RNAi在抗蚊媒病毒感染中的研究进展

蚊媒病因具有较高的发病率和传播率使其成为全球关注的重要公共卫生问题。蚊虫作为蚊媒病的传播媒介,研究其与蚊媒病毒两者之间的相互作用机制将有助于蚊媒病的防控。蚊虫抵御蚊媒病毒的先天免疫降低和病毒成功逃避蚊虫免疫屏障为病毒在蚊虫体内的持续感染和蚊媒病的暴发流行造成了潜在风险。RNA干扰(RNA interference, RNAi)途径作为蚊虫体内强大的抗病毒防御屏障,通过产生多种小RNA降解病毒RNA,从而达到抑制病毒复制和传播的目的。本文对小干扰RNA (small interfering RNA, si RNA)、微小RNA (micro RNA,mi RNA)、Piwi蛋白相作用RNA (Piwi-interacting RNA, pi RNA)等3种小分子RNA在蚊虫体内发挥抗蚊媒病毒感染的先天免疫机制的相关研究进行了综述,以期为蚊媒病的防控提供理论参考。     

本期重点推介

正登革病毒(dengue virus)是一种流行广泛的蚊媒病毒,主要经伊蚊Aedes传播,可导致登革热等重大疾病。由于长期使用杀虫剂对蚊媒进行防控,使蚊虫产生了抗药性。为了检验蚊虫抗药性对其感染和传播病毒的影响,南方医科大学公共卫生学院贾志荣和陈晓光等筛选建立了白纹伊蚊Aedes albopictus抗溴氰菊酯的实验室品系,并利用RT-PCR和RTq PCR检测了感染登革病毒后0,4,7和10 d白纹伊蚊溴氰     

立谷热人用灭活疫苗的研究进展

<正>立谷热(Rift valley Fever:RVF)是流行于非洲撒哈拉沙漠的一种蚊媒病毒人畜共患性传染病。本世纪初即发现此病存在于肯尼亚等地的羊群中,1930年Qaubney等首次从绵羊中分离到其病原因子RVF病毒。1975年Van Velden等首次报道RVF病毒可以引起人类严重致死性感染。1977年以前一般认为RVF只限于非洲撒哈拉沙漠地带的一些国家,感染人后引起登革热样的发热性疾病。1977—1978年秋冬季节RVF首次在中东埃及出现,并在家畜和人群中引起大流行,造成了大批家畜和数百人死亡。RYF对中东地区的远距离传播引起了世界卫生组织的高度重视,不少专家、学者担心RVF可能成为一种全球流行性传染病。近几年来,由于畜用灭活疫苗和减毒活疫苗在流行区的广泛使用,使RVF得到了一定的控制。为了防止该病在人群小的传播,很多     

基孔肯雅热疫苗的研发

正基孔肯雅热,是一种以急性或慢性关节痛为表征的疾病,慢性关节炎多见。该病由蚊虫传播的基孔肯雅病毒(CHIKV)引起,从2004年再度暴发以来已致上百万人患病。由于基孔肯雅病毒的抗原多样性有限,而且其是否具有再次感染的能力也不甚清楚,所以对于预防该病和防止流行期间病毒的蔓延就需要有效的疫苗。本文将回顾自20世纪70年代以来,针对基孔肯雅病毒的疫苗研发平台和候选疫苗,其中包括临床前研究末期或临床研究。文中     

寨卡病毒和寨卡病毒病

寨卡病毒自1947年首次在乌干达被发现以来,已经在非洲、东南亚和美洲等地造成多次暴发流行,且在中国已有输入性寨卡病毒感染病例的报道。寨卡病毒为黄病毒科黄病毒属,存在非洲型和亚洲型两个亚型。寨卡病毒主要依赖感染病毒的伊蚊类蚊媒叮咬传播,也可通过母婴传播以及血液和性传播。寨卡病毒感染人体后经血播散并可跨越血脑屏障进入中枢神经系统,患者一般临床症状较轻,但有可能出现格林巴利综合症,婴儿小头畸形也与寨卡病毒感染孕妇有关。寨卡病毒的实验室诊断主要包括核酸检测、血清学检测和病毒分离。目前尚无有效疫苗预防寨卡病毒感染,主要预防措施包括防蚊控蚊和提高个人防护意识,并在重点地区加强病例监测。     

基孔肯雅热

基孔肯雅热(Chikungunya fever,CHIK)是由基孔肯雅病毒(Chikungunya virus,CHIKV)病毒引起的,伊蚊叮咬传播的,以发热、关节疼痛等为主要特征的自限性传染性疾病。1952年在坦桑尼亚发生的暴发流行中首次分离CHIKV[1-2],亚洲地区于     

