吸虫(trematode） 扁形动物门 Phylum Platyhelminthes 吸虫纲 Class Trematoda 复殖目 Order Digenea

吸虫形态 背腹扁平，两侧对称 具口、腹吸盘 无体腔 雌雄同体 消化道：肠盲管

吸虫对寄生生活的适应 特殊的附着器官:吸盘等 消化系统退化 高度发达的生殖能力 有无性增殖世代

吸虫的雌性生殖系统 卵巢（1个）输卵管（卵黄腺通过卵黄总管，受精囊注入）卵模（梅氏腺）子宫（盘曲）生殖腔生殖孔

吸虫的雄性生殖系统 睾丸（1-2个） 输出管（2根） 输精管储精囊 射精管阴茎（阴茎袋） 生殖腔生殖孔

吸虫卵特点 卵圆形，大小差异大 多数具卵盖 卵内含卵细胞＋卵黄细胞 或毛蚴

吸虫生活史阶段 虫卵（Egg） 毛蚴（Miracidium） 胞蚴(Sporocyst) 雷蚴(Redia) 尾蚴(Cercaria) 囊蚴(Metacercaria) 童虫(Preadult) 成虫(Adult worm)

吸虫的无性世代 虫卵（水中或螺内孵化） 毛蚴（螺宿主淋巴系统内发育） 胞蚴（螺内无性增殖） 雷蚴（螺内无性增殖） 尾蚴（逸出螺体） 囊蚴（第二中间宿主）

常见医学吸虫 华支睾吸虫 （肝吸虫） 卫氏并殖吸虫(肺吸虫) 布氏姜片吸虫（姜片虫） 日本裂体吸虫(血吸虫)

华支睾吸虫 Clonorchis sinensis

概 述 寄生肝胆管 致肝吸虫病，主要分布远东地区 人体感染与饮食习惯有关 人体首例1874;国内1908上海

成虫形态 为吸虫的模式形态 大小、体形似葵花子 口吸盘略大于腹吸盘 睾丸分支，卵巢分叶

Adult of Clonorchis sinensis Clonorchis sinensis adult Adult of Clonorchis sinensis

Clonorchis sinensis, liver biopsy: most infections are asymptomatic. Section of C.sinensis

虫卵形态 蠕虫卵中之最小者 形似芝麻，具卵盖、肩峰， 另一端有小棘，内含毛蚴

egg of Clonorchis sinensis 疣状突起 毛蚴 卵盖 Clonorchis sinensis egg.  These are small operculated eggs.  Size 27 to 35 µm by 11 to 20 µm.  The operculum, at the smaller end of the egg,  is convex and rests on a visible "shoulder".  At the opposite (larger, abopercular) end, a small knob or hooklike protrusion is often visible (as is the case here).  The miracidium is visible inside the egg.   egg of Clonorchis sinensis

http://www. dpd. cdc. gov/dpdx/HTML/ImageLibrary/Clonorchiasis_il. asp http://www.dpd.cdc.gov/dpdx/HTML/ImageLibrary/Clonorchiasis_il.asp?body=A-F/Clonorchiasis/body_Clonorchiasis_il_th.htm Embryonated eggs are discharged in the biliary ducts and in the stool .  Eggs are ingested by a suitable snail intermediate host ; there are more than 100 species of snails that can serve as intermediate hosts.  Each egg releases a miracidia , which go through several developmental stages (sporocysts , rediae , and cercariae ).  The cercariae are released from the snail and after a short period of free-swimming time in water, they come in contact and penetrate the flesh of freshwater fish, where they encyst as metacercariae .  Infection of humans occurs by ingestion of undercooked, salted, pickled, or smoked freshwater fish .  After ingestion, the metacercariae excyst in the duodenum and ascend the biliary tract through the ampulla of Vater .  Maturation takes approximately 1 month.  The adult flukes (measuring 10 to 25 mm by 3 to 5 mm) reside in small and medium sized biliary ducts.  In addition to humans, carnivorous animals can serve as reservoir hosts.

肝吸虫的生活史 水 成虫 卵 毛蚴 豆螺 胞蚴 消化道 肝胆管 雷蚴 人 淡水鱼虾 尾 蚴 童虫 囊蚴

肝吸虫生活史要点 成虫寄生肝胆道 需2个中间宿主：豆螺、淡水鱼 经口吞食鱼虾中囊蚴感染 经粪便排出虫卵 猫,狗,猪等为重要储蓄宿主

The second intermediate host of C.sinensis

Metacercariae of C.sinensis

The first intermediate host of C.sinensis

Endemic area of clonorchiasis sinensis

肝吸虫的致病 成虫为主要致病阶段 机械及毒素致胆管炎症、黄疸、结石 重症慢性感染可导致肝纤维化、肝癌

肝吸虫保虫宿主感染率 1986年一组报告 猫 55.8% 犬 74.4% 猪 3.6%

实验室查诊 病原学诊断 粪检查卵：沉淀法首选 十二指肠引流液查卵 免疫学诊断：查Ab,CAg 其它：询问病史（食生鱼史）

肝吸虫的分布 分布：远东、中国、日本、朝鲜 国内：24省市 以广东、东北区为多

Clonorchis sinensis/Opisthorchis viverrini: geographic distribution.

