS, and found that NCP has a higher transmissibility than SARS. Time-varying production number indicates that rigorous control measures taken by governments are effective across China, and persistent efforts are needed to be taken for reducing instantaneous reproduction number below one.
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Objective To understand the status of infection and epidemic trend of Dengue fever and Chikungunya in Guangdong.Methods Retrospective survey and literature review were used to obtain data on the incidence,etiology of Dengue and Chikungunya.Serological survey was conducted to detect the specific-antibodies in healthy individuals for both Dengue virus (DENV) and Chikungunya virus (CHIKV).Results Three epidemics of Dengue fever were observed during 1990-2012,with the annual incidence rates as 9.75/100 000 in 1995,1.76/100 000 in 2002 and 1.25/100 000 in 2006,respectively.The predominant epidemic strains appeared to be DENV-2 and DENV-4 during 1990-1994.Since 1995,DENV-1 had become the predominant transmission strain which lasted for almost 13 years.Co-existence of multiple serotypes of DENV started in 2009.Of the 7 718 sera from healthy population during 2003-2012,180 specimens were detected positive for specific DENV-IgG antibody,ended with a sero-prevalence rate of 2.33％.All 2 132 sera in 2012 were detected negative for CHIKV-IgG antibody.Conclusion The overall exposure level to Dengue was considered to be low in Guangdong province.However,the predominant transmission mode caused by DENV-1 had been gradually changed into the co-existence of multiple serotypes with the endemic signs appeared in some part of the areas.Chikungunya was a newly emerging disease in Guangdong since local people were lack of basic immunity barrier.Surveillance and control programs thus seemed important.
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To compare and evaluate the discriminatory ability and potential value of pulsed field gel electrophoresis (PF-GE) and multiple locus VNTRs analysis (MLVA) on the genotyping of Brucella ,a total of 60 strains of Brucella and three standards (16M ,544A ,1330S) were genotyped simultaneously by PFGE and MLVA .The result indicated that the similarity coefficient among the 63 isolates was from 72 .1-100 .0% by PFGE ,and could distinguish three species of B .melitensis ,B .su-is and B .abortus at the similarity level of 94 .4% .There were 14 clusters and 29 PFGE types identified by PFGE with discrim-inatory index (DI) of 0 .957 5 at the similarity level of 100% ;the similarity coefficient among the 63 isolates was from 16 .9-100 .0% by MLVA ,and could distinguish three species of Brucella at the similarity level of 52 .3% .There were 8 clusters and 47 MLVA types identified by MLVA with discriminatory index (DI) of 0 .985 2 at the similarity level of 100% .It's suggested that PFGE and MLVA could be used to distinguish three species of Brucella in the similarity coefficient of certain ,but could not effectively distinguish the type in the same species .Both of these two methods could be used for Brucella molecular typing , but MLVA is better than PFGE for its relatively higher discriminating ability .
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BACKGROUND:Diabetic foot ulcers threaten the patients’ health and even survival seriously. It is an international difficult problem and lacks an effective treatment. But gene therapy and stem celltherapy possess special advantages and potential in wound healing. OBJECTIVE:To assess the therapeutic effect of transplantation of bone marrow mesenchymal stem cells transfected by human vascular endothelial growth factor 165 (hVEGF165) gene on foot wound healing in diabetic rats. METHODS:Recombinant adenovirus was established in vitro which expressed hVEGF165 gene and transfected into the third generation of bone marrow mesenchymal stem cells. Total y 120 male Wistar rats were divided into five groups:group A (non-diabetic controls), group B (diabetic controls), group C (Ad-hVEGF165 therapy), group D (stem celltherapy) and group E (transplantation of bone marrow mesenchymal stem cells transfected by Ad-hVEGF165 gene). Rats in the latter four groups were intraperitoneal y injected with streptozotocin to induce diabetic models. In al rats, a 3 mm×7 mm rectangular ful-thickness skin sample was cut from the instep of the hind foot to make a model of foot wound. The rats were subcutaneously injected at equidistant six points 5 mm distal to the wound edge on the dorsum of the foot:50μL PBS per point for group A, 50μL adenovirus suspension (1×1013 pfu/L) per point for group C, 50μL stem cellsuspension (1×1010/L) per point for group D, and 50μL adenovirus suspension+50μL stem cellsuspension per point for group E. RESULTS AND CONCLUSION:After injection, the rate of wound healing, the expression of VEGF and the qualities of capil aries in group E were higher when compared with groups B, C, D (P<0.05), but were lower than those in group A (P<0.05). Transplantation of bone marrow mesenchymal stem cells transfected by hVEGF165 gene can promote foot wound healing, angiogenesis and expression of VEGF in diabetic rats.
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BACKGROUND: This study was conducted to identify epidemiological characteristics of the first documented CHIK fever outbreak in China and evaluate the effect of the preventive measures taken. METHODOLOGY/PRINCIPAL FINDINGS: From September 1 to October 29, 2010, China's first documented outbreak of CHIK fever occurred in the Xincun community of Wanjiang District of Dongguan city, Guangdong province; 253 case-patients were recorded, of which 129 were laboratory confirmed, with an attack rate of 1%. Before September 18(th) the number of CHIK fever cases remained relatively low in the Xincun community; from September 19(th) onwards, the number of cases increased drastically, with an outbreak peak on October 4(th). Cases were distributed across nine small village groups in the Xincun community, with an attack rate of 0-12% at the village level. The household attack rates ranged between 20% and 100%. No significant difference was found in the attack rate between males and females. There was a significant difference in the attack rate in different age groups (chi-square=18.35, p=0.005); highest in patients aged 60 years or older and the lowest in patients aged under 10. The major clinical characteristics of patients are fever (100%), joint pain (79%) and rash (54%). Phylogenetic analysis of the E1 gene on the five earliest confirmed cases showed that the strains of CHIKV isolated from their sera were highly homologous (up to 99%) with isogeneic strains isolated in Thailand in 2009. After control measures were taken, including killing adult mosquitoes and cleaning breeding habitats of Aedes mosquitoes, the Breteau index and Mosq-ovitrap index decreased rapidly, and the outbreak ended on October 29. CONCLUSION/SIGNIFICANCE: The infection source of the outbreak was imported. Cases showed obvious temporal, spatial, and population aggregation during the outbreak. Comprehensive control measures based on reducing the density of Aedes mosquitoes were effective in controlling the epidemic.