寨卡病毒及其疫苗研究

寨卡病毒与黄热病毒、登革热病毒、日本脑炎病毒、西尼罗病毒等都属于蚊媒传播的黄病毒属病毒。寨卡病毒分离于1947年,但由于分布区域有限,所致寨卡热症状较轻,很长一段时间并没有引起太多的关注。最近一些年,特别是2015年后,巴西的寨卡疫情暴发及其与新生儿小头畸形的关联,引起了全球越来越多的关注。疫苗是应对寨卡疫情的重要手段,目前全球有30余个机构在进行寨卡病毒疫苗的研发。本文综述了寨卡病毒的生物学、流行病学、临床特征以及当前不同类型寨卡病毒疫苗研发现状,同时对其他几种黄病毒属病毒批准和临床阶段疫苗情况进行了概述,以为相关研究人员提供参考。     

登革热的传播模式、蚊媒及防控

在自然界存在两种登革热传播模式:人-伊蚊-人循环,蚊媒是埃及伊蚊与白纹伊蚊。猴-伊蚊-猴循环,蚊媒是白纹伊蚊与白雪伊蚊群。我国学者首先于1975年从无输入性病例的我国西南边疆山林地区的白纹伊蚊体内分离到登革热病毒4型,白纹伊蚊承担两种传播模式的中介。本研究介绍了埃及伊蚊与白纹伊蚊的生态习性与全球及在中国的分布。认为在我国厦门地区迄今为止还未曾发现过埃及伊蚊的存在,也简介了沃尔巴克体新技术防控蚊媒研究的进展。     

基肯孔雅病毒宿主因子和限制性因子的研究

基肯孔雅病毒(The chikungunya virus,CHIKV)是近年来重新暴发的甲病毒,主要由埃及伊蚊叮咬传播,可引起基肯孔雅热。由于对该病毒的研究尚不完全,目前缺少针对性的预防和治疗方法。CHIKV具有全球暴发的可能性,是公众健康的潜在威胁。近期的研究已经发现许多CHIKV的宿主因子和限制性因子,本文通过总结这些因子,为今后进一步研究CHIKV与宿主细胞的相互作用以及探索其致病机制提供思路。     

西尼罗病毒及其所致疾病的研究现状

西尼罗病毒是一种蚊媒病毒,原发于非洲,后传播至欧洲以及西亚,主要在鸟类中传播,也可以感染其他一些哺乳动物(如马、人等)引发脑炎及脑膜炎等症,重者可致死亡.1999年传入北美,在美国纽约地区首次流行,2004年以来被感染的人及动物数量不断增加,分布范围不断扩大,形成了迄今为止西半球最大的虫媒病毒性脑炎的流行.     

Aedes albopictus, vector of chikungunya and dengue viruses in Reunion Island: biology and control

Chikungunya virus (CHIKV) and dengue virus (DENV) are mosquito-borne viruses transmitted by the Aedes genus. Dengue is considered as the most important arbovirus disease throughout the World. Chikungunya, known from epidemics in continental Africa and Asia, has up to now been poorly studied. It has been recently responsible for the severe 2004-2007 epidemic reported in the Indian Ocean (IO), which has caused several serious health and economic problems. This unprecedented epidemic of the IO has shown severe health troubles with morbidity and death associated, which had never been observed before. The two major vectors of those arboviruses in the IO area are Aedes aegypti and Aedes albopictus. The latest is considered as the main vector in most of the islands of the area, especially in Reunion Island. Ae. albopictus showed strong ecological plasticity. Small disposable containers were the principal urban breeding sites, and preferred natural developmental sites were bamboo stumps and rock holes in peri-urban and gully areas. The virus has been isolated from field collected Ae. albopictus females, and in two out of 500 pools of larvae, demonstrating vertical transmission. Experimental works showed that both Ae. albopictus and Ae. aegypti from west IO islands are efficient vectors of dengue and chikungunya viruses. Since 2006 and all along the epidemic of CHIKV, measures for the control of larvae (temephos then Bacillus thuringiensis) and adults (fenitrothion, then deltamethrine) of Ae. albopictus where applied along with individual and collective actions (by the use of repellents, and removal of breeding sites around houses) in Reunion Island. In order to prevent such epidemics, a preventive plan for arboviruses upsurge is ongoing processed. This plan would allow a quicker response to the threat and adapt it according to the virus and its specific vector.     

