我国一些地区人血清的虫媒病毒抗体调查

本文调查了28个省、市、自治区的人血清对18种虫媒病毒抗原的血凝抑制抗体,发现我国广大地区主要存在乙组虫媒病毒,但也存在甲组和布尼安病毒的可能。甲组病毒的抗体阳性数占总阳性数的16.7%(58/347),新疆、青海、黑龙江、山西、福建、甘肃省占甲组虫媒病毒抗体阳性数的84%。布尼安病毒中特别是Aino病毒的抗体阳性率较高,占总阳性数的12.7%(45/347),黑龙江8/10人阳性,其HI滴度都大于1/80,最高为1/1280,平均滴度为1/320,黑龙江、新疆、福建、北京占布尼安总阳性数的70%。乙组虫媒病毒则以乙脑为主。但其它病毒的抗体如Zika、 Kunjin的抗体阳性也很高,故推测我国除已知有乙脑、森脑、登革热外,尚有其它乙组虫媒病毒存在的可能。     

云南省洱源县鸟吊山鸟血清虫媒病毒抗体调查

本文报道了检查云南省洱源县鸟吊山8目11科24属26种319份鸟血清对12种虫媒病毒抗原的血凝抑制抗体,发现鸟类既存在乙组虫媒病毒抗体,又存在甲组虫媒病毒抗体。其中9种鸟检出甲组虫媒病毒抗体,阳性率14.4%(46/319);15种鸟检出乙组虫媒病毒抗体,阳性率53.9%(172/319)。被检鸟中携带虫媒病毒抗体最多的是火鸠,抗体达12种之多,其血凝抑制滴度都大于1:80,最高达1:5120。乙组虫媒病毒中的圣路易脑炎抗体的检出,为我国首次报道,血凝抑制滴度高达1:5120。推测我省不仅有乙脑、登革热虫媒病毒存在,还可能有甲组虫媒病毒及其它乙组虫媒病毒存在的可能。由于鸟类生态和分布的关系,导致我省以外的其它地区亦可能存在有多种虫媒病毒。     

贵州地区人血清虫媒病毒抗体调查

从贵州省5个动物地理区划采集的402份人血清对3-11种虫媒病毒抗原的血凝抑制抗体检查结果,发现全省广大地区不仅存在乙组虫媒病毒的感染,而且存在甲组虫媒病毒的可能,这些病毒在不同或同一动物地理区划的分布不同,JE较普遍,DEN-3或相关抗原局限于东南及南部地区。甲组病毒的抗体阳性率为32.69％(102/312),用了3种抗原检测,仅查到MAY或相关抗原的抗体。乙组病毒的抗体阳性率为64.74(202/     

铜川市流行性乙型脑炎发病特征分析

目的了解铜川市乙脑发病特征及人群抗体水平,为有效防控乙脑提供科学依据。方法采用描述流行病学方法,对铜川市乙脑病例进行统计分析,并在铜川市宜君县随机抽取健康人群采集静脉血检测乙脑中和抗体。结果铜川市1960-2012年共报告乙脑病例649例,死亡59例,年均发病率为2.07/10万,死亡率为0.19/10万,病死率为9.09%。发病呈明显的季节特点,近年来职业分布上以农民、民工为多,15岁以上人群病例占总病例数的93.10%,年龄别发病率以60岁以上人群最高;共采集健康人群血样216对,乙脑流行季节前,健康人群中和抗体阳性率24.07%,抗体几何平均滴度(GMT)1∶3.04;流行季节后,健康人群乙脑中和抗体阳性率为26.39%,抗体几何平均滴度(GMT)1∶3.29,流行季节前后中和抗体阳性率和抗体几何平均滴度差异均无统计学意义。结论乙脑疫苗接种是铜川市预防乙脑最有效的途径,铜川市健康人群乙脑抗体水平主要受疫苗接种影响。在做好适龄儿童免疫接种的同时,对成人也应开展乙脑疫苗强化免疫,建立整个人群的免疫屏障。     

