一起突发炭疽疫情的病原分析

2011年7月海城某村有5名村民陆续出现发热、皮肤伤口出现破溃,周围红肿、渗出液,部分形成焦痂等症状。实验室采集了患者伤口渗出液10份,患者家中环境样本25份进行病原分离,现将结果报告如下:1流行病学调查2011年7月10日海城某村出现疑似炭疽病人,随后几天陆续有人发病入院,前后共有5人.临床表现为发热,皮肤出现破溃,伤口周围出现红肿,水泡,渗出液,伤口形成焦痂。经流行病学调查:发病人中有贩牛和宰杀病牛者,其他人均有不同的接触史。     

2012年锦州地区首例突发炭疽疫情中炭疽芽胞杆菌分离与鉴定

目的:2012年6月,位于锦州市某地两名村民宰杀牛后,疑似感染炭疽,采集样本对其做分离培养、鉴定炭疽芽孢杆菌。方法:采集样本进行分离培养炭疽芽孢杆菌,通过镜检、噬菌体裂解试验、串珠试验等方法及荧光PCR法、普通PCR法鉴定。结果:3份患者手分泌物样本在荧光PCR法检测中均为阳性,在普通PCR法采用三对引物PagA、Cap及rpoB检测在923 bp,1242 bp,618 bp处出现特异性目的条带。结论:本次检测在短时间内顺利完成,为疫情防控工作提供有力的实验室支持;同时为及时治疗患者疾病争取了宝贵时间。     

一起皮肤型炭疽疫情的调查报告

炭疽杆菌是需氧性芽胞杆菌属中唯一一种能引起人畜共患病的芽胞杆菌。人类的感染主要是通过接触病畜及其皮毛等病原。2002年夏天，我市许昌县和襄城县相邻的两个自然村在养殖和贩卖羊的农民中，发现了9例疑似皮肤型炭疽病人，经流行病学调查，临床治疗、实验室检验，最终确定为一起皮肤型炭疽爆发疫情。现将结果报告如下：     

一起皮肤炭疽疫情的调查处置

2007年8月24日，玉溪市疾病预防控制中心接到澄江县疾病预防控制中心报告：澄江县九村镇七江村委会七江村发现2例疑似皮肤炭疽病人。接到报告后，市疾控中心、市畜牧兽医站组织专业人员进行调查核实和疫情处置。     

对玛曲县一起肺炭疽疫情控制的反思

2004年6月甘肃省甘南藏族自治州玛曲县曼日玛乡发生一起炭疽疫情（一例皮肤炭疽，一例肺炭疽），就存在的一些问题进行反思。     

炭疽暴发疫情病原应急检测方法的应用与分析

目的 对延安市甘泉县突发炭疽疫情进行实验室检测,分离鉴定病原菌。方法 采集病例病灶渗出液、血液、疫点外环境等标本共147份,开展病原分离、免疫学、分子生物学检测。结果 共检出各类阳性标本37份,总阳性率为25.18%。病原学检测分离到1株炭疽芽胞杆菌,阳性率为1.28%;分子生物学检测中皮损渗出液荧光定量PCR(qPCR)阳性率最高,达89.47%,血清学(ELISA)检测阳性率为75%,在环境标本中未检出阳性结果。结论 炭疽疫情应急实验检测中,由于抗菌素使用,人体标本病原分离率较低,血清学试验只具有回顾诊断的价值,应引入敏感快速的分子生物学检测技术,以迅速明确诊断。     

一起皮肤型炭疽疫情控制措施探讨

目的　对我市发生的一起皮肤炭疽疫情探讨有效的控制策略。方法　从病原在人间和畜间感染分布特征着手 ,采取综合性控制措施。结果　通过隔离治疗病人 ,追踪病畜及人间、畜间的监测 ,对病原污染的地区进行彻底消毒等措施 ,快速控制了疫点。结论　对人间和畜间采取的控制措施 ,阻止了这一起皮肤型炭疽疫点疫情扩散。     

沈阳市一起人间皮肤炭疽疫情暴发调查

2005年7月29-31日沈阳市发生皮肤炭疽确诊病例7例,疑似病例5例,其中1例疑似病例死亡的炭疽疫情暴发流行,现将其流行病学调查处理与结果分析如下:     

思南县塘头镇一起皮肤炭疽疫情的调查分析

目的:确定炭疽疫情在我县的存在、掌握临床症状、治疗方法、传播途径及疫情处置办法.结论:皮肤炭疽可防可控可治,一般不会经消化道传播,规范隔离治疗是关键.     

