本文選題：西方馬腦炎病毒 + 淡色庫(kù)蚊　； 參考：《中國(guó)人民解放軍軍事醫(yī)學(xué)科學(xué)院》2007年博士論文

【摘要】： 西方馬腦炎病毒(western equine encephalomyelitis virus，WEEV)屬于披膜病毒科(Togaviridae)甲病毒屬(Alphaviruses)。它能夠引起人類(lèi)和馬等動(dòng)物的致死性疾病——腦炎，對(duì)馬的病死率可達(dá)50％，對(duì)人的病死率最高可達(dá)10％，嬰幼兒患者常會(huì)導(dǎo)致智力低下、行為失常等。目前已知該病主要分布于加拿大、美國(guó)西部和中部、墨西哥、圭亞那、巴西、阿根廷、秘魯、智利和烏拉圭等國(guó)家。該病在北美地區(qū)呈地方性流行，以不規(guī)則的間隔在馬和人群中引起流行。環(huán)跗庫(kù)蚊(Culex tarsalis)已被證明是北美地區(qū)西方馬腦炎病毒的主要傳播媒介，同時(shí)血清學(xué)調(diào)查證明了鳥(niǎo)類(lèi)在病毒循環(huán)中的作用。在自然界中，病毒只在野鳥(niǎo)—蚊之間進(jìn)行傳播，主要是在環(huán)跗庫(kù)蚊與野鳥(niǎo)之間；人和馬是其非固有的感染對(duì)象，稱(chēng)為“終末宿主”。此外，經(jīng)證實(shí)能夠自然或?qū)嶒?yàn)室感染W(wǎng)EEV的還有其它庫(kù)蚊屬(Culex)、按蚊屬(Anopheles)、伊蚊屬(Aedes)等7個(gè)屬20多種蚊蟲(chóng)，也有從虱、蜱、螨等節(jié)肢動(dòng)物體內(nèi)分離病毒的報(bào)道。雖然西方馬腦炎只在美洲大陸上發(fā)生，但其仍然是國(guó)際嚴(yán)密監(jiān)控的人畜共患傳染病。除了美洲以外，波蘭和前蘇聯(lián)也曾報(bào)道從正常人血中測(cè)得西方馬腦炎抗體，1962年首次從俄羅斯分離出西方馬腦炎病毒株Y62-33。我國(guó)1990年分別從新疆烏蘇縣的一組赫坎按蚊(Anopheles hyrcanus)和博樂(lè)縣的全溝硬蜱(Ixodes persulcatus)中分離出WEEV，這是在歐亞大陸除俄羅斯外發(fā)現(xiàn)的第二例WEEV分離的報(bào)道。在對(duì)我國(guó)人體血清學(xué)調(diào)查中發(fā)現(xiàn)，WEEV抗體陽(yáng)性率為2.71％。這些情況都表明了WEEV在我國(guó)的存在。近年來(lái)我國(guó)每年均有大量不明原因發(fā)熱及腦炎病例的報(bào)道，提示W(wǎng)EEV可能是我國(guó)感染性疾病的新病原之一。此外，WEEV被列為二類(lèi)生物恐怖試劑，如果WEEV經(jīng)氣溶膠方式撒布后，當(dāng)?shù)氐乃拗鲃?dòng)物如鳥(niǎo)類(lèi)等被感染，那么易感蚊蟲(chóng)就有可能通過(guò)吸血將西方馬腦炎傳播給人類(lèi)，造成更大范圍的傳染病暴發(fā)。因此針對(duì)WEEV對(duì)我國(guó)潛在的威脅，我們首先需要明確在我國(guó)的一些優(yōu)勢(shì)種蚊蟲(chóng)能否感染和傳播WEEV，了解它們對(duì)WEEV的傳播能力，結(jié)合生態(tài)習(xí)性確定哪些是主要的潛在媒介，以便制訂應(yīng)對(duì)一旦西方馬腦炎暴發(fā)后的相應(yīng)的防治策略。 在我國(guó)，淡色庫(kù)蚊(Cx.p.pallens)和致倦庫(kù)蚊(Cx.p.quinquefasciatus)是尖音庫(kù)蚊復(fù)合組(Cx.pipiens Complex)成員，嗜吸人血，兼吸禽血，是我國(guó)城鎮(zhèn)的優(yōu)勢(shì)蚊種；白紋伊蚊(Ae.albopictus)和埃及伊蚊(Ae.aegypti)是登革熱的主要傳播媒介，也是我國(guó)的重要蚊種；三帶喙庫(kù)蚊(Cx.tritaeniorhynchus)廣泛地分布于我國(guó)水稻種植區(qū)，嗜吸畜血，兼吸人、雞血等。本研究以這幾種在我國(guó)十分重要的蚊種為對(duì)象，在實(shí)驗(yàn)室條件下，通過(guò)蚊蟲(chóng)叮咬人工感染W(wǎng)EEV的來(lái)亨雞，采用免疫熒光檢測(cè)病毒抗原和RT-PCR檢測(cè)病毒核酸等方法檢測(cè)蚊蟲(chóng)體內(nèi)病毒，確定受試蚊蟲(chóng)對(duì)WEEV的易感性和傳播能力；探討蚊蟲(chóng)對(duì)WEEV的易感機(jī)制，為進(jìn)一步深入理解病毒與媒介的相互作用，尋求對(duì)病媒蚊蟲(chóng)的有效防控手段提供科學(xué)依據(jù)。本工作主要結(jié)果如下： 1．