肝吸虫流行因素 传染源：病人和储蓄宿主 传播途径： I、II中间宿主并存于同一水体 不科学的鱼养殖（人粪养鱼） 饮食习惯

肝吸虫的防治原则 治疗病人：吡喹酮 卫生教育：改变饮食习惯，科学养鱼 控制和处理储蓄宿主

并殖吸虫 我国约有28种，主要有二种： 卫氏并殖吸虫 斯氏狸殖吸虫 全球约有50种

Paragonimus westermani 卫氏并殖吸虫 Paragonimus westermani

概 述 人兽共患、兽主人次 世界性分布 成虫寄生于肺，致肺部病变 亦可异位寄生于脑，皮下等

The lungs of a dog infected by Paragonimus species have a number of foci of infection

Adult of Paragonimus westermani

Paragonimus westermani, adult, stained whole mount; approximate size = 9 mm in length.  Click here to view an image in which some of the internal organs are labeled, or click here to view a labeled line drawing 来源 http://www.biosci.ohio-state.edu/~parasite/paragonimus.html

成虫形态 肥厚、背部隆起似半粒黄豆 鳞状皮棘(利于组织内穿行) 生殖腺并列 口腹吸盘大小略同

Cuticular spines of adult P.westermani

虫卵特征 基本形态为水缸形 有宽而扁平的卵盖 内含卵细胞和卵黄细胞 大小、形状及卵壳厚薄多变

http://www.dpd.cdc.gov/dpdx/HTML/Paragonimiasis.htm The eggs are excreted unembryonated in the sputum, or alternately they are swallowed and passed with stool .  In the external environment, the eggs become embryonated , and miracidia hatch and seek the first intermediate host, a snail, and penetrate its soft tissues .  Miracidia go through several developmental stages inside the snail : sporocysts , rediae , with the latter giving rise to many cercariae , which emerge from the snail.  The cercariae invade the second intermediate host, a crustacean such as a crab or crayfish, where they encyst and become metacercariae.  This is the infective stage for the mammalian host .  Human infection with P. westermani occurs by eating inadequately cooked or pickled crab or crayfish that harbor metacercariae of the parasite .  The metacercariae excyst in the duodenum , penetrate through the intestinal wall into the peritoneal cavity, then through the abdominal wall and diaphragm into the lungs, where they become encapsulated and develop into adults (7.5 to 12 mm by 4 to 6 mm).  The worms can also reach other organs and tissues, such as the brain and striated muscles, respectively.  However, when this takes place completion of the life cycles is not achieved, because the eggs laid cannot exit these sites.  Time from infection to oviposition is 65 to 90 days.  Infections may persist for 20 years in humans. Animals such as pigs, dogs, and a variety of feline species can also harbor P. westermani.

肺吸虫生活史 成虫 卵 毛蚴 胞蚴 I、II雷蚴 童虫 囊蚴 尾蚴 川卷螺 （肺） 异位寄生 （皮下、脑、等） 人、 肉食哺乳动物 成虫 卵 毛蚴 胞蚴 I、II雷蚴 童虫 囊蚴 尾蚴 （肺） 异位寄生 （皮下、脑、等） 人、 肉食哺乳动物 溪蟹、蝲咕

肺吸虫生活史要点 感染期：囊蚴 童虫游走穿行性移行 成虫寄生肺部为主 卵由痰粪排离 有转续宿主和保虫宿主

Semisulcospira bensoni The first intermediate host of P.westermani

The second intermediate host of P.westermani

Metacercariae of P. westermani

溪蟹内囊蚴最高数报告 皖南 1773个 蚌埠 2531个 温州 4520个 南京 5833个（36克蟹）

致 病 主要阶段：成虫和童虫 成虫形成肺部脓肿和囊肿 童虫引起游走性结节 异位寄生常见于脑皮下腹腔等 斯氏肺吸虫引起幼虫移形症

肺吸虫病病型 胸肺型 脑脊髓型 腹型 皮下型

肺吸虫病的诊断 病史、X线 病原检查： 查卵:痰检（10%NaOH） 粪检（沉淀法） 皮下结节活检 免疫诊断

肺吸虫的分布 世界性、除欧洲外 中国24省有病例报告 国内流行区：山区为主 溪蟹型：华东、华南、华中地区 喇蛄型：东北松花江流域

Paragonimus westermani infection occurs in Paragonimus westermani infection occurs in Asia (especially in China, Corea, India, Japan, Laos, Philippines, Sri Lanka, Taiwan, Thailand, Viet-Nam), Central-West Africa, South America (Ecuador, Per? Venezuela). Paragonimus westermani infection occurs in Asia ，Central-West Africa， South America

