南宁市江南区2019年登革热流行病学特征和疫情应急处置分析

目的 分析总结南宁市江南区2019年登革热流行病学特征和疫情应急处置的工作情况,为今后有效地防制登革热提供对策、参考和技术支持。方法 收集南宁市江南区2019年登革热疫情相关数据,评价本次应急处置的工作成效。结果 2019年南宁市江南区登革热疫情严峻,共报告登革热病例370例,其中输入病例4例,本地病例366例;感染人数以家务待业和离退休者居多;男女性别比为1∶1.12;发病年龄最小1岁,最大92岁;发病的空间分布呈现高度聚集,福建园街道占本城区本地病例的87.70%。早期伊蚊应急监测布雷图指数和账诱指数合格率偏低,分别为72.17%和62.61%。针对本次疫情特性,制定有针对性的防控策略,做好精准疫情应急处置,有效压低峰值,迅速控制了疫情的扩散和蔓延。结论 本次疫情是由输入性病例导致本地病例社区水平暴发,疫情呈现多点暴发及扩散蔓延态势。需做好疫情研判、预警预测,准确分析流行病学特征,尽早实施登革热应急处置,精准防控、孳生地处理、健康宣教和病例管理是应急处置的关键措施。     

竹林区村庄白纹伊蚊孳生特点的调查

白纹伊蚊在竹林里孳生的阳性比为75.4%;而在竹林包围的居民区阳性比为15.3%。白纹伊蚊在居民区孳生密度布雷图指数为19.4,容器指数为6.2%。居民区孳生蚊虫的主要场所是泡菜坛,泡菜坛主要孳生蚊种是骚扰阿蚊,阳性比为73.7%,其次是淡色库蚊为20.2%,贪食库蚊为14.0%,白纹伊蚊最低,为9.1%。     

登革病毒感染蚊虫后几个器官敏感性的比较

以浓度为4×10~8TCID_(50)/ml和4×10～5TCID_(50)/ml的病毒液经口感染,4×10~8TCID_(50)/ml和4×10~2TCID_(50)/ml病毒液经胸接种白纹伊蚊(Aedes albopictus)。结果表明1、脑和神经节感染率相同,2、神经系统对病毒敏感性较涎腺高。     

长效驱避剂的筛选及剂型研究

本文以埃及伊蚊为试验对象,对新合成的4种化合物驱蚊效果进行了测定,其中有3种超过了DETA。当DETA加入保护剂或和其它化合物复配后,可延长防蚊时间。试验表明增大驱避剂的浓度和延长防蚊时间不成等比例关系。复配制剂和保护剂的研究是延长驱蚊效果的重要途径。     

A Quantitative Study of Specific Immunoglobulins to Mosquito Salivary Gland Antigen in Hypersensitive and Common Types of Mosquito Bite Reaction

This study was designed with two purposes: first, to elucidate immunologic mechanisms in different cutaneous reactions, particularly in hypersensitivity to mosquito bites, and, second, to develop a more reliable and safer method of identifying the causative species of mosquito in severe cases. The amounts of IgG, IgG₄ and IgE specific to the mosquito salivary gland extract of Aedes albopictus were determined in the sera of 116 volunteers with normal reactions, either immediate or delayed, and 4 patients with severe systemic symptoms caused by mosquito bites. Titers of IgG and IgE in the severe cases were considerably higher than in volunteers with normal reactions, but there were no differences in IgG, titers between the two groups. These results indicate that high titers of IgG and IgE may be involved in development of systemic symptoms in severe cases and verify the possibility of in vitro tests to identify causative species of the mosquito.     

二氧化碳对白纹伊蚊的引诱作用

目的 测试二氧化碳(CO2)浓度与诱效率之间的关系，探明CO2对白纹伊蚊种群的引诱作用，以提高诱蚊灯的诱蚊效果。方法 不同浓CO2运用化学反应获取，通过诱蚊试验测定诱杀率反应诱杀效果。结果：探索出一个对白纹伊蚊具有较好引诱效应的CO2浓度10．34pp，与SB980型紫外光诱蚊灯结合试验表明，用CO2后对白纹伊蚊的诱杀率比对照灯提高13％—30％，平均20％。结论 浓度很低的CO2即对蚊虫有引诱效应，并能增强诱蚊灯的诱杀效果，满足无公害无污染的要求；实验为现有除虫产品的改良提供了一条新途径。     

A trade-off in replication in mosquito versus mammalian systems conferred by a point mutation in the NS4B protein of dengue virus type 4