云南腾冲地区人群虫媒传染病的血清流行病学研究

目的 调查云南腾冲地区人群中虫媒病毒抗体,以了解当地虫媒病毒流行情况.方法 应用间接免疫荧光试验(IFA)对72例不明发热患者血清中虫媒病毒抗体进行测定,同时选取37名健康体检者作为对照组.结果 发热患者血清中乙型脑炎病毒(JEV)、西尼罗病毒(WNV)、基孔肯雅病毒(CHK)、辛德毕斯病毒(SIN)和西部马脑炎病毒(WEE) IgG抗体阳性率依次为41.67％、50.00％、2.78％、1.39％、0.00％;正常人群血清JEV、WNV抗体阳性率分别为18.92％、32.43％,CHK、SIN、WEE IgG抗体均未检出.21例JEV、WNV抗体均为阳性样本的几何平均滴度(GMRT)分别为1:28和1:31.结论 该地区存在着黄病毒和甲病毒感染,还可能存在着其他虫媒病毒感染.     

2012—2015年江苏省健康人群流行性乙型脑炎抗体水平

目的了解2012—2015年江苏省健康人群流行性乙型脑炎抗体水平。方法在苏中(扬州、南通市)、苏北(淮安、徐州市)8个监测点,采集7个年龄组健康人群2 669份血清标本,采用蚀斑减少中和实验测定乙脑抗体水平。结果乙脑抗体阳性率为66.47%,几何平均滴度(GMT)为1∶12.71;抗体阳性率随年龄的增长呈上升趋势(P<0.05),GMT与年龄增长呈正相关(P<0.05);不同年龄组、年份、地区及免疫接种次数乙脑抗体水平差异均有统计学意义(P值均<0.05)。结论江苏省>15岁人群乙脑抗体水平具有保护作用,乙脑低滴度抗体水平主要集中在小年龄组。     

呼和浩特市2003年外来民工麻疹白喉A群脑膜炎球菌和流行性乙型脑炎抗体水平监测

目的 了解外地驻呼和浩特市民工中麻疹、白喉、流行性乙型脑炎(乙脑)、A群脑膜炎球菌的抗体水平.方法 2003年对呼和浩特市的3个工地民工,采用酶联免疫吸附试验(ELISA)进行抗体水平监测.结果 麻疹抗体阳性率为95.04%,几何平均滴度(GMT)为11 339.7;白喉抗体阳性率为40.50%,GMT为10.282 4;A群脑膜炎球菌抗体阳性率为35.54%,GMT为11.459 5;乙脑抗体阳性率为50.41%,GMT为11.956 4.结论 外来民工白喉、乙脑、A群脑膜炎球菌抗体水平较低,应开展麻疹、白喉、A群脑膜炎球菌、乙脑监测和接种疫苗工作.     

流行性乙型脑炎减毒活疫苗两针免疫法免疫效果研究

目的了解流行性乙型脑炎(乙脑)减毒活疫苗当前使用的两针免疫法的免疫效果。方法在广州市海珠区选取未接种过乙脑疫苗且未患过乙脑的8月龄~10月龄儿童,按当前8月龄始初免、24月龄始加强的程序先后进行两针次免疫,并于免疫前和免疫后1个月各采集静脉血(共4次)进行乙脑中和抗体检测。结果 176名儿童的初免前抗体阳性率为9.6%,抗体几何平均滴度(GMT)为1:1.27;初免后抗体阳性率为86.9%,GMT为1:19.35;至加强免疫前抗体阳性率降至75.0%,GMT降至1:9.38;加强免疫后抗体阳性率为96.0%,GMT为1:40.92;免疫后抗体应答强弱与免疫前抗体滴度高低呈负相关关系。结论我国当前使用的乙脑减毒活疫苗两针免疫法的免疫效果良好。     

乙脑减毒活疫苗两针法免疫效果观察

目的观察流行性乙型脑炎(乙脑)减毒活疫苗现行的2针免疫法免疫效果。方法在广州市海珠区选取未接种过乙脑疫苗且未患过乙脑的8~10月龄儿童176人,进行乙脑减毒活疫苗的初免以及14~18月后加强免疫;于每剂次免疫前后1个月采集静脉血检测乙脑中和抗体。结果初免前抗体阳性率9.6%,抗体几何平均滴度(GMT)为1∶1.27;初免后抗体阳性率86.9%,GMT为1∶19.35,抗体阳转率85.5%。加强免疫前抗体阳性率75.0%,GMT为1∶9.38;加强免疫后抗体阳性率96.0%,GMT为1∶40.92,加强免疫抗体阳转率84.1%,2针次后抗体总体阳转率95.6%。结论现行的乙脑减毒活疫苗的免疫程序能取得很好的免疫效果。     

