甲型H1N1流感：不必惊慌 却需严防

近来,在美国和墨西哥发生人感染甲型H1N1流感病毒疫情,世界卫生组织已宣布此次疫情为”具有国际影响的公共卫生紧急事态”,并称所有国家都应加强对非正常暴发的流感类疾病和严重肺炎的监控。随着5月1日香港确认我国首宗甲型H1N1流感个案．我国各级政府和人民也进入了预防甲型H1N1流感的紧急状态。目前,加强对公众防控人感染甲型H1N1流感病毒的健康知识宣传,提高公众的自我保护能力成为第一要务。     

增强免疫力预防甲型H1N1流感的保健饮食

1918年的流感大流行虽已过去90多年,但现仍不时地滋扰着人类.甲型H3N2流感病毒是流行循环中季节性流感最主要的类型[1].2009年3～4月美国和墨西哥发现了流感病毒变异的新型流感,世界卫生组织(WHO)定名为甲型H1N1流感[2],6月中旬WHO将流感警戒从5级升至最高级6级,宣布甲型H1N1流感大流行.入冬以来,全球甲型H1N1流感暴发第2波,防控流感形势严峻.     

增强免疫力预防甲型H1N1流感的保健饮食

1918年的流感大流行虽已过去90多年,但现仍不时地滋扰着人类.甲型H3N2流感病毒是流行循环中季节性流感最主要的类型[1].2009年3～4月美国和墨西哥发现了流感病毒变异的新型流感,世界卫生组织(WHO)定名为甲型H1N1流感[2],6月中旬WHO将流感警戒从5级升至最高级6级,宣布甲型H1N1流感大流行.入冬以来,全球甲型H1N1流感暴发第2波,防控流感形势严峻.     

甲型H1N1流感专家谈

截至北京时间2009年5月16日23时30分，世界卫生组织（WHO）确认全球37个国家和地区共有甲型H1N1流感确诊病例8451例。基因序列分析显示，引发此次疫情的流感病毒包含了猪、禽和人三种流感病毒的基因片断，是一种新型“组合流感病毒”。针对此次疫情，世卫组织负责人近日表示，甲型H1N1流感病毒的全球性扩散预计将持续，且该病毒致病的严重程度可能因不可知因素而改变。当前世界面临一个非常不确定的时刻。     

预防流感，提高人体免疫力是关键

甲型H1N1病毒．从严格意义上讲也是一种人流感病毒。它属于是A型流感病毒。携带有H1N1亚型猪流感病毒毒株．包含有禽流感,猪流感和人流感三种流感病毒的脱氧核糖核酸基因片断．同时拥有亚洲猪流感和非洲猪流感病毒特征。简单地说,甲型H1N1病毒是“禽猪人流感三合一”进化型。     

甲型流感H1N1病毒遗传进化关系分析

探讨研究当前流行性甲型流感H1N1病毒与已知人流感H1N1病毒、禽流感H1N1病毒,猪流感H1N1病毒之间的遗传进化关系,对7株甲型H1N1、32株已知人流感H1N1、18株禽流感H1N1、33株猪流感H1N1病毒的基因组各基因片段分别进行基因序列遗传进化分析,选取同源性高的毒株构建进化树.结果显示,新型人流感病毒A型H1N1中HA,MP、NA,NP、NS、PB1基因片段与猪流感病毒分离株有很高的同源性,而PA、PB2基因与禽流感病毒分离株同源性较高.     

中美研究人员发现新型狗流感病毒

正美国《微生物学》网络杂志5日发表的一项研究显示,猪流感病毒H1N1已经传播给狗,并在狗体内与其他病毒基因发生重组,狗体内的流感病毒亚型正在增多。研究人员说,禽类和猪是导致流感病毒基因产生多样性的主要宿主,而狗和马携带的甲型流感病毒类型较少,并且几乎不传染人。此前研究发现,在狗之间流行的甲型流感病毒类型主要为H3N8和H3N2。     

