Protective efficacy of a polyvalent influenza A DNA vaccine against both homologous (H1N1pdm09) and heterologous (H5N1) challenge in the ferret model

This study describes the protective efficacy of a novel influenza plasmid DNA vaccine in the ferret challenge model. The rationally designed polyvalent influenza DNA vaccine encodes haemagglutinin and neuraminidase proteins derived from less glycosylated pandemic H1N1 (2009) and H3N2 (1968) virus strains as well as the nucleoprotein (NP) and matrix proteins (M1 and M2) from a different pandemic H1N1 (1918) strain. Needle-free intradermal immunisation with the influenza DNA vaccine protected ferrets against homologous challenge with an H1N1pdm09 virus strain, demonstrated by restriction of viral replication to the upper respiratory tract and reduced duration of viral shedding post-challenge. Breadth of protection was demonstrated in two heterologous efficacy experiments in which animals immunised with the influenza DNA vaccine were protected against challenge with a highly pathogenic avian influenza H5N1 virus strain with reproducible survival and clinical outcomes.     

Potential Threats to Human Health from Eurasian Avian-Like Swine Influenza A(H1N1) Virus and Its Reassortants

During 2018–2020, we isolated 32 Eurasian avian-like swine influenza A(H1N1) viruses and their reassortant viruses from pigs in China. Genomic testing identified a novel reassortant H3N1 virus, which emerged in late 2020. Derived from G4 Eurasian H1N1 and H3N2 swine influenza viruses. This virus poses a risk for zoonotic infection.     

2009年深圳新甲型H1N1流感病毒分离鉴定及分离株特征分析

目的比较新甲型H1N1流感病毒对MDCK细胞和鸡胚的敏感性差异,了解病毒分离株特征,为疫苗制备和开展实验室常规监测等奠定基础。方法用MDCK细胞和鸡胚进行流感病毒分离[1],收获病毒后提取病毒RNA,逆转录-聚合酶链式反应(RT-PCR)扩增,阳性扩增产物纯化后测序,测序结果使用Clustal和MEGA4.1软件进行比较分析,通过与NCBI数据库中不同时间和地区的流感病毒H1N1株同源比对后,绘制种系发生树。结果从334份患者呼吸道标本中,用MDCK细胞分离法分离出134株新甲型H1N1病毒,分离率为40.12%,用鸡胚分离法分离出150株新甲型H1N1病毒,分离率为44.91%;所测10株新甲型H1N1毒株HA1区的344个氨基酸,与2009年新甲型H1N1国际代表株A/California/07/2009相比,只有少数位点发生氨基酸替换,并且这些位点都不在抗原决定簇上;种系发生树显示,10株新甲型H1N1和国际代表株同源性较大,形成一簇,与A/Swine/guangxi/13/2006较为接近。结论新甲型H1N1病毒对MDCK细胞和鸡胚的敏感性相差不大;新甲型H1N1病毒未发生变异,短期内不会产生新变种。     

A Historical Perspective of Influenza A(H1N2) Virus

The emergence and transition to pandemic status of the influenza A(H1N1)A(H1N1)pdm09) virus in 2009 illustrated the potential for previously circulating human viruses to re-emerge in humans and cause a pandemic after decades of circulating among animals. Within a short time of the initial emergence of A(H1N1)pdm09 virus, novel reassortants were isolated from swine. In late 2011, a variant (v) H3N2 subtype was isolated from humans, and by 2012, the number of persons infected began to increase with limited person-to-person transmission. During 2012 in the United States, an A(H1N2)v virus was transmitted to humans from swine. During the same year, Australia recorded its first H1N2 subtype infection among swine. The A(H3N2)v and A(H1N2)v viruses contained the matrix protein from the A(H1N1)pdm09 virus, raising the possibility of increased transmissibility among humans and underscoring the potential for influenza pandemics of novel swine-origin viruses. We report on the differing histories of A(H1N2) viruses among humans and animals.     

