广东省英德市不同类型有螺环境灭螺效果评价分析

目的 评价广东省英德市不同类型有螺环境和不同灭螺方法的灭螺效果,为制定控螺措施提供科学依据.方法 选择清远市英德地区的荒地和沟渠有螺环境各2处作为研究现场,比较单纯喷洒26％四聚杀螺胺悬浮剂(药物)灭螺与单纯药物喷洒+新泥或黑色地膜覆盖的灭螺效果.结果 药物喷洒+新泥覆盖法对荒地环境灭螺7d后,其活螺框率为0％,低于单纯药物喷洒法(8.45％),活螺密度下降率为100.00％;灭螺30d后,两种方法的活螺密度下降率均在90.00％以上.药物喷洒+黑色地膜覆盖法对沟渠环境灭螺7d后,其活螺框率为11.94％,低于单纯药物喷洒法(31.25％),活螺密度下降率为83.46％;灭螺30 d后,两种方法的活螺密度下降率分别为76.85％和100.00％.结论 对荒地或沟渠有螺环境采用药物喷洒+新泥或黑色地膜覆盖法的灭螺效果优于单纯药物喷洒法.应根据有螺环境的特点采用不同的综合灭螺方案,评价灭螺效果时应考虑不同灭螺方案所需要的灭螺时间.     

2019-2020年英德市钉螺控制效果分析

目的 了解英德市钉螺复现区域实施综合灭螺后的钉螺控制效果.方法 收集2019-2020年英德市有螺环境各阶段灭螺措施实施情况,评价钉螺控制效果.结果 英德市23个有螺环境累计开展药物灭螺189环境次,灭螺面积714340m2,沟渠硬底化14906m,新建沉螺池1座、排水涵洞31座、节制闸5座,土地覆泥平整14001m2,重建塘下陂头l座.累计监测372环境次,三个阶段灭螺后累计查获活钉螺1326只,未发现感染性钉螺.活螺框出现率从灭螺前的16.78％,经第一阶段药物灭螺,第二阶段环境预处理、药物灭螺,第三阶段环境综合整治、药物灭螺后下降至0％;活螺平均密度由灭螺前的3.54只/0.1 m2下降至第三阶段综合整治灭螺后的0.00只/0.1 m2.结论 英德市灭螺效果明显,药物灭螺可以快速降低活螺平均密度,但以环境改造等为主的血防综合治理措施可以更有效地控制钉螺孳生和扩散.由于各有螺环境条件不同、复杂程度各异,环境改造工程维护和药物灭螺等措施仍需持续,以巩固钉螺控制效果.     

武汉汉口江滩血防综合整治灭螺效果初步评价

目的 初步评价汉口江滩血吸虫病防治综合整治后的灭螺效果.方法 采用工程灭螺结合药物灭螺对江滩进行综合整治,比较整治前后的有螺面积、活螺平均密度等螺情监测指标的变化.结果 项目工程灭螺面积30.55万m2,药物灭螺累计面积132.43万m2.灭螺后滩面有螺面积、有螺框出现率、活螺平均密度较去年同期分别下降了98.40％、92.08％和94.43％,未发现感染性钉螺.结论 江滩综合整治后,钉螺滋生环境得到彻底改变,初步评价灭螺效果较好,但仍需对既往有螺环境持续监测以巩固灭螺效果.     

灌渠内药物灭螺对钉螺及感染性钉螺的影响

目的了解在人工灌溉水渠干渠内，常规药物灭螺对钉螺及感染性钉螺消长的影响。方法在安徽钓鱼台水库灌区，根据当地灭螺规划，在其计划灭螺区干渠内选择螺情观察点，同时选非计划灭螺支渠为对照；2002年12月～2003年11月份，每月沿渠两边系统抽样查螺，室内压碎鉴定死活，并观察感染血吸虫情况。常规药物灭螺的时间、方法、药量及实施均由当地业务部门确定完成。结果灭螺前钉螺死亡率在干渠和支渠变化趋势基本一致；4月20日干渠灭螺，灭螺后10，37d时干渠钉螺死亡率分别为24．46％及43．01％，但8月底为1．25％，同期未灭螺的支渠钉螺死亡率变化不大；灭螺前干渠有3个月、支渠有1个月检出感染性钉螺，灭螺后4～6月份在干渠仅于灭螺后10d发现感染性钉螺，未灭螺支渠5月份检出感染性钉螺；8月31日以后钉螺感染率及感染性钉螺密度在干、支渠均上升。结论在人工灌区的引水干渠内，常规药物灭螺在预防人群感染方面可能起一定作用，但对年度钉螺及感染性钉螺螺口消长的作用有限。     

