寄生虫医学课件：机会致病寄生虫(双语)

1、思考题： 1.引起以腹泻为主要临床表现的原虫有哪些？ 2.机会致病寄生虫有哪些？最大的危害是什么？ 3.与优生优育有关的寄生虫有哪些？,parasite,李艳文 教授 广西医科大学寄生虫学教研室,Opportunistic,Opportunistic protozoa Some protozoa are nonpathogenic or cause only limited clinical symptoms in immunocompetent host, but can result in serious symptoms in immunodeficient persons.,Prefa

2、ce,Opportunistic parasite,Factors that cause immunity suppression: -Malignant tumor, long-term radiotherapy, organ transplantation, long-term using immunosuppressive drugs, severe protein-calorie malnutrition; -Congenital immune deficiency disease, acquired immunodeficiency syndrome (AID) etc., Toxo

3、plasma gondii 弓形虫 Cryptosporidium 隐孢子虫 Isospora 贝氏等孢球虫 Cyclospora 环孢子虫 Sarcocystis 肉孢子虫 Blastocystis hominis 人芽囊原虫 Strongyloides stercoralis 粪类圆线虫,Toxoplasma gondii,-1908年由Nicolle and Manceaux 在刚地梳趾鼠的肝、脾单核细胞内发现； -Definitive host is the cat； Intermediate host has a wide range, including humans, mamma

4、ls, birds and other； -Parasitizing nucleated cells in human, human and animal infection rate is extremely high；,Morphology,Trophozoite: tachyzoite and bradyzoite,-Pseudocyst:,速殖子,缓殖子,假包囊,C. Transmission electron micrograph of an intracellular tachyzoite.,Extracellular (arrow) released from host cell

5、s. B. Intracellular in cell culture.,c:类锥体conoid,r:棒状体rhoptry,Morphology,-Cyst: contain a lot of bradyzoites,缓殖子,-Schizont(裂殖体): -Oblong, with 4-29 merozoites(裂殖子) ； -Merozoite crescent-shape, and fan-shaped arrangement ； -Exist on the definitive host epithelial cells of intestinal villi .,-Gametoph

6、yte(配子体): - Gametophyte is round and development for female gamete after meiotic ; - Gametophyte development to 12-32 male gametes, which pointed at both ends, and the front end with a 2 flagellum ;,-Oocyst(卵囊):,Sporocyst and 4 sporozoites,Life cycle,Definitive host(cat),Intermediate host (human),Li

7、fe cycle,Intermediate host,Definitive host,Summary of life cycle,1. Definitive host: the domestic cat and other felids; 2. Intermediate host: such as human or mice, pig, cat, cattle, sheep, horse, rabbit, bird and fish etc.,4. Parasitic site：karyote. (lymph node, brain, liver, heart, lung, muscle).,

8、3. Infect stage: oocyst, cyst, pseudocyst, tachyzoite, bradyzoite.,5. Ways of transmission: 1) Prenatal infection -to cross the placenta to infect the fetus. 2) Postnatally acquired infection by ingesting food contaminated by oocysts from cat feces. through the consumption of uncooked infected meat.

9、 through blood transfusion, organ transplantation,Summary of life cycle,Pathogenesis,-Necrosis is caused by intracellular multiplication of tachyzoite;,-Necrosis may develop in many organs, such as intestinal and mesenteric lymph nodes, eye, heart, and adrenals, brain, liver;,-Bradyzoite death may p

10、rovoke delayed-type hypersensitivity, formation of granulomatous lesions.,-Cyst increased, squeezing the organ, caused by dysfunction;,1.Congenital toxoplasmosis .If it infects women during pregnancy, tachyzoite may cross the placenta to infect the fetus. .This may result in spontaneous abortion, a

