中华按蚊体内马腹腔丝虫各期幼虫形态的观察

为在基本消灭丝虫病地区纵向监测时提供区别蚊体内人、畜丝虫幼虫的科学依据,我们于1984年8～9月,对马腹腔丝虫(Setaria equina)在中华按蚊体内的各期幼虫形态进行了观察。 感染方法 将饲养驯化的中华按蚊蚊笼紧贴在马腹腔丝虫微丝蚴阳性马的腹部,让蚊虫吸血受染。感染后,蚊虫置于25.8～30.8℃和相对湿度85～94％的养蚊室     

班氏丝虫病人诊断用抗原——牛丝虫抗原分析和应用研究

丝虫每一虫体生活史之间和不同虫种之间,均存在交叉抗原——亦称共同抗原,由于人丝虫来源不足,因之可以利用容易获得的动物丝虫来大量制备人和动物丝虫病诊断用抗原。 一、动物丝虫来源 (一)牛腹腔指状丝虫(Setaroa digitata简称SD)。     

鲁南地区班氏丝虫与指状腹腔丝虫在蚊体内感染期幼虫形态的观察

为探讨动物丝虫与人体丝虫在蚊体内发育形态的鉴别方法,以便在基本消灭丝虫病地区,开展纵向监测。1982年以来,我们对班氏丝虫与牛指状腹腔丝虫(Setaria digitata)在蚊体内感染期幼虫的形态进行了观察。     

人房内中华按蚊,嗜人按蚊自然感染牛腹腔丝虫的纵向观察

中华接蚊、嗜人按蚊均可感染牛腹腔丝虫和马来丝虫。在马来丝虫病流行区进行蚊媒调查，特别是在马来丝虫病防治后期的蚊媒监测中，蚊体内人、畜丝虫幼虫的鉴别尤为重要[1]。为了排除牛腹腔丝虫幼虫对马来丝虫病防治后期蚊媒监测的干扰，1987～1992年，1995～1996年，我们选定已无微丝蚴血症者的蔡金镇两个原马来丝虫病流行村，总人口1963人为观察区、先后共8年观察人房内中华接蚊和嗜人按蚊自然感染牛腹腔丝虫的情况。材料与方法1．牛腹腔丝虫自然传染原调查：上午抽采观察区村民饲养的水牛耳背静脉血各6大滴（约120μl），涂制成1．5×3．0…     

指状腹腔丝虫的一种丝虫蛋白酶在班氏丝虫感染中的抗原性

丝虫蛋白酶在虫体发育、蜕皮和体内移行等方面起着关键作用。但人体丝虫感染中丝虫蛋白酶的抗原性未为人知。为了阐明丝虫感染中寄生虫蛋白酶在人体内的免疫学地位,从牛的指状腹腔丝虫(常被用于替代班氏丝虫的抗原)中分离出了两种蛋白水解酶:一种是低分子量的锌依赖性半胱氨酸蛋白酶(Sd30),另一种是高分子量蛋白酶(Sdp_1)。本文作者研究了人体丝虫病中针对该酶产生的IgG亚类及IgG对该蛋白酶活性的影响。     

人房中华按蚊检获牛丝虫幼虫及其传染源调查

筠连县流行马来丝虫病 ,中华按蚊为当地主要传播媒介之一。 1984年实现基本消除丝虫病后开展了监测工作。 1988年 7月进行蚊媒监测时在人房捕获的中华按蚊体内检出幼丝虫 ,经鉴定蚊体内的幼丝虫及牛体内的微丝蚴均系牛腹腔丝虫 ,并对其传染源进行了调查 ,现简报如下。1　方法1.1　中华按蚊幼丝虫自然感染调查　 1988年 7月上旬在丝虫病监测点选定原微丝蚴血症者的住房内 ,捕捉中华按蚊 2次 ,第 1次仅捕获人房帐内按蚊 ,第 2次分别捕获人房帐内按蚊和牛房内按蚊 ,按常规分头、胸、腹 3部分进行个体解剖、镜检 ,了解其幼丝虫自然感染情况。1.2…     