我國(guó)重要蚊種對(duì)WEEV的經(jīng)口感染率 在實(shí)驗(yàn)室條件下，叮咬人工感染W(wǎng)EEV的來(lái)亨雞后，淡色庫(kù)蚊、致倦庫(kù)蚊、三帶喙庫(kù)蚊、白紋伊蚊和埃及伊蚊對(duì)WEEV均易感，其感染率分別為45.5％、60.0％、80.0％、36.7％和25.0％，不同蚊種之間的感染率有顯著性差異(x~2=13.709，P=0.008)，其中三帶喙庫(kù)蚊感染率最高，為80.0％。 2．我國(guó)重要蚊種對(duì)WEEV的刺叮傳播率 在實(shí)驗(yàn)室條件下，淡色庫(kù)蚊、致倦庫(kù)蚊、白紋伊蚊和埃及伊蚊都能通過(guò)刺叮吸血將體內(nèi)的WEEV傳播給易感動(dòng)物1～3日齡的來(lái)亨雞，傳播率分別為40.74％、53.13％、57.14％和45.16％，不同蚊種之間的傳播率沒(méi)有顯著性差異(x~2=1.879，P=0.598)。 3．WEEV在蚊蟲(chóng)體內(nèi)的散布率 在實(shí)驗(yàn)室條件下，WEEV在已感染的淡色庫(kù)蚊、致倦庫(kù)蚊、三帶喙庫(kù)蚊、白紋伊蚊和埃及伊蚊體內(nèi)均能擴(kuò)散至足，散布率分別為60.0％、61.1％、75.0％、54.5％和50.0％。不同蚊種間的散布率沒(méi)有顯著性差異(x~2=1.229，P=0.873)。 4．WEEV在感染蚊蟲(chóng)體內(nèi)擴(kuò)散與蚊蟲(chóng)經(jīng)口傳播病毒的相關(guān)性研究 本研究通過(guò)對(duì)感染和傳播實(shí)驗(yàn)中的單只蚊蟲(chóng)進(jìn)行標(biāo)記，根據(jù)它們感染、擴(kuò)散和傳播的結(jié)果進(jìn)行統(tǒng)計(jì)分析發(fā)現(xiàn)，感染病毒并擴(kuò)散至足的絕大多數(shù)蚊蟲(chóng)能夠?qū)⒉《緜鞑ソo易感動(dòng)物、也有極少數(shù)不能經(jīng)口傳播；一些感染病毒但未擴(kuò)散至足的蚊蟲(chóng)也是一部分能夠經(jīng)口傳播而另一部分不能；還存在一些體內(nèi)檢測(cè)不出病毒，，其叮咬的來(lái)亨雞卻能被感染。 5．西方馬腦炎病毒抗原在經(jīng)口感染淡色庫(kù)蚊體內(nèi)的分布 淡色庫(kù)蚊在經(jīng)口感染W(wǎng)EEV 3～4天后，部分蚊蟲(chóng)中腸壁見(jiàn)有WEEV的侵染。個(gè)別蚊蟲(chóng)后腸出現(xiàn)陽(yáng)性斑塊；第7～10d，部分蚊蟲(chóng)中腸、馬氏管、卵巢、后腸均見(jiàn)病毒侵染；第10～14d，除中腸和卵巢等呈陽(yáng)性反應(yīng)外；可見(jiàn)唾液腺亦被病毒侵染；但有些蚊蟲(chóng)個(gè)體僅在中腸有陽(yáng)性反應(yīng)，其它組織器官均為陰性；還有部分蚊蟲(chóng)個(gè)體組織器官均未見(jiàn)陽(yáng)性反應(yīng)。因此認(rèn)為，淡色庫(kù)蚊對(duì)WEEV的易感性存在個(gè)體差異，不易感的個(gè)體體內(nèi)可能存在中腸屏障，而傳播能力的差異可能是由于唾液腺屏障的存在。
[Abstract]:The western equine encephalitis virus ( WEEV ) belongs to the genus Togaviridae . It can cause fatal disease _ encephalitis in humans and horses . The mortality rate of horses is up to 10 % . The disease is endemic in North America . The disease is endemic in the West and Central America , Mexico , Guyana , Brazil , Argentina , Peru , Chile and Uruguay .
In the past few years , China has reported that WEEV may be one of the new pathogens of infectious diseases in China . In recent years , China has reported that WEEV is one of the new pathogens of infectious diseases in China . In recent years , China has reported that WEEV is a new pathogen of infectious diseases in China .









