一种牛源扇头蜱及其携带梨形虫种类鉴定

为了鉴定从汉中市牛体表采集到的蜱种类及其携带病原梨形虫(Piroplasma)的种类,在形态学初步观察的基础上,用PCR技术基于线粒体16SrDNA对蜱种类进行了分子鉴定,并基于梨形虫18S rRNA基因分别检测蜱体内携带巴贝斯虫属(Babesia)、泰勒虫属(Theileria)等病原情况.结果显示,所采集到的67只...     

应用镰形扇头蜱及巴贝斯虫病水牛的染虫血感染黄牛试验

从非流行区购进无蜱寄生的健康黄牛５头与水牛犊１头,其中３头成年黄牛（２～８岁）在畜舍内用从流行区水牛身上采得的镰形扇头蜱Ｒｈｉｐｉｃｅｐｈａｌｕｓｈａｅｍａｐｈｙｓａｌｏｉｄｅｓｈａｅｍａｐｈｙｓａｌｏｉｄｅｓ成虫,置于牛耳壳内叮咬;１头运至流行区放牧,让蜱上身叮咬;１头黄牛犊（１０年龄）去蜱后２周,用液氮保存的患病水牛染虫血４ｍｌ（４×１０ ８个虫体）皮下注射;另一头去蜱水牛犊亦同时注射相同剂量的染虫血,作为对照。５头黄牛在试验期间其体温、精神、食欲正常,未出现任何临床症状,感染后１０～１２ｄ外周血液中出现少量不典型的牛巴贝斯虫,红细胞染虫率在０．１％以下,持续３～５６消失;对照牛则体温升高（３９．８～４１．１℃）,出现贫血、黄疸等症状,红细胞压积（ＰＣＶ）降至２６％,外周血液中出现典型的牛巴贝斯虫,红细胞染虫率（ＰＰＥ）高达１２％。对采用蜱叮咬及注射来自病水牛的染虫血为何不能使黄牛感染发病,文中进行了讨论。     

南德文种牛发生巴贝斯虫病

本文报道南德文种牛发生双芽巴贝斯虫和牛巴贝斯虫病的诊断和治疗。对病牛主要采用血虫净按４ｍｇ／ｋｇ体重剂量,用无菌蒸馏水配成５％溶液肌注,每天１次,连用３天,大部分病牛停止便血尿,开始采食。     

Evaluation of an enzyme-linked immunosorbent assay kit to detect Babesia bovis antibodies in cattle

The sensitivity and specificity of an enzyme-linked immunosorbent assay (ELISA) to detect antibodies; to Babesia bovis was evaluated in 1000 sera from Holstein heifers. Five hundred of them were from cattle naturally or experimentally infected with B. bovis and 500 from uninfected heifers born and raised in a region free of the vector of cattle babesiosis. Additionally, the ELISA was evaluated and compared with an indirect immunofluorescent antibody (IFA) test in 374 heifers inoculated with different kinds of B. bovis antigens in four trials. The cross-reaction was also evaluated in 50 heifers infected with Babesia bigemina and 50 heifers infected with Anaplasma marginale. The mean percentage positivity of negative sera in relation to the ELISA strong positive sera was 8%. The seropositive/seronegative cutoff point was set as twice the mean percentage positivity of negative cattle sera ( = 16%). The sensitivity of the ELISA was 98% with a 95% confidence interval (CI) of 96–99%. The specificity was 95% (CI 93–97%). The agreement was 97% and the kappa value was 0.93. The predictive values of positive and negative results were 95% and 98% respectively. ELISA showed a similar sensitivity to that of the IFA test to detect antibodies to different B. bovis antigens. Its sensitivity ranged from 97.1% to 100% (CI 89–100%), while the sensitivity of the IFA test ranged from 92.8% to 100% (CI 83–100%). ELISA cross-reacted in 8% and 6% of the sera carrying B. bigemina and A. marginale antibodies, respectively, while the IFA showed 4% cross-reaction in each situation. The ELISA evaluated has the advantages of a proper sensitivity, objectivity and capacity to be adapted to test large number of samples in a short period of time. The results indicate that the ELISA is a suitable replacement for the IFA test to detect B. bovis antibodies in cattle sera, especially in epidemiological studies.     

