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1.
子午岭地带椎实螺种属及自然感染状况调查 总被引：1，自引：0，他引：1
子午岭地带椎实螺种属及自然感染状况调查甘肃省庆阳地区兽医站张崇信，刘天斌，尚满堂肝片吸虫中间宿主椎实螺，是两栖复足类动物，种类多、繁殖快、适应性强。因受地理气候条件的影响和螺的区系不同，中间宿主的种类也不相同。庆阳子午岭地带植被茂盛，气候阴湿，椎实螺... 相似文献
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牛羊肝片吸虫是一种形似柳叶状的深棕色吸虫,寄生于牛羊肝脏中,多见于在河边、渠边、低洼潮湿地区放牧的牛羊,舍饲牛羊很少感染。1病因肝片吸虫中间宿主是一种形似蚕虫大小的椎实螺,牛羊摄入带有椎实螺的牧草或饮用含有椎实螺的水而感染。感染性囊蚴随着水草而进入消化道,孵化后又随血液循环而进入肝脏,定居于肝 相似文献
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椎实螺在世界上约有30多种,分布很广。它的许多种是人、畜、鱼类寄生吸虫的中间宿主,对传播寄生虫病起着极其重要的作用,本文通过氯硝榴胺控释剂杀灭椎实螺的效果观察,确认氯硝榴胺是一种高效而又安全的杀螺剂,值得推广。 相似文献
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绵羊肝片吸虫病的发生与湿地中生活的椎实螺息息相关,由于椎实螺是肝片吸虫的中间宿主,生活于低洼和沼泽等湿地,故该病多发生在夏秋两季,6~9月份为高发季节.新疆巴里坤县绵羊养殖多以放牧为主,特别是夏草场位于巴里坤湖周边,绵羊在放牧过程中容易感染该病,通过作者多年的兽医临床经验,特撰写此文,与同行分享. 相似文献
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牛羊肝片吸虫中间宿主——椎实螺的调查 总被引：1，自引：0，他引：1
对阿坝州牧区牛羊肝片吸虫中间宿主－－椎实螺的感染情况调查表明，从第3月至9月份感染率（13.9%-80.3％）逐渐上升，从第10月份(34.3%）又开始下降。终年放牧草地上的螺体感染率为91.7%，季节轮牧草地为80.3%，较前者低11.4%。 相似文献
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1病原学和流行病学肝片吸虫的繁殖受气候的影响,因为其中间宿主需要足够的湿度和合适的温度。其中间宿主是椎实螺属的各种螺,这些螺主要分布于潮湿的地带。椎实螺大多生活于中性和弱碱性土层,但在酸性相当强的条件下也能存活,不过在这种条件下个体较小而且数量较少。这种螺的壳长最长可达1cm。螺的数量是随季节而不断变化的,在冬季最少,在每年6月份和7月份最多,尤其是当年春季末降雨量超过其他年份的平均值时更是如此,如果有大量螺聚 相似文献
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采用活体观察，胚胎整体装片和石蜡切片法研究了甘肃省甘南牧区肝片吸虫中间宿主螺（青海萝卜螺和狭萝卜螺）的个体发育，同时对生殖习性进行了观察。明确了椎实螺在甘南牧区的交配时间，产卵时间、地点及繁殖代数等。阐明了椎实螺的早期发育过程，一般可以划分为七个不同时期，即卵裂期、桑椹期、囊胚期、原肠期、担轮幼虫期、面盘幼虫期和幼螺形成期。 相似文献
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肝片形吸虫病是由片形科片形属的肝片吸虫寄生于牛、羊、鹿和骆驼等反刍动物的肝脏胆管中,引起急性或慢性肝炎和胆管炎、实质性肝炎和肝硬化等病变,并伴发全身中毒现象和营养障碍,严重感染时可引起牛羊大批死亡,给畜牧业经济带来很大损失.毛毕吸虫病是由分体科的毛毕属的包氏毛毕吸虫寄生于鸭、鹅及野生水禽肝门静脉和肠系膜静脉内寄生并产卵引起肠黏膜发炎,影响肠道吸收功能,严重感染时呈现消瘦、发育受阻等症状.肝片形吸虫病及包氏毛毕吸虫病均属人畜共患病,肝片形吸虫、包氏毛毕吸虫的中间宿主同属椎实螺,椎实螺有小土蜗、静水椎实螺、斯氏萝卜螺、耳萝卜螺4种,在我国分布甚广,它们生活并大量繁殖于田园、沟渠、池塘、沼泽等地.当病畜病禽排出的虫卵随粪便于水中,孵出毛蚴游于水中并钻入椎实螺体内生长发育,椎实螺受肝片形吸虫及毛毕吸虫幼虫感染,其受感染率可以反映出当地患肝片形吸虫病和毛毕吸虫病的严重程度.为此,笔者对高安市郊农村椎实螺感染肝片形吸虫、毛毕吸虫幼虫情况进行了初步调查,旨为防治牛羊患肝片形吸虫病和鸭鹅患毛毕吸虫病提供依据. 相似文献
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1生活史肝片吸虫与大片吸虫的生活史相似。在发育过程中,都需要通过中间宿主椎实螺。成虫阶段寄生在绵羊和山羊的肝脏胆管中。虫卵随粪便排到宿主体外,在温度为15~30℃,而且水分、光线和酸碱度均适宜时,经过10~25天孵化为毛蚴。毛蚴周身有纤毛,能借着纤毛在水中迅速游动。当遇到椎实螺时,即钻 相似文献
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Cucher MA Carnevale S Prepelitchi L Labbé JH Wisnivesky-Colli C 《Veterinary parasitology》2006,137(1-2):74-82
Fasciolosis, caused by the trematode Fasciola hepatica, is a zoonosis of economic importance in livestock that is emerging as a chronic disease in humans. The intermediate hosts are lymnaeid snails, in which diagnosis of infection is traditionally based on cercarial shedding, tissue sectioning and crushing. We developed a PCR assay for the sensitive and specific detection of F. hepatica in field-collected Lymnaea sp. snails. A primer pair was designed to amplify a 405 bp fragment of the cytochrome c oxidase subunit 1 gene of F. hepatica. The PCR assay showed a limit of detection of 10 pg of genomic F. hepatica DNA. No cross-reactions were observed with samples from other related trematode species or from the snail hosts Lymnaea columella and Lymnaea viatrix. DNA sequencing of the amplicon showed 100% homology with F. hepatica, and 75-89% homology with other trematodes on regions that did not include the entire set of primers. Two samples from Argentina were analysed. For snails in sample 1 (n = 240), identified as L. columella, the infection rate was 17.5 and 51.3% by direct examination and PCR, respectively. For snails in sample 2 (n = 34), identified as L. viatrix, the infection rate was 2.9 and 61.8% by direct examination and PCR, respectively. Differences in infection rates between these diagnosis methods were significant for both samples. Our PCR technique showed to be effective for detecting specific F. hepatica infections of low intensity in the intermediate host, and hence it could be used to study the epidemiological situation in a given area, as well as to assess host suitability for the parasite. 相似文献