常山县实施血防灭螺承包责任制效果分析

目的分析血防灭螺承包责任制实施前后的灭螺效果,为山丘地区复杂环境消灭残存钉螺提供依据。方法根据《浙江省血吸虫病监测巩固方案》在常山县开展灭螺承包责任制,用土埋结合药物方法灭螺,并比较实施前后的灭螺效果。结果在全县实施药物灭螺承包责任制后,全县有螺面积从2006年的12.8万平方米下降到2013年的4.9万平方米;每消灭1 m2有螺面积灭螺所需投入从2006年的10.13元下降到2013年的3.00元,资金节约率达70.38%。结论采用政府出钱购买服务的方式,在山丘地区实施血防灭螺承包责任制,大幅度提高灭螺质量和灭螺资金使用效益。     

氯代水杨胺对山丘钉螺实验室和现场杀螺效果研究

目的观察新型灭螺药10％氯代水杨胺可湿性粉剂（LDS）对浙江省山丘地区钉螺和有螺环境的灭螺效果,为现场推广应用提供科学依据。方法采用浓度0．1、0．2、0．4、0．6、0．8mg／L的LDS分别进行实验室和现场浸杀法灭螺,采用浓度0．2、0．4、0．6、0．8、1．0g／m。的LDS分别进行实验室喷洒法、现场喷洒法和撒粉法灭螺,同时设50％氯硝柳胺乙醇胺盐可湿性粉剂（WPN）药物对照和清水对照,观察药物的灭螺效果。结果室内和现场浸杀试验LDS0．1mg／L浓度组,浸杀1d钉螺死亡率分别达100％和95％以上,与WPN药物对照组相比差异无统计学意义（P〉0．05）;室内喷洒灭螺LDS0．8g／m2浓度组,喷洒1d钉螺死亡率〉95％,现场喷洒灭螺LDS0．2g／m2浓度组,喷洒3d钉螺死亡率〉85％,现场撒粉灭螺LDS0．4g／m2浓度组,撒粉后1d钉螺死亡率〉85％。各LDS试验组钉螺死亡率随着药物浓度的升高和作用时间的延长而升高。结论10％LDS对浙江省山丘地区钉螺和有螺环境具有较好的灭螺效果。     

氯硝柳胺拌沙撒药灭螺控制血吸虫感染研究

氯硝柳胺拌沙撒药灭螺经过4年试验,钉螺密度下降44.30％,阳性钉螺密度下降了22.92％,人群感染率3年平均比1992年下降40.20％,急性感染下降38.89％,耕牛感染率下降17.64％。该药利用雨水或潮湿缓慢溶解药物,能较长时间维持低浓度,药效达到长效灭螺作用,而且方法简单,容易操作,不需特殊灭螺工具,为洲滩地区灭螺提供新方法。     

植物灭螺成分与机制的实验研究及应用进展

钉螺是血吸虫的中间宿主,它的生存对生态环境有依赖性。该文综述了近几年国内外研究灭螺植物的相关文献,阐述了植物影响钉螺生存环境、植物灭螺药物的毒理、机制,采用抑制钉螺的植物生态措施,有效减少灭螺化学药物的环境污染,降低灭螺费用,有利于阻断血吸虫病的传播。     

灭螺药物研究概况及其应用研究的思考

消灭钉螺是预防血吸虫病的一项有效措施,而药物灭螺则是其中一种省力、省时和见效快的重要方法[1].建国以来,我国研究了许多种灭螺药物.据不完全统计,化学灭螺药物就有2 000余种,植物的近1 000种,工业废料的约100种[2,4].这些药物中绝大多数对人、畜、鱼和农作物有毒害,有的灭效较差或价格昂贵或使用与运输不便等原因而被限制或禁止使用.所以,真正被推广应用的灭螺药物不多.然而,我国钉螺滋生面积仍然较广,有的地方血吸虫病的流行还相当严重,在长江流域段经退耕还林还草工程完成后,如对残存钉螺未彻底处理,则有可能形成新的滋生地,故消灭钉螺仍是一项艰难而繁重的任务.因此,寻找安全、有效和价廉的灭螺药物显得尤为必要.对此,作者收集与整理了解放以来我国灭螺药物的研究情况,并根据自己实践体会提出今后灭螺药物的应用研究设想,供同行参考.     