In our country , Cx . p . quinquefasciatus and Cx . p . quinquefasciatus were the members of Cx . pileus complex .
aegypti and aegypti are the main media of dengue fever , and it is also an important mosquito species in China ;
In order to determine the susceptibility and transmission ability of the infected mosquitoes to WEEV in the laboratory , the infected chickens infected with WEEV were detected by immunofluorescence assay and RT - PCR , and the susceptibility and transmission ability of the infected mosquitoes to WEEV were determined .
To explore the susceptibility mechanism of mosquitoes to WEEV , to further understand the interaction between virus and medium , to provide scientific basis for effective prevention and control of vector mosquitoes . The main results of this work are as follows :









1 . Infection rate of China ' s important mosquito species to WEEV









The infection rate was 44.5 % , 60.0 % , 80.0 % , 33.7 % and 25.0 % , respectively , and the infection rate among different species was significantly different ( x ~ 2 = 13.709 , P = 0.008 ) . Among them , the infection rate among the three species was the highest , which was 80.0 % .









2 . sting propagation rate of important mosquito species in China to WEEV









The WEEV in the body could be transmitted to the 1 - 3 day - old hen in the laboratory . The rate of transmission was 40.74 % , 53.13 % , 57.14 % and 45.16 % , respectively , and there was no significant difference between the different species ( x ~ 2 = 1.879 , P = 0.598 ) .









3 . Distribution rate of WEEV in mosquitoes









In laboratory conditions , WEEV was able to diffuse to the foot in the infected light - colored culex , quinquefasciatus , tritaeniorpius , aegypti , aegypti and aegypti , with the spreading rate of 60.0 % , 61.1 % , 75.0 % , 54.5 % and 50.0 % , respectively . There was no significant difference among the spreading rates among different species ( x ~ 2 = 1.229 , P = 0.873 ) .









Study on the relationship between the diffusion of WEEV and the spread of mosquitoes in infected mosquitoes









Based on the results of infection , diffusion and transmission , the study found that the majority of mosquitoes infected with the virus and spread to the foot were able to spread the virus to the susceptible animals , and that a small number of mosquitoes could not be transmitted through the mouth .
Some mosquitoes that are infected with the virus but not enough to spread to the foot are also part of the virus that can travel through the mouth and the other part cannot ;
There are also some in - vivo detection of the virus , but the bite of the hen can be infected .









5 . Distribution of the Western equine encephalitis virus antigen in the body of the infected pale - color culex piquefasciatus









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