人工感染弓形虫兔主要脏器病理形态学观察

将人工感染弓形虫兔于濒死期(3～46d不等)扑杀,取其心、肝、脾、肺和肾五种脏器组织,作了病理形态学观察。主要结果如下:肝、心、脾组织中有周边无炎性反应的凝固性坏死;肝组织中还有网状细胞增生形成的结节;肺脏表现为肺泡隔炎等,这些特征性病变与其他动物弓形虫病变基本相同。同时观察到在肝窦状隙、小叶间动、静脉、肺泡壁毛细血管、肺支气管动脉、心肌纤维间毛细血管和脾静脉窦内均有血栓形成,同时伴?坏死性血栓性血管炎;各脏器的动脉管壁呈现不同程度的玻璃样变,以及由血栓形成所致其周围组织的病变。另外,应用PAS、PTAH、Weigert-Gram等染色方法显示组织切片中的弓形虫,比H.E染色更易于观察。     

Long-Term Study of Toxoplasma gondii Infection in a Swedish Sheep Flock

Lundén, A., A. Näsholm and A. Uggla: Long term study of Toxoplasma gondii infection in a Swedish sheep flock. Acta vet. scand. 1994,35,273-281.– The infection rate of Toxoplasma gondii was studied during 6 years in a sheep flock in central Sweden. The flock consisted of 165-249 breeding ewes of which 20-35% were lambs less than 1 year old. Most ewes were slaughtered when 5 years old. The sheep were kept indoors from end of September to early May. Lambing took place in March and April. Individual serum samples were collected twice a year, once just before turning the sheep out to pasture in the spring, and again after housing in the autumn. Sera were analysed by ELISA for antibodies to T. gondii. The seroprevalence varied between 10% and 45% during the 6 years of observation. Seroconversion was detected predominantly at the autumn sampling, indicating that in most cases infection was acquired at pasture. Subclinical effects of T. gondii infection on lamb weight, litter size, total litter weight and ewe weight were also studied. Lambs born to chronically infected ewes were lighter at birth than those of uninfected ewes, but this disparity was no longer evident at weaning.     

弓形虫致密颗粒蛋白的生物学功能研究进展

刚地弓形虫（Toxoplasma gondii）是一种重要的人兽共患寄生原虫,具有中间宿主广泛、生活史复杂、传播方式多样、呈全球性分布等特点,可感染几乎所有的恒温动物,导致人兽共患的弓形虫病。弓形虫慢性感染约1/3的世界人口,对免疫缺陷患者、孕妇、孕畜的健康更是造成严重威胁。致密颗粒蛋白是由致密颗粒（弓形虫的一种亚细胞分泌器官）分泌的蛋白质,它们可通过操控宿主（细胞）基因表达、信号通路进而调控宿主细胞的免疫反应和细胞周期,并在蛋白质的转运和定位、营养物质的摄取、纳米管网络（IVN）的形成与稳定性的维持、逸出、慢性感染等生理过程中发挥重要作用。本文综述弓形虫致密颗粒蛋白基本生物学功能的最新研究进展,旨在为深入研究弓形虫的致病机制、鉴定新的抗弓形虫潜在药物靶点和疫苗候选分子提供借鉴。     

Cytologic detection of Toxoplasma gondii in the cerebrospinal fluid of a dog and in vitro isolation of a unique mouse-virulent recombinant strain

Parasites resembling Neospora caninum or Toxoplasma gondii were detected by cytologic examination of cerebrospinal fluid (CSF) from a dog with neurologic disease. The dog became severely ill and was euthanized. Canine tissue homogenates were used for direct parasite isolation in cell culture, bioassay in 2 mouse lineages, and PCR. T. gondii was isolated in monkey kidney cells, and species identity was confirmed by PCR. Inoculated parasites were highly virulent for mice, which developed clinical signs and were euthanized immediately. PCR-RFLP for T. gondii using the cultured isolate (TgDgBA22) was conducted with 12 genetic markers, and a unique recombinant strain was identified. Detection of T. gondii by CSF cytology, although described in humans, had not been reported previously in dogs, to our knowledge, and was crucial for the diagnosis of toxoplasmosis in the examined dog.     

Identifying factors which maximise the lambing performance of hoggets: a cross sectional study

AIM: To identity perceptions of farmers with respect to advantages of hogget lambing and to identify optimal management strategies for hogget lambing used in New Zealand.

METHODS: A questionnaire was sent to 1,038 sheep farmers in New Zealand who had indicated their hoggets would be lambing in 2002. Information was gathered on the practice of hogget lambing in New Zealand, in particular on the numbers and breeds of hoggets and rams used, selection criteria used for hoggets, use of teasers (vasectomised rams), length of mating period, use of mating crayons, vaccinations, medications and mineral supplements given, level of feed offered, use of pregnancy scanning, management during pregnancy and lambing, number of lambs present at docking, and shearing policies for hoggets. Farmers were also asked to indicate the relative importance of five stated reasons for choosing to have their hoggets mated in 2002.