11、stillborn or handicapped child.,Clinical Manifestations,资料,.请分析判断下列哪个说法是对的？,说法一：先天性弓形虫病只发生于初孕妇女. 说法二：母亲在产下一胎先天性弓形虫感染的婴儿后，因本身成为慢性感染者，故少见次胎再出现弓形虫先天性感染。 说法三：某母亲产下一畸形儿，因家中养有一条狗，认为是因与狗亲密接触造成弓形虫感染所致。,2. Postnatal toxoplasmosis (1)Immunocompetent individuals: .Disease is locally and generalized and is rare

12、ly severe. .Lymphadenitis is the most common manifestation.,2. Postnatal toxoplasmosis (2)Immunosuppressed individuals: .Acute toxoplasmosis (severe disease): encephalitis, lymphadenitis, myositis, hepatitis, pneumonitis, myocarditis, nephritis,Toxoplasma gondii encephalopathy,Toxoplasmosis ophthalm

13、opathy,Diagnosis,-Pathogenic diagnosis -Serologic test,-Molecular biological detection,Diagnosis,Smear staining method涂片染色法: Animal inoculation/cell culture 动物接种或细胞培养法:,-Pathogenic diagnosis,Diagnosis,the indirect fluorescent antibody test (IFAT) the indirect hemagglutination test the latex agglutin

14、ation test the enzyme-linked immunoabsorbent assay (ELISA),-Serologic test ( mainly),Diagnosis,-Molecular biological detection,-PCR detection technology -DNA probe diagnosis,Epidemiology,1.流行概况,-世界性分布； -各地感染率不一，欧美地区25-50%，我国平均感染率7.88%, 少数民族感染率较高； -家畜阳性率较高，可食用的肉类感染普遍； -感染与地理、自然气候条件关系不大，与饮食习惯、接触猫科动物、职

15、业有关；,Epidemiology,Reasons that toxoplasma infection is widely popular are 1. Trophozoite, cyst and oocyst have strong resistnce to enviroment. 2. Many infective stages. 3. Many animals act as intermediated hosts. 4. Transmission occur among difinitive hosts and intermediated hosts. 5. Cyst can exist

16、 in the tissue of intermediated host for a long time. 6. Great number of oocysts were discharged from final host.,2.流行环节 （1）传染源：动物是本病的主要传染源，而猫则为重要传染源; （2）传播途径：有先天和后天获得性两种; （3）易感人群：人类对弓形虫普遍易感，尤其是胎儿、婴幼儿、肿瘤与艾滋病患者等。长期应用免疫抑制剂及免疫缺陷者可使隐性感染复燃而出现症状。,The prophylaxis is important for preventing toxoplasmosis.,

17、Prevention and control,(1) To raise awareness of toxoplasmosis； (2) Strengthen quarantine of meat, not eating undercooked-food or raw meat, eggs； (3) No raising cat, no playing with cats, particularly pregnant women; (4) Periodic detection in pregnant women, and reduce the occurrence of congenital t

18、oxoplasmosis; (5) Acute toxoplasmosis treatment : Sulfonamides and pyrimethamine (乙胺嘧啶) . Spiramycin(乙酰螺旋霉素)- pregnant women.,Cryptosporidium,隐孢子虫,-广泛寄生于爬行类、鱼类、鸟类和哺乳类； -20多种，其中8种和3个基因型对人体有致病性，主要虫种是人隐孢子虫(Cryptosporidium hominis)和微小隐孢子虫(C.parvum)； -寄生人胃肠道上皮细胞，引起腹泻； -80年后，伴随艾滋病的发生，隐孢子虫病受到广泛重视。,Morpholo

19、gy,Oocyst:,-Round or oval, diameter 4-5 m； -1 remain body, 4 sporozoites； -Thin-wall and thick wall；,Morphology,A scanning electron micrograph of a broken meront of Cryptosporidium,Life cycle,1. Completing its entire life cycle within a single host. 2. A lot of mammals could act as host. 3. Infectio

20、n occurs by The ingestion of oocysts in contaminated water, food, or by the fecal-oral route; Autoinfective infection: through sporozoites rupturing from thin-walled oocysts. 4. Parasitic site: the ileum, the duodenum and large intestine, the stomach, biliary and pancreatic ducts, and respiratory tr

