广州市一起登革热家族聚集性暴发事件的调查与分析

目的探讨登革热家庭聚集性发病的流行病学特点及传播效率，为今后进行有效的预防和控制登革热暴发提供参考。方法采用现场流行病学调查方法对广州市一起登革热家庭聚集性暴发事件进行调查和分析；采用ELISA、RT-PCR和病毒分离的方法对标本进行检测。结果2006年8月广州市荔湾区发生一起登革热家庭聚集性暴发事件，该家族15名家庭成员先后共有6人发病，罹患率40．0％，其中6例患者登革热抗体IgM或IgG阳性3例，病毒分离阳性3例，荧光PCR检测阳性者1例，基因序列测序和病毒分离结果最终确定为登革I型病毒。结论根据临床表现、实验室检测结果以及流行病学调查．虽然该家族部分患者登革热抗体为阴性，但病例发病均在一个最长潜伏期内，因此可以确定该家族发生了登革热聚集性暴发，荔湾区龙津中路龙兴里最有可能是共同感染地．感染来源不明，感染时间为家庭聚会日可能性大。     

2009年广州市首起本地感染登革热家庭聚集性暴发疫情的调查与处理

目的 探讨登革热家庭聚集性发病的流行病学特点及采取的防控措施,为今后进行有效的预防和控制登革热暴发疫情提供参考。方法 采用现场流行病学调查方法对广州市首起登革热家庭聚集性暴发疫情进行调查和分析;采用ELISA和RT-PCR的方法对标本进行血清学检测和病毒分型。结果 2009年8月广州市越秀区发生的一起登革热家庭聚集性暴发事件中,该家庭4名成员中有3人同时发病,这3例患者登革热抗体IgM均阳性,其中RT-PCR检测阳性者2例,病毒分型均为登革Ⅲ型。并且,在实验室回顾性检测中发现,家庭聚集性疫情出现前有1例输入性登革病例,病毒分型也为登革Ⅲ型,且病毒基因测序结果提示两者之间存在明显关联。结论 根据流行病学调查结果、临床表现和实验室检测结果,可以确定该家庭发生了本地感染的登革热聚集性暴发。感染地是三元里大道景苑街居住地;感染来源可能是输入性疫情引起的,输入性疫情与本地疫情之间的这种流行病学关联在广州市还是首次获得。因此,广州市登革热疫情是由输入性疫情引发的本地疫情的趋势未改变,做好输入性疫情防控是防止疫情扩散的有力措施。     

深圳市龙岗街道3例输入性登革热病例的调查与处理

目的分析深圳市龙岗区3例输入性登革热病例的临床特点和流行病学特征。方法采用描述性流行病学方法对3例病例的发现、诊断和应急处置等进行回顾分析和效果评价。结果 3名患者起病前均在印度工作,都有白天蚊虫叮咬史和登革热患者接触史,在印度时均已出现登革热症状,患者雷某和方某的DEV-IgM、DEV-IgG均呈阳性,患者文某的DEV-IgM呈阳性、DEV-IgG呈阴性,均为实验室确诊病例。结论流行病学证据显示此起疫情为输入性登革热疫情,防控措施及时有效,没有二代病例的产生。     

2018年杭州市登革热流行病学及病原特征研究

目的:了解2018年杭州市登革热疫情的流行病学及病原特征。方法:应用RT-PCR方法检测血清标本中的登革病毒核酸及其型别,并对阳性标本进行病毒分离、 E基因扩增、序列测定及进化分析;描述病例的时间、人群和地区分布特征。 结果:2018年杭州市共检测登革热病例80例,其中输入性病例55例,本地病例2...     

昆明市登革热输入性病例的调查及C/PreM基因序列分析

目的 调查云南省昆明市登革热输入性病例分布状况及病原分子特征.方法 收集登革热病例资料,采集本病急性期病人血清标本,用ELISA法检测登革病毒(DENV) IgM抗体,RT-PCR法检测DENV核酸,核酸阳性者进行DENV-C/PreM区的基因核苷酸序列测定和分析,采用MEGA5软件的邻接法构建进化树.结果 2010-2013年在昆明市第三人民医院住院病人中采集到登革热临床诊断病例血清标本13份,经检测DENV-IgM抗体均为阳性,DENV核酸阳性2份.根据流行病学史、临床表现和实验室检测结果,这13例病人均被诊断为登革热.获得了两株病毒(YNH8和YNH12)的C/PreM区基因核苷酸序列,进化分析表明YNH8和YNH12株均为登革Ⅰ型病毒.其中YNH8株与南亚地区印度流行株进化关系最为接近,而YNH12株与泰国、缅甸、柬埔寨和越南等东南亚国家流行株具有较近亲缘关系.结论 昆明市登革热患者均为输入性病例.流行病学史和分子流行病学研究证实,YNH8和YNH12病例与印度和缅甸流行株具有较近亲缘关系.     

