浙江大学医学院：《寄生虫学》课程教学资源（PPT课件）吸虫 Trematode

Trematode (吸虫)

Trematode （吸虫）

Introduction ■ I axonomic position a Phylum platyhelminthes 口 Class Trematoda 口 Order Digenea

Introduction ◼ Taxonomic position  Phylum platyhelminthes  Class Trematoda  Order Digenea

Trematodes that have medical importance Species Reside in Clonorchis sinensis hepatic bile duct Fasciolopsis buski Small intestine Paragonimus westermani Lung subcutaneous, etc Schistosoma japonicum portal system S. mansoni etc

Species Reside in Clonorchis sinensis hepatic bile duct Fasciolopsis buski Small intestine Paragonimus westermani Lung, subcutaneous, etc. Schistosoma japonicum S.mansoni, etc portal system Trematodes that have medical importance

General features eaf-like flattened bodies with no body cavity; with oral and ventral suckers to aid attachment to their hosts

General features Leaf-like flattened bodies with no body cavity; with oral and ventral suckers to aid attachment to their hosts

General features The tegument is a syncytial layer equipped with spines and muscles a Digestive system degenerated with a mouth, enclosed by the oral sucker but no anus mouth→ pharynx→ esophagus→ two digestive tracts u Hermaphrodite or monoecious except blood flukes (dimorphism), possessing both male and female reproductive organs, the appearance and position of which are very important taxonomically

◼ The tegument is a syncytial layer equipped with spines and muscles ◼ Digestive system degenerated， with a mouth, enclosed by the oral sucker but no anus. mouth→pharynx →esophagus → two digestive tracts ◼ Hermaphrodite or monoecious except blood flukes (dimorphism) , possessing both male and female reproductive organs, the appearance and position of which are very important taxonomically General features

Reproductive system of trematode 卵巢 生殖窦 阴茎 子宫 前列腺 卵棋 子宫末段 一梅氏腺 贮精囊 输卵管 总卵黄管 阴茎袋 卵黄球 子宫 受櫝囊 劳氏管 输精管 Mehlis gland, seminal po Female: ovary, oviduct, ooty Male: testis, vas receptacle laurers canal efferens seminal vitellaria, vitelline duct vesical, cirrus &cirrus uterus pouch

Reproductive system of trematode Female: ovary, oviduct, ootype, Mehlis’ gland, seminal receptacle, Laurer’s canal, vitellaria, vitelline duct, & uterus Male: testis, vas efferens, seminal vesicale, cirrus,&cirrus pouch

General features Life cycle is complicated -indirect life cycle a Usually need one or two intermediate host 引io- helminths a The first intermediate hosts are usually fresh water snails

◼ Life cycle is complicated – indirect life cycle ◼ Usually need one or two intermediate host – bio-helmiths ◼ The first intermediate hosts are usually fresh water snails General features

General features a Eggs can only develop(hatch in the miracidium fresh water ■ Asexual phase: 口 Eggs>miracidium in water>sporocyst in snail > redia sporocyst cercaria release in water redia >encysted metacercaria in second intermediate host- infective stage a Sexual phase a Preadult(Juvenile)> migrated to cercaria metacercaria favorable residing site> adult worm ≠ lay eggs

◼ Eggs can only develop (hatch) in the fresh water ◼ Asexual phase:  Eggs→miracidium in water→sporocyst in snail →redia →cercaria release in water →encysted metacercaria in second intermediate host – infective stage ◼ Sexual phase  Preadult (Juvenile)→migrated to favorable residing site → adult worm → lay eggs General features cercaria metacercaria redia sporocyst egg miracidium

General features Encysted metacercaria is usually the infective stage Schistosoma--cercaria) Egg has operculum except blood fluke Features reflecting adaptation to parasitism o Organs of attachment developed D Retardation of digestive system a Highly developed reproductive system

◼ Encysted metacercaria is usually the infective stage (Schistosoma-- cercaria) ◼ Egg has operculum except blood fluke ◼ Features reflecting adaptation to parasitism  Organs of attachment developed  Retardation of digestive system  Highly developed reproductive system General features

Clonorchis sinensis 华支睾吸虫 liver fluke,肝吸虫) Clonorchis sinensis Peter Darben Adult- Carmine Stain Adult- Haematoxylin Stain

Clonorchis sinensis 华支睾吸虫 (liver fluke,肝吸虫)