中国首例iVDPVs病例粪便标本中病毒血清型分布和Ⅲ型iVDPVs VP1区基因特征

分析中国首例免疫缺陷疫苗衍生脊髓灰质炎病毒(immunodeficient vaccine-derived polioviruses,iVDPVs)急性弛缓性麻痹(acute flaccid paralysis,AFP)病例(实验室编号为9230)12份便标本中病毒血清型分布和分离物中Ⅲ型VP1区的基因特征。31个省的疾病预防控制中心脊髓灰质炎(脊灰)实验室网络,在2005年采用细胞培养、病毒分离和微量中和试验从5231例AFP病例中的293例的便标本中分离到脊灰病毒,其中从1例编号为9230的AFP病例发病2~150天的12份便标本中分离到17株脊灰病毒株,包括Ⅱ型12株,Ⅲ型5株。用PCR-RFLP和ELISA两种方法对送检的293例AFP病例中分离的病毒进行型内鉴定,VP1区序列测定和分析发现:从9230号病例粪便标本中分离的12株Ⅱ型为混合不同变异数目的Ⅱ型iVDPVs,5株Ⅲ型病毒为单一Ⅲ型iVDPVs;除9230号病例外未发现其它iVDPVs或疫苗衍生脊灰病毒(vaccine-derived polioviruses,VDPVs)。5株Ⅲ型iVDPVs的VP1区基因和SabinⅢ相比有22~24个碱基突变,同源性为97.33%~97.56%,是中国至今发现变异最大的Ⅲ型VDPVs。9230号病例临床诊断为X-连锁低/无丙种球蛋白血症,是在中国首次发现的iVDPVs病例,该病例的病毒分离物中同时存在Ⅱ型和Ⅲ型iVDPVs,Ⅲ型iVDPVs在患者体内至少复制2.5年以上,iVDPVs病例的持续排毒已经给中国维持无脊灰状态提出了新的挑战。     

福建省脊髓灰质炎疫苗转换前后AFP病例病原学监测结果分析

自2016年5月1日起,我国与全球另外154个国家和地区同步实施脊髓灰质炎(以下简称"脊灰")疫苗免疫策略转换,停用三价口服脊灰减毒活疫苗,改用二价口服脊灰减毒活疫苗.为探讨脊灰疫苗转换对福建省急性弛缓性麻痹(Acute flaccid paralysis,AFP)病例监测结果产生的变化,本研究收集2012-2018年福建省AFP病例的流行病学及实验室监测数据,对脊灰疫苗转换前后AFP病例的监测结果进行描述性分析,采集AFP病例及其接触者粪便标本,并使用RD细胞和L20B细胞进行病毒分离;对L20B阳性分离物进行脊灰病毒(Poliovirus,PV)的型内鉴别(Intratypic differentiation,ITD),对PV衣壳蛋白VP1编码区核苷酸序列测定和分析.使用SPSS 21.0软件对数据进行统计检验,比较采用X2检验.结果显示,2012-2018年福建省累计报告AFP病例1 776例,根据AFP病例分类流程确诊的AFP病例1 283例,排除的非AFP病例493例,疫苗转换前后报告发病率平均为2.83/10万和2.71/10万.实验室共检测3123份粪便标本(包括AFP病例、非AFP病例及接触者),其中合格标本采集率为92.42％,7日及时送检率为97.85％,14日内病毒分离完成率接近100％,疫苗转换前后PV平均分离率分别为1.91％(38/1986)、1.58％(18/1137),非脊灰肠道病毒平均分离率分别为10.22％(203/1 986)、5.45％(62/1 137).2016年5月1日之前分离出Ⅰ型PV6株,Ⅱ型PV 13株,Ⅲ型PV 19株;2016年5月1日之后分离出Ⅰ型PV 6株,Ⅲ型PV 12株.本研究结果提示,脊灰疫苗转换前后福建省AFP监测系统运转正常,始终保持较高的敏感性和及时性.2012-2018年福建省分离出的PV均为脊灰疫苗株,毒株血清型别以Ⅲ型为主,VP1编码区核苷酸以低变异为主,未发现疫苗衍生脊灰病毒及脊灰野病毒,疫苗转换后再未检出Ⅱ型PV,提示Ⅱ型脊灰疫苗株病毒可能已被阻断.     