流行因素 传染源：野生动物为主、人为次 两种中间宿主的存在:山区多 地区居民的饮食习惯 转续宿主的作用

肺吸虫防治 卫生教育为主:改变饮食习惯 杀虫治疗：吡喹酮为首选

布氏姜片吸虫 Fasciolopsis buski

成虫形态 形似姜片，肥厚 腹吸盘大于口吸盘 睾丸珊瑚状分支 卵巢呈佛手状

Adult fluke of Fasciolopsis buski Adult fluke of Fasciolopsis buski.  The adult flukes range in size: 20 to 75 mm by 8 to 20 mm.  Image contributed by Georgia Division of Public Health.

Fasciolopsis buskii adult worm

虫卵 最大、椭圆形、淡黄色 卵盖不明显 内含卵细胞和卵黄细胞

生活史 感染期：囊蚴 大型肠吸虫，寄生小肠 中间宿主：扁卷螺类 水生媒介植物：红菱、荸荠、茭白 猪为重要保虫宿主

http://www.dpd.cdc.gov/dpdx/HTML/Fasciolopsiasis.htm Immature eggs are discharged into the intestine and stool .  Eggs become embryonated in water , eggs release miracidia , which invade a suitable snail intermediate host .  In the snail the parasites undergo several developmental stages (sporocysts , rediae , and cercariae ).  The cercariae are released from the snail and encyst as metacercariae on aquatic plants .  The mammalian hosts become infected by ingesting metacercariae on the aquatic plants.  After ingestion, the metacercariae excyst in the duodenum and attach to the intestinal wall.  There they develop into adult flukes (20 to 75 mm by 8 to 20 mm) in approximately 3 months, attached to the intestinal wall of the mammalian hosts (humans and pigs) .  The  adults have a life span of about one year.

致病 肠道炎症，营养吸收不良 虫体量大可致肠梗阻

诊断与防治 粪便沉淀法：虫卵 水、粪管理 卫生教育，饮食卫生 驱虫：吡喹酮

Fasciolopsis buski: is endemic in China, Taiwan, South-East Asia, Malaysia and India.

main species of human schistosomes 日本血吸虫 Schistosoma japonicum (肠系膜静脉) 东南亚、中国、日本 曼氏血吸虫 S. mansoni (肠系膜静脉) 非洲、拉丁美洲 埃及血吸虫 S. haematobium (膀胱 痔静脉) 非洲、中东

日本裂体吸虫 Schistosoma japonicum

Distribution and Epidemic Situation Worldwide 200 million of population infected in 74 countries China 11 million in 12 provinces  0.7 million in 8 provinces 50 years

Regional distribution of S. japonicum infection in China Before control After control (1996) Regional distribution of S. japonicum infection in China

Morphology Difference from other trematodes Dioecious adults Non-opeculate egg Bifurcated (forked) cercaria invades the final host by skin Adults parasitize blood vessels

Morphology(adult) 雌雄异体 雌雄合抱,雄虫具抱雌沟(gynecophoral canal） 口、腹吸盘明显,有短蒂柄 雄虫睾丸（7个）排列成行 消化道先分后合

血吸虫雌雄合抱 雌虫发育成熟必需有雄虫的存在和合抱，促进雌虫生长发育的物质可能是来自雄虫的一种性信息素

Morphology (egg) 卵圆形，中等大小,无卵盖结构 卵壳薄, 侧面有小棘, 卵壳外常附有脏物 内含毛蚴

电镜观察成熟虫卵 卵壳表面呈网状,可见囊样微孔，贯通内外，毛蚴分泌的可溶性虫卵抗原(SEA)可经微孔释出卵外。

Life cycle 粪 入水 成虫 毛蚴 虫卵 （门脉、肠系膜静脉） 侵入钉 螺 移 行 童虫 尾蚴 胞蚴 I、II 皮肤钻入

Main Points of Life Cycle Residing site: mesenteric vein I.H.(Only one): Oncomelania hupensis No metacercaria and redia stage Two generation of sporocyst Infective stage: cercaria Route of infection: skin penetration

cercaria of S. japonicum 由体部及尾部组成，尾部又分尾干和尾叉。尾叉不及尾干的一半 ，是日本血吸虫的特征之一。

Adult of Schistosome in mesenteric veins of hamster 寄生部位 Adult of Schistosome in mesenteric veins of hamster

Adult worm in mesenteric venous 25% eggs are flowed into liver beds cause egg-granuloma