H1N1流感病毒的HA、NA蛋白序列进化树

为了从本质上揭示H1N1病毒分子的变异、流感流行等关系,提出一种构建H1N1型流感病毒进化树的新方法。在1902—2013年全球22 455条H1N1型流感病毒HA蛋白序列和16444条NA蛋白序列数据的基础上,利用其特征向量构建基于内积的蛋白序列相似度;采用基于相似度的完全聚类图的方法进行数据系统粗粒化的相似信息提取;最后,利用基于模糊邻近关系的结构聚类方法构建H1N1型禽流感病毒HA、NA蛋白序列的进化树及算法研究。试验结果表明:H1N1病毒的变异不仅与爆发时间密切相关,还与所分布地域及地域间的距离有很大关系,且分布地域间的距离越近,爆发的病毒进化的相似程度越高。因此这种基于大数据处理的新方法能有效揭示流感病毒的进化关系,为进一步研究流感病毒的变异、进化与预测奠定了基础。     

最新发现:类禽H1N1猪流感病毒均可感染人

正中国农业科学院动物流感基础与防控研究创新团队一项新研究显示,欧亚类禽H1N1猪流感病毒已获感染人能力,是引起下次人流感大流行可能性最大的病毒,应予以高度重视。该研究日前在线发表在美国《国家科学院学报》上。猪是流感病毒的重要宿主,猪群中主要流行经典H1N1猪流感病毒、类禽H1N1猪流感病毒。前者1918年进入猪群,经长期进化重组,于2009年在北美进入人群并引发全球人流感大流行,被称为甲型H1N1流感;后者1979年在欧洲由禽类传入猪群,随后在欧亚很多国家猪群     

香港大学研发出可对抗H7N9病毒新疫苗

近年全球受各种流感病毒威胁,包括H7N9及H5N1禽流感等。香港大学医学院与美国国家卫生研究院在天花疫苗中．加入流感病毒基因,成功研发新型甲型流感疫苗．可对抗禽流感病毒H7N9及H5N1、季节性流感H3N2及H1N1,及高致病性H7N7。一旦爆发大型流感,可于短时间内大规模生产疫苗。     

A(H1N1)流感病毒及抗病毒新药的筛选

A(H1N1)流感病毒是2009年3~4月在美国和墨西哥发现的一种流感病毒变异的新病毒株。这类流感疫情的蔓延引起了世界各国和世界卫生组织的严重关注。本文介绍了A(H1N1)流感新病毒株及感染这种病毒患者的症状,A(H1N1)流感病毒的致命力和传播,流感病毒变异对抗病毒药的抗药性,以及1918年流感大流行病毒聚合酶特性,人流感病毒和禽流感病毒聚合酶的结晶结构及其在感染中的作用。据此,提出了抗流感病毒药的筛选思路和研究方向,为抗流感病毒新药的设计和开发提供有益的参考。     

A(H1N1)流感病毒及抗病毒新药的筛选

A(H1N1)流感病毒是2009年3～4月在美国和墨西哥发现的一种流感病毒变异的新病毒株.这类流感疫情的蔓延引起了世界各国和世界卫生组织的严重关注.本文介绍了A(H1N1)流感新病毒株及感染这种病毒患者的症状,A(H1N1)流感病毒的致命力和传播,流感病毒变异对抗病毒药的抗药性,以及1918年流感大流行病毒聚合酶特性,人流感病毒和禽流感病毒聚合酶的结晶结构及其在感染中的作用.据此,提出了抗流感病毒药的筛选思路和研究方向,为抗流感病毒新药的设计和开发提供有益的参考.     

新疆琐琐葡萄提取物抗流感病毒A(H1N1)亚型作用研究

目的对新疆琐琐葡萄提取物抗流感病毒A(H1N1)亚型作用进行研究。方法1.采用狗肾传代细胞培养法和MTT法研究新疆琐琐葡萄多糖、琐琐葡萄总黄酮、琐琐葡萄总三萜对抗流感病毒A(H1N1)型作用。2.采用Read-muench法计算流感病毒A(H1N1)型在狗肾传代细胞中的半数感染量。3.通过观察细胞病变(CPE)、计算细胞病变CPE抑制率、MTT法测定药物对细胞的保护率等来评价琐琐葡萄多糖、总黄酮、总三萜的抗流感病毒效果。结果琐琐葡萄总黄酮的最大无毒作用浓度(TC0)为20μg/ml,琐琐葡萄总三萜的TC0为1500μg/ml。体外细胞试验中,琐琐葡萄黄酮、多糖提取物表现出对病毒的直接抑制作用,但是琐琐葡萄三萜提取物和利巴韦林(阳性对照)此作用不明显。体外细胞试验中,琐琐葡萄黄酮、多糖、三萜提取物均表现出对感染细胞后病毒的抑制作用,三萜的抑制效果要强于黄酮和多糖,利巴韦林的抑制作用强于黄酮、多糖、三萜。结论新疆特色植物资源—琐琐葡萄提取物抗流感病毒A(H1N1)亚型的作用是多途径的,琐琐葡萄总黄酮、琐琐葡萄多酚、琐琐葡萄三萜分别表现出对流感病毒A(H1N1)亚型感染细胞前、感染细胞后的抑制作用,以及直接抑制作用...     