Chikungunya Virus Infection Results in Higher and Persistent Viral Replication in Aged Rhesus Macaques Due to Defects in Anti-Viral Immunity

Chikungunya virus (CHIKV) is a re-emerging mosquito-borne Alphavirus that causes a clinical disease involving fever, myalgia, nausea and rash. The distinguishing feature of CHIKV infection is the severe debilitating poly-arthralgia that may persist for several months after viral clearance. Since its re-emergence in 2004, CHIKV has spread from the Indian Ocean region to new locations including metropolitan Europe, Japan, and even the United States. The risk of importing CHIKV to new areas of the world is increasing due to high levels of viremia in infected individuals as well as the recent adaptation of the virus to the mosquito species Aedes albopictus. CHIKV re-emergence is also associated with new clinical complications including severe morbidity and, for the first time, mortality. In this study, we characterized disease progression and host immune responses in adult and aged Rhesus macaques infected with either the recent CHIKV outbreak strain La Reunion (LR) or the West African strain 37997. Our results indicate that following intravenous infection and regardless of the virus used, Rhesus macaques become viremic between days 1–5 post infection. While adult animals are able to control viral infection, aged animals show persistent virus in the spleen. Virus-specific T cell responses in the aged animals were reduced compared to adult animals and the B cell responses were also delayed and reduced in aged animals. Interestingly, regardless of age, T cell and antibody responses were more robust in animals infected with LR compared to 37997 CHIKV strain. Taken together these data suggest that the reduced immune responses in the aged animals promotes long-term virus persistence in CHIKV-LR infected Rhesus monkeys.     

Proteomic analysis of CHIKV-infected human fibroblast-like synoviocytes: Identification of host factors potentially associated with CHIKV replication and cellular pathogenesis

Chikungunya virus (CHIKV) is a mosquito-borne virus that causes arthralgic fever. Fibroblast-like synoviocytes play a key role in joint damage in inflammatory arthritides and can additionally serve as target cells for CHIKV infection. To gain a better understanding of CHIKV-induced arthralgia, the interaction between CHIKV and synoviocytes was investigated at the protein level. A gel-enhanced liquid chromatography-mass spectrometry (GeLC-MS/MS) approach was used to examine protein expression from primary human fibroblast-like synoviocytes (HFLS) infected with clinical isolates of CHIKV at 12 and 24 hr post infection. Our analysis identified 259 and 241 proteins of known function that were differentially expressed (>1.5 or <−1.5 fold change) following CHIKV infection at 12 and 24 hpi, respectively. These proteins are involved in cellular homeostasis, including cellular trafficking, cytoskeletal organization, immune response, metabolic process, and protein modification. Some of these proteins have previously been reported to participate in arthralgia/arthritis and the death of infected cells. Our results provide information on the CHIKV-induced modulation of cellular proteins of HFLS at an early stage of infection, as well as highlighting biological processes associated with CHIKV infection in the main target cells of the joint.     

Evidence of Experimental Vertical Transmission of Emerging Novel ECSA Genotype of Chikungunya Virus in Aedes aegypti

Background

Chikungunya virus (CHIKV) has emerged as one of the most important arboviruses of public health significance in the past decade. The virus is mainly maintained through human-mosquito-human cycle. Other routes of transmission and the mechanism of maintenance of the virus in nature are not clearly known. Vertical transmission may be a mechanism of sustaining the virus during inter-epidemic periods. Laboratory experiments were conducted to determine whether Aedes aegypti, a principal vector, is capable of vertically transmitting CHIKV or not.

Methodology/Principal Findings

Female Ae. aegypti were orally infected with a novel ECSA genotype of CHIKV in the 2^nd gonotrophic cycle. On day 10 post infection, a non-infectious blood meal was provided to obtain another cycle of eggs. Larvae and adults developed from the eggs obtained following both infectious and non-infectious blood meal were tested for the presence of CHIKV specific RNA through real time RT-PCR. The results revealed that the larvae and adults developed from eggs derived from the infectious blood meal (2^nd gonotrophic cycle) were negative for CHIKV RNA. However, the larvae and adults developed after subsequent non-infectious blood meal (3^rd gonotrophic cycle) were positive with minimum filial infection rates of 28.2 (1∶35.5) and 20.2 (1∶49.5) respectively.

Conclusion/Significance

This study is the first to confirm experimental vertical transmission of emerging novel ECSA genotype of CHIKV in Ae. aegypti from India, indicating the possibilities of occurrence of this phenomenon in nature. This evidence may have important consequence for survival of CHIKV during adverse climatic conditions and inter-epidemic periods.     