致病阶段及相应损害 尾蚴：尾蚴性皮炎 童虫：肺部症状 成虫：静脉内膜炎 虫卵：虫卵肉芽肿 （嗜酸性脓肿、假结核结节、纤维化）

组织性虫卵 (Tissue egg) 在组织内沉积、发育、存活并能形成虫卵肉芽肿的虫卵 成虫产出的卵需在肝、肠组织内发育10天成熟, 生存11天, 与致病、诊断、疗效考核有关

虫卵 虫卵主要是沉着在宿主的肝及肠壁等组织，所 引起的肉芽肿和纤维化是血吸虫病的主要病变。 肉芽肿形成 虫卵内毛蚴成熟后分泌可溶性虫卵抗原（soluble egg antigen，SEA） SEA透过卵壳微孔释放，致敏T细胞 当再次遇到相同抗原后，刺激致敏的T细胞产生一系列淋巴因子 各种淋巴因子吸引相应细胞（巨噬细胞、嗜酸性粒细胞及成纤维细胞等）聚集到虫卵周围，形成肉芽肿，也称虫卵结节。 肉芽肿常出现中心坏死称嗜酸性脓肿

虫卵肉芽肿所致病变 肠壁： 脓肿溃疡增生、狭窄、癌变 肝脏： 脓肿、结节、肝纤维化、门脉高压 肠壁： 脓肿溃疡增生、狭窄、癌变 肝脏： 脓肿、结节、肝纤维化、门脉高压 （脾肿大、腹水、侧枝循环-食道、痔腹壁浅 静脉曲张） 异位损害：肺、脑及其它组织血吸虫病

异位寄生与异位损害 日本血吸虫成虫在门脉系统以外的静脉内寄生称异位寄生； 门脉系统以外的器官或组织的血吸虫虫卵肉芽肿则称异位损害或异位血吸虫病。 人体常见的异位损害在脑和肺。 血吸虫卵进入脑和脊髓产生异位损害，可致严重的神经系统并发症；经侧支循环进入肺的虫卵可引起肺动脉炎，甚至肺源性心脏病。

血吸虫性变态反应 尾蚴性皮炎：I、IV型、 急性血吸虫病血清病样反应 血吸虫性肾病：III型 虫卵肉芽肿：IV型

临床表现 急性血吸虫病 Acute schistosomiasis 慢性血吸虫病 Chronic schistosomiasis 晚期血吸虫病 Advanced schistosomiasis 门脉高压后果:巨脾型、腹水型、侏儒型

肝 肠 静脉

Brazilian with portal hypertension and ascites due to S.mansoni.

A patient with S. j has marked ascites, splenomegaly, umbilical hernia and distended superficial abdominal veins.

日本血吸虫病晚期病人 骨瘦如柴 腹大如鼓

晚期血吸虫病直肠癌变

Difference from other trematodes Dioecious adults 雌雄异体 Non-opeculate egg 无卵盖虫卵 Bifurcated (forked) cercaria invades the final host by skin 分叉尾蚴经皮肤侵入终宿主 Adults parasitize blood vessels 成虫寄生于血管 tissue eggs are the major pathogenic stage 组织性虫卵为主要致病期

Immunity 非消除性免疫 伴随免疫(concomitent immunity) 对原有成虫不发生作用 对再感染的童虫具抵抗力 免疫效应：免疫保护和免疫病理

Diagnosis 临床诊断：疫水接触史、临床症状 病原学诊断：粪便沉淀孵化法 免疫诊断:检测抗体(ELISA)、CAg、环卵沉淀 综合查病 改良加藤（Kato）法 直肠粘膜活检法 免疫诊断:检测抗体(ELISA)、CAg、环卵沉淀 综合查病

Schistosome miracidium

血吸虫毛蚴特点 入水迅速孵化 向清性 向上性 向光性 直线游动呈“之”字形

毛蚴孵化条件 水清 温度：25-30oC 光照 pH：6.8-9.2 无氯、去盐分

血吸虫病的流行 分布：长江以南12省市 流行因素:粪便污染水源 中间宿主钉螺 病人和保虫宿主 生活和生产接触疫水

Factors of Transmission and Prevention Source of infection: patients and reservoir host Intermediate host: Oncomelania Contact with cercaria-infected water

intermediate host of S.japonicum are snails of the genus Onchomelania, hupensis spp. Oncomelania hupensis

钉螺生态特点 水陆两栖 喜荫蔽，杂草丛生处 以腐植质为营养 活动范围小

防治原则 查病治病：首选吡喹酮 查螺灭螺：土埋、药杀、火烧 做好个人防护

三种人体血吸虫虫卵特点 S.japonicum侧细刺型 S.mansoni粗大侧刺型 S.haematobium端刺型