2017—2021年南通市螺情监测分析

目的 掌握南通市钉螺的分布以及螺情变化。方法 收集2017—2021年南通市的螺情监测资料,采用描述性流行病学方法进行分析。结果 2017—2021年累计查螺5 488.562 5 hm²,共发现钉螺1 217只,无水网型和湖沼型,均属山丘型钉螺,无感染性钉螺;期内查出有螺面积共2.74 hm²,均属内陆型;有螺原因主要是灭螺残留,复现或新发有螺面积0.8 hm²。共计药物灭螺22.038 hm²,巩固药物灭螺3.8 hm²,环境改造灭螺1.482 hm²,历史有螺环境改造22.798 hm²。结论 南通市尚存有螺环境,须因地制宜,采取适宜的灭螺方法,并强化血防意识和预警监测工作。     

Molluscicides in schistosomiasis control

Although mollusciciding can be a cost-effective method of controlling schistosomiasis transmission, only one organic molluscicide, niclosamide, is now being produced commercially, and only a few compounds are at present being tested in the laboratory. In future, improved cost-effective use of molluscicides will require more precise knowledge of schistosomiasis transmission patterns in each endemic area and improved application techniques. In snail control studies using controlled-release formulations only the organotins, especially tributyltin oxide (TBTO), have given satisfactory long-term results. However, large-scale field trials of organotin formulations have not been implemented and their use cannot be recommended as their chronic toxicity in mammals has not yet been determined. The development of molluscicides of indigenous plant origin deserves support. Endod, derived from the berries of the climbing plant Phytolacca dodecandra, is the most extensively tested plant molluscicide, but data on its chronic toxicity to non-target organisms are lacking. The mode of action of molluscicides has not been extensively studied, though knowledge of the properties required of molluscicidal molecules has contributed to the discovery and development of niclosamide and nicotinanilide. In general, molluscicides probably cause stress on the water balance system, which in gastropods in thought to be under neurosecretory control.     

Use of molluscicides in the control of bilharziasis in Venezuela; equipment and methods of application

The application of molluscicides to the breeding-places of Australorbis glabratus—the intermediate host of Schistosoma mansoni in Venezuela—is discussed, with special reference to the equipment required and the techniques employed. The characteristics of the three molluscicides in use—copper sulfate, sodium pentachlorophenate, and copper pentachlorophenate—are outlined, and the treatment both of running waters (irrigation canals and streams) and of still waters (ponds and marshes) is described in detail.     

Ecotoxicological Assessment of Persistent Organic and Heavy Metal Contamination in Hong Kong Coastal Sediment

The effects of sublethal treatments (20% and 60% of LC₅₀/24 h) with plant-derived molluscicides on the reproduction of the giant African snail Achatina fulica were studied. Azadirachta indica oil, Cedrus deodara oil, Allium sativum bulb powder, and Nerium indicum bark powder singly and binary combinations on reproduction and survival of A. fulica were investigated. Repeated treatment occurred on day 0, day 15, and day 30. These plant-derived molluscicides significantly reduced fecundity, egg viability, and survival of A. fulica within 15 days. Discontinuation of the treatments after day 30 did not lead to a recovery trend in the next 30 days. Day 0 sublethal treatment of all the molluscicides caused a maximum reduction in protein, amino acid, DNA, RNA, and phospholipid levels and simultaneous increase in lipid peroxidation in the ovotestis of treated A. fulica. It is believed that sublethal exposure of these molluscicides on snail reproduction is a complex process, involving more than one factor in reducing the reproductive capacity of A. fulica. Received: 12 March 2000/Accepted: 31 May 2000     

Effect of Herbal Molluscicides and Their Combinations on the Reproduction of the Snail <Emphasis Type="Italic">Lymnaea acuminata</Emphasis>

Effects of sublethal treatment (20 and 60% of LC₅₀/24 h) of the plant-derived molluscicides Annona squamosa Linn. and Lawsonia inermis Linn. and their combinations with other herbal molluscicides, such as Cedrus deodara Roxb, Azadirachta indica A. Juss, bulb powder of Allium sativum Linn. and Polianthes tuberosa Linn., and oleoresin of Zingiber officinale Rosc., and acetogenins extracted from the seeds of A. squamosa Linn., on the reproduction of the snail Lymnaea acuminata have been studied. It was observed that the plant-derived molluscicides singly and in binary combinations with other herbal molluscicides and the extracted acetogenins caused a significant reduction in the fecundity, hatchability, and survival of young snails. Withdrawal of the snails to fresh water after the above treatment caused a significant recovery in the fecundity of the snail Lymnaea acuminata. Twenty-four-hour sublethal treatment with the acetogenins caused a maximum reduction in the protein, amino acid, DNA, and RNA in the ovotestis of treated Lymnaea acuminata.     

