斑须按蚊产卵对不同器官出丝诱导物质的影响

目的 探讨雌性斑须按蚊产卵对蚊体内不同器官中疟原虫雄配子体出丝诱导物质的影响。方法 应用体外雄配子体出丝分析方法，检测吸血后产卵的雌性斑须按蚊头、唾液腺和卵巢组织中出丝诱导物质对柏氏疟原虫雄配子体出丝诱导活性的变化。结果 斑须按蚊头匀浆上清中所含出丝诱导物质的活性与产卵是否完成没有显关系；按蚊产卵完成后，唾液腺抽提物的出丝诱导活性显升高，而卵巢匀浆上清的诱导活性显降低。结论 雌性斑须按蚊产卵影响唾液腺雄配子体出丝诱导物质的活性。     

斑须按蚊头及唾液腺疟原虫出丝诱导物质的比较

目的 比较斑须按蚊头与唾液腺中疟原虫雄配子体出丝诱导物质的相对含量。方法 应用体外雄配子体出丝分析方法，分别检测斑须按蚊头及唾液腺匀浆上清在单位器官和单位蛋白浓度条件下的出丝诱导活性。结果 斑须按蚊头和唾液腺含有疟原虫雄配子体出丝诱导物质；在相同单位器官浓度条件下，斑须按蚊头部匀浆上清的雄配子体出丝诱导活性高于唾液腺上清：在相同单位蛋白浓度条件下，斑须按蚊唾液腺匀浆上清的出丝诱导活性高于头部上清。结论 雌性斑须按蚊唾液腺含有较高浓度的疟原虫雄配子体出丝诱导物质，并在蚊胃腔内疟原虫雄配子发生过程中发挥重要的生理作用。     

大劣按蚊对食蟹猴疟原虫配子体最佳敏感期观察

以食蟹猴疟原虫大劣按蚊为动物模型,观察大劣按蚊对疟原虫不同密度及雄雌配子体不同比例情况下的敏感性。结果显示:猴体内疟原虫配子体密度在不治疗情况下不断增高,但雄雌配子体的比例在不断变化,当雄雌配子体比例为1:2.2的情况下,大劣按蚊可获得较高的感染率,蚊胃卵囊感染率为95.5%,腺感染率为91.7%。     

外源性一氧化氮对约氏疟原虫配子体感染力影响的初步研究

目的 探讨其在约氏疟原虫感染早期、外源性NO对配子体感染力及红内期虫体血症水平的影响。方法 以BLAB／c小鼠及斯氏按蚁为实验对象,观察NOC5处理前、后感染小鼠虫体血症水平和蚊血食后其胃部囊合子形成状况。结果 NOC5能够显抑制配子体对蚊的感染力,而且其抑制作用与其剂量呈正比,但未发现对疟原虫红内期虫体的明显影响。结论 外源性NO是介导约氏疟原虫配子体感染力下降的效应分子。     

间日疟原虫配子体感染力与宿主体温变化关系的实验研究

<正> 间日疟原虫配子体对按蚊的感染力的变化规律,国内学者通过人工感染按蚊的实验研究证明,间日疟原虫不存在“HsWking 氏现象”,而其配子体的感染力与宿主的临床发作周期有关,即在宿主临床发作期,间日疟原虫对按蚊的感染率较低,甚至为零,而在发作间歇期感染率则明显增高。这种原现     

蒿甲醚阻断食蟹猴疟原虫孢子增殖期发育研究

用蒿甲醚（Ａｒｔｅｍｅｔｈｅｒ）注射液在食蟹猴疟原虫———大劣按蚊动物模型中的试验结果显示：给感染猴一次性肌注６４ｍｇ／ｋｇ蒿甲醚后，９ｈ内原虫密度无明显变化，配子体数量仍在增加，与治疗前相比，吸血按蚊蚊胃内卵囊阳性率和蚊胃中卵囊数以及唾腺子孢子阳性率均明显降低。２３ｈ后，蚊胃未有卵囊形成；一次性给药达２５５ｍｇ／ｋｇ体重时，５ｈ后吸血按蚊蚊胃内未有卵囊形成。结果提示：蒿甲醚不仅具有快速杀灭疟原虫无性体，毒性低、用量少、在体内滞留时间长等特点，而且还具有抑制蚊胃内卵囊形成的作用。在一定量的药物作用情况下，可阻断疟原虫孢子增殖期的发育，而且时间快     

