Novel measles virus genotype,East Timor and Australia

Measles outbreaks in 1999 in Queensland and Victoria, Australia, were caused by a novel strain of clade G virus (proposed name g3). Epidemiologic and molecular evidence supports independent circulation of this virus in Queensland, northern Australia, in addition to importation of the virus by East Timor refugees seeking safe haven in Australia.     

福建省发现输入性B3基因型麻疹病毒

目的 分析福建省2018年输入性B3基因型麻疹病毒的病原学特征。方法 采用实时荧光定量RT-PCR筛查和扩增麻疹病毒核酸阳性咽拭子及Vero/Slam细胞培养阳性产物。对麻疹病毒N基因羧基末端634个核苷酸片段进行扩增测序,比对分析构建基因亲缘性关系树。结果 分离获得2株麻疹病毒株,18条病毒核酸序列。所有福建株在亲缘关系上与WHO B3基因型参考株同属一个分支,其中标本MV18-41和MV18-42与2018年分离于中国香港地区的毒株（HongKong.CHN/35.18）核酸同源性为100.0%;其他毒株序列与2018年分离于日本的毒株（Mvs/Osaka.JPN/38.18/B3）同源性最高（99.9%）。福建株与除B3基因型外,23种WHO不同麻疹基因型参考株之间比较,福建株与B1基因型参考株核苷酸和氨基酸同源差异性最小,分别为95.1%～95.4%和95.3%;与H1基因型参考株同源差异性最大,其中与中国目前优势流行的参考株MVi/Hunan.CHN/0.93/7核苷酸和氨基酸同源差异分别为88.7%～89.0%和87.3%;在病毒N蛋白羧基末端150个氨基酸位点上,福建株与疫苗株（Shanghai-191）之间存在13个变异位点,但这些位点并未引起该蛋白区域的功能变化。结论 福建省成功分离获得2株B3基因型麻疹毒株,B3基因型麻疹病毒是福建省发现的新基因型麻疹病毒,在补充和丰富福建省麻疹病毒分子流行病学本底资料的同时也进一步警示必需加强输入性病例的监测,才能更好地完成福建省麻疹病毒的控制和消除工作。     

浙江省宁波市2004-2015年麻疹流行病学和基因型特征分析

目的 了解浙江省宁波市2004-2015年麻疹流行病学特征及野毒株的基因型特征,为制定防控对策提供参考依据。方法 收集宁波市2004年1月-2015年12月麻疹发病监测数据及各县（市、区）报告的麻疹野毒株样本,采用逆转录-聚合酶链反应（RT-PCR）进行扩增,对PCR产物进行序列测定和分析。结果 宁波市2004-2015年麻疹发病率依次为9.93/10万、21.09/10万、2.46/10万、12.73/10万、33.38/10万、4.10/10万、2.41/10万、0.93/10万、6.60/10万、2.11/10万、2.30/10万、2.74/10万,麻疹发病率总体呈下降趋势（χ_趋势²=2 743.496,P<0.01）;麻疹全年均有发病,以2~5月为发病高峰,病例数占总发病数的66.74%;宁波市11个市（区、县）麻疹均有发病,发病率居于前3位的地区分别为海曙区520例（13.81/10万）、江北区485例（13.33/10万）及江东区450例（12.19/10万）;麻疹<8月龄、8月龄~7岁、8~14岁、15~19岁和≥ 20岁病例构成比分别为23.13%、20.89%、4.02%、6.40%和45.56%;宁波市2004-2015年共分离到麻疹野毒株90株,其中11株为B3基因亚型,79株为H1基因型（H1a基因亚型73株,H1b基因亚型6株）。结论 宁波市2004-2015年麻疹发病率总体呈下降趋势;H1a亚型为该地区麻疹优势基因型。     

Intra- and intergenotype characterization of D6 measles virus genotype.

