The Contribution of Electron Microscopic Studies to the Taxonomy and Biology of Parasitic Trematodes

Electron microscopy has proved to be a very helpful those at posterior end consisting of powerful adhesive instrument in the study of biology in general. Since it has disks usually provided with chitinoid hooks or anchors; been invented a lot of information has accumulated in with single host, parasites of cold-blooded aquatic different aspects of biology. Studying the ultrastructure vertebrates (fishes, amphibians and reptiles). No of the different animals has added a great deal of representative in man (Beaver et al., 1984). knowledge to biologists. Electron microscopy is also a very good diagnostic instrument used in hospitals and III-Subclass: Digenea: Almost all species endoparasitic; medical centers. The present review aims to pile up the organs of attachment consisting of one or more suckers, available information concerning the biology and of which one is circumoral; with one or two changes of taxonomy of trematodes, platyhelminthes. The review hosts, of which that harboring the intermediate stages is deals with studies on the taxonomy of this group of a mollusc; larva hatched from egg has ciliated epithelium helminthes, using the scanning (SEM) and transmission (Beaver et al., 1984). They are regarded as the first (TEM) electron microscopy. Also it deals with the studies trematodes in terms of the amount of electron microscopic on the developmental stages of these worms. Other works investigations. This is because it is the most diverse deal with the studies of drug efficacy on these worms as group of trematodes or even of all helminthes. Digenean seen under electron microscopy. trematodes include several groups of helminthes, such as: Members of the platyheminthes phylum include liver flukes, pulmonary flukes, intestinal flukes and blood the various dorsoventrally flattened animals that are flukes. They parasitize a wide range of vertebrate hosts. commonly known as the flatworms. The body shap of The trematodes have been the subject of diverse these heminthes varies from a broad, dorsoventrally investigation using electron microscopy and the flattened leave like-worms to that of a long chain of improvement of high resolution apparatus has permitted proglottids as in tape-worms. The phylum includes three the detailed study of some structures so far overlooked. classes: the exclusively free-living organisms; rarely This review is intended to draw attention to all the commensals or parasites Turbellaria, the parasitic studies that contributes a great deal about these Trematoda and the totally parasitic Cestoidea important organisms. (Beaver et al., 1984). All trematodes are obligatory parasites as adults. The The ultrastructure studies on aspirogasridea: This class Trematoda is divided into three subclasses: subclass is the least trematodes, investigated by