IFN—γ，TNF—α介导约氏疟原虫配子体感染力作用的探讨

目的：确定的氏疟原虫感染早期配子体感染力与一些细胞因子的相关性。方法：应用直接蚊吸血实验。观察了约氏疟原虫感染早期小鼠血液中配子体在蚊体内的发育情况,检测来自感染小鼠血清和蚊血食后其胃内血液中IFN－γ,TNF－α的含量,同时观察蚊血食8小时后胃内动合子的形成。结果：在感染后第3天,小鼠血清中IFN－γ显升高,而TNF－α未发现有意义的变化。蚊吸食这样的血液,其胃部囊合子形成数目却达到峰值。蚊胃内吸食的血液中两种细胞因子的含量和蚊体内动合子的形成与上述结果相一致。结论：在约氏疟原虫感染早期发生的自然传播阻断过程中,IFN－γ不是直接灭活配子体感染力的效应分子。     

应用DNA探针估量单克隆抗体对伯氏疟原虫的中和作用

作者应用特异的DNA探针对单克隆抗体(3D11) 对伯氏疟原虫子孢子环孢子蛋白的中和作用进行了定量分析,比较了完整的3D11和它的Fab段对伯氏疟原虫子孢子的作用效果。斯氏按蚊在吸入感染性血液后14至18天,解剖其唾液腺,取伯氏疟原虫子孢子(NK65株),置于含10％热灭活正常大鼠血液的199培养基内。实验动物为40～50日龄的Norway Brown雌性大鼠和2～4月龄的仓鼠。取腹水内的3D11(IgG)经过硫酸胺纯化,然后进行对流离子交换和排阻层     

用受X线照射的恶性疟原虫免疫后获得长期免疫

用受Ｘ线照射的恶性疟原虫免疫后获得长期免疫迄今为止，用受Ｘ线照射的恶性疟原虫（ｐｆ）孢子免疫人后，获得的最长免疫力仅为５６天，而本文报告一例可保持至少９个月。实验中以１７０～２００ＧｙＸ射线照射感染ｐｆ的斯氏按蚊（Ａｓ）。然后用这种Ａｓ叮咬成年男性志...     

苏联蚊虫对输入疟原虫株敏感性资料的回顾

<正> 苏联蚊虫对输入人体疟原虫种株敏感性的研究表明,黑小按蚊、麦赛按蚊和萨(哈罗夫)氏按蚊对来自非洲、亚洲和南美洲的间日疟原虫都具有高度的敏感性。这些疟原虫对各种媒介蚊虫适应的程度,都没有大的变化。用由非洲和东南亚输入的恶性疟原虫株感染黑小按蚊和麦赛按蚊,全部实验结果均为阴性。     

An estimation of the number of malaria sporozoites ejected by a feeding mosquito

Restrained Anopheles stephensi mosquitoes infected with Plasmodium falciparum were made to produce time-dependent series of saliva droplets in mineral oil. The relative volume of each droplet and the number of sporozoites each contained were determined microscopically; gland sporozoites were estimated with an enzyme-linked immunosorbent assay. Median gland infection was 8170 and median number of sporozoites ejected was 15 (range, 0-978). Inoculum size was positively correlated to the number of sporozoites in the salivary glands. Most mosquitoes ejected sporozoites only at the beginning of salivation; this suggests that only those parasites in the common and secondary salivary ducts at the time of feeding can be ejected. The small size of inocula may explain some aspects of malaria transmission, including the often observed discrepancy between inoculation and incidence rates.     

日月潭按蚊对间日疟原虫易感性的实验研究

本文报告日月潭按蚊对间日疟原虫易感性的实验观察结果。以8例间日疟患者血离体感染8批日月潭按蚊,其中4批腺感染率达100%,阳性腺指数平均为3.73。原虫在蚊体内发育良好,在感染后第8天卵囊分化,第9天涎腺阳性,其发育速度和分化卵囊体积均和在微小按蚊体内者一致。说明该蚊对间日疟原虫具高度易感性。其自然感染率低主要是偏嗜畜血的习性所致。显然,该蚊在一定条件下可起重要传疟作用,不应忽视。     

Detection of mature malaria infections in live mosquitoes.

A method has been developed which detects malaria parasites in the salivary glands of live Anopheles stephensi. The method exploits the sugar feeding behaviour of the mosquito and requires only routine Western blotting techniques on nitrocellulose membrane (NCM). Infectivity can be determined without any direct manipulation of individual mosquitoes. Female A. stephensi were infected with the rodent malaria parasite, Plasmodium berghei, and after 14-16 d were starved of fructose overnight (12-18 h), then resupplied with fructose presented through a small piece of NCM. Mosquitoes were allowed to probe the membrane for several hours; the NCM was then removed and subjected to a standard immunoblotting protocol using an anti-P. berghei circumsporozoite protein (CSP) monoclonal antibody as the primary reagent, and a horseradish peroxidase-coupled secondary antibody. NCMs taken from cages containing infected mosquitoes showed a variable number of small black dots where individual females had probed and deposited either CSP or sporozoites. Infectivity could be detected easily from 13-14 d after feeding, and in as few as 10 mosquitoes at 19 d after infection; in one instance, infection in a single mosquito was clearly determined. After blocking with goat serum, the NCMs could be stored for 3-4 months and still provided positive reactions, offering some potential for applicability to field research studies.     