Determination of inter- and intragenotype stability and variability are the basic tools for the molecular epidemiology and evolutionary investigation of measles virus (MV). We made a comparison between complete genome sequences of four MVs (two wt MV strains-WA.USA/17.98 and 97-45881, and two SSPE MV strains-MVs/Zagreb.CRO/47.02/and MVs/Zagreb.CRO/08.03/), all belonging to genotype D6. Results of analyses clearly confirm that MV genome continuously changes within the viruses of the same or different genotypes by accumulation of mutations in different parts of the genome. Only a small number of these accumulated mutations induce amino acid substitutions and thus possibly introduce new biological characteristics or a new genotype over a long time period. This study clearly reveals a long untranslated region between M and F genes as the most variable region of the MV genome and detects the presence of unique residues on the level of the entire genome as a new important parameter in the investigation of molecular evolution of MVs.     

贵州省B3基因型麻疹病毒分子特征

目的 分析贵州省2014年首次发现B3基因型麻疹病毒分子特征。方法 采集咽拭子经实时荧光定量逆转录-聚合酶链反应(real-time RT-PCR)筛查麻疹病毒核酸。用逆转录-聚合酶链反应(RT-PCR)扩增麻疹病毒核酸筛查阳性咽拭子,对麻疹病毒N基因羧基末端634个核苷酸片段进行扩增,对扩增产物进行序列测定和分析,构建基因亲缘性关系树。结果 Guizhou14-06(MVs/Guizhou.CHN/11.14/01)在亲缘关系上与WHO B3基因型参考株MVi/Ibadan.NGA/0.97/1(AJ232203)同属一个分支,与MVi/Ibadan.NGA/0.97/1(AJ232203)的核苷酸和氨基酸差异分别为2.00%和2.67%;与中国目前的优势流行参考株MVi/Hunan.CHN/0.93/7(AF045212)的核苷酸和氨基酸差异分别为10.8%和12.0%;与其他WHO 22个基因型参考株的核苷酸和氨基酸差异分别为4.40%~11.0%和4.67%~12.0%。结论 B3基因型麻疹病毒是贵州省首次发现的新基因型麻疹病毒,丰富贵州省麻疹病毒分子流行病学基线数据,并有助于麻疹病毒的控制和消除工作。     

一起缅甸输入新型麻疹病毒(d11基因型)引发暴发疫情的调查分析

目的 研究缅甸输入新型麻疹病毒(d11基因型)导致暴发疫情的相关因素及阻断传播的有效策略和措施.方法 应用流行病学方法进行现场暴发调查.结果 云南省孟连县4个乡镇(66%)报告麻疹15例,6月龄至5岁儿童7例,2例有麻疹疫苗(MV)免疫史;21～49岁8例,免疫史均不详.缅甸入境人员就诊14例,年龄10月龄至13岁,仅1例接种过MV.除1例缅甸病例未采到标本外,其余28例患者麻疹IgM抗体均为阳性,有6例标本检测到麻疹病毒核酸,扩增后测序为麻疹病毒d11基因型,为缅甸输入的d11基因型野病毒.MV接种率和抗体水平调查184人,接种率61.96%,麻疹IgG抗体阳性率87.50%.及时开展MV应急接种,麻疹疫情得到有效控制.结论 境外输入麻疹病例可以引发境内麻疹流行,预示云南省消除麻疹面临巨大困难和挑战;应急接种MV可以阻断传播,说明目前使用的MV对预防d11基因型麻疹病毒感染同样有效.

Abstract：

Objective To study the relevant factors on an measles outbreak caused by imported new virus (d11 genotype)from Myanmar and to develop effective strategies and measures.Methods On-site investigation on the outbreak was carried out. Results There were four townships (66%) in Menglian county reported 15 cases of measles, with 7 cases aged 6 months to 5 years old, 2 cases with the history of measles vaccination (MV). Another 8 cases were 21 to 49 year-olds but their histories on immunization were unclear. 14 of the measles cases with Myanmar citizenship came to China for treatment. They were aged 10 months to 13 years old, with only one case had ever received MV vaccination. For all the 29 cases, except for one case who did not adopt the sample case of Myanmar, the remaining 28 patients were positive for measles IgM antibodies. 6 cases of measles virus RNA were detected in the amplified sequence which showed genotype d11, and was considered Myanmar imported wild virus. 184 people received the MV inoculation, with a rate of 61.96% and the serum samples showed a measles IgG antibody positive rate of 87.50%. Manner MV emergency vaccination was carried out timely in that county so the measles outbreak was effectively controlled.Conclusion Imported measles cases from foreign countries might lead to epidemic, indicating the difficulty and challenge in the elimination of measles in our province. Emergent vaccination of MV could interrupt the transmission of the disease. Our experience showed that MV was effective in the prevention of d11 genotypes measles infection in the area.     

