Climate change effects on trematodiases,with emphasis on zoonotic fascioliasis and schistosomiasis

The capacity of climatic conditions to modulate the extent and intensity of parasitism is well known since long ago. Concerning helminths, among the numerous environmental modifications giving rise to changes in infections, climate variables appear as those showing a greater influence, so that climate change may be expected to have an important impact on the diseases they cause. However, the confirmation of the impact of climate change on helminthiases has been reached very recently. Only shortly before, helminthiases were still noted as infectious diseases scarcely affected by climate change, when compared to diseases caused by microorganisms in general (viruses, bacteriae, protozoans). The aim of the present paper is to review the impact of climate change on helminthiases transmitted by snails, invertebrates which are pronouncedly affected by meteorological factors, by focusing on trematodiases. First, the knowledge on the effects of climate change on trematodiases in general is reviewed, including aspects such as influence of temperature on cercarial output, cercarial production variability in trematode species, influences of magnitude of cercarial production and snail host size, cercarial quality, duration of cercarial production increase and host mortality, influence of latitude, and global-warming-induced impact of trematodes. Secondly, important zoonotic diseases such as fascioliasis, schistosomiasis and cercarial dermatitis are analysed from the point of view of their relationships with meteorological factors. Emphasis is given to data which indicate that climate change influences the characteristics of these trematodiases in concrete areas where these diseases are emerging in recent years. The present review shows that trematodes, similarly as other helminths presenting larval stages living freely in the environment and/or larval stages parasitic in invertebrates easily affected by climate change as arthropods and molluscs as intermediate hosts, may be largely more susceptible to climate change impact than those helminths in whose life cycle such phases are absent or reduced to a minimum. Although helminths also appear to be affected by climate change, their main difference with microparasites lies on the usually longer life cycles of helminths, with longer generation times, slower population growth rates and longer time period needed for the response in the definitive host to become evident. Consequently, after a pronounced climate change in a local area, modifications in helminth populations need more time to be obvious or detectable than modifications in microparasite populations. Similarly, the relation of changes in a helminthiasis with climatic factor changes, as extreme events elapsed relatively long time ago, may be overlooked if not concretely searched for. All indicates that this phenomenon has been the reason for previous analyses to conclude that helminthiases do not constitute priority targets in climate change impact studies.     

2012年全国家畜血吸虫病疫情状况

本文通报了2012年全国家畜血吸虫病疫情状况。在2012年,湖南省、湖北省、江西省、四川省、安徽省、云南省、江苏省等7省共有存栏牛1 033 056头,存栏羊2 024 512只,其他家畜存栏数891 301头（匹、只）。2012年共检查了684 899头牛,其中牛血吸虫病阳性3961头,阳性率0.58%,比2011年的阳性数下降了42.57%;检查了71 473只羊,其中羊血吸虫病阳性406只,阳性率0.57%,比2011年的阳性数下降了4.19%,并对142 976头其他家畜进行了检查,其中血吸虫病阳性为21头,阳性率0.01%。湖南省和江西省的病牛数占到了全国病牛数的80.06%。2012年,全国家畜血吸虫病疫情较之2011年继续下降,但是洞庭湖和鄱阳湖地区依然是今后家畜血吸虫病疫情控制的难点和重点。     

仁寿血防疫区人工种植益母草构型分支与生物量配置

本文研究了仁寿兴林抑螺示范区抑螺植物益母草的生长与结实特性。益母草存在基部优先与顶部优先两种构型,前者适应于肥沃生境,而后者适宜贫瘠生境。埂边生境高度较大(1.6 vs 0.95),分支数量较大(一级枝8.5vs 6.6;二级枝32.6 vs 9.7;三级枝:0.7 vs 0),分支率较高(4.7 vs 2.3),瘠薄的间作生境明显较低。两种生境中,个体高度与一级枝无关,而与二级枝数量呈现明显抛物线曲线关系。不同位置或节点枝径、间距长度、结实数量都呈现直线或曲线关系,表明位置效应明显,益母草呈现向基性发育模式。深入分析发现,益母草生殖枝结构性参数,如枝径、节间长度都与结实数量呈现明显的线性关系,暗示这种位置效应实质上是结构大小引起的,归为结构限制。随着个体生长,益母草枝干、根系、花果、叶片生物量增长速度依次降低,暗示培育目标实现可能需要优化构型特征。总体分析,益母草通过构型优化(如分支率)来适应异质性生境,而构件生殖存在结构依赖性。     

日本血吸虫候选疫苗免疫保护力研究进展

血吸虫病是危害严重的寄生虫病之一,其疫苗的研究是血吸虫病防治的一项工作重点也是一大难题。本文综述了日本血吸虫疫苗侯选分子筛选、模拟表位疫苗和多价疫苗的研究现状,并对血吸虫疫苗的深入研究进行了分析。     