云南省西双版纳地区2011年蚊虫及虫媒病毒调查

目的了解云南省西双版纳地区蚊虫媒介的分布特点及当地虫媒病毒情况,为虫媒病毒病防治提供科学依据。方法在云南省西双版纳州采集蚊虫标本,用细胞培养法分离病毒,并用RTPCR法检测常见虫媒病毒核酸;在西双版纳州采集发热患者血清及脑脊液标本,并用ELISA法检测常见病毒性脑炎IgM抗体。结果共采获蚊虫5属29种13337只,其中三带喙库蚊、中华按蚊、带足按蚊分别占蚊虫标本总数的79.98%(10667/13337)、7.95%(1060/13337)和7.38%(984/13337),三带喙库蚊为当地优势蚊种。采用流行性乙型脑炎(乙脑)病毒、版纳病毒、甲病毒属、环状病毒等多种虫媒病毒引物对214批蚊虫标本进行PCR检测,结果均为阴性;采用多种细胞对蚊虫标本进行病毒分离,结果也为阴性。用相关脑炎病毒试剂盒对采集到的52份急性期血清标本及54份脑脊液标本进行ELISA检测,发现乙脑病毒IgM阳性16例,单纯疱疹病毒IgM抗体阳性4例,腮腺炎病毒IgM抗体阳性13例,埃可病毒IgM抗体阳性3例,登革热病毒IgM抗体阳性1例。结论 2011年西双版纳地区采集到的蚊虫标本中未检测到乙脑、版纳及环状病毒等虫媒病毒,但血清学检测结果表明当地发热患者存在乙脑等多种病毒性脑炎感染。     

云南白纹伊蚊分布特点及与虫媒病毒的关系

目的：阐明白纹伊蚊分布特点,掌握其自然感染虫媒病毒情况,方法;白天在居民点周围和野外竹林区捕蚊,用细胞法和乳鼠法分离病毒。结果：采获成年雌性蚊虫8属45种24885只,其中白纹伊蚊7622只,占30．62％,从该蚊中分离到登革4型病毒4株,登革3型病毒1株,流行性乙型脑炎病毒2株,基孔肯雅病毒2株,]甲病毒2株。结论：白纹伊蚊在云南广泛分布,属竹林区优势蚊种,是云南登革热和基孔肯雅病的主要传播媒介及流行性乙型脑炎的传播媒介。     

A sero-epidemiological survey for certain arboviruses (Togaviridae) in Pakistan

Complement-fixation test reactions to eight viruses of the family Togaviridae were studied in 372 serum samples (157 rodents, 172 domestic animals, 43 humans) from Pakistan. Antibodies to each tested virus were detected. The highest over-all prevalence rates were for West Nile (WN) (7.8%), Japanese encephalitis (JE) (3.2%) and Zika (ZIKA) (2.4%) viruses, followed by Sindbis (SIN), Chikungunya (CHIK), Uganda S (UGS) and Royal Farm (RF) viruses (1.6 to 1.3%). One human serum (male, age 58 years) reacted with Dengue-1 (DEN) virus antigen (titre 1:32). Antibodies to each virus except RF were detected in human sera; antibodies to RF virus were detected only in rodent and domestic animal sera. The roles of rodents in the epidemiology of WN, JE and ZIKA viruses should be investigated. At least six of these eight viruses cause fevers in humans (fevers of unknown origin comprise about one third of the febrile episodes recorded in Pakistan).     

云南白纹伊蚊感染,传播登革和乙型脑炎病毒的研究

云南株白纹伊蚊通过吸食含病毒的血餐或叮吸有病毒血症的小鸡血，能感染登革和乙型脑炎病毒，并能在蚊体内增殖。感染蚊经叮咬吸血，能将这两种病毒传播给乳鼠或小鸡。雌蚊感染后第10天，对乳鼠的传播率登革1、2、3、4型和乙型脑炎依次为22．22％、37．50％、25．00％、44．44％和37．50％；对小鸡的传播率登革4型和乙型脑炎分别为100％和66．67％。实验结果表明，白纹伊蚊在登革和乙型脑炎病毒保存和传播中起重要作用。     

A yellow fever epizootic in Zika Forest, Uganda, during 1972: Part 2: Monkey serology.

