脉冲媒体报道对H7N9影响的定性研究

本文主要考虑脉冲媒体报道和媒体报道冲击下引起的脉冲出生对H7N9的影响,并运用上下解方法、不动点理论、LambertW函数的性质以及脉冲微分方程的相关理论定性地讨论了无病平衡点和地方病平衡点的存在性。     

真情流露、爱浙一生——H7N9禽流感病友会

初秋,一则“绍兴新增一例禽流感”报道让人们霎那间回忆起上半年那惊心动魄的时刻。所不同的是,老百姓此刻并没有恐慌,更像是在提醒人们,曾经的那些禽流感患行,他们如今怎么样了？     

H7N9疫情形势下野生动物保护工作的现状、问题及建议

简要概述了塘沽野生动物保护工作的发展现状,结合当下H7N9禽流感疫情形势,浅析野生动物保护和监测工作中所面临的热点、难点问题,按照天津市滨海新区十二五总体发展战略要求和布局,提出了改进措施和工作建议。     

媒体报道对H7N9人禽传染的影响及其动力学分析

考虑媒体报道对疾病传播的影响以及H7N9饱和传染率的特点,建立了媒体报道对H7N9人禽传染影响的数学模型。研究了平衡点的存在性,局部稳定性和全局稳定性。最后对本文所得到的结果进行数值模拟,并指出了本文研究的实际意义。     

中国人感染H7N9的时空传播特性分析

为揭示中国人感染H7N9疫情的时空发展规律和演变规律,基于2013年至2017年人感染H7N9统计数据,分别进行时间序列和标准差椭圆分析.首先以月为时间单位分析疫情时间序列,识别疫情的高峰期和低谷期,在此基础上将整个疫情期进行阶段划分,并对各阶段的疫情变化规律进行分析.然后根据疫情病例的发生位置建立标准差椭圆,通过各阶...     

江浙沪地区H7N9禽流感事件中的脆弱性与康复力影响因素

2013年春季在我国发生的H7N9禽流感事件,是一次公共卫生领域的恶性突发事件,在全国产生了严重的影响。研究和评估该事件的脆弱性与康复力,对于我国突发公共卫生体系的建设具有较大的借鉴意义。本文选择江浙沪地区感染H7N9禽流感的病例为研究对象,从承灾体脆弱性以及响应主体康复力的角度分析、审视我国突发性公共卫生事件的管理体系,以期探求改进我国公共卫生疫情处置的最佳途径和方法。     

政府干预对H7N9型禽流感疫情发展的影响

以2013年春季中国大陆爆发的H7N9型禽流感疫情实际数据为例,在建立数学模型的基础上,通过最小二乘法、欧拉迭代法等定量分析与模拟,考察政府干预对该疫情的影响,所得数值结果反映了政府干预的必要性.     

基于WebGIS的H7N9信息查询系统开发

我国至2014年7月为止,总共报告出447例人感染H7N9禽流感病毒确诊病例,基于该背景,开发H7N9信息查询系统,为大家查询提供方便有效的手段.     

Molecular characterization of avian influenza virus (H7N8) isolated from poultry in Central China in the mid-1980s

The molecular and pathogenic properties of avian influenza virus (A/duck/Hubei/216/1985/H7N8) isolated from Hubei Province of China in 1985 were characterized.The hemagglutinin gene (HA) of Dk/Hb/216/85/H7N8 had the multiple amino acid se-quences (-PEIPKGRG-) at the connecting peptide between HA1 and HA2, which is considered to be a distinguishing molecular characteristic of low pathogenicity.The key sites of host markers among the genes (M, NP, NS, PA and PB2) of Dk/Hb/ 216/85/H7N8 were similar to those of...     