福建省丝虫病流行病学调查

分别由致倦库蚊和雷氏按蚊嗜人亚种传播的班氏和马来两种丝虫在福建均属夜现周期型。由于两蚊孳生习性的不同,在地理环境中形成明确的两种丝虫病流行区。马来丝虫感染率常高于班氏丝虫,马来丝虫病以较高的肢体发病率为特征,由于其易使人体产生免疫力,导致其微丝蚴率不随年龄的增长而升高。 提高居民生活水平、改善居住环境、控制蚊媒孳生,则防治丝虫病较易收效。进行蚊媒调查可监测丝虫病的流行态势。福建丝虫病未发现动物传染源,但动物丝虫种类不少,尤其是鸟类丝虫,有待进一步调查研究提供鉴别。     

丝虫病残留疫点毗邻地区湖南省江永县丝虫病调查

目的了解与广西富川县朝东乡丝虫病残留疫点毗邻的湖南江永县境内是否存在残留疫点。方法选择与广西富川县朝东乡丝虫病残留疫点毗邻的江永县马蹄、上村、黄家和香花井4个行政村为调查点。采取召开座谈会、查阅资料和走访的方法进行调查;用常规厚血膜法检查微丝蚴,用班氏丝虫快速免疫色谱试验(ICT)测试班氏丝虫抗原,并对原微丝蚴血症者追踪调查;了解近5年内新发的鞘膜积液、睾丸炎、附睾炎、精索炎和乳糜尿患者;逐户登记外出人员,内容包括外出时间、地点和从事职业。结果病原学检查177人,均未发现微丝蚴血症者;ICT卡测试1 097人,无班氏丝虫抗原阳性者;健在的原微丝蚴血症者占36.70%,未发现新发的慢性丝虫病病人。结论江永县与富川县朝东乡丝虫病残留疫点毗邻地区未发现残留疫点,丝虫病防治效果巩固。     

抗生素对马来丝虫体外存活及繁殖的影响

丝虫可引起人体几种重要疾病 (如盘尾丝虫病和淋巴丝虫病 ) ,在动物体内则是犬恶丝虫病。目前仍没有较好的方法用以杀灭宿主体内所有虫体 ,但最近研究发现 :丝虫体内的Wolbachia能影响丝虫的生存繁殖 ,其分泌的毒素和部分代谢产物参与了丝虫病的发病机制。虽然抗生素治疗丝虫病的研究已有很大进展 ,其作用在马来丝虫 (成虫和微丝蚴 )的体外实验中也已得到证实 ,但仍有些问题有待解决 ;何种抗生素有此活性 ,作用剂量 ,持续时间 ,及其作用时期等。本实验则是针对以上问题设计的。终宿主 :沙鼠 ;传播媒介 :埃及伊蚊 ;传染源 :已感染的犬。丝虫…     

广东省丝虫病防治和监测

广东省65个市、县有丝虫病流行。1953～1969年调查,平均微丝蚴为3.05%,平均微丝蚴密度为32.9条/60μl,全省微丝蚴血症者约200万人,班氏丝虫病媒介是致倦库蚊,马来丝虫病传播媒介为中华按蚊和嗜人按蚊。1953～1986年,全省共血检61 280 516人次,海群生对象治疗1 307 529人,全民服药防治4 175 785人,海群生药盐防治2 474 506人。65个市、县的丝虫病防治效果考核共血检487 971人,发现微丝蚴血症590人,平均微丝蚴率为0.12%,以行政村为单位均在1%以下,1987年卫生部确认全省范围基本消灭丝虫病。1988～1989年开展监测工作,共血检356 016人,发现微丝蚴血症818人,平均微丝蚴率0.23%。解剖致倦库蚊29 662只,14只蚊体内发现幼丝虫,感染率为0.05%,中华按蚊2 412只,未发现幼丝虫。1989年,全国丝虫病防治科研指导组对广东省丝虫病监测工作进行调查,血俭3 217人,发现微丝蚴血症者4人,微丝蚴率为0.12%。     

In Vitro and In Ovo Host Restriction of Aquatic Bird Bornavirus 1 in Different Avian Hosts

