Introduction of Trematodes PDF

Introduction of Trematodes By Dr. Mona Mohammed Saleh lecturer of parasitology Faculty of medicine Menoufia university Medical parasitology is calssified into:  Helminthology: a) Class:Trematoda b) Class:Cestoda c) Class:Nematoda  Protozology  Arthropodology ...

Introduction of Trematodes By Dr. Mona Mohammed Saleh lecturer of parasitology Faculty of medicine Menoufia university Medical parasitology is calssified into:  Helminthology: a) Class:Trematoda b) Class:Cestoda c) Class:Nematoda  Protozology  Arthropodology  Class: Trematoda General charatristics  They are called flukes.  The body surface of trematodes comprises of a tough syncytial tegument which protects against digestive enzymes, and it is also the surface of gas exchange.  Unsegmented body.  Leaf-shaped flattened dorsoventrally worms except in schistosomes.  Organs of attachment:  Oral sucker surrounding the mouth.  Ventral sucker on the ventral surface of the body.  There are no respiratory organs.  The mouth opens into a muscular, pumping pharynx, connects via a short oesophagus (except in shistosomes in which the pharnx is absent).  There is no anus, and waste material egested through the mouth.  The eggs of trematodes are operculated except for schistosomes.  Eggs need water and snail to continue their cycle.  The excretion occurs mostly through the tegument. Some of the species of trematodes possess an excretory system, which consists of two or more proton ephridia (the unit of excretory system in invertebrates)  The brain consists of a pair of ganglia in the head region, from which two or three pairs of nerve cords  Trematodes generally lack any specialized sense organs.  Most trematodes are hermaphrodites (both the male and the female genital organs present in one worm).  Life cycle pass through sexual development inside the definitive host and asexual development inside the intermediate host:  -Adult (inside the definitive host).  -Miracidium – sporocyst- daughter sporocyst – redia – cercariae. (Inside the intermediate host). Fasciola gigantica adult Fasciola hepatica adult  Egg: (Diagnostic stage) ◦ Size: 150 x 90 um. ◦ Shape: ovoid. ◦ Shell: thin, operculated. ◦ Color: bile stained (yellowish brown). ◦ Content: embryonic cells (immature). Fasciola egg