刚地弓形虫

A, B, C: Oocysts of Isospora belli. The oocysts are large (25 to 30 µm) and have a typical ellipsoidal shape. When excreted, they are immature and contain one sporoblast (A, B). The oocyst matures after excretion: the single sporoblast divides in two sporoblasts (C), which develop cyst walls, becoming sporocysts, which eventually contain four sporozoites each. Images contributed by Georgia Division of Public Health.
Indirect immunofluorescence using monoclonal antibodies against Pneumocystis jiroveci. Specimen from a patient with AIDS, seen in Georgia.
Molecular Diagnosis
Toxoplasma gondii in tissue from a cat.
toxoplasmic pseudocyst within an inflammatory tissue reaction. (H&E stain).
the pseudocysts of T.gondii can be observed in tissue sections with monoclonal antibodies.
Pneumocystis jiroveci trophozoites in bronchoalveolar lavage (BAL) material; Giemsa stain. The trophozoite are small (size: 1 to 5 µ m), and only their nuclei, stained purple, are visible (arrows). AIDS patient seen in Atlanta, Georgia.
刚地弓形虫
（Toxoplasma
gondii）
简称弓形虫，弓浆虫。寄生于人和许多 种动物的有核细胞，引起人畜共患的弓 形虫病(toxoplasmosis )。特别在宿主免 疫功能低下时致病，属机会致病原虫 (opportunistic protozoa)
一、形态
在发育过程中，有5种形态。
滋养体
在有核细胞内，假包囊内滋养体叫速殖子tachyzoite
三、致病
人对弓形虫普遍易感，免疫功能正常时常处 于隐性感染状态，当宿主免疫功能低下时异 常增殖而致病。 速殖子是主要致病阶段。 虫体侵入有核细胞大量增殖，组织细胞被破 坏，炎症细胞侵润，导致组织的炎症、坏死。
虫株毒力
RH 株（强毒株）可使宿主迅速死亡
Beverley 株（弱毒株） 增殖缓慢，易形成包囊
T. gondii: transmision electron microscopic picture. Longitudinal section of an endozoid.
T. gondii: cross-section through an endozoid in an advanced stage of endodiogeny. The daugther cells appear to be surrounded. In each of these news cells there are two round bodies that lengthen forming the first rhoptries.
广泛流行的原因
1、多个生活史阶段均有感染性。
2、中间宿主极广泛。 3、可在终宿主间、中间宿主间、终宿主与 中间宿主间互相感染。 4、包囊可在中间宿主组织内长期存在。 5、卵囊排放量大，抵抗力强。
六、防治
对本病重在预防。 1、急性期患者常用乙胺嘧啶、磺胺类和增效 剂联合用药。疗程中可配用免疫增强剂。 2、加强对家禽、家畜和可疑动物的监测。 3、加强肉类检疫和食品卫生管理。 4、定期对孕妇作弓形虫常规检查。
大量虫体分泌物形成的囊状结构，包囊内滋养体 叫缓殖子bradyzoite 内含2个孢子囊，每个孢子囊内含4个子孢子。
包囊 cyst
卵囊oocyst
裂殖体
配子体
Toxoplasma gondii in the bronchoalveolar lavage (BAL) material from an HIV infected patient. Numerous trophozoites (tachyzoites) can be seen, which are typically crescent shaped with a prominent, centrally placed nuclபைடு நூலகம்us. Most of the tachyzoites are free, some are still associated with bronchopulmonary cells.
危害因素
弓形虫毒素(toxotoxin) 一种抗原， 致死因子，可致
小鼠惊厥、后肢麻痹，几分钟后死亡。
弓形虫素(Toxoplasmin) 对鸡胚胎有致畸作用。
弓形虫因子(Toxofactor) 培养的上清液提取物，可阻
止母鼠受孕，或流产，或胚胎发育停滞。
临床分型： 1、先天性弓形虫病 孕早期弓形虫通过胎盘传给胎儿,可造成流 产，早产，畸胎或死产。 2、获得性弓形虫病 因侵犯部位和机体反应性不同临床表现。 常见的是发热（中、长程热），淋巴结肿 大（颌下、颈后），神经系统的炎症（脑 炎、脑膜炎），眼部炎症（视网膜脉络膜 炎）。
in cell cultures T.gondii proliferates to form a pseudocyst of 8-20 parasites. (Trophozoites in a THP-1 cell, Giemsa stain).
