Urban structure and the risk of influenza A (H1N1) outbreaks in municipal districts

Changsha was one of the most affected areas during the 2009 A (H1N1) influenza pandemic in China. Here, we analyze the spatial–temporal dynamics of the 2009 pandemic across Changsha municipal districts, evaluate the relationship between case incidence and the local urban spatial structure and predict high-risk areas of influenza A (H1N1). We obtained epidemiological data on all cases of influenza A (H1N1) reported across municipal districts in Changsha during period May 2009–December 2010 and data on population density and basic geographic characteristics for 239 primary schools, 97 middle schools, 347 universities, 96 malls and markets, 674 business districts and 121 hospitals. Spatial–temporal K functions, proximity models and logistic regression were used to analyze the spatial distribution pattern of influenza A (H1N1) incidence and the association between influenza A (H1N1) cases and spatial risk factors and predict the infection risks. We found that the 2009 influenza A (H1N1) was driven by a transmission wave from the center of the study area to surrounding areas and reported cases increased significantly after September 2009. We also found that the distribution of influenza A (H1N1) cases was associated with population density and the presence of nearest public places, especially universities (OR = 10.166). The final predictive risk map based on the multivariate logistic analysis showed high-risk areas concentrated in the center areas of the study area associated with high population density. Our findings support the identification of spatial risk factors and high-risk areas to guide the prioritization of preventive and mitigation efforts against future influenza pandemics.     

甲型H1N1流感超敏感诊断方法的建立及优化

利用几种助沉剂和核酸纯化方法富集病毒RNA,建立甲型H1N1流感超敏感诊断方法。收集31份甲型H1N1流感确诊病人提取的病毒RNA,稀释至1000分之一倍后分别应用酵母tRNA、糖原、AcrylCarrier助沉剂和磁珠、硅胶颗粒和离心柱的9种组合进行病毒RNA的富集,富集后分别进行RealtimePCR检测。并对检测结果进行统计学分析。利用几种助沉剂和核酸纯化方法的组合时,发现磁珠+AcrylCarrier助沉剂方法是最佳的核酸富集方法,能够大大提高病毒核酸的检出效率。建立了甲型H1N1流感超敏感诊断方法,该方法能够大大提高甲型H1N1流感的检出率。     

Genome evolution of novel influenza A （H1N1 ） viruses in humans

The epidemic situation of A H1N1 flu arose in North America in April 2009, which rapidly expanded to three continents of Europe, Asia and Africa, with the risk ranking up to 5. Until May 13th, the flu virus of A H1N1 had spread into 33 countries and regions, with a laboratory confirmed case number of 5728, including 61 deaths. Based on IRV and EpiFluDB database, 425 parts of A H1N1 flu virus sequence were achieved, followed by sequenced comparison and evolution analysis. The results showed that the current predominant A H1N1 flu virus was a kind of triple reassortment A flu virus： （i） HA, NA, MP, NP and NS originated from swine influenza virus; PB2 and PA originated from bird influenza virus; PB1 originated from human influenza virus. （ii） The origin of swine influenza virus could be subdivided as follows： HA, NP and NS originated from classic swine influenza virus of H1N1 subtype; NA and MP originated from bird origin swine influenza virus of H1N1 subtype. （iii） A H1N1 flu virus experienced no significant mutation during the epidemic spread, accompanied with no reassortment of the virus genome. In the paper, the region of the representative strains for sequence analysis （A/California/04/2009 （H1N1） and A/Mexico/4486/2009 （H1N1）） included USA and Mexico and was relatively wide, which suggested that the analysis results were convincing.     

The mutation network for the hemagglutinin gene from the novel influenza A （H1N1 ） virus

A mutation network for the hemagglutinin gene （HA） of the novel type A （H1N1） influenza virus was constructed. Sequence homology analysis indicated that one HA sequence type from the viruses mainly isolated from Mexico was likely the original type in this epidemic. Based on the 658A and 1408T mutations in HA, the viruses evolving into this epidemic were divided into three categories, the Mexico, the transitional and the New York type. The three groups of viruses presented distinctive clustering features in their geographic distributions.     

Orisin and future distribution of the new A （H 1N1 ） influenza virus emerging in North America in 2009

The origin of the new A （H1N1） influenza virus recently emerging in North America is a hot controversial topic of significance in disease control and risk assessment. Some experts claimed that it was an unusually mongrelized mix of human, avian and swine influenza viruses, while some others concluded that it was totally a simple re-assortment hybrid of two lineages of swine influenza viruses. Here the phylogenetic diversity of the viral PB1, PA and PB2 gene sequences using online web servers, and the results suggest that all the 8 genetic segments of the new virus were possibly from two lineages of swine influenza viruses, and one of the lineage was a mongrelized mix of human, avian and swine influenza viruses emerging in the world approximately 10 years ago. Considering the recent epidemiological trends of the new virus, we believe it will spread more widely in the world and persist long in human populations. It also could spread among swine populations. The future wide spreading of the new virus may coincide the disappearance of a subtype of previous human influenza A virus.     