21、act.,Summary of life cycle,Pathogenesis,Arrows point to the Cryptosporidium in the microvillus border,An electron micrograph showing several stages of Cryptosporidium (two are marked with asterisks) on the intestinal epithelium of a sheep.,A scanning electron micrograph of Cryptosporidium lining the

22、 intestinal tract.,The trachea of a turkey lined with numerous Cryptosporidium.,Pathogenesis,-Parasite invasion, multiplication, and extrusion; -Through T cell-mediated inflammation;,Epithelial cells are damaged:,-Producing distortion of villus architecture; -Villus atrophy and crypt hyperplasia;,Nu

23、trient malabsorption and diarrhea.,Clinical Manifestations,The most common symptom is watery diarrhea.,-Immunocompetent individuals: Watery diarrhea are self-limiting, rarely more than two weeks .,-Immunosuppressed individuals: Watery diarrhea are serious, long-lasting, and sometimes fatal.,1. Patho

24、genic diagnosis (1) Stool or tissue fluid checks: search oocyst -Direct smear staining method or smear staining after concentrated,Diagnosis,1）Gold amino-phenol method(金胺-酚染色法):需要用荧光显微镜，难鉴别酵母菌及非特异荧光颗粒，用于筛查； 2）The modified acid-fast method(改良-抗酸染色法):难鉴别红色抗酸颗粒； 3）金胺酚-改良抗酸染色法：背景为绿色，卵囊为玫瑰红色，非特异颗粒则染成蓝黑色;

25、,2.Immunologic methods -The enzyme-linked immunoabsorbent assay (ELISA) . -The antibody immunofluorescence assay (IFA) .,Diagnosis,3.Molecular biological detection -PCR detection technology -DNA probe diagnosis.,.流行情况 -本虫呈世界性分布，国外在腹泻患者中，隐孢子虫的检出率为0.6-4.3%； -国内的检出率平均为2.14%,儿童的感染率比成人高,农村居民的感染率高于城市; -卵囊

26、污染水源常引起本病的局部暴发性流行；,Epidemiology,英、美等国报道了水源受染引起暴发流行的问题，如只有不到65000人口的西部佐治亚洲，大约13000人发生了胃肠炎，其中39的患者粪检隐孢子虫卵囊阳性，饮用自来水者患胃肠炎的危险性高于不饮用者，危险度为3：1，在自来水中也找到了卵囊，这是一次大范围的暴发。 用于消毒自来水的氯化物的浓度不能杀死卵囊，因此一旦水源污染，易引起暴发流行。,-我国已将隐孢子虫和贾第虫列为影响水质的重要病原体.,. Epidemiologic factors 1. Source infection: patient, carrier and reservoi

27、r host; 2. Susceptible population: Immunosuppression and immunodeficient persons are more vulnerable; 3. Infection occurs by the ingestion of oocysts in contaminated water, food, or by the fecal-oral route.,Epidemiology,1. Strengthen the management of manure, protecting water sources from pollution;

28、 2. Strengthening personal diet health; 3. Protection of immunocompromised persons; 4. Treatment: the lack of effective drugs. Barron adriamycin, garlic capsules, spiramycin, azithromycin, high titer immune milk have a certain effect.,Prevention and control,肉孢子虫,Sarcocystis,.牛-人肉孢子虫(S. bovihominis)：

29、人是终宿主，中间宿主是牛，也称人肉孢子虫(S. hominis)； .猪-人肉孢子虫(S. suihominis)：人是终宿主，中间宿主是猪，也称人猪肉孢子虫；,人肠肉孢子虫,林氏肉孢子虫(S. lindemanni)：人是中间宿主，终宿主尚不明确，也称人肌肉肉孢子虫。,最早于1882年在猪肉中发现，到20世纪初才被确认为一种常见于食草动物(如牛、羊、马和猪等)的寄生虫。 1983年左仰贤首次在我国云南发现2例猪-人肉孢子虫病人，1986年李逸明和连自强在云南首次报道了牛-人肉孢子虫病例，随后进行了人肉孢子虫人-牛间的循环感染研究，阐明了孢子虫的生活史。,1.卵囊 oocyst,成熟卵囊椭圆形

