实时聚合酶链反应检测O1群和O139群霍乱弧菌方法的建立及应用

目的建立检测O1群和O139群霍乱弧菌的实时荧光聚合酶链反应（RT—PCR）方法并进行水体标本的检测评价。方法根据O1群和O139群霍乱弧菌O抗原编码基因rfb序列设计引物，利用SYBRGreen染料，建立同时检测霍乱弧菌O1群和O139群的RT—PCR方法，对所建立的方法分别进行实验室内的灵敏度、特异性及重复性评价。采集河口水标本增菌后进行RT—PCR检测，与分离培养方法比较评价实际应用价值。结果建立了检测O1群和O139群霍乱弧菌的双重RT—PCR方法，根据扩增产物的溶解温度能有效区分O1群和O139群霍乱弧菌两种目标片段的扩增；对其他10种弧菌染色体DNA没有扩增；RT—PCR检测524份河口水体标本的增菌液，与常规分离方法相比显示了明显的灵敏性，并且所有常规分离方法阳性标本其荧光PCR检测亦为阳性。结论以O1群和O139群rfb基因为目标检测片段建立的霍乱弧菌RT—PCR方法可用于环境水体样本中霍乱弧菌常规分离前的快速筛查。     

浙江省温州市啮齿动物中汉坦病毒的分子流行病学研究

目的 研究浙江省温州市啮齿动物中汉坦病毒(HV)流行情况及病毒型别,为该地区肾综合征出血热(HFRS)的预防控制提供科学依据.方法 采用间接免疫荧光法(IFA)检测鼠肺中HV抗原;用RT-PCR法扩增阳性样品中HV的部分S片段及部分M片段;构建系统发生树进行系统发生分析及分型.结果在温州市HFRS疫区共捕获啮齿动物96只,在6份鼠肺样品中检测到HV抗原,其中4只褐家鼠,1只黄胸鼠与1只黄毛鼠,病毒携带率为6.3%.用汉城病毒(SEOV)特异引物从其中5份HV抗原阳性样品中扩增出部分S片段(620～999nt)及部分M片段(2001～2301nt)并测定序列.对扩增出的部分S及M片段的核苷酸序列分析发现,5株病毒与现有的SEOV有高同源性,均为汉城型HV.但在用部分S片段及部分M片段核苷酸序列所构建的系统进化树上,5株病毒的聚集模式不同.结论温州市的褐家鼠、黄胸鼠、黄毛鼠均携带汉城型HV,并可能发生基因片段的重排.     

Molecular analysis of G3 rotavirus among infants and children in Dhaka City, Bangladesh after 1993

Between 2004 and 2005, 917 fecal specimens were collected from children below age 5 who presented to Child Health Institute for treatment of diarrhoea in Dhaka City, Bangladesh. The specimens were screened by RT-PCR for the presence of group A rotavirus and positive stools genotyped. Group A rotavirus was detected in 307 stools and serotype G3P[8] strains were detected in nine specimens. Sequence analysis clustered the G3 strains into one distinct lineage (lineage I) with other Asian G3 strains. In addition, one amino acid change at position 96 in antigenic region A, similar to lineage II G3 Chinese strains, was noted. To our knowledge this is the first report of serotype G3 strains in Bangladesh since 1993 and the first report of the molecular characterization of these strains.     

Climate associated size and shape changes in Aedes aegypti (Diptera: Culicidae) populations from Thailand

In spite of the adult body size variability of Aedes aegypti (Linnaeus) and its likely association with life history and vectorial capacity, the causes of size variation itself have been only partially identified. In particular, possible important factors such as climatic variation have not received much attention.The objective of this 2-year study was to describe from field collections the relationship of Ae. aegypti metric properties with available climatic data. The study took place in a dengue hyperendemic area of Thailand. Fourth instar larvae (L₄) and pupae were collected from the same breeding places allowing the comparisons between seven successive collections, four in 2007 and three in 2008. Climatic data were relative humidity (RH) and temperature (T). They were considered for the periods covering either the pre-imaginal development or, assuming heritability of size, the previous generation. The pre-imaginal period was further subdivided into embryonic and larval phases of development. Size was estimated by traditional and geometric techniques, the latter based on 18 landmarks collected at the intersections of veins also allowing estimation of shape.The shape variation of the wing followed similar patterns as for size and was shown to be a passive allometric change. No significant correlation of size or shape could be disclosed with T. In contrast, significant correlation with RH was found during two periods of examination: (i) the period affecting the generation previous to the time of collection, suggesting possible selective mechanisms on genitors, and (ii) the one occurring during pre-imaginal development. The subdivision of the latter into embryonic and larval phases allowed to evidence a possible selecting effect on embryonic development. The selection would act through the resistance to water loss which is known to depend on the relative surface of the cuticle.In conclusion, our data highlight the importance of the emerged period of Ae. aegypti eggs as a critical time for the size of future adults, and point to the relative humidity as the likely selecting factor.     