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Li-Na Xie Hong-Yu Guo Wei-Zhong Chen Zhe Liu Song Gu Cheng-Cang Ma 《Strength and Conditioning Journal》2018,71(1):98-105
Shrubs are important plant species in grassland ecosystems worldwide, and their density and cover have been gradually increasing globally. However, the interaction effect of grazing and aridity on population recruitment and population growth of shrub species in grasslands has not been examined explicitly. We examined sapling establishment, sexual recruitment, population mortality, and population growth of Caragana stenophylla along a climatic aridity gradient and a grazing intensity gradient in the Inner Mongolia Steppe, using manipulative field experiments. Sapling establishment, sapling height, and sexual recruitment of C. stenophylla decreased as climatic aridity and grazing intensity increased. The negative effects of grazing on sapling establishment and sexual recruitment gradually increased as climatic aridity increased. The effect of climatic aridity and grazing on population mortality was influenced by sexual recruitment. In the combined treatments of climatic aridity and grazing, population mortality was relatively high when sexual recruitment was relatively high, while population mortality increased as climatic aridity and grazing increased when sexual recruitment was relatively low. C. stenophylla population increased under relatively low drought stress and mild grazing but declined under strong drought stress and/or severe grazing. Our results suggested that to maintain viable Caragana populations, appropriate grazing policies must be made according to climate aridity gradient. 相似文献
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P.L. Hughes 《New Zealand veterinary journal》2013,61(12):201-203
Extract Animals are protected from infectious diseases by non-specific and specific mechanisms. The non-specific defenses include a number of physical host factors, such as intact epithelium, mucus secretions and cilia of the respiratory system, which act to prevent or impede infection. Occasionally, either because of trauma or adverse effects of the environment on such barriers or because of the invasiveness of a particular pathogen, an infection becomes established and disease develops; host resistance then becomes mainly a function of specific, acquired immunity. 相似文献
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This study deals with the development and validation of an original PCR protocol to assess the presence of Fasciola hepatica in Galba truncatula its main intermediate host in Western Europe. In the present study two DNA extraction techniques are compared and a new multiplex PCR is described. The Chelex(?) DNA extraction technique showed to be more appropriate than the classical Phenol/Chloroform/Proteinase K based method because of the absence of toxic organic solvent, shorter duration and lower cost, and a higher reproducibility regarding DNA concentrations and wavelength ratios. The multiplex PCR was set up to amplify the lymnaeid internal transcribed spacer 2 sequence (500-600 bp) that act as an internal control and a 124 bp Fasciola sp. sequence that is repeated more than 300,000 times in fluke whole genome. Ninety six snails were pooled and 6 snails (6.25%) found positive for Fasciola sp. The limit of detection is lower than the minimal biological infestation unit (one miracidium). DNA extracts from Paramphistomum daubneyi, Dicrocoelium lanceolatum, and Fascioloides magna did not cross react. 相似文献