An acceptable live-attenuated dengue virus vaccine candidate should have low potential for transmission by mosquitoes. We have identified and characterized a mutation in dengue virus type 4 (DEN4) that decreases the ability of the virus to infect mosquitoes. A panel of 1248 mutagenized virus clones generated previously by chemical mutagenesis was screened for decreased replication in mosquito C6/36 cells but efficient replication in simian Vero cells. One virus met these criteria and contained a single coding mutation: a C-to-U mutation at nucleotide 7129 resulting in a Pro-to-Leu change in amino acid 101 of the nonstructural 4B gene (NS4B P101L). This mutation results in decreased replication in C6/36 cells relative to wild-type DEN4, decreased infectivity for mosquitoes, enhanced replication in Vero and human HuH-7 cells, and enhanced replication in SCID mice implanted with HuH-7 cells (SCID-HuH-7 mice). A recombinant DEN4 virus (rDEN4) bearing this mutation exhibited the same set of phenotypes. Addition of the NS4B P101L mutation to rDEN4 bearing a 30 nucleotide deletion (Delta30) decreased the ability of the double-mutant virus to infect mosquitoes but increased its ability to replicate in SCID-HuH-7 mice. Although the NS4B P101L mutation decreases infectivity of DEN4 for mosquitoes, its ability to enhance replication in SCID-HuH-7 mice suggests that it might not be advantageous to include this specific mutation in an rDEN4 vaccine. The opposing effects of the NS4B P101L mutation in mosquito and vertebrate systems suggest that the NS4B protein is involved in maintaining the balance between efficient replication in the mosquito vector and the human host.     

白纹伊蚊和埃及伊蚊defensin A基因克隆及序列分析

应用PCR技术从白纹伊蚊和埃及伊蚊基因组中扩增出defensinA基因 ,并与文献报道的defensinA的5个型的cDNA序列进行同源性比较 ,发现此两序列中存在内元 ;从埃及伊蚊体内扩增的片段为蚊虫defen sinAl的前体AaDefAl;从白纹伊蚊体内扩增的片段为defensinA的 1个新型 ,命名为DefA6。     

贵州白纹伊蚊对登革病毒易感性的研究

目的 用细胞、分子生物学技术进行贵州省白纹伊蚊不同地理株对登革病毒(DEN)易感性的研究。方法 采集贵州省9个地(州)市共计15个县(区)白纹伊蚊幼虫标本，饲养为成蚊；取羽化后3～5日龄期的贵州不同地理株白纹伊蚊，用不同型别的DEN分别经口连续感染3d，于首次感染后的4、7、10、14d收集感染成蚊标本；制备蚊悬液，碘化钠法提取RNA，用DENNS1基因区通用引物经逆转录．聚合酶链反应(RT-PCR)检测DEN核酸；蚊悬液接种C6／36细胞进行病毒分离，制作细胞抗原片，经间接免疫荧光法检测DEN抗原；同时感染白纹伊蚊海南株作为对照。结果 DEN1-4型国际参考株感染白纹伊蚊贵州省不同地方株，其感染比率分别为12／15、12／15、8／15和13／15。结论 白纹伊蚊贵州省不同地方株对DEN1-4型国际参考株普遍易感，表明贵州省具备引起登革热流行的条件。     

溴氰菊酯对白纹伊蚊C6／36细胞株的杀伤作用及对其形态影响的研究

本文采用ＭＴＴ微量酶反应比色法，研究了溴氰菊酯对白纹伊蚊Ｃ６／３６细胞的杀伤作用、形态影响以及受损细胞的恢复。结果发现用溴氰菊酯处理２４ｈ后，对Ｃ６／３６细胞的半数毒性浓度（ＩＣ５０）为７４８８μｇ／ｍｌ，且毒性作用强度随着药物浓度增加而增强。溴氰菊酯浓度在２０μｇ／ｍｌ以上时可以诱发Ｃ６／３６细胞形态学改变，表现为细胞呈多形性、细胞间有间隙、胞质内充满颗粒，以后随药物浓度的升高，胞质出现空泡、染色质凝成粗大颗粒或无结构大块、大片细胞脱落、崩解、死亡。高浓度溴氰菊酯（１６０μｇ／ｍｌ）作用于Ｃ６／３６细胞，其受损细胞的恢复与作用时间有关，作用２４ｈ的细胞，在经历一段生长停滞后，可缓慢恢复，而作用４８ｈ的细胞，则不可逆转的死亡