Aquatic bird bornavirus 1 (ABBV-1) is associated with chronic meningoencephalitis and ganglioneuritis. Although waterfowl species act as the natural host of ABBV-1, the virus has been sporadically isolated from other avian species, showing the potential for a broad host range. To evaluate the host restriction of ABBV-1, and its potential to infect commercial poultry species, we assessed the ability of ABBV-1 to replicate in cells and embryos of different avian species. ABBV-1 replication was measured using multi- and single-step growth curves in primary embryo fibroblasts of chicken, duck, and goose. Embryonated chicken and duck eggs were infected through either the yolk sac or chorioallantoic cavity, and virus replication was assessed by immunohistochemistry and RT-qPCR in embryonic tissues harvested at two time points after infection. Multi-step growth curves showed that ABBV-1 replicated and spread in goose and duck embryo fibroblasts, establishing a population of persistently infected cells, while it was unable to do so in chicken fibroblasts. Single-step growth curves showed that cells from all three species could be infected; however, persistence was only established in goose and duck fibroblasts. In ovo inoculation yielded no detectable viral replication or lesion in tissues. Data indicate that although chicken, duck, and goose embryo fibroblasts can be infected with ABBV-1, a persistent infection is more easily established in duck and goose cells. Therefore, ABBV-1 may be able to infect chickens in vivo, albeit inefficiently. Additionally, our data indicate that an in ovo model is inadequate to investigating ABBV-1 host restriction and pathogenesis.     

Bancroftian filariasis in a Philippine village: entomological findings.

Bancroftian filariasis in an isolated Philippine village has been intensively investigated; this paper reports the entomological findings. Surveys were carried out six months apart in the driest and wettest months. Significant transmission was demonstrated only during the wet season. Aedes poicillius was the major vector of Wuchereria bancrofti. Ae. poicilius accounted for 58% of larvae found in the axils of banana plants and 31% of those in abaca axils; negligible numbers of larvae of this species were found in pandanus and gabi axils. Mosquitoes were collected from indoor harbourages twice weekly for five weeks during the wet season; 615 mosquitoes were caught of which 80% were Ae. poicilius and 9% were Culex quinquefasciatus. 11% of the former and 13% of the latter contained filariae; whereas all stages of development were seen in Ae. poicilius, no development beyond the first stage was seen in Cx. quinquefasciatus. Human bait trapping was used for 110 manhours; 371 mosquitoes were caught of which 58% were Ae. poicilius and 24% were Culex summorosus. Filarial larvae were seen only in Ae. poicilius; 3.7% of mosquitoes were positive and all stages of filarial development were seen. The mean landing/biting rate between 1900 and 0500 hours was 3.37 mosquitoes per man-hour with a maximum of almost seven mosquitoes per man-hour at midnight. Overall, 2.26% of vectors collected in the human studies were infective. There was an average of 3.38 third-stage larvae per infective mosquito. The efficiency of transmision was estimated as 6.1 x 10-5, or one new case of microfilaraemia for every 16, 400 bites by infective mosquitoes in the village population. In contrast to the human studies, large numbers of mosquitoes were caught by animal bait trapping in both the wet and dry seasons. The distribution of mosquito species was similar in the two seasons. Ae. poicillius represented only 1.0-1.5% of all mosquitoes seen. No filarial larvae were seen. It was concluded that transmission of filariasis in the village was inefficient and postulates were advanced to explain the increased intensity and severity of filariasis inmen as compared to women.     

Quantitative studies on the development of inoculated Brugia malayi microfilariae in Anopheles sinensis and Culex quinquefasciatus

Definite numbers of B. malayi mf were inoculated into An. sinensis and Cx. quinquefasciatus, and their subsequent development was observed. The relationships between the dosage and the L3 positive rate on the one hand and the average filarial maturity rate on the other were defined. At the same dosages of 4 and 10 mf/mosquito, the L3 positive rates and the average filarial maturity rates in An. sinensis were much higher than those in Cx. quinquefasciatus (p less than 0.01). It was demonstrated that the immune response to filariae of the mosquitos was the main factor resulting in these differences. The intensity of the immune response not only varied with the species, but also declined with the aging of mosquitos. The results of our experiment might be useful to studies on the dynamics of filariasis transmission and the interaction between filariae and their insect hosts.     