Evaluation of an ELISA for detection of antibodies to Babesia bovis in cattle in Australia and Zimbabwe

An enzyme-linked immunosorbent assay (ELISA) for antibodies to Babesia bovis was evaluated in comparison with the indirect fluorescent antibody test (IFAT) in Australia and Zimbabwe. Positive and negative threshold values for the ELISA were set using sera from cattle of known infection status. Sensitivity and specificity estimates for the ELISA based on 158 positive sera from cattle experimentally infected with Australian isolates of B. bovis and 318 negative sera collected from B. bovis-free herds in Australia were 100% and 99.4%, respectively. The specificity of the assay in Africa, based on 328 sera from B. bovis-free herds in Kenya and South Africa, was 99.7%. The ELISA was compared with the IFAT using sequential sera from 16 calves experiencing primary B. bovis infections, and a total of 777 field sera collected from B. bovis-endemic herds in Australia and Zimbabwe. In primary infections, the ELISA and IFAT detected antibodies at or about the same time. With sera from endemic herds, the performance of the ELISA was at least comparable with that of the IFAT. Two hundred and fourteen of 221 sera that were negative by IFAT, were negative by ELISA, and 428 of 439 sera that were clearly positive by IFAT were positive by ELISA. Of 117 sera that gave equivocal (suspect or weak positive) results in the IFAT, 20 were positive by ELISA, 7 were suspect and 90 were negative. We conclude that the ELISA will be useful for epidemiological studies on B. bovis in Australia and Zimbabwe, and probably elsewhere.     

用重组的牛巴贝斯虫棒状体蛋白1作为ELISA诊断抗原进行牛群中牛巴贝斯虫病的血清流行病学调查

用重组的牛巴贝斯虫棒状体蛋白1（Bc—RAP-1）作为ELISA诊断抗原,对采自青海省湟中县的120份奶牛血清样品,进行抗Bc—RAP-1特异性抗体的检测。结果检出7份阳性,阳性率为5．83％,说明该地区牛群存在牛巴贝斯虫的感染。     

湖北省水牛巴贝斯虫病调查研究 Ⅴ.镰形扇头蜱经卵传递牛巴贝斯虫的证实

1986年从病牛身上摘下饱血雌蜱,经实验室饲养,孵化为第二代成蜱,人工越冬。于1987年将上述蜱100只接种于已去脾23天的一岁龄健康水牛,以后每天从该牛身上取蜱查其唾液腺。结果在吸血期间,始终查到梨形虫体,其平均大小为1.3×0.68微米。接种后第4天,牛血中开始出现巴贝斯虫,至第19天,红细胞感染率高达9.6％,单梨形虫体大小为0.84～2.64×0.42～1.22微米,双梨形虫体大小为0.64～1.64×0.37～0.97微米,以后逐渐下阵。该牛出现体温升高)41.6℃)、严重贫血(血红蛋白量2克,红细胞压积14％,红细胞总数177万/毫米~3)、黄疸及精神萎顿等症状。上述结果表明,该牛感染了巴贝斯虫病,由此证实镰形扇头蜱是经卵传递巴贝斯虫,其感染阶段是成蜱。     

寄生于中国水牛Bubalus Vbubalis的巴贝斯虫一新种(梨形虫目:巴贝斯科)

经作者等深入研究，发现湖北省水牛巴贝斯虫病病原不是牛巴贝斯虫Ｂａｂｅｓｉａｂｏｖｉｓ与双芽巴贝斯虫Ｂ．ｂｉｇｅｍｉｎａ，而是一新种——东方巴贝斯虫Ｂａｂｅｓｉａｏｒｉｅｎｔａｌｉｓｓｐ．ｎｏｖ．。病牛红细胞中的虫体呈梨形（单梨形多于双梨形）、椭圆形、指环形、边虫形及杆状。以梨形虫体居多，病的初期其长度均小于红细胞半径，其平均大小为２．２×１．３μｍ，双梨形虫体尖端相连多排列成钝角或一字形，位于红细胞偏中央处。病的后期（出现虫血症后５～６ｄ）及体外培养７２ｈ，有少部份（１～２％）虫体直径大于红细胞半径。新种的传播者为镰形扇头蜱Ｒｈｉｐｉｃｅｐｈａｌｕｓｈａｅｍａｐｈｙｓａｌｏｉｄｅｓｈａｅｍａｐｈｙｓａｌｏｉｄｅｓ经卵传递（由第二代成蜱传给健康牛）。在成蜱的血淋巴中的虫样体（裂殖子）呈圆锥状、一端钝圆、尾部直而尖，不形成钩。新种对黄牛不能感染致病，只能使水牛致病。以１９９培养基加黄牛血清进行体外培养（微气静相培养技术）不能生长繁殖     

光生物素标记DNA探针检测牛巴贝斯虫研究初报

光生物素标记重组质粒DNA(c51A)探针检测牛巴贝斯虫研究的初步试验结果表明,能特异地检出感染牛血中的巴贝斯虫,灵敏度为10pg质粒DNA,相当于约150个感染红细胞的虫体DNA。     