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Harp JA 《Animal health research reviews / Conference of Research Workers in Animal Diseases》2003,4(1):53-62
Cryptosporidium parvum is recognized as a major cause of diarrheal disease in neonatal bovine calves. In addition, this protozoan parasite has emerged as an important cause of disease in both immunocompromised and immunocompetent humans. Despite years of research, no consistently effective means of prevention or treatment are readily available for cryptosporidiosis in any species. Infection through ingestion of contaminated water has been widely documented; C. parvum was reported to be responsible for the largest waterborne outbreak of infectious disease in US history. In addition to its role as a primary disease agent, C. parvum has potential to initiate or exacerbate other gastrointestinal disorders, such as inflammatory bowel disease. Thus, control of C. parvum infection in both animals and humans remains an important objective. Research in our laboratory has focused on understanding mechanisms of resistance to C. parvum. We have demonstrated that acquisition of intestinal flora increases resistance to C. parvum. Substances present in the intestinal mucosa of adult animals can transfer resistance when fed to susceptible infants. Both expression of intestinal enzymes and rate of proliferation of epithelial cells may be altered following C. parvum infection. These and other changes may have profound effects on host resistance to C. parvum. 相似文献
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对樱桃病毒病的发生情况进行了田间调查,运用鉴别寄主反应型、病原传播特性、负染法电镜观察、琼脂双扩散法测定血清学反应等方法进行检测,查明多数为李属坏死环斑病毒单独感染,其余为李属坏死环斑病毒和苹果褪绿叶斑病毒或苹果茎沟病毒混合感染,总感染率为93.94%,对其感染的症状进行描述。 相似文献
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根寄生植物是禾草生长过程中的一种生物逆境,禾草内生真菌能增强其对生物或非生物逆境的耐受能力;然而,有关禾草内生真菌对不同密度根寄生逆境下禾草生长、内源激素水平和生物碱含量变化的研究鲜有报道。基于此,通过开展温室盆栽试验,以建立根寄生关系的带菌(E+)和未带菌(E-)紫花针茅及根寄生植物-甘肃马先蒿为研究对象,比较E+和E-紫花针茅在不同甘肃马先蒿寄生强度下生长、内源激素和生物碱含量变化。结果表明,与未寄生紫花针茅相比,随着甘肃马先蒿密度增加,紫花针茅生物量降低80%,株高、分蘖数和根长均降低25%,吲哚乙酸、脱落酸含量分别增加43%和51%,细胞分裂素含量降低50%。内生真菌侵染显著提高紫花针茅生长特性,增加内源激素和生物碱含量;带菌紫花针茅在根寄生逆境下生物碱含量持续增加,同时甘肃马先蒿利用根部木质部通道可获取寄主内生真菌合成的生物碱。由此可见,内生真菌通过调控紫花针茅体内有关生长和逆境预警相关内源激素水平及改变生物碱含量的方式增强紫花针茅对甘肃马先蒿根寄生逆境的耐受能力,为利用禾草内生真菌共生体修复甘肃马先蒿型退化草地提供新视角。 相似文献
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Sayers G Sweeney T 《Animal health research reviews / Conference of Research Workers in Animal Diseases》2005,6(2):159-171
Efforts to curb production losses caused by nematode parasitism in sheep have led to the development of a number of control methods to complement or replace anthelmintics. The need for alternative control measures stems from the emergence of anthelmintic-resistant parasitic nematodes with reports of multi-class resistance to these drugs now emerging. A number of these control methods such as predacious microfungi, protein supplementation, plant extracts in feed and vaccines have demonstrated potential to control infection but require development and examination under natural conditions. Breeding for natural resistance to nematode infection has already shown success in controlling the disease under natural conditions. Selection for resistance is currently based on fecal egg count measurements but identification of genetic indicators of resistance will provide a more efficient method of selection. Current quantitative trait loci for nematode resistance include the MHC genes, interferon gamma gene, IgE gene and microsatellites on chromosome 1, 5 and 6. This paper reviews the current alternatives to anthelmintics to control infection, with an emphasis on breeding for host resistance and identification of genetic indicators of resistance. 相似文献