30、，囊壁较薄，内含2个孢子囊，其内各含4个子孢子。,Morphology,2.孢子囊sporocyts,孢子囊呈椭圆形或卵圆形，壁双层而透明，内含4个子孢子，大小为（13.616.4）m（8.310.6）m。,卵囊,3.肉孢子囊 sarcocyst,肉孢子囊呈圆柱形或纺锤形，长1-5cm,横径0.1-1cm,囊壁内有许多间隔把囊内虫体-缓殖子分割成簇。,寄生于猪肉中的肉孢子虫肉孢子囊形态（40）,寄生于猪肉中的肉孢子虫肉孢子囊（10）,镜下观察猪人肉孢子虫肉孢子囊及头端形态 （左侧图片40，右侧图片100）,Life cycle,卵囊/孢子囊,（终宿主粪便排出）,中间宿主食入，释放,子孢子,穿过

31、肠壁，侵入血流， 血管内皮细胞裂体增殖,肉孢子囊,裂殖子在肌肉细胞 内移行，发育成,终宿主,中间宿主,卵囊,孢子囊,缓殖子,内皮细胞内的裂殖体,肌肉内的肉孢子囊,小肠细胞,随粪便排出,裂殖子,子孢子,Summary of life cycle,.牛-人肉孢子虫和猪-人肉孢子虫: -终宿主：人 -中间宿主：牛和猪 -感染阶段：肉孢子囊/缓殖子 -感染方式：生吃、半生吃含肉孢子囊的肉类 -寄生部位：小肠,.林氏肉孢子虫/人肌肉肉孢子虫： -中间宿主：人 -感染阶段：卵囊/孢子囊 -感染方式：经口食入卵囊或孢子囊污染的食物或水 -寄生部位：肌肉组织,1.牛-人肉孢子虫和猪-人肉孢子虫: 免疫力正常者

32、多无明显症状，免疫力低下者可出现严重感染。厌食、恶心、呕吐、腹泻、腹痛等，严重有贫血、坏死性肠炎等；,Pathogenesis and clinical manifestation,2.林氏肉孢子虫/人肌肉肉孢子虫： 可直接破坏所侵犯的肌细胞，压破性萎缩等，若寄生在重要部位，如心肌、舌肌、膈肌、喉头肌可引起心肌炎、呼吸困难、语言障碍等。 一旦肉孢子虫囊破裂，其液体中含有毒力很强的肉孢子虫毒素(sarcocystin)，作用于神经系统、心脏等多系统，引起休克，甚至死亡。,牛-人肉孢子虫和猪-人肉孢子虫:,.问病史：有无生食肉类的不良习惯 .粪便检查：查孢子囊或卵囊 直接涂片法、蔗糖浮聚法或硫酸锌

33、浮聚法,Diagnosis,活体组织检查：在肌肉中查找肉孢子囊,林氏肉孢子虫/人肌肉肉孢子虫：,-世界性分布 -国内主要分布在云南、广西和西藏,-动物源性寄生虫病: 世界各地黄牛的人肉孢子虫感染率为4.0-92.4%。左仰贤1983年首次报告国内病例。云南大理的猪人肉孢子虫自然感染率平局为29.7%。,Epidemiology,广西的流行情况,1李锦辉、林珍、覃业新、杜进发.广西发现猪人肉孢子虫感染J.中国寄生虫学与寄生虫病杂志,2004,22(2):82. 2李锦辉、林珍、杜进发、覃业新等.广西猪人肉孢子虫感染情况的调查J.中国寄生虫病防治杂志,2005,18:195-196.,人均感染率2.4；邕宁、横县感染率相对较高,文章摘要: 目的：研究确定广西是否