我国西北地区奶牛双芽巴贝斯虫病血清流行病学调查及风险因素分析

本研究旨在调查我国西北部的甘肃省和宁夏回族自治区奶牛双芽巴贝斯虫的感染情况,分析影响其感染的风险因素。本次调查共采集奶牛血清1 657份,通过ELISA试剂盒检测抗体,结果显示总体感染率为8.09%。采用Logistic回归分析,评估奶牛双芽巴贝斯虫感染的风险因素,结果显示奶牛所在的地区是影响奶牛双芽巴贝斯虫感染的重要风险因素(P0.05)。本研究弥补了我国西北地区奶牛双芽巴贝斯虫感染数据的空白,对预防和控制双芽巴贝斯虫感染提供了帮助。     

牛巴贝斯虫PCR检测及体外培养试验

本试验通过PCR方法检测出牛巴贝斯虫单一感染的牛全血样本,并探讨了牛巴贝斯虫病患牛全血体外培养方法及培养条件。试验结果表明,PCR检测结果显示检测方法效果较好,单一感染样本的新鲜血液中虫体在含40%牛血清的完全培养液和37 ℃、5% CO₂的条件下能建立起牛巴贝斯虫的体外培养,虫体可以连续培养14 d,传代13次,最高染虫率可以达到12.5%,平均染虫率为4%。     

Identification of an immunodominant 40 kDa merozoite antigen common to the Australian T and Dixie vaccine strains of Babesia bovis and the development of diagnostic tests specific for these strains

Antigenic differences among Australian vaccine and field strains of Babesia bovis were investigated in an attempt to identify strain specific antigens. Immunoblots revealed substantial differences between the current vaccine strains, designated T and Dixie, and previous vaccine strains and field isolates collected on properties where vaccination with the T or Dixie strains had failed to provide complete protection against tick-borne challenge. A major difference was an immunodominant 40 kDa antigen (T40) present in only the T and Dixie strains. The molecular weight and immunodominant nature of this antigen suggest that it may be the equivalent of the major merozoite surface antigen (MSA-1) described by others in North American strains of B. bovis. MSA-1 was shown to be conserved in north American isolates but not in an isolate from Israel or in the Australian S and L isolates. The work presented here suggests that merozoite surface antigen diversity exists among geographically different isolates of B. bovis within Australia.

Monospecific antiserum to T40 was used to develop an indirect fluorescent antibody (IFA) test specific for T and Dixie strain parasites, and a blocking enzyme-linked immunosorbent assay (ELISA) specific for antibody to the T and Dixie strains. In cases of babesiosis in recently vaccinated cattle, the IFA test will be a useful tool for determining whether clinical symptoms are due to a severe vaccine reaction or to a concurrent tick-borne infection. In a preliminary assessment of potential of the ELISA for the serological identification of vaccinated cattle using a total of 160 sera, the test clearly differentiated between animals vaccinated with the T or Dixie strains and non-vaccinated animals, and was not affected by presence of antibodies to other B. bovis strains.     

新疆南疆微小牛蜱Bm86基因及其编码蛋白剖析

为了能高效表达理想的微小牛蜱抗原,本研究对新疆生产建设兵团塔里木畜牧科技重点实验室已获得的Bm86基因（Bm86 Tarim）进行遗传进化分析,并对其编码蛋白进行生物学信息分析。结果显示本研究获得的新疆南疆微小牛蜱Bm86 Tarim序列与已登录的所有国外Bm86基因完整阅读框序列的核苷酸和氨基酸同源性分别为95.9%～98.6%和93.8%～97.8%,差异极小;遗传进化树分析结果显示本研究毒株与已登录多数毒株在同一分支内;生物学信息预测结果显示该蛋白不稳定,不溶性的概率为93.26%,有4个潜在糖基化位点。本试验结果为后续Bm86基因表达、免疫抗原制备和抗微小牛蜱疫苗的研制奠定基础。     

巴贝斯虫病水牛血清钙镁浓度变化与染虫率的关系

自水牛巴贝斯虫病非疫区购买的无任何血液原虫寄生的健康水牛犊２头,人工摘除脾脏后,用从疫区采集的饥饿镰形扇头蜱叮咬感染,观察巴贝斯虫的消长与血清钙、镁浓度的变化,结果发现二者关系密切,其中钙离子浓度与红细胞染虫率呈负相关,镁离子浓度与红细胞染虫率呈正相关,这一发现为进一步研究水牛巴贝斯虫病及在体内外研究巴贝斯虫的生长繁殖均具有重要意义。