中国脊髓灰质炎病毒疫苗株基因变异的分析

从急性弛缓性麻痹（ＡＦＰ）病例分离的３２株脊髓灰质炎（脊灰）病毒,在ＶＰ１编码区,经ＰＣＲ－ＲＦＬＰ方法鉴定,并经核酸测序进一步证实力疫苗株,其中５株为Ｉ型疫苗,１６株Ⅱ型疫苗株,１１株Ⅲ型疫苗株,以同样的分析方法检测这些毒株基因组的３Ｄ聚合酶编码区,发现２株Ｉ型疫苗株在３Ｄ区的４３１个核苷酸序列为野毒序列,即这２株Ｓａｂｉｎ１基因型（ＶＰ１）与野毒基因型（３Ｄ）重组株;其余３株Ｉ型疫苗株未发现基     

贵州省贞丰县疫苗衍生脊髓灰质炎病毒循环的病毒学分析

为及时发现和阻断疫苗衍生脊髓灰质炎（脊灰）病毒（vaccine-derived polioviruses, VDPVs）循环、脊灰野病毒的输入和能够引起临床脊灰的其它脊灰疫苗相关病毒,做好贵州省无脊灰状态下脊灰病毒学监测工作,采用病毒分离、鉴定与核苷酸序列测定和分析方法,对贵州省贞丰县及周围10个县2003～2004年报告的急性弛缓性麻痹（AFP）病例及2004年接触者粪便标本的病毒学监测的结果进行了分析. 对收集到的105例AFP病例和47例密切接触者的278份便标本进行了病毒学监测,结果从66例中共分离到肠道病毒（EV）66株,阳性率为43.4%,其中脊灰病毒（PV）29例,分离率为19.1%,非脊灰肠道病毒（NPEV）37例,分离率为24.3%.29例PV经中国疾病预防控制中心病毒病预防控制所国家脊灰实验室鉴定,24例为疫苗相似株,5例为脊灰Ⅰ型VDPVs,这5例均为2004年从贞丰县所分离到.贞丰县及周围县EV阳性检出率（43.4%）高于2003～2004年全省水平（22.9%～24.6%）,2004年PV分离率比2003年高达2.6倍,29株PV中单个Ⅰ型占34.5%,明显高于往年（2000～2002年全省平均4.1%）.本研究提示,Ⅰ型VDPVs在贞丰县引起了循环（cVDPVs）,通过口服脊灰疫苗强化免疫已经阻断cVDPVs的传播.人群中PV和NPEV带毒率明显增高,非VDPVs引起的临床符合脊灰病例不容忽视;应加强脊灰病毒学监测数据的分析和早期疫情预警工作.     

西安市1995-2008年检出脊髓灰质炎疫苗病毒的急性弛缓性麻痹病例流行病学分析

分析脊髓灰质炎(脊灰)病毒(PV)的急性弛缓性麻痹(AFP)病例流行病学特征,提高对疫苗衍生脊灰病毒(VDPVs)和循环的疫苗衍生脊灰病毒(cVDPVs)的认识,增加AFP病例监测系统敏感性。对西安市1995-2008年检出的PV阳性AFP病例进行流行病学分析。对疫苗变异PV采用VP1基因核苷酸序列测定方法进行分子生物性状分析。西安市1995-2008年共检出PV13株,检出率4.29%。分离到的PV以II、III型为主,AFP病例散在发生,无聚集性。未全程免疫儿童(全程免疫儿童,年龄以≤1岁儿童为主(84.62%)。麻痹残留率高达84.62%。脊灰相关病例(VAPP)的发生危险性为0.24/100万。型内特征鉴定有1株为疫苗变异PV,经VP1基因核苷酸序列测定未达到VDPV的分类标准。维持无脊灰阶段,存在着VDPV和发生cVDPVs的可能,在保持高水平脊髓灰质炎疫苗(OPV)免疫覆盖率的同时,高质量的AFP病例流行病学监测和病毒学监测工作,具有重要的现实意义。     

脊髓灰质炎疫苗研究进展

脊髓灰质炎是由脊髓灰质炎病毒感染所引起的疾病,只能以接种疫苗进行预防。口服脊髓灰质炎疫苗已大幅度降低了全球脊髓灰质炎的发病率,然而,由于疫苗相关麻痹型脊灰和疫苗衍生脊髓灰质炎病毒风险的出现,今后必须停止使用口服脊髓灰质炎疫苗,以彻底根除脊髓灰质炎。消灭脊髓灰质炎野病毒之后,将会严格管理来源于野毒株的传统脊髓灰质炎灭活疫苗生产,而用Sab in株研制的脊髓灰质炎灭活疫苗抗原性及免疫原性与传统脊髓灰质炎灭活疫苗不同。脊髓灰质炎病毒样颗粒可能成为一种可开发的脊髓灰质炎疫苗。     