长沙市甲型H1N1流感病毒神经氨酸酶基因序列分析

目的对长沙市甲型H1N1流感病毒A/changsha/78/2009的神经氨酸酶（neuraminidase,NA）基因进行测序分析,以期了解该病毒的来源及变异情况。方法利用国家流感中心（CNIC）和世界卫生组织（WHO）推荐的NA基因测序引物和CEQTM8000 Genetic Analysis System对2009年长沙市甲型H1N1流感患者阳性鼻咽拭子标本（A/changsha/78/2009）进行测序,测序结果提交至GenBank并利用Lasergene和Mega5软件对测序结果进行氨基酸比对和进化树分析。结果 A/changsha/78/2009 NA基因GenBank登录号为：GQ463958.1,与瑞典斯德哥尔摩甲型H1N1流感病毒分离株A/Stockholm/37/2009（H1N1）核苷酸同源性为100%;进化树分析显示A/changsha/78/2009 NA基因属于欧亚猪流感分支,包含A/changsha/78/2009在内的甲型H1N1流感病毒与A/swine/Spain/WVL6/1991（H1N1）亲缘关系近;A/chang-sha/78/2009与A/swine/Spain/WVL6/1991 NA基因均有7个潜在糖基化位点,A/changsha/78/2009 NA基因未发生H274Y位点突变。结论包含A/changsha/78/2009在内的甲型H1N1流感病毒NA基因可能来源于欧亚猪流感病毒,A/changsha/78/2009病毒对神经氨酸酶抑制剂类药物敏感。     

甲型H1N1流感病毒基因组序列分析及其特性研究

目的 分析甲型H1N1流感病毒的基因组序列特征,阐明该毒株的遗传变异及分子特性.方法 GenBank中获取流感病毒全序列,对各段基因与已知序列进行分析比较,绘制进化树,并分析和预测甲型毒株的致病性、药物敏感性和现有疫苗的预防保护作用.结果 甲型H1N1病毒的HA、PB2、PB1、PA、NP、NS基因与美国本土的猪流感病毒序列具有高度同源性,NA和M基因具有典型的欧亚株系猪流感病毒特征.该病毒具有人传人的分子基础,HA上HA1和HA2裂解位点序列为PSIQSR↓+GLFGAI,尚不具备高致病性流感病毒的特征.病毒对金刚烷胺类药物耐药,而对达菲和扎那米韦敏感.HA片段5个抗原决定区氨基酸序列与人用流感疫苗具有较大差异,推测现有疫苗对预防本次疫情基本无效.结论 甲型H1N1是一种北美和欧亚两种猪流感病毒的混合体,开发针对本病毒的流感疫苗有助于进一步控制疫情蔓延.     

Reassortant Pandemic (H1N1) 2009 virus in pigs, United Kingdom

Surveillance for influenza virus in pigs in the United Kingdom during spring 2010 detected a novel reassortant influenza virus. This virus had genes encoding internal proteins from pandemic (H1N1) 2009 virus and hemagglutinin and neuraminidase genes from swine influenza virus (H1N2). Our results demonstrate processes contributing to influenza virus heterogeneity.     

Novel Influenza A(H7N2) Virus in Chickens,Jilin Province,China, 2014

In February 2014, while investigating the source of a human infection with influenza A(H7N9) virus in northern China, we isolated subtypes H7N2 and H9N2 viruses from chickens on the patient’s farm. Sequence analysis revealed that the H7N2 virus is a novel reassortant of H7N9 and H9N2 viruses. Continued surveillance is needed.     

Influenza A(H6N1) Virus in Dogs,Taiwan

We determined the prevalence of influenza A virus in dogs in Taiwan and isolated A/canine/Taiwan/E01/2014. Molecular analysis indicated that this isolate was closely related to influenza A(H6N1) viruses circulating in Taiwan and harbored the E627K substitution in the polymerase basic 2 protein, which indicated its ability to replicate in mammalian species.     

2018-2019年宁夏甲型H1N1流感病毒血凝素基因组序列分析

目的 了解宁夏2018-2019流感监测年度流感病毒病原学检测情况,分析甲型H1N1流感病毒血凝素（HA）基因特征。方法 采用real time RT-PCR方法对流感监测哨点医院采集的流感样病例（ILI）标本进行核酸检测;对阳性标本进行毒株分离;提取甲型H1N1毒株的RNA,采用RT-PCR方法扩增HA片段并测序,利用生物信息软件对测序结果进行比对分析。结果 宁夏流感网络实验室检测咽拭子标本共5214份,核酸检测阳性数为760份,其中甲型H1N1阳性数为485份,占总阳性数的63.82%,分离出甲型H1N1毒株 161株。宁夏分离毒株与疫苗株A/Califaoria/07/2009不在同一进化分支,同源性为92.6%~96.3%;与疫苗株A/Michigan/45/2015(H1N1)为同一进化分支,同源性为96.6%~98.1%。与疫苗株A/Califaoria/07/2009比较,抗原位点、受体结合位点及其他位点均有变异,除毒株 A/Ningxia_Xixia/SWL1176/2019(H1N1)第222位氨基酸发生D222G变异外,其他甲型H1N1流感毒株均未发生D222G变异。所有毒株增加糖基化位点162NQT,个别毒株糖基化位点增加2~3个。结论 宁夏2018 -2019年度流感优势毒株为甲型H1N1毒株。序列分析表明甲型H1N1病毒发生了不同程度的变异,在抗原特异性、毒力和感染性上有可能已经发生变化,需要及时更换疫苗株成分。     