免疫荧光技术在一起炭疽疫情处理中的应用

目的：为了更快地防控疫情，使病例尽早确诊，及时提供实验室检测依据，我们应用了免疫荧光技术进行荚膜抗体的检测。方法：首先是制备荚膜抗原，然后采用间接免疫荧光的方法检测病人血清中的荚膜抗体。结果：我们用该方法共检测了11位患者的急性期及恢复期血清，其中8位患者双份血清抗体滴度呈4倍以上增高，与临床诊断完全相符。结论：免疫荧光方法进行炭疽荚膜抗体的检测具有一定的可行性及可操作性，可在今后处理类似炭疽的疫情诊断中得到应用。     

铁岭市一起皮肤炭疽疫情中炭疽芽胞杆菌的快速检测与分析

目的 对2015年7月铁岭市发生一起皮肤炭疽疫情中运用UPT上转发光免疫分析仪联合荧光定量PCR技术进行描述与分析,探讨可以快速现场检测炭疽芽胞杆菌的方法。方法 采集疑似皮肤炭疽患者的焦痂下涂抹样本10份和炭疽疫区外环境样本19份,运用上转发光免疫层析技术联合荧光定量PCR技术对标本进行检测,与此同时进行细菌分离培养。结果 10份患者的痂下涂抹物样本和2份病死牛血污染土壤样本在上转发光免疫层析技术和荧光定量PCR技术检测结果均呈现阳性。细菌分离培养技术仅分离到1株炭疽芽胞杆菌。结论 实验室检测结果充分证明此次疫情的病原体为炭疽芽胞杆菌的感染。上转发光免疫层析技术和荧光定量PCR方法的联合应用,能快速、特异、灵敏检测出炭疽芽胞杆菌,具有推广应用价值。     

Protection of rhesus macaques against inhalational anthrax with a Bacillus anthracis capsule conjugate vaccine

The efficacy of currently licensed anthrax vaccines is largely attributable to a single Bacillus anthracis immunogen, protective antigen. To broaden protection against possible strains resistant to protective antigen-based vaccines, we previously developed a vaccine in which the anthrax polyglutamic acid capsule was covalently conjugated to the outer membrane protein complex of Neisseria meningitidis serotype B and demonstrated that two doses of 2.5 μg of this vaccine conferred partial protection of rhesus macaques against inhalational anthrax . Here, we demonstrate complete protection of rhesus macaques against inhalational anthrax with a higher 50 μg dose of the same capsule conjugate vaccine. These results indicate that B. anthracis capsule is a highly effective vaccine component that should be considered for incorporation in future generation anthrax vaccines.     

A novel live attenuated anthrax spore vaccine based on an acapsular Bacillus anthracis Sterne strain with mutations in the htrA,lef and cya genes

We recently reported the development of a novel, next-generation, live attenuated anthrax spore vaccine based on disruption of the htrA (High Temperature Requirement A) gene in the Bacillus anthracis Sterne veterinary vaccine strain. This vaccine exhibited a highly significant decrease in virulence in murine, guinea pig and rabbit animal models yet preserved the protective value of the parental Sterne strain. Here, we report the evaluation of additional mutations in the lef and cya genes, encoding for the toxin components lethal factor (LF) and edema factor (EF), to further attenuate the SterneΔhtrA strain and improve its compatibility for human use. Accordingly, we constructed seven B. anthracis Sterne-derived strains exhibiting different combinations of mutations in the htrA, cya and lef genes. The various strains were indistinguishable in growth in vitro and in their ability to synthesise the protective antigen (PA, necessary for the elicitation of protection). In the sensitive murine model, we observed a gradual increase (ΔhtrA < ΔhtrAΔcya < ΔhtrAΔlef < ΔhtrAΔlefΔcya) in attenuation – up to 10⁸-fold relative to the parental Sterne vaccine strain. Most importantly, all various SterneΔhtrA derivative strains did not differ in their ability to elicit protective immunity in guinea pigs. Immunisation of guinea pigs with a single dose (10⁹ spores) or double doses (>10⁷ spores) of the most attenuated triple mutant strain SterneΔhtrAlef^MUTΔcya induced a robust immune response, providing complete protection against a subsequent respiratory lethal challenge. Partial protection was observed in animals vaccinated with a double dose of as few as 10⁵ spores. Furthermore, protective immune status was maintained in all vaccinated guinea pigs and rabbits for at least 40 and 30 weeks, respectively.     

