Hypergastrinaemia of sheep infected with Haemonchus contortus

Radioimmunoassay of plasma gastrin has shown that a hypergastrinaemia occurs in yearling sheep, after infection with 10(6) infective third stage larvae of Haemonchus contortus. Plasma gastrin concentrations began to rise two to four days after infection, that is, at about the same time as, or slightly before, the abomasal pH was observed to increase.     

捻转血矛线虫ZJ株滞育虫体的获得及其形态特征

为进一步研究寄生性线虫的滞育机制,参照Adams(1986)的方法,通过瘤胃灌注,将捻转血矛线虫感染性三期幼虫攻入绵羊体内,对绵羊进行处理后,获得捻转血矛线虫滞育虫体。滞育虫体发育程度一致,虫体长(1 067±97)μm(n=18),肠道细胞中含有大量棒状结晶块;性腺开始发育,出现雌驱器原基;颈部出现颈乳突。通过温度检测分析,温度可能不是滞育现象的主要刺激因素。棒状结晶块可以被DAPI特异性着色,其成分可能含有核酸。本试验将为进一步研究捻转血矛线虫的滞育机制及其防治奠定基础。     

A strain of Haemonchus contortus resistant to thiophanate

The occurrence of a field strain of Haemonchus contortus resistant to thiophanate is reported for the first time in New Zealand. In a controlled anthelmintic trial with experimentally infected animals, thiophanate at 50-100 mg/kg had no appreciable effect on the Haemonchus burden. Albendazole reduced faecal strongylate egg counts by 95% in animals with naturally acquired 59 infections.     

Rapid selection for ivermectin resistance in Haemonchus contortus

Lambs infected with two isolates, one British and one American, of Haemonchus contortus were treated with increasing doses of ivermectin. Eggs from the highest dose that had not eliminated the infection were cultured and larvae used to infect another lamb. After three generations the H. contortus was resistant to 0.2 mg/kg ivermectin. The results stress the ease with which ivermectin resistance can be selected if high selection pressure is applied.     

The establishment and development of Haemonchus contortus in goats

Twelve goats were inoculated with 40,000 third-stage Haemonchus contortus larvae and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. More worms established in the fundic, than in the middle or pyloric thirds of the abomasum. Early development occurred within the mucosa; emergence into the lumen started between 7 and 11 days after infection. By 4 DAI, all worms had completed the third moult to the L4 stage. At 11 DAI the majority of the worms were adults. A mean of 13.2% of the female worms had eggs in their uteri at 18 DAI; by 21 DAI more than half of the female worms had eggs in their uteri. The development of H. contortus was essentially similar to that described in sheep.     

捻转血矛线虫中肠超微结构

捻转血矛线虫中肠由单层上皮细胞所组成，未见明确的细胞界限，并向肠腔内伸出相互平行、排列整齐的微绒毛，长约6.5μm，微绒毛中心由纵贯微绒毛并相互平行的微丝构成；细胞核位于细胞中部，核膜清楚，体形大，形状不规则，有一较大的核仁，异染色质凝集成块状，电子致密度甚高。分散于核质中；上皮细胞中部细胞器丰富，有粗面内质网、线粒体、高尔基体及溶酶体；基部为胶原纤维样，并含有丰富的内质网。     

基于ITS序列的捻转血矛线虫系统进化分析

为分析捻转血矛线虫ITS序列的变异与虫株特性之间的关系,对捻转血矛线虫不同药物抗性虫株(苯并咪唑类药物抗性虫株、伊维菌素抗性虫株、莫西菌素抗性虫株、药物敏感虫株)、不同宿主来源虫株(长颈鹿、牛、绵羊、山羊、牦牛)和不同地理位置(中国、美国、意大利、法国、也门、马来西亚、澳大利亚)的分离株,以及毛圆科的其他线虫的ITS序列进行了分析。结果发现捻转血矛线虫与毛圆科其他线虫的ITS-2基因的相似性高,基于该基因建立的系统进化树可以很好地区分毛圆科不同属的线虫;捻转血矛线虫的抗药性特点与其ITS-1基因的变异进化关系不大;不同地理位置的捻转血矛线虫分离株的ITS-2基因变异很小;从野生动物长颈鹿体内分离的捻转血矛线虫的ITS-1基因与家养反刍动物分离株的差异较明显。研究结果表明捻转血矛线虫ITS序列在种内相对保守,不同虫株间变异较小,在毛圆科线虫的分子分类中具有一定意义。     

捻转血矛线虫重组H11抗原山羊免疫保护性试验

以重组H11-1、H11-2及H11-1与H11-2混合物分别免疫山羊后,ELISA检测发现血清抗体均在首次免疫后14 d达到较高水平,在第2次免疫后10 d达到高峰。用10 000只捻转血矛线虫第3期幼虫攻击山羊后,对不同免疫组山羊排出虫卵数、虫卵孵化率和成虫数的统计分析结果表明,免疫组与对照组间差异不显著,但免疫组雌虫数显著少于对照组,这对防治捻转血矛线虫病可能会起一定的作用。