Comparative susceptibility of three species of Anopheles from Belize, Central America, to Plasmodium falciparum (NF-54)

In August of 2000, a comparative susceptibility study was conducted using 3 species of Anopheles mosquitoes from Belize, Central America, and a standard species used in laboratory infection studies, Anopheles stephensi. Test populations were fed human blood infected with cultured Plasmodium falciparum (NF-54 strain) parasites via a membrane feeder. The control species, An. stephensi, exhibited the highest infections, with 73.8% of dissected specimens positive for sporozoites in the salivary glands. The control species also showed heavier sporozoite loads; 74.0% of positive glands having greater than 200 sporozoites. Of species from Belize, Anopheles darlingi was the most susceptibile, e.g., 41.0% of salivary glands were positive, with more than 200 sporozoites per gland. Anopheles vestitipennis had a low salivary gland infection rate (9.3%) and a moderate number of sporozoites in glands (i.e., 85.7% containing 50-250 sporozoites). Anopheles albimanus was the least susceptible species to infection. No specimens of An. albimanus from the Golden Stream population developed sporozoites in the salivary glands, yet 20.7% of dissected specimens had positive midgut infections. The An. albimanus Buena Vista population showed similar results with only a 2.2% salivary gland infection rate and a 21.5% midgut infection rate. Oocysts in An. stephensi increased in size by 20% after day 10. Development peaked at day 12, with a mean oocyst diameter of 58 microm at onset of oocyst differentiation. Oocysts developed more slowly in An. vestitipennis until day 10. After day 10, there was a 53% increase in oocyst development over the previous 10 days. Oocyst differentiation was not observed until day 13 postfeed. As with An. vestitipennis, both populations of An. albimanus showed similar slow rates of oocyst development; however, no dramatic growth increase occurred after day 10. The oocysts in the Golden Stream population exhibited a cessation of growth after day 10, peaking at a mean of 30 microm. The Buena Vista population did not exhibit the same level of reduced oocyst development. A gradual increase in growth continued until days 13 and 14 (36.7 and 35.7 microm, respectively).     

Aggregation in malaria parasites places limits on mosquito infection rates.

Gametocytes are responsible for the transmission of malaria parasites, Plasmodium spp., from man to mosquito. Although transmission success, as measured by the proportion of mosquitoes infected, generally increases with gametocyte density, the proportion of parasites that are gametocytes is always paradoxically only a few percent of the asexual blood parasites. To address this paradox, we analyse transmission data sets from an urban and an adjacent rural setting in Cameroon to elucidate whether there are discernable lower and upper limits to Plasmodium falciparum gametocyte density that are linked to transmission success. We find that there exists a lower gametocyte density at which mosquito infection rates considerably increase. In addition, we identify upper gametocyte densities at which mosquito infection rates level off. Greatest increases in infection rates occur at low gametocyte densities and coincide with maximum oocyst aggregation within the infected mosquito population. This aggregated oocyst distribution remains despite increases in gametocyte density and ever-decreasing gains in mosquito infection rates. There is increasing suggestion that malaria parasites have evolved sex allocation strategies to ensure transmission in response to a changing, transmission-blocking environment. Here transmission-blocking immunity is proposed not only to ensure low density gametocyte transmission success but also to impose upper limits on transmission success.     