云南省1例疫苗衍生株脊髓灰质炎病毒病例的调查分析

本调查旨在了解2010年云南省昭通市1株脊髓灰质炎Ⅱ型疫苗衍生毒株(Vaccine-derived poliovirus,VDPV)引起的病例的流行病学特征、该病例的排毒情况及其周围健康儿童的肠道病毒(EV)携带情况和病毒型别特征。在该病例的发生地进行现场流行病学调查,连续采集病例粪便标本,采集密切接触者及病例居住地健康儿童粪便标本进行病毒分离和型别鉴定。经省级专家组最终分类诊断为VDPV病例;实验室结果显示病例标本中未再检出VDPV;密切接触者及周围健康儿童标本中均未检测到脊灰疫苗株病毒及VDPV,AFP病例入户主动搜索未发现类似病例,表明该病毒未在当地造成循环;在健康儿童中检测到NPEV 21株,病毒携带率为20.0%;经VP1区核苷酸序列测定,21株NPEV分别属于HEV-A组(11株,3个血清型,占52.4%)和HEV-B组(10株,4个血清型,47.6%)。     

1989－1994年中国脊髓灰质炎病毒的分子流行病学

１９８９～１９９４年中国发生的脊髓灰质炎流行,疫情开始集中于华东、中南地区,后期趋于南部沿海一带。对近百份来自１８个省、市、自治区脊灰病毒流行期间标本的分子生物学特征分析,发现流行主要由脊灰病毒Ⅰ型野毒株引起,未发现Ⅱ型野毒株,但１９９３年在新疆分离到１株Ⅲ型野毒株。Ⅰ型野毒株中共存在４个基因型病毒,其中ＣＨＮＰ１－Ｒ９１型病毒为这几年流行中新产生的重组病毒,在ＶＰ１／２Ａ区含有一段疫苗株序列,另一段野毒株序列很可能来自ＣＨＮＰ１－ＪＸ８９型病毒。这两个基因型病毒分布在全国大部份地区。病毒核酸的亲缘关系研究还证明,９２～９４年流行在南方沿海一带的脊髓灰质炎,主要由９１年产生的重组病毒引起。此研究揭示了各地区、各基因型病毒与疫情之间的流行病学关系及传播模式。     

中国脊髓灰质炎Ⅰ型野毒株的PCR－RFLP法分析

近年来我国流行地区分离的脊髓灰质炎病毒多为Ⅰ型野毒。本文报导对我国一些省、自治区防疫站从急性驰缓性麻痹病人粪便中分离的７７株Ⅰ型野毒株,经ＰＣＲ－ＲＦＬＰ法分析结果,发现不同地区分离的野毒株在电泳图像上有明显差异。根据电泳图像所显示的三种酶切条带的数目,可分为１４个类型,而且同一省、自治区内不同地区（如新疆）,或同一地区不同年份（如广东）的毒株也存在着明显差异。但在某些相邻省份如广东省与海南省,９２年流行毒株电泳图像完全一致。说明本法虽不如核酸序列分析精确,但在一定程度上也能反映毒株间的差异,有助于说明流行株的亲疏关系,可用于研究毒株的分子流行病学。     

Putting together the pieces of polio: how Dorothy Horstmann helped solve the puzzle

Dr. Dorothy Horstmann, epidemiologist, virologist, clinician, and educator, was the first woman appointed as a professor at the Yale School of Medicine. Horstmann made significant contributions to the fields of public health and virology, her most notable being the demonstration that poliovirus reached the central nervous system via the bloodstream, upsetting conventional wisdom and paving the way for polio vaccines. In 1961, she was appointed a professor at Yale School of Medicine, and in 1969, she became the first woman at Yale to receive an endowed chair, which was named in honor of her mentor, Dr. John Rodman Paul. In this review, the major scientific contributions of Dr. Dorothy Horstmann will be highlighted from her more than 50-year tenure at Yale School of Medicine.     

Engineering the Live-Attenuated Polio Vaccine to Prevent Reversion to Virulence

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The final stages of the global eradication of poliomyelitis

The global incidence of poliomyelitis has dropped by more than 99 per cent since the governments of the world committed to eradication in 1988. One of the three serotypes of wild poliovirus has been eradicated and the remaining two serotypes are limited to just a small number of endemic regions. However, the Global Polio Eradication Initiative (GPEI) has faced a number of challenges in eradicating the last 1 per cent of wild-virus transmission. The polio endgame has also been complicated by the recognition that vaccination with the oral poliovirus vaccine (OPV) must eventually cease because of the risk of outbreaks of vaccine-derived polioviruses. I describe the major challenges to wild poliovirus eradication, focusing on the poor immunogenicity of OPV in lower-income countries, the inherent limitations to the sensitivity and specificity of surveillance, the international spread of poliovirus and resulting outbreaks, and the potential significance of waning intestinal immunity induced by OPV. I then focus on the challenges to eradicating all polioviruses, the problem of vaccine-derived polioviruses and the risk of wild-type or vaccine-derived poliovirus re-emergence after the cessation of oral vaccination. I document the role of research in the GPEI''s response to these challenges and ultimately the feasibility of achieving a world without poliomyelitis.     