Molecular subtyping of Bacillus anthracis and the 2001 bioterrorism-associated anthrax outbreak,United States

Molecular subtyping of Bacillus anthracis played an important role in differentiating and identifying strains during the 2001 bioterrorism-associated outbreak. Because B. anthracis has a low level of genetic variability, only a few subtyping methods, with varying reliability, exist. We initially used multiple-locus variable-number tandem repeat analysis (MLVA) to subtype 135 B. anthracis isolates associated with the outbreak. All isolates were determined to be of genotype 62, the same as the Ames strain used in laboratories. We sequenced the protective antigen gene (pagA) from 42 representative outbreak isolates and determined they all had a pagA sequence indistinguishable from the Ames strain (PA genotype I). MLVA and pagA sequencing were also used on DNA from clinical specimens, making subtyping B. anthracis possible without an isolate. Use of high-resolution molecular subtyping determined that all outbreak isolates were indistinguishable by the methods used and probably originated from a single source. In addition, subtyping rapidly identified laboratory contaminants and nonoutbreak-related isolates.     

Evaluating detection of an inhalational anthrax outbreak

Timely detection of an inhalational anthrax outbreak is critical for clinical and public health management. Syndromic surveillance has received considerable investment, but little is known about how it will perform relative to routine clinical case finding for detection of an inhalational anthrax outbreak. We conducted a simulation study to compare clinical case finding with syndromic surveillance for detection of an outbreak of inhalational anthrax. After simulated release of 1 kg of anthrax spores, the proportion of outbreaks detected first by syndromic surveillance was 0.59 at a specificity of 0.9 and 0.28 at a specificity of 0.975. The mean detection benefit of syndromic surveillance was 1.0 day at a specificity of 0.9 and 0.32 days at a specificity of 0.975. When syndromic surveillance was sufficiently sensitive to detect a substantial proportion of outbreaks before clinical case finding, it generated frequent false alarms.     

Presentation of peptides from Bacillus anthracis protective antigen on Tobacco Mosaic Virus as an epitope targeted anthrax vaccine

The current anthrax vaccine requires improvements for rapidly invoking longer-lasting neutralizing antibody responses with fewer doses from a well-defined formulation. Designing antigens that target neutralizing antibody epitopes of anthrax protective antigen, a component of anthrax toxin, may offer a solution for achieving a vaccine that can induce strong and long lasting antibody responses with fewer boosters. Here we report implementation of a strategy for developing epitope focused virus nanoparticle vaccines against anthrax by using immunogenic virus particles to present peptides derived from anthrax toxin previously identified in (1) neutralizing antibody epitope mapping studies, (2) toxin crystal structure analyses to identify functional regions, and (3) toxin mutational analyses. We successfully expressed two of three peptide epitopes from anthrax toxin that, in previous reports, bound antibodies that were partially neutralizing against toxin activity, discovered cross-reactivity between vaccine constructs and toxin specific antibodies raised in goats against native toxin and showed that antibodies induced by our vaccine constructs also cross-react with native toxin. While protection against intoxication in cellular and animal studies were not as effective as in previous studies, partial toxin neutralization was observed in animals, demonstrating the feasibility of using plant-virus nanoparticles as a platform for epitope defined anthrax vaccines.     

国家传染病自动预警系统的设计与应用

提高早期发现传染病暴发的能力是公共卫生部门有效应对疫情的重要前提.近些年来,随着新发传染病及生物恐怖袭击事件引起的广泛关注,全球许多国家通过加强传统监测系统、增加新监测数据源和手段、研究有效的监测数据分析技术等方式,逐步探索并建立和完善了传染病监测与预警系统.中国疾病预防控制中心(CDC)早在2003年SARS暴发之前就着手开展了传染病流行预警技术研究,并成功建立了探测传染病暴发和流行的移动百分位数法.在此基础上,中国CDC又历时多年,先后开发完成了国家传染病自动预警信息系统,制定统一的预警信号响应流程,并在国内10个省份试点测试,于2008年4月在全国CDC系统中投入运行.该系统采用国内最为庞大的法定传染病监测数据,开发了简便实用的预警方法,实现预警信号的自动产生和及时发送,并对预警信号响应过程的信息进行及时收集.目前,该系统已成为各级CDC机构早期发现潜在传染病暴发的重要手段之一.     