Short communication: Antiviral activity of subcritical water extract of Brassica juncea against influenza virus A/H1N1 in nonfat milk

Subcritical water extract (SWE) of Brassica juncea was studied for antiviral effects against influenza virus A/H1N1 and for the possibility of application as a nonfat milk supplement for use as an “antiviral food.” At maximum nontoxic concentrations, SWE had higher antiviral activity against influenza virus A/H1N1 than n-hexane, ethanol, or hot water (80°C) extracts. Addition of 0.5 mg/mL of B. juncea SWE to culture medium led to 50.35% cell viability (% antiviral activity) for Madin-Darby canine kidney cells infected with influenza virus A/H1N1. Nonfat milk supplemented with 0.28 mg/mL of B. juncea SWE showed 39.62% antiviral activity against influenza virus A/H1N1. Thus, the use of B. juncea SWE as a food supplement might aid in protection from influenza viral infection.     

Characteristic features of InfA-15 monoclonal antibody recognizing H1, H3, and H5 subtypes of hemagglutinin of influenza virus A type

Hemagglutinin molecule is an envelope protein of influenza virus and plays an important role in the infection to human cells. Many mutations are observed in the molecule, which generates sixteen subtypes (H1–H16) of the hemagglutinin molecule for influenza virus A type. The subtypes such as H1, H2, H3, and H5 out of the sixteen are underlined molecules, which are responsible to Spain, Asia, Hong Kong, and Avian Flu, respectively. Based on the sequence analysis, three short sequences, which are highly conserved in the subtypes of influenza virus A type, were extracted. The sequence peptides were chemically synthesized and conjugated with BSA for immunization into Balb/c mice. A sequence GMVDGWYG located at the domain of fusion protein in the hemagglutinin molecule exhibited a high immuno-response, resulting in the production of a monoclonal antibody (mAb; InfA-15). The unique features of InfA-15 mAb were investigated from the viewpoint of immunological reaction, the binding affinity, the steric conformation, etc. The InfA-15 mAb could react with the H1, H3, and H5 subtype of hemagglutinin molecule of influenza virus A type. ELISAs using InfA-15 mAb suggested a wide reaction spectrum for the hemagglutinin of many important influenza viruses A type.     

Microassay for measuring thermal inactivation of H5N1 high pathogenicity avian influenza virus in naturally infected chicken meat

A precise, reproducible microassay was developed to measure thermal inactivation of high pathogenicity avian influenza (HPAI) virus in chicken meat. Small pieces of breast or thigh meat (0.05 g) from chickens infected with A/chicken/Pennsylvania/1370/1983 (H5N2) (PA/83) or A/chicken/Korea/ES/2003 (H5N1) (Korea/03) HPAI viruses were tested for inactivation in the heating block of a thermocycler. Korea/03 infected thigh and breast meat had higher virus concentrations (10(6.8) and 10(5.6) mean embryo infectious doses [EID(50)]/g, respectively) compared to PA/83 infected thigh and breast meat (10(2.8) and 10(2.3) EID(50)/g, respectively). The samples were ran through a ramp-up cycle from 25 to 70 degrees C, and meat samples were removed and examined for virus infectivity at 30, 40, 50, 60 and 70 degrees C, and after treatment for 1, 5, 10, 30 and 60 s at 70 degrees C. The reduction in virus infectivity titers was dependent on virus concentration and no HPAI virus was isolated after 1 s of treatment at 70 degrees C. A change in coloration from pink-tan to white was associated with a loss in recovery of infectious virus. The microassay provided a predictable and reproducible method to measure thermal inactivation of HPAI virus in chicken meat.     