广州市白云区2006年登革热流行特征分析

目的分析白云区2006年登革热流行病学特征。为制定登革热预防控制措施提供科学依据。方法应用流行病学方法调查分析白云区登革热流行病学特点，应用ELISA法对疑似登革热病例血清进行IgM／IgG抗体检测。结果2006年白云区登革热由I型登革热病毒引起。流行历时83d，共发生病例70例，发病全部集中在8—11月。病例主要集中在人口流动大的城乡结合部。全部病例中男性发病25例，女性发病45例；发病年龄最小6岁，最大81岁。职业分布以家务、农民、学生发病率较高。结论2006年白云区登革热流行形势严峻．在实践中不断探索和完善登革热预防控制技术和管理模式能有效地预防控制其发生和流行。     

广州市2009年登革热疫情监测结果分析

目的分析广州市2009年登革热疫情的流行病学特征。方法对广州市疫情监测与报告信息系统、实验室监测信息系统,以及相关的现场调查报告,疫情简报等数据信息进行统计与分析。结果广州市2009年报告登革热病例18例,本地感染病例3例,累计发病率0.08/10万,无死亡病例,输入性病例或来广州就诊病例占全年报告病例的83.33%（15/18）,实验室监测表明,2009年广州市病毒流行株为登革Ⅲ型病毒。结论 2009年广州市登革热流行处于散发流行状态,流行的登革病毒型别与往年监测结果有所不同,较多的输入性病例或异地来广州就诊的登革热病例对广州市登革热流行存在潜在风险。     

登革热病毒多重荧光PCR检测及基因分型方法的研究

目的建立一种登革热病毒双靶基因多重荧光PCR检测方法,用于登革热病毒的实验室诊断和基因分型。方法选取登革热病毒Ⅰ-Ⅳ型病毒保守区设计型特异性引物探针和通用型引物探针。评估多重荧光PCR检测方法的特异性、重复性和检测限;并对20份阳性样本进行检测。结果20个登革热阳性核酸标本在通用型检测全部为阳性,特异性型别检测发现登革热病毒Ⅰ型10例、登革热病毒Ⅱ型3例、登革热病毒Ⅲ型3例、登革热病毒Ⅳ型4例;20名正常无症状人群标本提取的核酸和HIV、HCV和HEV通用型和特异性型别检测全部为阴性。梯度检测的变异系数均小于5％。对登革热Ⅰ-Ⅳ型病毒检测最低检测限达10^3 eopies／ml。结论本研究建立的登革热病毒双靶基因多重荧光PCR检测及分型方法具有特异性好、重复性好、快速易操作等优点,可用于登革热病毒的快速检测和基因分型鉴定。     

阳江市一起基孔肯雅热暴发疫情流行病学调查

目的了解基孔肯雅热的流行特征,探索有效的防控策略,为今后防控工作提供依据。方法根据病例定义进行病例搜索,对符合病例定义的病例进行流行病学调查;采用酶联免疫吸附试验方法检测登革热病毒IgM和IgG抗体;采用实时荧光定量逆转录聚合酶链反应方法检测登革热病毒核酸和基孔肯雅热病毒核酸。结果 2010年9月12日至10月21日,阳江市某建筑工地发生基孔肯雅热病27例,总罹患率为11.07%（27/244）;其中男性17例,占62.96%,女性10例,占37.04%;检测15份恢复期病例血样登革热病毒IgM和IgG抗体,其中2份病例血样IgM抗体阳性,其余13份为阴性,15份病例血样IgG抗体均为阴性;检测5份现症病例血样,登革热病毒核酸均为阴性,2份基孔肯雅热病毒核酸阳性。结论这是一起基孔肯雅热暴发疫情,加强出入境检疫、开展医疗机构症状监测和控制传播疾病的媒介密度是预防控制孔肯雅热的重要措施。     

广东登革3型病毒株的分离培养和鉴定

目的对2009年发生于广东地区的3例家庭聚集性登革热患者血清进行登革病毒的鉴定和病毒株的培养分离。方法用胶体金法检测患者血清中登革病毒特异性IgM、IgG抗体;C6／36细胞培养患者血清中登革病毒;RT—PCR扩增C．PrM基因序列的片段以检测患者血清中登革病毒RNA,PCR产物经序列测定后进行生物信息学分析。结果3例患者血清学检测均为登革病毒特异性IgM阳性、IgG阴性;特异性RT—PCR产物长约290bp,经琼脂糖电泳和测序分析,证实3例患者血清中均存在登革3型病毒;从1例患者血清中培养分离到了登革病毒株,经RT—PCR和测序证实为登革3型病毒。结论2009年发生于广东地区的3例登革热患者经病毒培养和分子生物学鉴定,证实均为登革3型病毒感染。     

Transient CD4/CD8 ratio inversion and aberrant immune activation during dengue virus infection