从引发自墨西哥的A(H1N1)型流感说起

2003年春夏暴发的SARS疫情,带给我们的恐惧和惊慌仍然记忆犹新;今年4月由墨西哥引发继而波及全球21个国家和地区的A(H1N1)型流感事件,给世人呈现的却是中国人在处置时的镇定自若和从容不迫.     

甲型H1N1流感病毒性肺炎的临床及影像学表现3例报告

目的:总结3例甲型H1N1流感病毒性肺炎患者的呼吸道表现和胸部影像学特点,积累临床经验.方法:回顾性分析3例甲型H1N1流感患者入院时的呼吸道表现特点和胸部影像学动态变化.结果:3例男性患者,均有慢性基础病和吸烟史,发热持续1周以上,伴有咳嗽、咳痰、胸闷及气促等,但无咽痛和流涕症状.可有紫绀,咽部充血,双下肺散在湿啰音等表现.3例患者胸部X线和CT平扫检查显示双肺下野斑片状、云絮状、磨玻璃样或网格状高密度影等特征性表现,后期出现纤维化改变,双肺正常组织呈过度充气状态.结论:根据肺部影像学表现,结合临床,可做出甲型H1N1流感病毒性肺炎的诊断.     

Special features of the 2009 pandemic swine-origin influenza A H1N1 hemagglutinin and neuraminidase

Since the 2009 pandemic H1N1 swine-origin influenza A virus (09 S-OIV) has reminded the world about the global threat of the ever changing influenza virus,many questions regarding the detailed re-assortment of influenza viruses yet remain unanswered.Influenza A virus is the causative agent of the pandemic flu and contains 2 major antigenic glycoproteins on its surface:(i) hemagglutinin (HA);and (ii) neuraminidase (NA).The structures of the 09 S-OIV HA and NA proteins (09H1 and 09N1) have recently been resolved in our laboratory and provide some clues as to why the 09 S-OIV re-assortment virus is highly infectious with severe consequences in humans.For example,the 09H1 is highly similar to the HA of the 1918 influenza A pandemic virus in overall structure and especially in regards to its 5 defined antibody binding epitopes.For 09N1,its most distinctive feature is the lack of a 150-loop active site cavity,which was previously predicted to be present in all N1 NAs,and we hypothesize that the 150-loop may play a important role in the substrate specificity (α2,3 or α2,6 linked sialic acid receptors) and enzymatic mechanism of influenza NA.Combination of the HA and NA with special characteristics for the 09 S-OIV might contribute to its high increased transmissibility in humans.     

2009年甲型H1N1流感临床研究回顾

2009年全球爆发的甲型H1N1流感由一种源于猪流感病毒、致人急性呼吸道疾病的新型流感病毒所致.本文总结了甲型H1N1流感病毒感染病例的临床特征、治疗及研究展望.     

Molecular characterization of H1N1 influenza A viruses from human cases in North America

Subtypes of H1N1 influenza virus can be found in humans in North America, while they are also associated with the infection of swine. Characterization of the genotypes of viral strains in human populations is important to understand the source and distribution of viral strains. Genomic and protein sequences of 10 isolates of the 2009 outbreak of influenza A （H1N1） virus in North America were obtained from GenBank database. To characterize the genotypes of these viruses, phylogenetic trees of genes PB2, PB1, PA, HA, NP, NA, NS and M were constructed by Phylip3.67 program and N-Linked glycosylation sites of HA, NA, PB2, NS1 and M2 proteins were analyzed online by NetNGlyc1.0 program. Phylogenetic analysis indicated that these isolates are virtually identical but may be recombinant viruses because their genomic fragments come from different viruses. The isolates also contain a characteristic lowly pathogenic amino acid motif at their HA cleavage sites （IPSIQSR↓GL）, and an E residue at position 627 of the PB2 protein which shows its high affinity to humans. The homologous model of M proteins showed that the viruses had obtained the ability of anti-amantadine due to the mutation at the drug-sensitive site, while sequence analysis of NA proteins indicated that the viruses are still susceptible to the neuraminidase inhibitor drug （i.e. oseltamivir and zanamivir） because no mutations have been observed. Our results strongly suggested that the viruses responsible for the 2009 outbreaks of influenza A （H1N1） virus have the ability to cross species barriers to infect human and mammalian animals based on molecular analysis. These findings may further facilitate the therapy and prevention of possible transmission from North America to other countries.     

