弓形虫P30基因及其功能

弓形虫 P30基因所编码的蛋白为弓形虫主要表面抗原 SAG1 ,其约占速殖子总蛋白量的 5 %,SAG1对虫体侵入宿主细胞及其毒力具重要性 ,并有高度免疫原性和免疫保护性 ,被用于弓形虫疫苗的研制和弓形虫感染的分子诊断     

检测实验动物弓形虫感染的两种PCR方法的建立和比较

为了建立敏感、稳定、特异的PCR检测体系，用于实验动物弓形虫感染的检测。采用B1基因设计引物，建立常规PCR，用P30基因设计引物，建立巢式PCR；用两种PCR方法检测实验感染弓形虫小鼠血液和腹腔波中的DNA动态变化；用巢式PCR检测自然状态下的普通级豚鼠、教学和科研用兔的弓形虫感染率，并和常规PCR检到结果比较。结果，巢式PCR可检测到1fgDNA含量，比常规PCR敏感lOO倍；对其他微生物DNA无交叉现象，特异性强；对同一样品重复检测3次，阴、阳性结果一致，稳定性好。小鼠感染弓形虫2d后，巢式PCR对小民腹腔液的阳性检出率为83．3％，对血液的阳性检出率为33．3％；感染3d后，腹腔液阳性检出率为100％；而常规PCR在小鼠感染3d和4d后才能在腹腔液和血液中检测到，检出率各为16．7％。受检普通级豚鼠没有感染弓形虫，教学和科研用兔的弓形虫总感染率为14．3％。结论认为，巢式PCR方法可用于实验动物弓形虫早期感染的检测，具有敏感性高、特务性强、稳定性好的特点。     

新疆阿勒泰地区绵羊弓形虫病的血清学调查

为了解新疆阿勒泰地区绵羊弓形虫病的感染情况以及感染弓形虫病与绵羊流产的关系,对阿勒泰地区6县1市的绵羊随机采集血清共565份,采用间接血凝试验进行了弓形虫感染的血清学检测。结果显示,阿勒泰地区各县(市)绵羊均有弓形虫感染,感染率高低不一,平均感染率为6.5%;在有流产史的绵羊中发现存在布鲁菌和弓形虫双重感染的情况,提示在预防和治疗绵羊流产时,除了要考虑布鲁菌感染的因素以外,还应考虑弓形虫感染这一因素。     

刚地弓形虫GRA3基因的克隆与表达

采用PCR方法扩增弓形虫GRA3基因,将扩增产物与pMD18-T Simple载体连接,重组质粒经PCR、双酶切鉴定后测序;构建pGEX-4T-1／GRA3表达载体,经IPTG诱导表达后,进行SDS-PAGE、Western blot分析。结果显示,克隆的GRA3基因片段长687bp,含有1个669bp的开放阅读框,编码222个氨基酸,与GenBank中UK株（AF414079）的同源性为99．8％;表达的融合蛋白为50Ku,能被弓形虫阳性血清识别;表明该融合蛋白具有较好的免疫反应活性。     

弓形虫MIC3基因真核表达质粒的构建及在 IBRS-2细胞内的表达

采用PCR技术从弓形虫RH株的基因组DNA中扩增编码MIC3的基因,克隆入pMD18-T载体,转化至E.coliDH5α感受态细胞,经抗性平板筛选、小量抽提质粒进行酶切、PCR及DNA测序鉴定后,亚克隆入真核表达载体pcDNA3.1。然后筛选含有目的基因的重组质粒,并转染IBRS-2细胞,在G418压力下进行筛选,利用SDS-PAGE、Western blot和ELISA检测表达情况。结果显示,扩增的MIC3基因与GenBank上相应基因序列(AJ132530)的一致性达99.9%,构建的真核表达质粒pcMIC3能在转染的IBRS-2细胞中表达分子量约为39.2ku的MIC3,且表达的蛋白质具有良好的免疫活性,为进一步研究该质粒的动物免疫试验奠定了基础。     

北京地区犬猫弓形虫病流行病学调查

为初步调查北京地区犬猫弓形虫感染的流病学特征,用酶联免疫吸附试验(ELISA)方法检测2010年5月至2011年4月采集的家养犬猫、流浪猫血清样本.其中,家养犬血清样本1876份,家养猫血清样本561份,检测发现,家养犬动物弓形虫IgG抗体阳性率24.9％;家养猫弓形虫IgG阳性率21.2％;同时检测流浪猫样本201份,阳性率30.3％.家养犬弓形虫血清抗体阳性率不同季节间差异显著(P＜0.05),夏季最高,为30.0％,家养猫弓形虫血清抗体阳性率不同季节间无显著差异(P＞0.05).不同性别犬猫弓形虫血清抗体阳性率无显著差异(P＞0.05).随着年龄增长,犬猫弓形虫抗体阳性率均有明显增长.对25例弓形虫抗体阳性家养犬病例和37例弓形虫抗体阳性家养猫病例进行了回访调查,结果发现,该62例动物主人的弓形虫检测结果均为阴性.     