Bilharziasis control by application of molluscicides; a review of its present status

The author discusses various aspects of the control of bilharziasis by the application of molluscicides, including the chemicals to be used, the preparation of molluscicidal suspensions or emulsions, the rate, season, frequency and methods of application, tests for evaluating the results of treatment, factors affecting the efficacy of molluscicides and the repopulation of snails after treatment, and the cost of molluscicidal operations. In addition, he reviews briefly some of the encouraging results obtained in the field with three of the most effective molluscicides-sodium pentachlorophenate, dinitro-cyclohexylphenol and copper sulfate-and puts forward a number of suggestions as to future research on this method of snail control.     

海藻不同成分诱螺效果研究

目的利用分离和提取的海藻主要成分,作为钉螺食物引诱素在灭螺药物中应用,以提高灭螺药物的杀灭效果。方法提取和分离海藻主要成分,在不同温度、湿度条件下,用不同成分提取物对钉螺进行诱食实验。结果初步确定海藻主要诱螺物质成分为膳食纤维和褐藻糖胶。膳食纤维和褐藻糖胶在25℃时,48h诱螺率分别为79.33%和56.33%,高于15℃和35℃下的诱螺率;湿度在60%环境下,褐藻糖胶、膳食纤维48h诱螺率分别为47.67%和72.33%,高于湿度在30%的环境。结论海藻中膳食纤维成分具有很好的诱螺效果,是一种具有开发利用价值的资源物质。     

Statistical analysis of molluscicide field trials

The paper describes the methods used in the statistical analysis of field trials of acrolein, Bayluscide, ICI 24223 and NaPCP molluscicides. The study shows the importance of adequate sampling of the snail population both before and after the application of the molluscicide and the necessity of obtaining equally complete data from the controls. For kills above 99%, if the pretreatment collection contains fewer than 400-500 snails, the range between the confidence limits exceeds 5% and, if the pretreatment sample contains fewer than 1200-1500 snails, the range exceeds 2%. For all the molluscicides except acrolein, a cube-root transformation was found to be applicable. After treatment with acrolein, the snails were distributed at random. It most of the trials there were significant changes in the snail populations in the control canals, possibly due to sampling. No significant differences were observed between samplings taken 48 hours and one week after treatment; one of these could be omitted in future trials.     

The effect of sublethal doses of a molluscicide (Bayluscide) on the development of Schistosoma mansoni in Biomphalaria sudanica tanganyicensis

The complete eradication of snails from waterbodies is rarely achieved with existing molluscicides. This communication describes laboratory experiments designed to show whether snails surviving such treatment are still capable of transmitting Schistosoma mansoni. The treatment, with Bayluscide, was given at various times during the development of the infection. Snails that survived treatment were as susceptible to infection as were untreated controls but, although the initial survival rate of infected snails was as good as that of uninfected snails, their ultimate survival rate was poorer. Treatment had no permanent effect on the development of the schistosome, although there is some evidence of a delay in some cases. Infected snails may survive a field application of Bayluscide and continue parasite transmission, and uninfected survivors are susceptible to infection. Thus, while it may curtail transmission dramatically, the use of molluscicides will not eliminate transmission in the absence of other measures to prevent infection of the surviving snails.     

The aerial application of molluscicides with special reference to schistosomiasis control

Some recent aerial applications of molluscicides are reviewed. Compared with conventional techniques, aerial spraying appears to be cheaper, quicker, and in some habitats no less efficient. It may be possible to use this method in certain difficult terrains previously considered unsuitable for snail control by conventional techniques.     

湖北钉螺的酶学研究方法及应用

随着钉螺酶学研究方法的进展和应用,不仅使钉螺的分类日臻完善,而且对钉螺与血吸虫相容性的研究以及改变生态环境制约钉螺的机制、化学和植物灭螺药物机制等方面的研究也起到大力推进作用。该文介绍了国内外用于钉螺酶学研究方法的发展历程,总结了多种酶学检测方法以及应用这些方法所获得的钉螺软体内酶的分布情况,并比较了不同酶学检测方法的优势所在,同时指出钉螺的酶学研究方法中还存在着一定的局限性,更多种类酶的显示方法还有待于探索。