贝氏柯克斯体的分子生物学进展

Q热是由贝氏柯克斯体引起的呈世界性分布的一种人兽共患疾病。目前，世界反恐组织已将该病病原体列为生物战剂之一。早期应用抗生素对Q热有疗效,而慢性Q热治疗周期长、易复发,死亡率高。贝氏柯克斯体能以气溶胶的形式传播,一旦流行将难以控制，因此对人类危害极大。为进一步研究该病的致病机制、及时有效的诊断手段及其疫苗的开发提供参考依据，本文就贝氏柯克斯体的分子生物学研究进展作简要概述。     

利用实时荧光定量聚合酶链式反应快速检测鸭沙门菌

目的为快速检测、鉴定鸭沙门菌，避免血清型误判，提高鸭沙门菌暴发应对能力，建立一种实时荧光定量聚合酶链式反应（qPCR）检测方法。方法随机挑选60株鸭沙门菌及238株肠道常见病原菌代表菌株，针对鸭沙门菌血清型特异基因AW58_15605设计引物并建立qPCR检测体系，通过纯菌菌株、模拟粪便样本及临床样本评价该体系的特异度、灵敏度及检测下限。结果60株鸭沙门菌株及临床感染的50份样本扩增结果均为阳性，而对鸭沙门菌血清型以外的其他沙门菌及肠道菌的扩增均为阴性。 对鸭沙门菌纯菌DNA的最低检测下限为8拷贝/反应。 粪便模拟样本检测中，增菌后qPCR检测下限达59.10 cfu/g，明显低于分离培养及增菌前。结论本研究建立的基于特异基因的鸭沙门菌分子检测方法具有可操作性强、特异度高、灵敏度高的特点，建议在应急情况下优先选择qPCR用于沙门菌暴发筛查、鉴别及诊断由其引起的腹泻性疾病。     

2006－2016年我国畜禽动物源性沙门菌血清型分布及其耐药特征

目的了解2006 — 2016年我国畜禽动物来源沙门菌的血清型分布及其耐药特征，完善我国动物源性沙门菌耐药数据，为多重耐药沙门菌感染的预防控制决策提供依据。方法利用传统血清凝集试验，对主要来源于鸡、猪的沙门菌进行血清分型；采用微量肉汤稀释法测定所有实验菌株对16种抗生素的最小抑菌浓度，依据美国临床和实验室标准协会 2017版进行药敏结果判读。结果2006 — 2016年776株沙门菌分为49种血清型，以肠炎沙门菌（31.57%）、德尔卑沙门菌（17.53%）和鼠伤寒沙门菌（14.82%）为主。 猪和鸡源沙门菌的优势血清型分别为德尔卑沙门菌（39.15%）和肠炎沙门菌（51.62%）。 沙门菌对磺胺异恶唑、链霉素和萘啶酸的耐药率最高，分别为73.32%、70.88%、69.59%；对环丙沙星的耐药率为10.70%；对三代头孢的敏感性较高，达92.00%以上。 菌株多重耐药率达63.40%，鼠伤寒沙门菌多重耐药率最高（90.44%），次之为德尔卑沙门菌（63.24%）和肠炎沙门菌（58.78%）。结论我国主要畜禽动物源性沙门菌的多重耐药现象较严重。 随着时间的推移，菌株对多数药物的耐药水平呈上升趋势，需密切关注并实时监测耐药性的变迁、播散及其对环境、人群的潜在威胁，同时加强养殖业抗菌药物的合理应用及监管。     

我国流行病学学科发展70年的历程与成就

流行病学是在人类预防疾病和促进健康的实践中发展起来的一门学科,是公共卫生与预防医学的骨干学科。新中国成立70年来,随着人类疾病谱的变化和医学模式的转变,流行病学的应用范围由传染性疾病扩展到慢性非传染性疾病、伤害和其他健康相关领域。流行病学在疾病防控、科研教学、学会建设和期刊发展等方面取得了显著成就。本文拟梳理和概括我国流行病学学科发展历程,展示我国流行病学领域70年来的成就和贡献,探讨未来流行病学的学科发展方向,为我国流行病学学科发展留下历史印迹。