RESULTS: A total of 629 (60.6%) responses were incorporated in the analysis, and the average percentage of hogget lambing was 60%. Use of vaccinations, length of the mating period, number of rams used, breed of hogget, weight at mating, management during lactation, and shearing policy were associated (p<0.05) with the lambing performance of hoggets, in the multivariate analysis.

CONCLUSIONS: This study indicated that to ensure high lambing percentages (LP) in hoggets in New Zealand, sheep farmers should: vaccinate hoggets against toxoplasmosis and campylobacteriosis; utilise a 40-day mating period; use 2.6–3.5% of rams during mating; incorporate Finn or East Friesian genetics; ensure liveweights at mating are as high as possible; manage single- and multiple-bearing/-rearing hoggets separately during the lambing and lactation periods; and shear hoggets pre-mating.     

Toxoplasma gondii inclusions in peripheral blood leukocytes of a red-necked wallaby (Macropus rufogriseus)

Abstract A 2-year-old, male, red-necked (Bennett's) wallaby ( Macropus rufogriseus ) from a zoological facility was presented for peracute onset of severe depression, unresponsiveness, ataxia, and loose feces. Serum biochemical abnormalities included azotemia, hypoalbuminemia, increased alanine aminotransferase activity, hyperbilirubinemia, hyperphosphatemia, and hyperkalemia, consistent with multi-organ system failure. Severe thrombocytopenia suggested possible disseminated intravascular coagulation. Peripheral blood smear examination revealed numerous ovoid, protozoal inclusions within monocytes and occasionally within neutrophils. Despite aggressive supportive therapy, the patent died within 5 hours of presentation. Gross necropsy and histopathologic findings included severe multifocal necrotizing lesions in multiple organs. Numerous intralesional protozoal organisms were observed and were identified as Toxoplasma gondii by immunohistochemistry. Macropods (wallabies and kangaroos) are known to be highly susceptible to toxoplasmosis, with high mortality rates; diagnosis most often is obtained at necropsy. Detection of protozoal organisms in peripheral blood leukocytes is reported rarely and has not been documented previously in a macropod. Parasitemia in this case was attributed to severe, disseminated disease. Careful examination of peripheral blood smears in macropods suspected of toxoplasmosis may be warranted.     

Seroprevalence of Toxoplasma gondii among Nunavik Inuit (Canada)

As a result of their intimate contact with the land and their nutritional habits, the Inuit of Nunavik are considered to be at risk from zoonotic infections. To better understand the risk factors for Toxoplasma gondii infection, a serosurvey was conducted in Nunavik, Québec, in September 2004. A representative sample of the Inuit adult population of Nunavik participated in this cross-sectional study (n = 917). Antibodies (IgG) against T. gondii were detected by immunoassay. Information on sociodemographic characteristics, traditional activities, domestic environment and nutrition was gathered by questionnaire and explored as variables explanatory of seropositive results. Associations found to be statistically significant in univariate analyses were assessed by multivariable logistic regression to control for confounding factors. Almost two thirds (59.8%) of the Inuit of Nunavik were found to be seropositive for T. gondii. In multivariate analyses, risk factors for seropositivity were: increasing age, gender (women > men), lower level of education, consumption of potentially contaminated water (determined by an index of risk from waterborne infections), frequent cleaning of water reservoirs, and consumption of seal meat and feathered game. There was some variation in seroprevalence between the Ungava Bay coast (52.3%) and the Hudson Bay coast (65.6%), the two main regions of Nunavik, but this variation was not significant in the multivariable logistic regression model. This cross-sectional study demonstrated high T. gondii seroprevalence in the Inuit population and revealed that age, gender, schooling and community of residence all influence serostatus in this population. Variables related to drinking water and food choices may also influence the risk of infection. These results raise important questions about T. gondii transmission in Nunavik including possible links between terrestrial and marine cycles.     

三种免疫血清学方法检测弓形虫抗体的比较

用斑点酶联免疫吸附试验、金萄菌A蛋白酶联免疫吸附试验及间接血球凝集试验二种血清学方法检测弓形虫感染鼠血清及健康鼠血清各100份,平均阳性率分别为96.0％、94.0％和88.0％,平均假阳性率分别为4.0％、7.0％及8.0％;检测10份阿米巴肝脓肿病人血清及20份日本血吸虫感染兔血清,平均交叉反应率分别为3.3％、10.0％及13.3％。结果表明,三法对弓形虫特异性抗体的检测均有较好的敏感性、特异性、重现性及较低的交叉反应率。三法中,以斑点酶联免疫吸附试验的敏感性最好,且有省试剂、反应快、操作简便等优点,是一种很有实用价值前景的免疫诊断方法。     

信阳地区猪弓形虫病血清学调查与分析

为了解信阳地区猪弓形虫病的感染情况,于2011年5月-2012年9月,应用酶联免疫吸附试验(ELISA)方法对信阳地区部分规模养猪场进行了调查分析。结果显示:猪弓形虫病总体阳性率为23.2%,其中,经产母猪阳性率为26.2%,育肥猪阳性率为22.9%,哺乳仔猪阳性率为14.4%。由此可见,猪弓形虫病感染在信阳地区规模化猪场已普遍存在。