The immune status after dengue virus infection was studied in dengue patients from an outbreak of serotype 3 dengue virus infection in the southern part of Taiwan during November and December 1998. Consecutive blood samples from 29 dengue patients, of whom 21 had dengue fever and 8 had dengue hemorrhagic fever/dengue shock syndrome, were collected, and the immunophenotypes of the peripheral blood mononuclear cells were determined by flow cytometry. The early activation marker CD69 appeared on lymphocytes and monocytes at day 4 after the onset of fever, and declined afterward. However, a transient reverse in the CD4/CD8 ratio occurred at days 6-10 after the onset of fever. The CD4/CD8 ratio inversion was manifested in 10 of 29 dengue patients and was encountered more frequently in dengue hemorrhagic fever/dengue shock syndrome than in dengue fever patients. Analysis of the clinical blood cell count of these 10 cases showed that increase of immature neutrophils developed at fever days 5-6, CD4(dim) or CD8(dim) monocytosis at days 6-7, and atypical lymphocytosis at days 8-10 after the onset of fever. Serum IL-6 was found at either day 7 or day 9-11. The PHA-stimulated T-cell response was depressed as well. These changes in immune parameters indicate aberrant immune activation during dengue virus infection and might be involved in the pathogenesis of dengue virus infection.     

北京市37例输入性登革热的临床特点及诊断思路分析

目的 回顾性分析北京地区输入性登革热患者的诊治经过、临床特征,探讨早期诊断方法.方法 统计北京地坛医院(以下简称我院)2001-2016年收治的登革热住院患者37例,分析患者诊治经过、流行病学史、临床症状、血常规、登革热抗体等指标,形成登革热规范诊治思路.结果 输入性登革热37例,以男性25例,女性12例,均无严重基础疾病,合并疟疾3例,均可追溯到明确的流行病学史,均在病前2周内在登革热流行区有停留史.患者到我院就诊时间为病程2～ 12d,平均5.5 d.半数以上患者出现典型症状体征,所有患者血登革病毒特异性IgM阳性.治疗主要给予保肝、对症支持治疗,预后好.结论 在登革热非流行区,接诊医师应对本病保持警惕,详细询问流行病学史,全面查体,及早行血登革病毒特异性IgM或登革热抗原(NS1)检测及病毒核酸检测,进行早期诊断,并给予及时治疗.     

MIP-1 alpha and MIP-1 beta induction by dengue virus

Dengue virus (DV) infection can result in either a mild febrile illness known as dengue fever (DF) or a life-threatening disease called dengue hemorrhagic fever (DHF). DHF is more prevalent in patients undergoing secondary DV infection. This observation has led to the hypothesis that DHF may be the result of immune reactions to the secondary DV infection; an event termed immunopathology. Two cellular factors, MIP-1 alpha and MIP-1 beta, have been found to be induced by infection with DV. MIP-1 induction by DV infection was observed in a myelomonocytic cell line, as well as in peripheral blood mononuclear cells isolated from a dengue naive donor. MIP-1 induction was not due to factors secreted by infected cells. In fact, replication-competent virus was required to induce MIP-1. Evidence is also provided that MIP-1 genes are expressed in patients with dengue disease. It is hypothesized that these chemokines may have roles in the immunopathology of dengue infections and may contribute to fever and bone marrow suppression observed in patients with DV infections.     

Association of increased platelet-associated immunoglobulins with thrombocytopenia and the severity of disease in secondary dengue virus infections

Severe thrombocytopenia and increased vascular permeability are two major characteristics of dengue haemorrhagic fever (DHF). To develop a better understanding of the roles of platelet-associated IgG (PAIgG) and IgM (PAIgM) in inducing thrombocytopenia and its severity of disease in patients with secondary dengue virus infection, the relationship between the PAIgG or PAIgM levels and disease severity as well as thrombocytopenia was examined in 78 patients with acute phase secondary infection in a prospective hospital-based study. The decrease in platelet count during the acute phase recovered significantly during the convalescent phase. In contrast, the increased levels of PAIgG or PAIgM that occurred during the acute phase of these patients decreased significantly during the convalescent phase. An inverse correlation between platelet count and PAIgG or PAIgM levels was found in these patients. Anti-dengue virus IgG and IgM activity was found in platelet eluates from 10 patients in an acute phase of secondary infection. Increased levels of PAIgG or PAIgM were significantly higher in DHF than those in dengue fever (DF). An increased level of PAIgM was associated independently with the development of DHF, representing a possible predictor of DHF with a high specificity. Our present data suggest that platelet-associated immunoglobulins involving antidengue virus activity play a pivotal role in the induction of thrombocytopenia and the severity of the disease in secondary dengue virus infections.     

Immunity and immunopathology in dengue virus infections.

Dengue virus infections are a serious public health problem in tropical and subtropical areas of the world. Based on epidemiological data, it has been postulated that immune responses to dengue virus contribute to the pathogenesis of severe dengue illness, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Host immune responses are also important for controlling dengue virus infection. Therefore, dengue virus infections are an interesting model to explore the interactions between viruses and the immune system which result in immunopathology or recovery from infection. In this paper, we review immune responses to dengue viruses with an emphasis on the human T cell responses, and discuss possible roles of these immune responses in the control of dengue virus infection and in the pathogenesis of DHF/DSS.