During the 1972 yellow fever epizootic in Zika Forest, Uganda, sera from 21 monkeys shot in a number of forests around the Entebbe area were tested for the presence of a number of arbovirus antibodies. All sera were tested for antibodies against Chikungunya (CHIK), O'nyong-nyong (ONN), Zika, yellow fever (YF) West Nile (WN) and Wesselsbron (WESS) by the haemagglutination-inhibition (HI) test. Because of the crossreaction within the flaviviruses (group B arboviruses) mouse protection test (PT) was also carried out on the sera against YF, WESS and Zika viruses. Serological studies carried out on monkey sera from different parts of Uganda, including the Entebbe area, during 1968 gave results which reflected a surprisingly low rate of YF immune monkeys (3%) throughout the country compared with the rate of over 40% immune monkeys obtained by Haddow et al. in 1951. 40% of the monkey sera collected during 1972 were immune to YF by the PT. Since no YF virus had been isolated between 1968 and 1972 the results indicate strongly that the monkeys in the Entebbe area were involved in the epizootic of 1972. No sick or dead monkeys were found in all the forests checked around Entebbe area during the epizootic. This indicates that the animal-to-animal cycle of the equatorial African forests involved the mild endemic infection characteristic of a virus in its natural habitat and infecting its natural host.     

Virus isolations from mosquitoes collected during the 1982 Japanese encephalitis epidemic in northern Thailand

From 16 June to 15 August, 1982 CDC light traps were used to collect mosquitoes in the province of Kamphaengphet, N. Thailand. 353,042 mosquitoes comprising 59 species were collected and identified, and 345,173 were placed in pools for attempted virus isolation by inoculation of C6/36 Aedes albopictus mosquito cell cultures. Viruses were isolated from 63 mosquito pools. These comprised 56 flaviviruses, identified as 35 isolates of Japanese encephalitis (JE) virus strains, 18 strains of Tembusu (TEM) virus and three untyped flaviviruses (FLA); three alphaviruses, identified as the first isolates of Getah (GET) virus to have been made in Thailand; and four viruses which are still unidentified. Most virus isolates were from Culex tritaeniorhynchus mosquitoes collected in carbon dioxide baited light traps. JE virus was isolated only over a ten-day period and the last isolate was obtained one week before the peak of admission of human encephalitis cases at Kamphaengphet Provincial Hospital. Rapid screening of isolates grown on Ae. pseudoscutellaris (LSTM-AP-61) mosquito cells by indirect immunofluorescence using flavivirus group-specific and JE-specific monoclonal antibodies showed a high degree of correlation with plaque reduction neutralization tests. An antigen capture enzyme immunoassay (EIA) test successfully identified about 50% of the JE virus positive pools, but the method saved considerable processing time.     

Evaluation of the Langat/dengue 4 chimeric virus as a live attenuated tick-borne encephalitis vaccine for safety and immunogenicity in healthy adult volunteers

With the steady rise in tick-borne encephalitis virus (TBEV) infections in Europe, development of a live attenuated vaccine that will generate long-lasting immunity would be of considerable benefit. A chimeric flavivirus, designated LGT/DEN4, was previously constructed to have a genome containing the prM and E protein genes of Langat virus (LGT), a naturally attenuated member of the TBEV complex, and the remaining genetic sequences derived from dengue 4 virus (DEN4). LGT/DEN4 was highly attenuated in rodents and non-human primates, and clinical trials in humans were initiated. Twenty-eight healthy seronegative adult volunteers were randomly assigned in a 4:1 ratio to receive 10(3) plaque-forming units (PFU) of LGT/DEN4 or placebo. Volunteers were closely monitored for clinical responses and for blood chemistry and hematological changes, and the level of viremia and the magnitude and duration of the neutralizing antibody response were determined. The LGT/DEN4 vaccine was safe and viremia was seen in only one vaccinee. Infection induced a neutralizing antibody response to wild-type LGT in 80% of volunteers with a geometric mean titer (GMT) of 1:63 present on day 42 post-immunization; however the antibody response against TBEV was both much less frequent (35%) and lower in magnitude (GMT=1:9). To assess the response to a booster dose, 21 of the original 28 volunteers were re-randomized to receive a second dose of either 10(3) PFU of vaccine or placebo given 6-18 months after the first dose. The immunogenicity against either LGT or TBEV was not significantly enhanced after the second dose of vaccine. Thus, chimerization of LGT with DEN4 yielded a vaccine virus that was highly attenuated yet infectious in humans. The level of replication was sufficiently restricted to induce only a weak cross-reactive antibody response to TBEV. To provide a sufficient level of immunity to widely prevalent, highly neurovirulent strains of TBEV in humans, vaccine candidates will likely need to be based on the TBEV structural protein genes.     