Increased substitution rate in H5N1 avian influenza viruses during mass vaccination of poultry

As a means of heated debate,mass vaccination of poultry has been used in some countries to control H5N1 highly pathogenic avian influenza(HPAI),which remains of global economic and public health significance.Theoretically,mass vaccination can act as an evolutionary selective force facilitating the emergence of vaccine-resistant viruses,similar to that widespread use of antibiotics facilitates the emergence of antibiotic-resistant bacteria.To support the hypothesis,the substitution rates in the two subunits,HA1 and HA2,of the viral hemagglutinin gene,were calculated using a Bayesian Markov Chain Monte Carlo(MCMC) approach.It was found that the rate in the HA1 subunit,but not in the HA2 subunit,increased significantly during periods of mass vaccination(2005 2010 in China and 2003 2009 in Indonesia),in contrast to the periods when no mass vaccination programs took place(1996 2004 in China and 2004 2008 in Thailand).Because substitutions in the HA1 subunit rather than in the HA2 subunit can lead to vaccine-resistant viruses,the results support that mass vaccination programs facilitate the emergence of vaccine-resistant viruses,which,in turn,will render mass vaccination programs less effective.Therefore,caution must be taken when adopting mass vaccination as a long-term strategy to control HPAI.     

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.     

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.     

Molecular characterization of H3N2 and H4N6 subtypes avian influenza viruses isolated from mallards in Poyang Lake, China in 2010

Poyang Lake is the largest inland freshwater lake in China and contains many species of wild birds and waterfowls.We conducted a survey of avian influenza viruses in nine semi-artificial waterfowl farms in Poyang Lake during January to March of 2010.Out of 1036 cloacal swabs collected,three H3N2 and one H4N6 influenza viruses were isolated from healthy mallards.All the isolates were genetically and phylogenetically characterized.The analysis of putative HA cleavage sites showed that all the four isolates possessed the molecular characteristics(QTRGL for H3N2 viruses,PEKASR for H4N6 virus) of lowly pathogenic avian influenza(LPAI) virus.The phylogenetic analysis of the viral genomes showed that all four virus isolates clustered in the Eurasian clade of influenza viruses.The M gene of the viruses possessed the highest homology with highly pathogenic H5N1 influenza viruses.In addition,co-infection of H3N2 and H4N6 in the same farm was observed.And interestingly,we isolated two subtypes viruses(H3N2 and H4N6) and their progeny virus(H3N2) with evidence of genome reassortment from the same farm,in which the PB1 and PB2 gene segments of H4N6 replaced those of the H3N2 strain.The results of animal infection experiments showed that all the four isolated viruses were lowly pathogenic to chickens and not pathogenic to mice,which was consistent with the results of genetic analysis.     

成都地区10例H7N9患者实验室检测分析

目的探讨成都市公共卫生临床医疗中心2017年收治的10例H7N9患者治疗前、后实验室指标变化及其临床意义。方法 (1)病例组(死亡组3例,治愈组7例)治疗前后和对照组(20例)分别检测心肌损伤标志物、D-二聚体,进行比较分析;(2)比较分析死亡组与痊愈组血常规、C反应蛋白、降钙素原、乳酸等感染指标的动态变化。结果与正常对照组比较,治疗前的病例组心肌损伤指标升高(P <0. 05),D-二聚体变化不大(P> 0. 5);治愈组治疗后各项指标除α-HBDH、LDH外较治疗前降低(P <0. 05),而死亡组各项指标大幅度升高(P <0. 05),尤其D-二聚体升高明显(P <0. 05); 3例死亡病例各项感染均升高,白细胞及中性粒细胞计数升高,淋巴细胞及血小板计数降低;痊愈病例随病情好转各指标降至正常。结论上述实验室指标是反映H7N9患者病情严重程度的重要指标,对其动态观察对病情发展、病情严重程度、及预后判断提示具有一定的临床意义。     

中国大陆H9N2亚型禽流感病毒HA基因遗传分析及抗原相关性研究

为研究我国大陆H9N2亚型禽流感病毒血凝素(HA)基因的分子进化及抗原相关性, 本研究对来自15个省、市、自治区的34株H9N2亚型禽流感病毒的HA基因进行了测序及系统发育分析, 并采用交叉血凝抑制试验及交叉攻毒保护试验对不同遗传分支下毒株间抗原相关性进行了分析. 结果表明, 所有34个毒株HA基因均符合低致病性禽流感病毒的特征, 但毒株间变异程度增加. 系统发育分析表明, 我国大陆H9N2亚型禽流感病毒主要分为三个系列, 各系列内毒株没有明显的地区及时间特征. 抗原相关性研究表明, 不同遗传系列下的毒株其抗原相关性明显低于同一系列内部毒株间的抗原相关性, 说明我国H9N2亚型禽流感病毒抗原性差异较大. 此外, 本研究同时筛选得到了用于制备多价苗的代表毒株.