移动百分位数法不同阈值在传染病暴发预警中的效果比较

目的 比较国家传染病自动预警系统(CIDARS)中移动百分位数法采用不同阈值对传染病预警效果的影响.方法 分别采用P50、P60、P70、P80和P90 5个阈值作为移动百分位数法的候选预警阈值,对全国范围2008年7月至2010年6月期间报告的19种法定传染病病例数进行暴发探测和结果的比较.以暴发探测起数最多、暴发探测时间最短和预警信号数最少作为移动百分位数法最优阈值的筛选标准.结果 细菌性和阿米巴性痢疾的最优阈值为P50,其他感染性腹泻和流行性腮腺炎的最优阈值为P60,甲型肝炎、流行性感冒和风疹的最优阈值为P70,流行性乙型脑炎的最优阈值为P80,猩红热、伤寒和副伤寒、戊型肝炎、急性出血性结膜炎、疟疾、流行性出血热、流行性脑脊髓膜炎、钩端螺旋体病、登革热、流行性和地方性斑疹伤寒、丙型肝炎和麻疹12种疾病的最优阈值为P90;对19种传染病分别采用最优剧值进行探测,与所有疾病均采用P50作为阈值相比,2年可减少64 840条(12.20%)预警信号,而暴发探测起数与暴发探测时间没有变化.结论 不同传染病采用移动百分位数法进行暴发探测的最优阈值不同,CIDARS可进一步优化各病种的预警阈值,从而在确保暴发探测准确性和及时性的前提下,减少预警信号数量.

Abstract：

Objective To compare the different thresholds of 'moving percentile method' for outbreak detection in the China Infectious Diseases Automated-alert and Response System (CIDARS). Methods The thresholds of P50, P60, P70, P80 and P90 were respectively adopted as the candidates of early warning thresholds on the moving percentile method. Aberration was detected through the reported cases of 19 notifiable infectious diseases nationwide from July 1,2008 to June 30,2010. Number of outbreaks and time to detection were recorded and the amount of signals acted as the indicators for determining the optimal threshold of moving percentile method in CIDARS. Results The optimal threshold for bacillary and amebic dysentery was P50. For non-cholera infectious diarrhea,dysentery, typhoid and paratyphoid, and epidemic mumps, it was P60. As for hepatitis A, influenza and rubella, the threshold was P70, but for epidemic encephalitis B it was P80. For the following diseses as scarlet fever, typhoid and paratyphoid, hepatitis E, acute hemorrhagic conjunctivitis, malaria, epidemic hemorrhagic fever, meningococcal meningitis, leptospirosis, dengue fever, epidemic endemic typhus,hepatitis C and measles, it was P90. When adopting the adjusted optimal threshold for 19 infectious diseases respectively, 64 840(12.20%)signals had a decrease, comparing to the adoption of the former defaulted threshold(P50)during the 2 years. However, it did not reduce the number of outbreaks being detected as well as the time to detection, in the two year period. Conclusion The optimal thresholds of moving percentile method for different kinds of diseases were different.Adoption of the right optimal threshold for a specific disease could further optimize the performance of outbreak detection for CIDARS.     

Evaluation of early immune response-survival relationship in cynomolgus macaques after Anthrax Vaccine Adsorbed vaccination and Bacillus anthracis spore challenge

Anthrax Vaccine Adsorbed (AVA, BioThrax) is approved by the US Food and Drug Administration for post-exposure prophylaxis (PEP) of anthrax in adults. The PEP schedule is 3 subcutaneous (SC) doses (0, 14 and 28 days), in conjunction with a 60 day course of antimicrobials.The objectives of this study were to understand the onset of protection from AVA PEP vaccination and to assess the potential for shortening the duration of antimicrobial treatment (http://www.phe.gov/Preparedness/mcm/phemce/Documents/2014-phemce-sip.pdf). We determined the efficacy against inhalation anthrax in nonhuman primates (NHP) of the first two doses of the PEP schedule by infectious challenge at the time scheduled for receipt of the third PEP dose (Day 28). Forty-eight cynomolgus macaques were randomized to five groups and vaccinated with serial dilutions of AVA on Days 0 and 14. NHP were exposed to Bacillus anthracis Ames spores on Day 28 (target dose 200 LD₅₀ equivalents). Anti-protective antigen (PA) IgG and toxin neutralizing antibody (TNA) responses to vaccination and in post-challenge survivors were determined. Post-challenge blood and selected tissue samples were assessed for B. anthracis at necropsy or end of study (Day 56). Pre-challenge humoral immune responses correlated with survival, which ranged from 24 to 100% survival depending on vaccination group. Surviving, vaccinated animals had elevated anti-PA IgG and TNA levels for the duration of the study, were abacteremic, exhibited no apparent signs of infection, and had no gross or microscopic lesions. However, survivors had residual spores in lung tissues.We conclude that the first two doses of the PEP schedule provide high levels of protection by the scheduled timing of the third dose. These data may also support consideration of a shorter duration PEP antimicrobial regimen.