Nosocomial and community transmission of measles virus genotype D8 imported by a returning traveller from Nepal

Measles is uncommon in Australia due to effective national vaccination strategies. In mid-2003, a cluster of nine cases of measles occurred in western Sydney. The index case was a 29-year-old traveller recently returned from Nepal. The case presented to hospital and transmitted the disease to two others in the Emergency Department. Further cases resulted from both community and nosocomial transmission. The median age of cases was 24 years, with three cases in children aged under four years. Only one person had a documented history of measles vaccination, a child who had received one dose of vaccine overseas. One case was a 2-month-old infant whose mother was immune and two cases were hospital staff members. Molecular analysis of measles virus isolates from four cases revealed the same D8 genotype, a strain previously identified in Nepal. Staff vaccination strategies implemented as a result of the outbreak were poorly patronised despite nosocomial transmission. As diseases such as measles become rare it is important to thoroughly investigate any outbreaks, and to maintain a high index of suspicion of measles, particularly in travellers presenting with a rash having returned from measles-endemic areas. Genetic analysis is important in tracing the origins of an outbreak, and to confirm relatedness between cases. The highly infectious nature of measles virus also underscores the need for appropriate infection control in minimising risk of nosocomial transmission. Such policies are of increasing importance with the emergence of novel viruses or the threat of pandemic influenza.     

北京市2013年新发现D8基因型麻疹病例的流行病学调查

目的调查2013年l-6月北京市新发现D8基因型麻疹病例的流行病学特征。方法开展现场流行病学调查,采用描述流行病学方法进行分析。结果2013年1-6月北京市共报告疑似麻疹病例661例,经血清学和病原学检测确诊麻疹病例416例,经基因型鉴定发现D8基因型28例,其中14例病例分属于2起暴发疫情,14例为散发病例。暴发疫情和散发病例发病高峰均在4-5月,分布城区和近郊区25例(89.3%),15～39岁成年人22例(78.5%),外省户籍人口19例(67.9%)。暴发疫情病例中有12例(85.7%)为从事服装销售的外省来京务工人员,2起暴发疫情间存在流行病学联系。结论D8基因型麻疹病例为北京市首次监测到的新基因型病例,发病人群主要为外省户籍成年人,并引起局部暴发和本地传播。     

Identification of a new clade of hepatitis B virus genotype F

Hepatitis B virus (HBV) is classified into eight main genotypes (A–H) and several subgenotypes. Here, three new genotype F complete genome sequences isolated from patients from Buenos Aires city are reported. The new sequences form a separate monophyletic group from the previously known subgenotype F4 strains. Based on results of phylogenetic, genetic distance and evolutionary analyses, the name F4b is proposed for these isolates and F4a for the formerly known as F4. The identification of new clusters allows deepening the knowledge about the diversification process and evolutionary history of HBV.     

河北省D8基因型麻疹病毒输入性疫情监测及基因型特征分析

目的:分析河北省D8基因型麻疹病毒输入性疫情流行及基因型特征。方法:对麻疹监测病例的流行特征进行分析,对采集的急性期咽拭子标本进行荧光定量RT-PCR鉴定、病毒分离培养及核苷酸序列测定和分析。结果:监测到输入性D8基因型麻疹病例36例,主要集中在邯郸市的8个县（区）,其中成安县确诊病例数最多,占报告病例数的58.33%...     

