Trematodes (Flukes) Department of Parasitology, Xiangya Medical School, Central South University
Trematodes (Flukes) Department of Parasitology, Xiangya Medical School, Central South University
General Introduction I.Classification and Species o Phylum Platyhelminthes(flatworms) Class Trematoda Order Monogenea > Order Aspidogastrea > Order Digenea All trematodes parasitizing human belong to the Order Digenea
General Introduction I. Classification and Species ⚫ Phylum Platyhelminthes (flatworms) ⚫ Class Trematoda ➢ Order Monogenea ➢ Order Aspidogastrea ➢ Order Digenea All trematodes parasitizing human belong to the Order Digenea
General Introduction I.Classification and Species Common human trematodes: Clonorchis sinensis(liver flukes) Heterophyes heterophyes Fasciolopsis buski Fasciola heptica Paragonimus westermani (lung fukes) Pagumogonimus skrjabini Schistosoma japonicum Echinochasmus japonicus
I. Classification and Species Common human trematodes: Clonorchis sinensis (liver flukes) Heterophyes heterophyes Fasciolopsis buski Fasciola heptica Paragonimus westermani Pagumogonimus skrjabini Schistosoma japonicum Echinochasmus japonicus (lung fukes) General Introduction
General Introduction I.Important species in China Clonorchis Fasciolopsis Paragonimus Schistosoma sinensis buski westermani japonicum
I. Important species in China Clonorchis Fasciolopsis Paragonimus Schistosoma sinensis buski westermani japonicum General Introduction
General Introduction Il.Morphological characteristics 1、Adult worms Mouth Oral sucker o flattened,bilaterally symmetric,leaf- Pharynx Esophagus shaped or tongue-like Caecum- Common genital pore Ejaculatory duct about 0.3-80.0mm in length Cirrus pouch Metraterm- Seminal vesicle Ventral sucker o two suckers,an oral and a ventral sucker 9 Vas deferens Ovary Most of trematodes are hermaphroditic, Vas efferens Seminal receptacle Vitelline gland Oviduct Vitelline duct except schistosomes Mehlis'gland Vitelline reservoir Ootype incomplete digestive tract,the caeca end Uterus Testes Laurer's canal blindly,without anus Without body cavity (acoelomate)
1、Adult worms ⚫ flattened, bilaterally symmetric, leafshaped or tongue-like ⚫ about 0.3-80.0mm in length ⚫ two suckers, an oral and a ventral sucker ⚫ Most of trematodes are hermaphroditic, except schistosomes ⚫ incomplete digestive tract, the caeca end blindly, without anus ⚫ Without body cavity (acoelomate) II.Morphological characteristics General Introduction
General Introduction ll.Morphological characteristics 2、EggS oval or elliptical different in size,depending on species ●most species have& an operculum or cap at one end. apart from schistosomes o In many species the egg contains a fully developed miracidium
2、Eggs ⚫ oval or elliptical ⚫ different in size,depending on species ⚫ most species have an operculum or cap at one end, apart from schistosomes ⚫ In many species the egg contains a fully developed miracidium II.Morphological characteristics General Introduction
Introduction to trematode lll.Characteristics of life cycle o Typical developmental stages: Ovum(egg) miracidium sporocyst redia cercaria metacercaria adult
Introduction to trematode III. Characteristics of life cycle ⚫ Typical developmental stages: adult Ovum(egg) miracidium sporocyst redia cercaria metacercaria
Generalntroduction lll.Characteristics of life cycle Requiring one or two intermediate hosts: 1st intermediate host is usually snail in fresh water, the secondary intermidate host belongs to species of animals in water,such as fishes and crabs
III.Characteristics of life cycle ⚫ Requiring one or two intermediate hosts: 1st intermediate host is usually snail in fresh water, the secondary intermidate host belongs to species of animals in water,such as fishes and crabs General Introduction
General Introduction Ill.Characteristics of life cycle O Alternation of generations: Asexual generations in the intermediate host Sexual generations in definitive host They have their reservoir hosts.The fluke diseases are zoonoses
III.Characteristics of life cycle ⚫ Alternation of generations: Asexual generations in the intermediate host Sexual generations in definitive host ⚫ They have their reservoir hosts. The fluke diseases are zoonoses. General Introduction
Clonorchis sinensis (liver fluke) The worms blocking the bile passages cause clonorchiasis, which finally may become the biliary cirrhosis
Clonorchis sinensis (liver fluke) The worms blocking the bile passages cause clonorchiasis, which finally may become the biliary cirrhosis