Influenza Virus A (H1N1) in Giant Anteaters (Myrmecophaga tridactyla)

In February 2007, an outbreak of respiratory disease occurred in a group of giant anteaters (Myrmecophaga tridactyla) at the Nashville Zoo. Isolates from 2 affected animals were identified in March 2007 as a type A influenza virus related to human influenza subtype H1N1.     

2009-2011年杭州地区甲型H1N1流感病毒神经氨酸酶基因的遗传进化分析

目的了解2009年7月以来杭州地区甲型H1N1流感病毒神经氨酸酶基因(NA)的变异情况,分析其遗传进化特征。方法在流行季节采集发热病人咽拭子样本,经病毒分离培养及亚型鉴定后,用特异性引物扩增NA基因,测序并分析其遗传进化特征。结果 2009年7月至2011年3月,共检测监测样本1 898份,流感病毒阳性率为37.9%。期间经历了两次甲型H1N1流感病毒流行高峰。各时间段分离株间NA基因高度同源,序列相似性97.9%~100%,但2010/2011年流行株在进化树上分为两支,且与2009/2010年流行株遗传距离相对较远。进一步分析后发现,虽然耐药位点、酶活性位点及其附近氨基酸相对保守,但多个氨基酸变异发生于抗原决定簇上,且增加了NA蛋白茎部第42位糖基化位点。结论结果预示着酶抑制剂类药物对预防和治疗甲型H1N1流感病毒仍将有效,但在开发新疫苗时应该尽可能的避开已经发生漂变的抗原决定簇。     

Genomic Signatures of Influenza A Pandemic (H1N1) 2009 Virus

Adaptive mutations that have contributed to the emergence of influenza A pandemic (H1N1) 2009 virus, which can replicate and transmit among humans, remain unknown. We conducted a large-scale scanning of influenza protein sequences and identified amino acid–conserving positions that are specific to host species, called signatures. Of 47 signatures that separate avian viruses from human viruses by their nonglycoproteins, 8 were human-like in the pandemic (H1N1) 2009 virus. Close examination of their amino acid residues in the recent ancestral swine viruses of pandemic (H1N1) 2009 virus showed that 7 had already transitioned to human-like residues and only PA 356 retained an avian-like K; in pandemic (H1N1) 2009 virus, this residue changed into a human-like R. Signatures that separate swine viruses from human viruses were also present. Continuous monitoring of these signatures in nonhuman species will help with influenza surveillance and with evaluation of the likelihood of further adaptation to humans.     

湖北省2009年甲型H1N1流感流行病学特征分析

目的分析湖北省2009年甲型H1N1流感的流行病学特征,为防治提供科学依据。方法应用甲型H1N1流感信息管理系统和疫情监测信息管理系统收集湖北省各市(州)报告的甲型H1N1流感病例相关信息,采用Excel软件建立病例信息库,并进行统计学分析。结果 2009年全省共报告甲型H1N1确诊病例5527例,其中重症病例63例,死亡6例。疫情在全省17个市、州均有分布;9～12月报告病例数占总报告数的99.57%;主要发病年龄组为10岁～与15岁～年龄组;86%的病例为在校学生。结论通过采取科学防控措施,加强疫情监测,积极救治病人及对易感人群的保护,湖北省2009年甲型H1N1流感疫情得到有效控制,其危害也降到最低程度,保障了社会经济生活的正常秩序。     

四川省成都市甲型H1N1流感血清学调查结果分析

目的了解成都市人群甲型H1N1流感感染现状。方法按照国家方案采集不同年龄组人群血清标本,用血凝抑制(HI)试验方法进行抗体检测,HI抗体滴度≥1∶40判为阳性。结果成都市甲型H1N1流感阳性率8.85%(108/1221);13～17岁组阳性率最高(13.85%,P0.05);男女性阳性率差异无统计学意义;就诊人群阳性率低于一般人群,但差异无统计学意义。结论成都市发生了甲型H1N1流感社区流行,但在人群中的自然感染未形成有效免疫屏障,甲型H1N1流感疫苗接种仍有必要。     