浙江省平湖市2017年由D8基因型麻疹病毒引起的暴发调查

目的 调查浙江省由D8基因型麻疹病毒引起暴发的流行病学特征,为麻疹疫情防控工作提供参考依据。方法 资料来源于中国疾病预防控制信息系统报告的麻疹监测病例,对D8基因型麻疹病例发生地浙江省平湖市开展现场流行病学调查,查阅门诊记录和出入院记录,现场个案调查和疫情处置,采集病例急性期血标本、咽拭子标本。实验室检测包括血清学检测、RNA提取和扩增、麻疹病毒分离和基因型鉴定,采用SPSS 17.0和Excel 2016软件进行数据分析。结果 2017年浙江省平湖市报告一起麻疹暴发疫情,确诊病例10例,>40岁成年人8例。采集病原学标本6例,其中D8基因型5例,1例病原学培养阴性。10例病例之间存在3条传播链同时传播,涉及工厂、医院、家庭内3个场所的传播链。D8和H1a基因型麻疹病例临床表现的差异无统计学意义。及时开展应急接种后,疫情得到有效控制。结论 由D8基因型麻疹病毒引起的暴发疫情,早期病例不易发现,未及时发现和处置首例麻疹病例,形成院内感染传播,成年人麻疹免疫屏障薄弱是本起疫情暴发的原因。应急接种可以阻断传播,说明目前使用的麻疹疫苗对预防D8基因型麻疹病毒感染有效。     

Waning immunity and subclinical measles infections in England

Following the introduction of vaccination against measles, levels of clinical infection have dropped markedly. As we move further into the vaccine era, increasingly many individuals owe their measles immunity to vaccination and have had few (if any) exposures to wild virus. A number of recent reports suggest that vaccinated individuals with low levels of immunity may be at risk of subclinical measles infection. We explore the interplay between levels of infection and immunity over time using a mathematical model that simulates infection, waning and boosting of immunity. We focus particularly on the situation in England, where vaccination has been in place since 1966. Simulations of our model demonstrate a rise in the levels of subclinical measles infection over time, and a corresponding rise in clinical measles infections if vaccination levels are too low. We compare the impact of intervention strategies, and find that the rise in cases is most effectively reduced by 'catch-up' vaccination of children. In recent years, vaccination levels in England have dropped from above 90% in the 1990s to 84% in 2001/2002. We discuss the impact of declining vaccination levels on clinical and subclinical infections.     

Hepatitis B virus detected in a golden monkey fatal case,China

Hepatitis B virus (HBV) is distributed worldwide and poses a significant threat to human health. Cross-species transmission of HBV from human to non-human primates could occur, which has been confirmed in three individual events. In this study, HBV DNA was detected in one golden monkey fatal case in China. The following genetic sequencing and analysis demonstrated the virus had a close genetic relationship with HBV genotype C in humans. To our knowledge, this is the first report suggested that HBV is related with a non-human primate fatal case in China.     

The potential for measles transmission in England

Background  

Since the schools vaccination campaign in 1994, measles has been eliminated from England. Maintaining elimination requires low susceptibility levels to keep the effective reproduction number R below 1. Since 1995, however, MMR coverage in two year old children has decreased by more than 10%.     

Genetic variability of the measles virus hemagglutinin gene in B3 genotype strains circulating in Northern Italy

Sequencing the whole measles virus hemagglutinin (H) gene, in conjunction with a 450-nucleotide region of the nucleoprotein gene (N-450), is helpful for the identification of new genotypes and as an auxiliary in outbreak characterization. In addition, it is essential to be able to predict the antigenic changes of the H protein to gain a better monitoring of the response to the vaccine. In this study, we obtained the full-length H gene sequences from 19 measles virus (MV) strains belonging to two B3 genotype variants circulating in Lombardy (Northern Italy) between July 2015 and February 2016 and evaluated the variability of the whole MV-H gene. Furthermore, we compared the obtained H amino acid sequences to all MV sequences available in the GenBank database (n = 1152 in total) and analyzed the amino acid substitutions in the H protein within clades where the Italian strains were included. We identified a higher variability in the H gene compared to the N-450 region and our results support previous studies, highlighting that the H gene is more informative for characterizing the MV B3 genotype than the N-450 sequence. Some of the amino acid substitutions were fixed in the viral population and, remarkably, some of the amino acid substitutions were typically present only in the Italian sequences. Accumulating further molecular information about MV-H gene will be necessary to enable in-depth analyses of the variability of this gene in the vaccinated population.     