Effective Chikungunya Virus-like Particle Vaccine Produced in Insect Cells

The emerging arthritogenic, mosquito-borne chikungunya virus (CHIKV) causes severe disease in humans and represents a serious public health threat in countries where Aedes spp mosquitoes are present. This study describes for the first time the successful production of CHIKV virus-like particles (VLPs) in insect cells using recombinant baculoviruses. This well-established expression system is rapidly scalable to volumes required for epidemic responses and proved well suited for processing of CHIKV glycoproteins and production of enveloped VLPs. Herein we show that a single immunization with 1 µg of non-adjuvanted CHIKV VLPs induced high titer neutralizing antibody responses and provided complete protection against viraemia and joint inflammation upon challenge with the Réunion Island CHIKV strain in an adult wild-type mouse model of CHIKV disease. CHIKV VLPs produced in insect cells using recombinant baculoviruses thus represents as a new, safe, non-replicating and effective vaccine candidate against CHIKV infections.     

A DNA vaccine against chikungunya virus is protective in mice and induces neutralizing antibodies in mice and nonhuman primates

Chikungunya virus (CHIKV) is an emerging mosquito-borne alphavirus indigenous to tropical Africa and Asia. Acute illness is characterized by fever, arthralgias, conjunctivitis, rash, and sometimes arthritis. Relatively little is known about the antigenic targets for immunity, and no licensed vaccines or therapeutics are currently available for the pathogen. While the Aedes aegypti mosquito is its primary vector, recent evidence suggests that other carriers can transmit CHIKV thus raising concerns about its spread outside of natural endemic areas to new countries including the U.S. and Europe. Considering the potential for pandemic spread, understanding the development of immunity is paramount to the development of effective counter measures against CHIKV. In this study, we isolated a new CHIKV virus from an acutely infected human patient and developed a defined viral challenge stock in mice that allowed us to study viral pathogenesis and develop a viral neutralization assay. We then constructed a synthetic DNA vaccine delivered by in vivo electroporation (EP) that expresses a component of the CHIKV envelope glycoprotein and used this model to evaluate its efficacy. Vaccination induced robust antigen-specific cellular and humoral immune responses, which individually were capable of providing protection against CHIKV challenge in mice. Furthermore, vaccine studies in rhesus macaques demonstrated induction of nAb responses, which mimicked those induced in convalescent human patient sera. These data suggest a protective role for nAb against CHIKV disease and support further study of envelope-based CHIKV DNA vaccines.     

Impact of Chikungunya virus on Aedes albopictus females and possibility of vertical transmission using the actors of the 2007 outbreak in Italy

We investigated the impact of CHIKV strains on some Aedes albopictus (Skuse) reproductive parameters and the possibility of vertical transmission. Two strains were collected in the area where the epidemic occurred in 2007, one isolated from mosquitoes, the other one isolated from a viraemic patient. Different types of blood meals, either infected or non-infected, were offered to Ae. albopictus females, that were then analyzed at increasing time post infection. The virus titre, measured by two RT-PCR methods in the blood meals, influenced the rate of infection and the rate of dissemination of CHIKV in Ae. albopictus body. We found individual variability with respect to the infection/dissemination rates and their latency both considering the female's body and appendages. The hatching rate was significantly lower for the eggs laid by the infected females than for the control eggs, while the mortality during the larval development (from first instar larva to adult emergence) was similar among the progeny of infected and non-infected female groups. Our findings seem to support the hypothesis that the vertical transmission is a rare event under our conditions, and that a certain time period is required in order to get the ovarioles infected. Field observations conducted during the Spring 2008 showed no evidence of the presence of infected overwintering progeny produced by Ae. albopictus females infected during the 2007 outbreak.     

Structure–activity relationship study of arbidol derivatives as inhibitors of chikungunya virus replication

Chikungunya virus (CHIKV), a mosquito-borne arthrogenic Alphavirus, causes an acute febrile illness in humans, that is, accompanied by severe joint pains. In many cases, the infection leads to persistent arthralgia, which may last for weeks to several years. The re-emergence of this infection in the early 2000s was exemplified by numerous outbreaks in the eastern hemisphere. Since then, the virus is rapidly spreading. Currently, no drugs have been approved or are in development for the treatment of CHIKV, which makes this viral infection particularly interesting for academic medicinal chemistry efforts.Several molecules have already been identified that inhibit CHIKV replication in phenotypic virus-cell-based assays. One of these is arbidol, a molecule that already has been licensed for the treatment of influenza A and B virus infections. For structural optimization, a dedicated libraries of 43 indole-based derivatives were evaluated leading to more potent analogues (IIIe and IIIf) with anti-chikungunya virus (CHIKV) activities higher than those of the other derivatives, including the lead compound, and with a selective index of inhibition 13.2 and 14.6, respectively, higher than that of ARB (4.6).     

In Vitro Inhibition of Alphaviruses by Lycorine

Virologica Sinica - Chikungunya virus (CHIKV) is a mosquito-borne alphavirus. As an emerging virus, CHIKV imposes a threat to public health. Currently, there are no vaccines or antivirals available...