甲型H1N1流感大流行前后沈阳地区流感病原学流行特征

目的分析甲型H1N1流行性感冒(流感)大流行前后沈阳流感病原学流行特征。方法采集2005年10月—2011年3月连续5.5 a哨点医院的流感样病例咽拭子,进行流感病毒的分离和分型鉴定,并按甲型H1N1流感流行前后划分为3个时期。结果 3个时期共采集流感样病例咽拭子样本6 808份,分离到流感病毒861株,总分离率为12.6%;流行前、流行中和流行后3个时期流感病毒检出率分别为13.8%、18.2%和5.2%。男性和女性流感病毒感染率差异无统计学意义,不同时期流感样病例的年龄构成差异有统计学意义。新的甲型H1N1流感侵袭的人群主要是低年龄组人群,新的甲型H1N1流行期间和流行后,流感季节高峰发生前移。不同年度流感流行毒株型别不同,前1年监测周期的优势株在下1个周期中可被其他型别抑制甚至取代。结论甲型H1N1流感流行后沈阳的流感流行特征已发生了部分改变,这种改变是否持续存在还有待持续监测来得以验证,在2011—2012年监测周期中应密切关注A3(H3N2)亚型和新的甲型H1N1亚型流感毒株的活动情况。     

Reassortant Avian Influenza A(H5N1) Viruses with H9N2-PB1 Gene in Poultry,Bangladesh

Bangladesh has reported a high number of outbreaks of highly pathogenic avian influenza (HPAI) (H5N1) in poultry. We identified a natural reassortant HPAI (H5N1) virus containing a H9N2-PB1 gene in poultry in Bangladesh. Our findings highlight the risks for prolonged co-circulation of avian influenza viruses and the need to monitor their evolution.     

Reassortant Influenza A(H1N1)pdm09 Virus in Elderly Woman,Denmark, January 2021

A case of human infection with influenza A(H1N1)pdm09 virus containing a nonstructural gene highly similar to Eurasian avian-like H1Nx swine influenza virus was detected in Denmark in January 2021. We describe the clinical case and report testing results of the genetic and antigenic characterizations of the virus.     

Potency of an inactivated influenza vaccine prepared from A/duck/Mongolia/119/2008 (H7N9) against the challenge with A/Anhui/1/2013 (H7N9)

H7N9 influenza virus infection in humans was reported in China on March 31, 2013. Humans are immunologically naïve to the H7N9 subtype, for which the seasonal influenza vaccine is not effective. Thus, the development of an H7N9 influenza virus vaccine is an urgent issue. To prepare for the emergence of an influenza pandemic, we have established a library comprising more than 1300 influenza virus strains with 144 different combinations of 16 HA and 9 NA subtypes. An H7N9 virus strain isolated from a 35-year-old woman, A/Anhui/1/2013 (H7N9), was found to be antigenically similar to H7N9 influenza viruses isolated from migratory ducks. In the present study, the potency of an inactivated whole virus particle vaccine prepared from an H7N9 low pathogenic avian influenza virus, A/duck/Mongolia/119/2008 (H7N9), selected from the library, was assessed by a challenge with A/Anhui/1/2013 (H7N9). The results indicate that the test vaccine was potent enough to induce sufficient immunity to reduce the impact of disease caused by the challenge with A/Anhui/1/2013 (H7N9) in mice. The present results indicate that an inactivated whole virus particle vaccine prepared from an influenza virus strain stored in the library could be useful as a vaccine strain in case of an influenza pandemic.     

Outbreaks of pandemic (H1N1) 2009 and seasonal influenza A (H3N2) on cruise ship

To determine the extent and pattern of influenza transmission and effectiveness of containment measures, we investigated dual outbreaks of pandemic (H1N1) 2009 and influenza A (H3N2) that had occurred on a cruise ship in May 2009. Of 1,970 passengers and 734 crew members, 82 (3.0%) were infected with pandemic (H1N1) 2009 virus, 98 (3.6%) with influenza A (H3N2) virus, and 2 (0.1%) with both. Among 45 children who visited the ship's childcare center, infection rate for pandemic (H1N1) 2009 was higher than that for influenza A (H3N2) viruses. Disembarked passengers reported a high level of compliance with isolation and quarantine recommendations. We found 4 subsequent cases epidemiologically linked to passengers but no evidence of sustained transmission to the community or passengers on the next cruise. Among this population of generally healthy passengers, children seemed more susceptible to pandemic (H1N1) 2009 than to influenza (H3N2) viruses. Intensive disease control measures successfully contained these outbreaks.