2000年东莞市麻疹病毒流行株基因型分析

目的 了解东莞市麻疹病毒（measles virus,MV)流行株的基因型。方法 2000年4-7月间东莞市发生有55例患者的麻疹流行,采用逆转录-聚合酶链反应（RT-PCR）方法直接检测麻疹病人急性期唾液中的麻疹病毒核糖核酸（RNA）的N基因和M基因,对任意选取的5份RT-PCR阳性标本和疫苗株沪-191的N基因扩增片段进行核酸序列测定,并进行序列系统树分析。结果 用RT-PCR方法直接检测的阳性率为87.3%;用血清抗-MV-IgM ELISA方法检测的阳性率为70.9%,抗MV-IgM阴性的病人唾液中有68.8%的标本MV-RNA阳性。序列分析结果表明此流行株的基因型与世界麻疹病毒流行株不同,差异为1.4%-11.7%,可归属于H基因型。结论 2000年东莞市麻疹病毒流行核酸序列完全相同,为H基因型,说明本次流行的麻疹病毒具有同源性,来源于同一传染源。     

Evolution of new genotype of West Nile virus in North America

Previous studies of North American isolates of West Nile virus (WNV) during 1999-2005 suggested that the virus had reached genetic homeostasis in North America. However, genomic sequencing of WNV isolates from Harris County, Texas, during 2002-2009 suggests that this is not the case. Three new genetic groups have been identified in Texas since 2005. Spread of the southwestern US genotype (SW/WN03) from the Arizona/Colorado/northern Mexico region to California, Illinois, New Mexico, New York, North Dakota, and the Texas Gulf Coast demonstrates continued evolution of WNV. Thus, WNV continues to evolve in North America, as demonstrated by selection of this new genotype. Continued surveillance of the virus is essential as it continues to evolve in the New World.     

Possible new hepatitis B virus genotype, southeast Asia

We conducted a phylogenetic analysis of 19 hepatitis B virus strains from Laos that belonged to 2 subgenotypes of a new genotype I. This emerging new genotype likely developed outside Southeast Asia and is now found in mixed infections and in recombinations with local strains in a geographically confined region.     

The efficiency of measles and pertussis notification in England and Wales

This paper examines methods for estimating the efficiency of measles and pertussis notification with particular reference to England and Wales. Crude estimates are obtained from a comparison of annual numbers of births and notifications, and this approach is modified to include detailed age-specific data. Other sources of data, notably the Hospital In-Patient Enquiry, are used to give detailed estimates over time. These analyses provide evidence for a strong positive correlation between notification efficiency and incidence for both diseases and for a dramatic fall in the notification efficiency for pertussis between 1957 and 1976. This decrease is of particular interest insofar as it could explain in part the apparent fall in size of successive pertussis epidemics during that period. It is estimated that since 1976 the spotter practices of the Royal College of General Practitioners General Practice Research Unit have been approximately 1.5 times more efficient at reporting measles and 2.5 times more efficient at reporting pertussis than the national average for reporting to the Office of Population Censuses and Surveys. Finally it is noted that estimates of notification efficiency are positively correlated with the assumed level of vaccine efficacy, and that all these methods require assumptions concerning the proportion of vaccinations which are recorded, the proportion of vaccinations which are successful in immunizing the recipient, and the proportion of the population which ultimately contracts the infection. In general, measles notification in England and Wales is considerably better than that for pertussis, being of the order of 40-60% for the former and only 5-25% for the latter.     

Attenuated measles virus as a vaccine vector

Live attenuated measles virus (MV) vaccines have an impressive record of safety, efficacy and ability to induce life-long immunity against measles infection. Using reverse genetics technology, such negative-strand RNA viruses can now be rescued from cloned DNA. This technology allows the insertion of exogenous genes encoding foreign antigens into the MV genome in such a way that they can be expressed by the MV vaccine strain, without affecting virus structure, propagation and cell targeting. Recombinant viruses rescued from cloned cDNA induce immune responses against both measles virus and the cloned antigens. The tolerability of MV to gene(s) insertion makes it an attractive flexible vector system, especially if broad immune responses are required. The fact that measles replication strictly occurs in the cytoplasm of infected cells without DNA intermediate has important biosafety implications and adds to the attractiveness of MV as a vector. In this article we report the characteristics of reporter gene expression (GFP, LacZ and CAT) and the biochemical, biophysical and immunological properties of recombinant MV expressing heterologous antigens of simian immunogeficiency virus (SIV).