二、生活史
终末宿主： 猫科动物 肠上皮细胞 裂体增殖 裂殖体—裂殖子 肠上皮细胞 配子生殖 ♀♂配子—合子 —卵囊
弓形虫脑病
眼弓形虫病
CT scan of a toxoplasmic encephalitis. The typical lesion is an ipodense focal area with ring contrastenhancement and edema.
四 、实验诊断
1、病原学诊断 （1）体液涂片染色法 （2）动物接种和细胞培养法 2、血清学诊断 （1） IHA、IFA、ELISA 查抗原或抗体 （2） PCR及DNA探针技术 可早期诊断
•Lane S: Molecular base pair standard (100-bp ladder). Black arrows show the size of standard bands. •Lane 1: Single step PCR amplification with the pAZ102E/pAZ102-H primer pair1 diagnostic band size: 346 bp. •Lane 2: Nested PCR amplification with the ITS nested PCR primers, 1724F/ITS2R (first round) and ITS1F/ITS2R1 (second round)2 - diagnostic band size: 550 bp.
其他机会致病原虫
• 肺孢子虫 寄生肺泡上皮细胞，引起间质性肺炎。 • 隐孢子虫 寄生肠粘膜，引起腹泻。 • 等孢球虫 寄生小肠上皮细胞内，引起腹泻。 • 圆孢子虫 寄生肠粘膜，引起腹泻。
A: 3 cysts in bronchoalveolar material, Giemsa stain; the rounded cysts (size 4 to 7 µ m) contain 6 to 8 intracystic bodies, whose nuclei are stained by Giemsa; the walls of the cysts are not stained; note the presence of several smaller, isolated trophozoites. B: cysts in lung tissue, silver stain; the walls of the cysts are stained black; the intracystic bodies are not visible with this stain; baby who died with pneumonia in California.
A: Agarose gel (2%) analysis of PCR-amplified products from DNA extracted from a broncho alveolar lavage (BAL) diagnostic specimen of a patient with pulmonary symptoms.
T. gondii: direct detection of T.gondii in clinical specimens
五、流行
本病是人兽共患寄生虫病，人群抗体阳性率25-50%。 许多与人关系密切的动物感染率亦高，是重要传染源。
流行因素： 1、传染源 猫科动物、其他哺乳动物、感染者
2、传播途径 胎盘；食入、伤口接触、输血等 3、易感人群 普通人，胎儿、肿瘤和AIDS患者更易感
Oocysts of Isospora belli can also be stained with acid-fast stain, and can be visualized by epifluorescence on wet mounts, as illustrated. Three coccidian parasites that most commonly infect humans, seen in acid-fast stained smears (A, C, and F), bright-field differential interference contrast (B, D, and G) and epifluorescence (E and H, C. parvum oocysts do not autofluoresce).
microscopical features of tachizoites of Toxoplasma gondii and peritoneal macrophages of mouse in peritoneal exudate. (SEM)
microscopical features of tachizoites of Toxoplasma gondii and peritoneal macrophages of mouse in peritoneal exudate. (SEM)
随猫粪 排出
卵囊——子孢子
滋养体—速殖子 包囊——缓殖子
有核细胞内 内二芽/二分裂 滋养体 有核细胞外 免疫力 包囊
中间宿主： 极广泛，包 括人及猫
寄生部位：所有有核细胞
宿主：广泛 感染阶段：卵囊，滋养体（速殖子、假包囊）， 包囊 感染方式： 1）后天感染 a)误食被卵囊污染的食物。 b)生吃肉类、乳类 c)通过器官移植、输血等医疗手段 2）先天感染 孕早期感染弓形虫，通过胎盘传给胎儿