牛日本血吸虫病5种血清学诊断技术比较

为找寻特异性强、敏感性高,且操作简便、费用低廉,并能大规模应用于临床的日本血吸虫病血清学诊断方法,以疫区黄牛为研究对象,应用环卵沉淀试验(COPT)、血清法间接血凝试验(sIHA)和血纸法间接血凝试验(bpIHA)、胶乳凝集试验(PAPS)、三联斑点酶联免疫吸附试验(三联Dot-ELISA)5种血清学诊断方法与粪检方法检测牛日本血吸虫病,并对5种血清学检测结果进行评价.检测分析结果表明,用血清学方法COPT,sIHA,三联Dot-ELISA对疫区黄牛进行血吸虫病检测,与三粪九检结果符合率高,具有灵敏度高、特异性好、简捷方便、费用低等特点,特别适用于疫区家畜血吸虫病的诊断、普查,是比较理想的现场检测方法,值得推广.血清学方法bpIHA和PAPS检测血吸虫病,尽管方法简便、费用低廉,但其灵敏度、特异性与三粪九检结果符合率低于血清学方法COPT,sIHA,三联Dot-ELISA,易造成漏检,假阳性,故在普查时,不建议采用.     

Presence–absence sampling for Tetranychus urticae and its predator Neoseiulus californicus (Acari: Tetranychidae; Phytoseiidae) on strawberries

The use of snails as biocontrol agents against other snails and against aquatic weeds is reviewed, evaluating their success and their impacts on non-target organisms. The predatory snail Euglandina rosea (and other species), although widely used against Achatina fulica (the giant African land snail) on Pacific and Indian Ocean islands, has not been shown to control A. fulica but has seriously impacted endemic island species. The facultative predator Rumina decollata , used in California against Helix aspersa (brown garden snail), is widely considered to be environmentally benign. However, evidence of its effectiveness is weak and it will also consume native snails. Ampullariid and thiarid freshwater snails have been used as competitors (and incidental predators) of snail vectors of human schistosomes, the parasites causing schistosomiasis (bilharzia). Successful control has been reported but impacts on native biotas have been essentially ignored. Ampullariids have been used in attempts to control aquatic weeds, sometimes successfully, but again with little consideration of impacts on native biota. Most snails have generalist feeding habits. Thus they are inappropriate biocontrol agents because of their potential nontarget effects. Rarely has adequate pre-release testing of snails been undertaken and post-release monitoring of non-target impacts has always been incidental. The use of non-native snails for biocontrol purposes is poorly regulated; many introductions are unofficial and sometimes illegal. Use of snails as biocontrol agents, if implemented, must be based on adequate pre-release testing, post-release monitoring and genuine concern for preservation of native biodiversity.     

加速兴林抑螺生态工程建设,实现江西血吸虫病的可持续防治

从5个方面论述了兴林抑螺生态工程是实现血吸虫病可持续防治的有效途径，即①改变钉螺生境。抑制钉螺孳生，控制血吸虫病流行；②调整农村产业结构，改变农民的作业方式，减少感染血吸虫病的机会；③加速农村经济发展，增强控制血吸虫的能力：④提高农村劳力的吸纳能力与土地资源的有效利用，促进粮食生产；⑤改善疫区的生态环境、确保疫区资源、环境、经济、社会可持续发展。为了加速兴林抑螺生态工程的建设，实现血吸虫的有效防治和疫区经济、社会的可持续发展。提出了4条对策：①加强对兴林抑螺工作重要性的认识：②发挥政府的主导作用；③依靠科技，确保质量；④拓宽经营体制，调动社会力量。     

四川山丘型林业血防特点及其作用机理

本文以四川省山丘型血吸虫病疫区为研究对象,对四川山丘型抑螺防病林模式构建技术问题进行了探讨,分析提出了山丘型钉螺分布的典型特征,即具有明显的小流域特征、山体广域分布特征和边缘效应分布特征;深入研究了山丘型抑螺防病林的作用机理,提出了控螺、阻螺、驱螺灭螺3种功能;在此基础上,研究提出了抑螺防病林结构模式和以小流域为单元的抑螺防病林体系布局,并调查总结了四川山丘型林业血防工程建设的5个典型模式。     

安徽省林业血防工程之建设

本文阐述了安徽省血吸虫病及其中间宿主钉螺分布状况和特点、控制措施与方法。总结与分析了近年来安徽省实施的林业血防工程建设概况、综合治理措施、实施效果及其效益。     

2011年中国家畜血吸虫病疫情状况

本文通报了2011年中国家畜血吸虫病疫情状况。湖南省、湖北省、江西省、安徽省、江苏省、四川省、云南省7个流行省共对784679头牛、41110只羊以及30005头（匹）其他家畜进行了检测,阳性率分别为O．88％、0．95％和0．09％。根据各省放牧家畜数和阳性率推算,全国共有病畜10894头（只、匹）,比2010年下降了27．28％,其中病牛为8433头,比2010年下降了33．71％。从病畜的地域分布看,湖南省、江西省两省病畜数占全国病畜数的62．06％,两省合计病牛数占全国病牛数的67．21％。调查结果显示,2011年家畜血吸虫病疫情与2010年相比继续下降。洞庭湖和鄱阳湖地区是今后家畜血吸虫病疫情控制的难点和重点。