Comparison of live and inactivated tick-borne encephalitis virus vaccines for safety, immunogenicity and efficacy in rhesus monkeys

Three antigenic chimeric live attenuated tick-borne encephalitis virus (TBEV) vaccine candidates were compared for level of replication in murine and human neuroblastoma cells, for neurovirulence and neuroinvasiveness in mice, and for safety, immunogenicity and efficacy in rhesus monkeys. Two chimeric viruses were generated by replacing the membrane precursor and envelope protein genes of dengue type 4 virus (DEN4) with the corresponding genes of a Far Eastern TBEV, Sofjin strain, in the presence (TBEV/DEN4Delta30) or absence (TBEV/DEN4) of a 30 nucleotide deletion (Delta30) in the 3' noncoding region of the DEN4 part of the chimeric genome. A third chimeric TBEV vaccine candidate was based on the antigenically distant, but naturally attenuated Langat virus (LGT). Chimerization of LGT with DEN4 resulted in decreased neurovirulence and neuroinvasiveness in mice and highly restricted viremia in rhesus monkeys. Also, the LGT/DEN4 chimera was highly restricted in replication in both murine and human neuroblastoma cells. In contrast, TBEV/DEN4 and TBEV/DEN4Delta30 were neither attenuated for neurovirulence in the mice nor restricted in replication in the neuroblastoma cells. However, both were highly attenuated for neuroinvasiveness in mice. TBEV/DEN4 replicated to moderately high titer in rhesus monkeys (mean peak viremia=10(3.1)PFU/ml) indicating that the TBEV/DEN4 chimerization had only a modest, if any, attenuating effect in monkeys. However, the addition of the Delta30 mutation to TBEV/DEN4 greatly attenuated the chimeric virus for rhesus monkeys (mean peak viremia=10(0.7)PFU/ml) and induced a higher level of antibody against the TBEV than did LGT/DEN4. A single dose of either highly attenuated TBEV/DEN4Delta30 or LGT/DEN4 vaccine candidate or three doses of an inactivated TBEV vaccine were efficacious in monkeys against wild-type LGT challenge. These results indicate that both TBEV/DEN4Delta30 and LGT/DEN4 are safe and efficacious in rhesus monkeys and should be further evaluated as vaccine candidates for use in humans.     

贵州省健康人群流行性乙型脑炎血清流行病学调查

目的 调查贵州省健康人群流行性乙型脑炎（乙脑）中和抗体水平。方法 采用分层随机抽样的方法,在乙脑流行季节采集6个市（州）8个年龄组健康人群血清共960份,应用蚀斑减少中和试验法检测乙脑中和抗体。结果 960名调查对象中乙脑中和抗体阳性率为64.69%,几何平均滴度（GMT）为1∶30.32。男、女性乙脑中和抗体阳性率分别为59.82%、68.77%（χ2 = 8.364, P = 0.004）;不同年龄乙脑中和抗体阳性率在52.50%～84.17%之间（χ2 = 35.893, P＜0.001）,GMT在1∶20.00～1∶41.40之间（χ2 = 22.207, P = 0.002）,其中中和抗体阳性率最低为＜ 1岁组,最高为＞40岁组,GMT最低为11～15岁组,最高为＞40岁组;不同地区乙脑中和抗体GMT在1∶18.62～1∶43.66之间（χ2 = 56.581, P＜0.001）。结论 贵州省健康人群乙脑中和抗体水平总体较低,应加强乙脑监测,提高人群免疫水平,尤其是应加强对学龄儿童和青少年的免疫接种工作。