牛双芽巴贝斯虫病的防制研究

在流行病学调查基础上，采取控制传播媒介和药物预防注射为中心的综合防制措施，在蜱活动的４－１１月份，选用双甲脒和螨净，进行牛体表喷洒灭蜱，两种灭蜱药每半月交替使用一次。在牛双芽巴贝斯虫病发病季节５－９月份，选用贝尼尔、咪唑苯脲进行两次预防注射或缓释剂一次预防注射，经过二年防制工作，防制点没有发生牛双芽巴贝斯虫病。牛体蜱数从９－２８２只／头次下降到０－１１．３只／头次。间接血凝试验结果显示，牛阳性率从     

THE DURATION OF LATENT INFECTION AND FUNCTIONAL IMMUNITY IN DROUGHTMASTER AND HEREFORD CATTLE FOLLOWING NATURAL INFECTION WITH BABESIA ARGENTINA AND BABESIA BIGEMINA

Tne Droughtmaster and 9 Hereford cattle were born in an enzootic babesiasis area and became naturally infected with Babesia argentina and B.bigemina during a 3 year period. They were then kept free of cattle ticks (Boophilus microplus) for the remainder of the experiment. Annually for the next 3 years their individual infection status with Babesia was determined by sub-inoculation of blood into splenectomised calves. At the end of this period the functional immunity of all cattle was challenged by blood inoculation of heterologous strains of B. argentina and B. bigemina. Infection with B. argentina persisted in all Herefords for 2 years and in 7 for 3 years after they had been freed of B. microplus. The number of Droughtmasters with detectable B. argentina infection progressively declined, and at the end of 3 years only 2 of 10 were still infected. No Herefords were shown to be infected with B. bigemina following 1 year's freedom from B. microplus but latent B. bigemina infection of at least 2 year's duration was demonstrated in one of the Droughtmasters. A marked degree of resistance was apparent in all cattle when they were challenged with an heterologous strain of B. argentina. There were no differences between the response to challenge of the Herefords and Droughtmasters nor between the reactions of cattle which had apparently naturally sterilised B. argentina infection and those which were still infected. The heterologous strain of B. bigemina produced parasitaemia in the majority of animals but only minimal fever and anaemia resulted with no significant differences between the breeds.     

DEVELOPMENT OF A HIGHLY INFECTIVE BABESIA BIGEMINA VACCINE OF REDUCED VIRULENCE

The virulence of a strain of Babesia bigemina was reduced by syringe passaging at 3 to 16-week intervals in a series of 7 calves. The calves were splenectomised 1 to 14 weeks after inoculation to induce the relapse parasitaemias used for passaging. Parasites taken at relapse from the last 3 calves in the series were inoculated into splenectomised calves from which highly parasitised blood for vaccine was obtained.
The vaccine produced mild infections in 32 recipient cattle. When challenged either 5 weeks or 7 months after vaccination, the cattle had substantial immunity to a heterologous strain of B. bigemina .     

马驽巴贝斯虫Bc48蛋白的纯化及其应用

为了解新疆南北疆部分疫区马匹携带驽巴贝斯虫(Babesia caballi)抗体情况,运用实验室已构建保存的地方虫株重组Bc48为靶抗原,将重组原核表达质粒pGEX4T-1-Bc48转化至BL21表达系统中,诱导表达出36 KDa的重组蛋白。经KCl法切胶纯化重组蛋白后作为rELISA包被抗原,对阿克苏、伊犁、和硕等7个区域的随机采集样品(n=256)进行马驽巴贝斯虫抗体检测。结果显示,Bc48重组抗原能够精确识别马驽巴贝斯虫标准阳性和阴性血清;所检测的临床样品中,驽巴贝斯虫抗体阳性率为19.5%,其中,南疆2个地区(和硕、阿克苏)马驽巴贝斯虫病阳性率分别为30%、9%;北疆5个地区(昭苏种马场、伊犁卡拉苏、洪纳海乡、阿尕什敖包乡和富蕴县区域)马驽巴贝斯虫抗体阳性率分别为17%、12.5%、17%、5%和35%。本次调查结果为新疆驽巴贝斯虫防控措施及疫苗和驱虫药的使用提供必要的理论依据。     

青海省海西地区马焦虫病的血清学诊断

用ELISA方法调查了青海省海西地区马焦虫病的流行情况。从海西地区的格尔木市和乌兰县的牧户中收集了199份马属动物的血清样品，用马巴贝斯原虫的重组抗原P蚰48（GST-BcSAGlt）蛋白作为ELISA诊断抗原。进行了马巴贝斯原虫的诊断检查。从199份血清样品检出61份马巴贝斯原虫阳性，阳性率为30，65％。结果显示马焦虫病已在该地区广泛传播，并已严重威胁该地区的马属动物。