The Early Evolution of Oral Poliovirus Vaccine Is Shaped by Strong Positive Selection and Tight Transmission Bottlenecks

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Wistar大鼠皮内免疫Sabin株脊髓灰质炎灭活疫苗的免疫持久性及加强免疫效果研究

脊髓灰质炎野毒株消灭后,口服脊髓灰质炎减毒活疫苗(Oral polio vaccine,OPV)将被停止使用,脊髓灰质炎灭活疫苗(Inactivated poliovirus vaccine,IPV)将全面替代OPV,但IPV成本过高,难以满足全球需要。皮内免疫可以降低Sabin株脊髓灰质炎灭活疫苗(Inactivated poliovirus vaccine derived from Sabin strain,sIPV)的免疫剂量,本研究将观察sIPV疫苗皮内免疫大鼠后的免疫持久性及加强免疫效果。本研究采用sIPV,设皮内免疫组、全剂量肌肉免疫组和皮内免疫阴性对照组,接种Wistar大鼠,于3剂基础免疫程序完成后第1个月、12个月采血;第12个月采血后加强免疫1剂,并于加强免疫1个月后采血。中和试验检测各血清抗脊灰病毒中和抗体效价,评价皮内免疫sIPV的免疫持久性及加强免疫效果。Wistar大鼠3剂基础免疫后1个月,1/5、1/3剂量皮内免疫组与全剂量肌肉免疫组Ⅰ、Ⅱ、Ⅲ型抗体阳转率均达到了100%,各型别中和抗体几何平均滴度(Geometric mean titer,GMT)均远高于1∶8保护水平。基础免疫后12个月,sIPV全剂量组各型阳转率均维持在80%以上,1/10剂量皮内免疫组在50%以上,1/5剂量皮内免疫组维持在70%以上,1/3剂量皮内免疫组维持在80%以上,除1/10剂量组Ⅱ型外其余各组各型别GMT均维持在1∶8以上。加强免疫后1个月,1/5剂量皮内免疫组、1/3剂量皮内免疫组及全剂量组的Ⅰ型、Ⅱ型、Ⅲ型各组中和抗体阳转率均达到100%,并能够诱导产生远高于1∶8的抗体水平。本研究结果显示sIPV疫苗皮内免疫具有良好的免疫持久性及加强免疫效果。     

Complete nucleotide sequences of all three poliovirus serotype genomes. Implication for genetic relationship, gene function and antigenic determinants

The complete nucleotide sequences of the genomes of the type 2 ( P712 , Ch, 2ab ) and type 3 (Leon 12a1b ) poliovirus vaccine strains were determined. Comparison of the sequences with the previously established genome sequence of type 1 (LS-c, 2ab ) poliovirus vaccine strain revealed that 71% of the nucleotides in the genome RNAs were common, that the 5' and 3' termini of the genomes were highly homologous, and that more than 80% of the nucleotide differences in the coding region occurred in the third letter position of in-phase codons, resulting in a low frequency of amino acid difference. These results strongly suggested that the serotypes of poliovirus derived from a common prototype. A comparison of the amino acid sequences predicted from the genome sequences showed highest variation in the capsid protein region, whereas non-structural proteins are highly conserved. Initiation of polyprotein synthesis occurs in all three strains more than 740 nucleotides downstream from the 5' end. An analysis of the non-coding region suggests that small peptides that could potentially originate from this region are conserved. The amino acid sequences immediately surrounding the cleavage signals, however, show a higher than average degree of variation. The analysis of the amino acid sequences of the capsid protein VP1 of all serotypes has led to the prediction of potential antigenic sites on the virion involved in neutralization.     

Evaluation of an enzyme-linked immunosorbent assay based on binding inhibition for type-specific quantification of poliovirus neutralization-relevant antibodies

To detect neutralization-relevant antibodies against 3 types of poliovirus (PV) without using tissue cultures and live viruses, an enzyme-linked immunosorbent assay (ELISA) based on monoclonal antibody-binding inhibition was evaluated using sera from 80 vaccinated Japanese children and 60 Pakistani poliomyelitis patients. Compared with the neutralization test, the sensitivity of the inhibition ELISA was 100% (111/111) for detection of anti-PV1 antibody, 98.3% (118/120) for anti-PV2, and 96.5% (82/85) for anti-PV3, and the specificity was 93.1% (27/29), 100% (20/20), and 92.7% (51/55), respectively. Thus, the inhibition ELISA showed excellent potential as a seroepidemiologic tool in both vaccinated and naturally-infected populations.