2008年河南省永城市疟疾媒介防制比较研究

目的通过现场试验,评价永城市不同媒介防制方法的防制效果。方法在不同媒介防制措施处理村,以旬为单位,采用清晨室内50顶蚊帐内捕捉按蚊、夜间室外人饵诱捕按蚊方法进行媒介监测。结果清晨室内50顶蚊帐内共捕获按蚊79只,占33.33%,其它蚊虫158只,占66.67%。对照组平均按蚊密度为0.18只/（顶·次）,浸泡蚊帐组、滞留喷洒组、浸泡蚊帐＋灭蚊幼组、滞留喷洒＋灭蚊幼组分别为0.03、0.03、0.05和0.06只/（顶·次）;几种措施均对降低按蚊密度有效（F=4.553,P〈0.01）,但还不能认为各处理措施之间在降低蚊密度方面存在差异。对照组平均按蚊叮人率为0.10只/（人·夜）,浸泡蚊帐组、滞留喷洒组、浸泡蚊帐＋生物灭蚊幼组、滞留喷洒＋生物灭蚊幼组分别为0.02、0.01、0.03和0.03只/（人·夜）;几种处理措施均对降低按蚊叮人率有效（F=5.261,P〈0.01）,但还不能认为各处理措施之间在降低按蚊叮人率方面存在差异。不同监测点夜间室外人诱按蚊183只,占15.69%,其它蚊983只,占84.31%。对照组平均按蚊密度为2.48只/h,浸泡蚊帐组、滞留喷洒组、生物灭蚊幼组、浸泡蚊帐＋灭蚊幼组、滞留喷洒＋灭蚊幼组分别为0.76、2.12、0.24、1.08和0.64只/h。与对照组相比,浸泡蚊帐组、生物灭蚊幼组、浸泡蚊帐＋灭蚊幼组、滞留喷洒＋灭蚊幼组按蚊密度较低;滞留喷洒组与浸泡蚊帐组、生物灭蚊幼组、滞留喷洒＋灭蚊幼组相比,按蚊密度较高。对照组平均叮人率为12.40只/（人·夜）,浸泡蚊帐组、滞留喷洒组、生物灭蚊幼组、浸泡蚊帐＋灭蚊幼组、滞留喷洒＋灭蚊幼组分别为3.80、10.60、1.20、5.40和3.20只/（人·夜）。与对照组相比,浸泡蚊帐组、生物灭蚊幼组、浸泡蚊帐＋灭蚊幼组、滞留喷洒＋灭蚊幼组按蚊叮人率较低,滞留喷洒组与浸泡蚊帐组、生物灭蚊幼组、滞留喷洒＋灭蚊幼组相比,按蚊叮人率较高。经Pearson相关分析,10月室外人帐诱按蚊密度与11月疟疾发病率呈正相关关系（r=0.945,P〈0.01）;10月校正叮人率与11月疟疾发病率呈正相关关系（r=0.927,P〈0.05）。结论不同媒介防制方法对降低永城市室内外按蚊密度、叮人率效果均较明显,但各处理措施在降低室内外按蚊密度、叮人率效果方面孰优孰劣,尚待进一步研究证实。     

泸州市基本消灭疟疾后疟疾流行特征

目的了解泸州市基本消灭疟疾达标后疟疾流行特征及防治效果,为防治策略和措施的调整提供依据,以便如期实现消除疟疾目标。方法采用描述流行病学方法对泸州市2005-2012年疟疾疫情资料进行分析。结果 8年间共报告疟疾95例,无死亡,年均报告发病率为0.03/万,无继发二代病例和暴发疫情发生。其中间日疟56例,恶性疟32例（混合感染1例）,未分型7例,各年度报告发病率呈波动下降趋势;本地病例31例（无恶性疟）,输入性病例64例（恶性疟32例）,输入性疟疾构成比逐年上升。中华按蚊为唯一传疟蚊种,平均雌蚊密度为0.13只/（台.h）。结论泸州市实现基本消灭疟疾达标后采取的以消灭传染源、控制传播途径、加强疫情监测、及时发现和治管现症患者的综合性防治措施成效显著。由于疟疾传播媒介客观存在,输入性疟疾已成为泸州市的主要危险因素,加强流动人口的监测管理及媒介控制工作是巩固疟疾防治成果,实现消除疟疾的关键。     

Study of the distribution of circumsporozoite antigen in Anopheles gambiae infected with Plasmodium falciparum, using the enzyme-linked immunosorbent assay

Anopheles gambiae, experimentally infected with Plasmodium falciparum, were dissected 14 days later for microscopical detection of sporozoites and oocysts. The head, salivary glands, thorax, midgut, legs, ovaries, Malpighian tubules, the remainder of the abdominal tissues and the dissection fluid of each mosquito were examined by a two-site enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of circumsporozoite antigen (CS ag). 19 mosquitoes had CS ag in at least one of the specimens examined. Very large individual variability was observed in the presence and/or quantity of CS ag in the various parts. 7 mosquitoes were ELISA-positive in all 9 specimens; the salivary glands and thorax contained most CS ag, whereas the Malpighian tubules and ovaries contained the least; all the thoraces contained CS ag, even that of one mosquito of which the salivary glands lacked both sporozoites and CS ag; of 17 ELISA-positive salivary glands, 15 were found to contain sporozoites. The existence of free antigen associated with sporozoites, and the limitations of the ELISA technique in demonstrating the infectivity of a malaria vector, are discussed.