单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,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),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,1,一、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,包囊,cyst,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,卵囊,oocyst,内含2个孢子囊，每个孢子囊内含4个子孢子。,裂殖体,配子体,一、形态在发育过程中，有5种形态。,2,刚地弓形虫-课件,3,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 nucleus.Most of the tachyzoites are free,some are still associated with bronchopulmonary cells.,Toxoplasma gondii in the bronc,4,microscopical features of tachizoites of,Toxoplasma gondii,and peritoneal macrophages of mouse in peritoneal exudate.(SEM),microscopical features of tach,5,microscopical features of tachizoites of,Toxoplasma gondii,and peritoneal macrophages of mouse in peritoneal exudate.(SEM),microscopical features of tach,6,T.gondii:,transmision electron microscopic picture.Longitudinal section of an endozoid.,T.gondii:transmision electro,7,T.gondii:,cross-section through an endozoidin an advanced stage of endodiogeny.The daugther cells appear to be surrounded.In each of these news cells there are two round bodiesthat lengthen forming the first rhoptries.,T.gondii:cross-section throu,8,Toxoplasma gondii,in tissue from a cat.,Toxoplasma gondii in tissue fr,9,toxoplasmic pseudocyst within an inflammatory tissue reaction.(H&E stain).,toxoplasmic pseudocyst within,10,the pseudocysts of,T.gondii,can be observed in tissue sections with monoclonal antibodies.,the pseudocysts of T.gondii ca,11,刚地弓形虫-课件,12,刚地弓形虫-课件,13,刚地弓形虫-课件,14,刚地弓形虫-课件,15,in cell cultures,T.gondii,proliferates to form a pseudocyst of 8-20 parasites.(Trophozoites in a THP-1 cell,Giemsa stain).,in cell cultures T.gondii prol,16,二、生活史,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,有核细胞内,内二芽/二分裂滋养体,有核细胞外,包囊,卵囊子孢子,终末宿主：猫科动物,中间宿主：极广泛，包括人及猫,随猫粪排出,免疫力,滋养体速殖子包囊缓殖子,二、生活史肠上皮细胞裂体增殖裂殖体裂殖子肠上皮细胞,17,刚地弓形虫-课件,18,刚地弓形虫-课件,19,刚地弓形虫-课件,20,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,寄生部位：所有有核细胞,21,三、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。,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,22,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,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。,虫株毒力危害因素,23,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）。,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,24,刚地弓形虫-课件,25,弓形虫脑病,弓形虫脑病,26,刚地弓形虫-课件,27,眼弓形虫病,眼弓形虫病,28,CT scan of a toxoplasmic encephalitis.,The typical lesion is an ipodense focal area with ring contrast-enhancement and edema.,CT scan of a toxoplasmic encep,29,四、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,四、实验诊断1、病原学诊断（1）体液涂片染色法（2）动,30,T.gondii:,direct detection of,T.gondii,in clinical specimens,T.gondii:direct detection of,31,五、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,五、流行本病是人兽共患寄生虫病，人群抗体阳性率25-50%,32,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。,广泛流行的原因,33,刚地弓形虫-课件,34,六、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,。,六、防治 对本病重在预防。,35,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。,其他机会致病原虫肺孢子虫,36,Last Modified:11/20/2000 16:53:26,Pneumocystis jiroveci(syn.Pneumocystis carinii),Pneumocystis jiroveci,cysts.,A:,3 cysts in bronchoalveolar material,Giemsa stain;the rounded cysts(size 4 to 7 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,B,Last Modified:11/20/2000 16:53:26,Pneumocystis jiroveci(syn.Pneumocystis carinii),Pneumocystis jiroveci,cysts.,A:,3 cysts in bronchoalveolar material,Giemsa stain;the rounded cysts(size 4 to 7 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,B,A:3 cysts in bronchoalveolar material,Giemsa stain;the rounded cysts(size 4 to 7 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:c