Clinical and biological study of Loa loa filariasis in Congolese

Clinical and biological evaluations were carried out on 84 Congolese patients with parasitologically confirmed Loa loa filariasis (without concurrent infection with other filariae) and on 98 controls without filariasis. On the patients, 72 presented with microfilaremia; another 12 with negative blood tests were seen towards the end of an episode of subconjunctival migration of the adult worm. The incidence and severity of the clinical signs depended upon the method of recruitment. The 3 most common signs were pruritus and edema (both occurring in successive acute episodes affecting mainly the hands and forearms) and subconjunctival migration of adult filariae. Papulovesicular eruptions were located mainly on the arms. Headaches and arthralgia were noted more frequently than in the controls. No relation was found between the ABO blood groups and loiasis. Eosinophilia (higher in patients with symptoms) and raised serum IgE levels were found in nearly all patients and were strongly marked in approximately 66%. A positive correlation was observed between these 2 parameters. Fluorescent antibody levels (adult filaria Dipetalonema viteae antigen) were comparatively low in patients with microfilaremia.     

Filariasis and its control in Fujian, China

Epidemiological survey of filariasis in Fujian Province, China showed that malayan filariasis, transmitted by Anopheles lesteri anthropophagus was mainly distributed in the northwest part and bancroftian filariasis with Culex quinquefasciatus as vector, in middle and south coastal regions. Both species of filariae showed typical nocturnal periodicity. Involvement of the extremities was not uncommon in malayan filariasis. In contrast, hydrocele was often present in bancroftian filariasis, in which limb impairment did not appear so frequently as in the former. Hetrazan treatment was administered to the microfilaremia cases identified during blood examination surveys, which were integrated with indoor residual spraying of insecticides in endemic areas of malayan filariasis when the vector mosquito was discovered and with mass treatment with hetrazan medicated salt in endemic areas of bancroftian filariasis. At the same time the habitation condition was improved. These factors facilitated the decrease in incidence. As a result malayan and bancroftian filariasis were proclaimed to have reached the criterion of basic elimination in 1985 and 1987 respectively. Surveillance was pursued thereafter and no signs of resurgence appeared.     

应用DNA探针检测蚊体内丝虫幼虫的研究

本文用人工合成的寡核苷酸探针，经斑点杂交法检测蚊体内马来丝虫幼虫。可测到丝虫和微丝蚴２ｎｇ的ＤＮＡ量，不与其它动物丝虫标本发生交叉反应。将单个蚊直接压于硝酸纤维素膜上进行检测，感染蚊中含有１条感染期幼虫就可出现阳性反应。将一组蚊虫在裂解液中研磨集体检测时，在２０只蚊虫中有１只感染蚊即可检出。显示该探针可用于马来丝虫地区的蚊媒监测。     

The control and surveillance of filariasis in Hainan Province, China

Hainan is a single bancroftian filariasis endemic province where filariasis is prevalent in all 18 cities and counties. A program to control filariasis was started in 1953. The strategy of eliminating infection sources has been adopted as the principal intervention measure in filariasis control. Over 30 years, the sustained effort throughout the province reached the point of basic elimination of filariasis in 1987. After the basic elimination of filariasis, the patterns of filariasis transmission in residual microfilaremia cases in Hainan Province were studied so as to provide a scientific basis for formulating strategies to eliminate filariasis. According to the "Technical scheme for surveillance in areas where fialariasis has been basically eliminated" issued by the Ministry of Health, a longitudinal and cross-sectional and entomological surveillance of fialariasis was carried out using parasitological and entomological and serological methods in the whole province during 1983-2004. In the cross-sectional and entomological surveillances, the last microfilaremia case was found in 1999, no mosquitoes were found to be infected with filarial larvae. A total of 132 microfilaremia cases found in the longitudinal surveillance become negative by 10 years. Since 1997 no mosquitoes were found to be infected with filarial larvae in the longitudinal surveillance. Serological surveillance of the population showed the mean positive rate of IFAT dropped from 10.63% in 1990 to 0.28% in 2000, which being similar to that of nonendemic areas. The results show that residual sources of infection after basic elimination of filariasis were tending to be naturally eliminated and transmission of filariasis has been interrupted in Hainan Province.     

Filariasis in Ceylon then (1961) and in Sri Lanka now (1990-30 years on)

The changes in the prevalence and distribution of bancroftian filariasis in Ceylon/Sri Lanka since Professor Kershaw's visit in 1961 show that the infection has spread over a wider area, although the microfilaria rates have decreased. New information is available on the vector, Culex quinquefasciatus, and more details are available on the animal filariae and their vectors. Dirofilaria repens infection of dogs is now a proven zoonosis in the country.