Effects of yogurt containing probiotics on respiratory virus infections: Influenza H1N1 and SARS-CoV-2

Respiratory virus infections are an escalating issue and have become common worldwide. Influenza and COVID-19 are typical infectious respiratory diseases, and they sometimes lead to various complications. In a situation in which no established drug or treatment exists, consumption of proper food might be beneficial in maintaining health against external infections. We studied the potential effects of mixtures of probiotic strains on various viral infections. The purpose of this study was to assess the ability of yogurt containing probiotics to reduce the risk of respiratory viruses such as influenza H1N1 and SARS-CoV-2 infection. First, we performed in vitro tests using infected Madin-Darby canine kidney (MDCK) and Vero E6 cells, to evaluate the potential effects of yogurt containing high-dose probiotics against influenza H1N1 and SARS-CoV-2 infection. The yogurt significantly reduced plaque formation in the virus-infected cells. We also performed in vivo tests using influenza H1N1-infected C57BL/6 mice and SARS-CoV-2-infected Syrian golden hamsters, to evaluate the potential effects of yogurt. Yogurt was administered orally once daily during the experimental period. Yogurt was also administered orally as pretreatment once daily for 3 wk before viral infection. Regarding influenza H1N1, it was found that yogurt caused an increase in the survival rate, body weight, and IFN-γ, IgG1, and IL-10 levels against viral infection and a decrease in the inflammatory cytokines TNF-α and IL-6. Although the SARS-CoV-2 copy number was not significantly reduced in the lungs of yogurt-treated SARS-CoV-2-infected hamsters, the body weights and histopathological findings of the lungs were improved in the yogurt-treated group. In conclusion, we suggest that consumption of yogurt containing probiotics can lead to beneficial effects to prevent respiratory viral infections.     

Inactivation of avian influenza virus by heat and high hydrostatic pressure

Avian influenza viruses threaten the life of domestic terrestrial poultry and contaminate poultry meat and eggs. Recently, these viruses rarely infected humans but had a high mortality rate in Southeast Asia, the Middle East, and Egypt. Thereby, these viruses caused high economic costs for production of poultry and health protection. We inactivated a highly pathogenic avian influenza A virus of subtype H7N7 in cell culture medium and chicken meat by heat and high hydrostatic pressure. Because heat and pressure inactivation curves of the H7N7 virus showed deviations from first-order kinetics, a reaction order of 1.1 had to be selected. A mathematical inactivation model has been developed that is valid between 10 and 60 degrees C and up to 500 MPa, allowing the prediction of the reduction in virus titer in response to pressure, temperature, and treatment time. Incubation at 63 degrees C for 2 min and 500 MPa at 15 degrees C for 15 s inactivated more than 10(5) PFU/ml, respectively. Thus, we suggest high-pressure treatment of poultry and its products to avoid the possible health threat by highly pathogenic avian influenza viruses.     

Integrating silicon nanowire field effect transistor, microfluidics and air sampling techniques for real-time monitoring biological aerosols

Numerous threats from biological aerosol exposures, such as those from H1N1 influenza, SARS, bird flu, and bioterrorism activities necessitate the development of a real-time bioaerosol sensing system, which however is a long-standing challenge in the field. Here, we developed a real-time monitoring system for airborne influenza H3N2 viruses by integrating electronically addressable silicon nanowire (SiNW) sensor devices, microfluidics and bioaerosol-to-hydrosol air sampling techniques. When airborne influenza H3N2 virus samples were collected and delivered to antibody-modified SiNW devices, discrete nanowire conductance changes were observed within seconds. In contrast, the conductance levels remained relatively unchanged when indoor air or clean air samples were delivered. A 10-fold increase in virus concentration was found to give rise to about 20-30% increase in the sensor response. The selectivity of the sensing device was successfully demonstrated using H1N1 viruses and house dust allergens. From the simulated aerosol release to the detection, we observed a time scale of 1-2 min. Quantitative polymerase chain reaction (qPCR) tests revealed that higher virus concentrations in the air samples generally corresponded to higher conductance levels in the SiNW devices. In addition, the display of detection data on remote platforms such as cell phone and computer was also successfully demonstrated with a wireless module. The work here is expected to lead to innovative methods for biological aerosol monitoring, and further improvements in each of the integrated elements could extend the system to real world applications.