Pathologic and immunohistochemical findings in an outbreak of systemic toxoplasmosis in a mob of red kangaroos

Toxoplasma gondii is a zoonotic protozoan pathogen that infects many endothermic vertebrates, including humans; the domestic cat and other felids serve as the definitive host. Macropodids are considered highly susceptible to toxoplasmosis. Here, we describe the clinical, pathologic, and immunohistochemical findings of an outbreak of systemic toxoplasmosis in a mob of 11 red kangaroos (Macropus rufus), with high morbidity (73%) and mortality (100%) rates. Affected animals had either severe and rapidly deteriorating clinical conditions or sudden death, which was correlated with widespread necrotizing lesions in multiple organs and intralesional T. gondii organisms identified via MIC3-specific immunohistochemistry and confirmed by REP529-specific rtPCR. Quantification of parasites demonstrated the highest parasite density in pulmonary parenchyma compared with other tissues. Our study highlights the continued importance of this severe condition in Australian marsupials.     

孕妇弓形虫病防治研究进展

弓形虫病是一种世界性分布的人兽共患寄生虫病,在人和动物中广泛传播。孕妇感染弓形虫后多表现为隐性感染,无明显的临床表现,但该虫可通过垂直传播影响胎儿发育,造成早产、流产、畸形和死胎等不良妊娠现象。论文对弓形虫病流行病学、感染因素、免疫学、诊断和治疗等方面阐述弓形虫感染对孕妇的影响,为孕妇弓形虫病的防治提供参考。     

Risk factors associated with sero-positivity to Toxoplasma gondii in captive neotropical felids from Brazil

From September 1995 to February 2001, blood samples were collected from 865 neotropical felids belonging to 8 different species. These animals were housed in 86 institutions located in 78 cities of 20 Brazilian states. Our goal was to identify the risk factors associated with sero-positivity to Toxoplasma gondii in captive neotropical felids from Brazil. All serum samples were tested by the modified agglutination test (MAT), using formalin-fixed whole tachyzoites and mercaptoethanol. For each animal an individual questionnaire was filled with questions about tattoo number, felid species, age, sex, origin, number of animals in the group, introduction of new animals in the group, time in the institution, eating meat previously frozen for a period <7 days in the last 6 months, eating meat of run-over or euthanized animals in the last 6 months, predation of rodents or birds in the last 6 months and presence of domestic cats near the enclosures in the last 6 months. The total sero-prevalence was 55% (95% CI: 52%, 57%). We estimated a prevalence of 46% (95% CI: 40%, 54%) for jaguarundi (Puma yagouaroundi); 58% (95% CI: 53%, 63%) for ocelot (Leopardus pardalis); 50% (95% CI: 45%, 56%) for oncilla (L. tigrinus); 54% (95% CI: 46%, 62%) for margay (L. wiedii); 12% (95% CI: 4%, 31%) for Pampas-cat (L. colocolo); 83% (95% CI: 65%, 93%) for Geoffroy's-cat (L. geoffroyi); 64% (95% CI: 50%, 68%) for jaguar (Panthera onca) and 48% (95% CI: 42%, 54%) for puma (Puma concolor). Multiple logistic regression was used to evaluate the association between the variables in the questionnaire and sero-positivity to T. gondii. We concluded that the independent risk factors for toxoplasmosis were: age >3 years (OR = 4.75 [2.75; 8.2]), eating meat previously frozen for a period <7 days (OR = 2.23 [1.24; 4.01]), and consumption of animals that were run-over or euthanized (OR = 1.64; [1.14; 2.37]).     

血清法监测人工感染弓形虫病猪特异抗体的比较

应用ELISA、LAT、IHA血清试验对8头人工感染弓形虫猪的血清抗体滴度变化规律进行了监测,并对不同检测方法的结果进行了比较.结果发现,试验猪在皮下感染弓形虫RH株速殖子后,血清中的特异性抗体首次检出的时间方面,LAT(第4 d)早于ELISA(第14 d)和IHA(第20 d);检出持续时间方面,LAT(54 d)长于ELISA(44 d)和IHA(19 d);平均检出率方面,LAT(7/8)高于ELISA(6.7/8)和IHA(5/8).试验结果表明,ELISA和LAT适合于猪弓形虫病的诊断和血清学调查,LAT更适合于猪弓形虫病的早期检测.