媒体报道对禽流感(H7N9)传播影响的研究

研究媒体报道对传染病传播的影响。建立了受媒体影响的禽流感(H7N9)传播动力学模型,得到了模型的基本再生数。利用V函数、Dulac函数及极限方程理论等方法对模型进行了动力学性态的分析。证明了当基本再生数不大于1时,无病平衡点全局渐近稳定;当基本再生数大于1时,地方病平衡点全局渐近稳定。进一步,数值模拟显示了媒体报道对H7N9传播的具体影响。可通过媒体报道来控制传染病的规模。     

Influenza A （HIN1） transmission by road traffic between cities and towns

Influenza A (H1N1) was spread widely between cities and towns by road traffic and had a major impact on public health in China in 2009. Understanding regulation of its transmission is of great significance with urbanization ongoing and for mitigation of damage by the epidemic. We analyzed influenza A (H1N1) spatiotemporal transmission and risk factors along roads in Changsha, and combined diffusion velocity and floating population size to construct an epidemic diffusion model to simulate its transmission between cities and towns. The results showed that areas along the highways and road intersections had a higher incidence rate than other areas. Expressways and county roads played an important role in the rapid development stage and the epidemic peak, respectively, and intercity bus stations showed a high risk of disease transmission. The model simulates the intensity and center of disease outbreaks in cities and towns, and provides a more complete simulation of the disease spatiotemporal process than other models.     

甲型H1N1流行与气象因子显著关联

2009年3月18日,墨西哥发现甲型H1N1流感疑似病例:2009年4月21日,美国疾病预防控制中心(CDC)报告2名儿童感染甲型H1N1流感病毒.随后,墨西哥、美国、加拿大等国家出现大量病例,甲型H1N1流感自美洲暴发流行.随着甲型H1N1流感在全球蔓延,世界卫生组织(WHO)将警告级别由3级逐渐提升为6级,表明全球进入流感大流行阶段.截至2010年4月14日,超过213个国家和地区报告了经实验室确诊的甲型H1N1流感病例,至少17770人死亡.     

简述甲型(H1N1)流感疫情

一场突如其来的猪流感疫情在2009年4月13日起在墨西哥蔓延.墨西哥于2009年4月26日晚宣布,墨西哥确认和疑似死于猪流感的总人数升至103人,继之很快上升到1 300人.     

H5N1亚型禽流感毒株A/Duck/HuBei/3/2005的分子特征及致病性研究

采用分子生物学方法,对1株2005年从湖北省某县分离获得的禽流感病毒株(A/Duck/HuBei/3/2005)进行全基因组序列测定.序列分析显示,该分离株为H5N1亚型.HA蛋白在HA1和HA2连接处,含有连续多碱性氨基酸模体(-RRKKR-).根据进化分析结果,分离株A/Duck/HuBei/3/2005的7个基因来源于2004～2005年湖南地区流行株(CK/HN/999/05,DK/HN303/04),但是PA基因片段发生了重排,来源于野禽.动物实验显示DK/HB/3/05对鸡和鸭均具有高致病性;对小鼠有较低致病性.     

发生甲型流感疫情时大学生体育行为变化调查研究——以河北省在校大学生为例

通过问卷调查对河北省6所大学在校大学生在发生甲型H1N1流感后的体育行为进行调查与研究,发现在疫情发生之后大学生的体育行为向积极的方向发展.在显性体育行为上,表现为参加体育锻炼的时间增多、参加项目增加等等;在隐性体育行为上,表现在参加体育锻炼的态度变得积极、体育绩效感增强等方面,并且所调查的绝大多数大学生有今后继续参加体育锻炼的愿望.讨论这种现象的原因,研究其与"终身体育"的关系.     

甲型H1N1流感在预防控制措施下的传播数学模型构建

从数学应用的角度,研究甲型H1N1流感的传播规律,将人群分为易感人群、病毒潜伏人群、发病人群、退出者人群四类. 分析了甲型H1N1流感在人群间的转化过程;日接触率和"聚集性突然爆发"事件被数学刻画,尝试性地构建了一个在预防控制阶段的传播数学模型.     

Official： China might have A（H1N1） Influenza vaccine by July

Chinese scientists have named the country＇s most recently discovered meat-eating dinosaur after its centuries-old Great Wall.
Xiongguanlong, the name of an early Cretaceous predator whose fossilized remains were found near the Jiayuguan, the western start point of the 8,850-km-long Ming Dynasty Great Wall, literally means ＂Dinosaur of the Grand Pass＂, said Li Daqing, a paleontologist with Gansu Provincial Bureau of Geo-Exploration and Mineral Development, on Friday.     

无血清微载体培养MDCK细胞和甲型流感病毒H1N1的条件优化

 血清微载体培养MDCK细胞,并接种流感病毒H1N1,优化培养条件,为细胞流感疫苗的工艺研发奠定基础.采用不同的细胞接种量在50mL无血清微载体搅拌瓶中培养MDCK细胞,并接种甲型流感病毒H1N1,检测不同pH值和TPCK-胰酶含量的病毒培养液,不同病毒接种量,补加TPCK-胰酶,以及不同收毒时间对血凝效价的影响.以1.0×10⁵mL^-1的MDCK细胞数量接种到无血清微载体上,病毒培养液pH值为7.2~7.4范围内,TPCK-胰酶质量浓度为1.0μg/mL,接种后不补加胰酶,病毒接种量MOI=1.0,并在72h收获,最高血凝效价达到512.由此获得了在无血清为载体上培养MDCK细胞和甲型流感病毒H1N1的适宜条件.