Trematoda, Monogenea, Cestoda
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NEODERMATA FLUKES ▸ Class Trematoda—flukes ▸ Vertebrate endoparasites spine distal ▸ Adhesive sucker(s) or cytoplasm hooks ▸ Often with a multi-stage muscle life cycle golgi CHAPTER 8, 9, 10 ▸ example life cycle nucleus tegument ▸ overview -- egg -> cell body miracidium -> sporocyst mitochondrion -> redia -> cercaria parenchymal PLATYHELMINTHES, ET AL. (secondary larvae) -> cell metacercaria (eaten by primary host)-> adult TREMATODA TREMATODA ▸ liver fluke life cycle FLUKES ▸ eggs passed in feces ▸ Freshwater snail eats eggs ▸ Miracidium transforms cercaria into a sporocyst redia ▸ Redia reproduce sporocyst asexually miracidium ▸ Cercaria leave snail, egg burrow into fish ▸ ▸ development inside intermediate host Metacercaria are eaten ▸ egg -> miracidium -> sporocyst -> redia -> cercaria (secondary larvae) MIND CONTROL!!! TREMATODA ▸ Dicrocoelium dendriticum ▸ Some fluke cercariae enter humans directly ▸ schistosome dermatitis or “swimmer’s itch” TREMATODA MONOGENIC FLUKES ▸ Tropical blood ▸ Class Monogenea— Male flukes ▸ Single host ▸ survive and use ▸ oncomiracidium (ciliated larva) Human host Female humans as hosts ▸ opisthaptor ▸ 1 mm dioecious prohaptor ▸ gynecophoric canal mouth sexual reproduction in host larvae burrow into human Motile larva Ciliated larva asexual reproduction in snail larvae infect snails sucker Snail host opisthaptor anchor CESTODES CESTODES ▸ Class Cestoda—tapeworms ▸ Scolex ▸ Gut parasites of vertebrates ▸ two dorsal nerve cords ▸ Monoecious ▸ Proglottids ▸ No gut ▸ New proglottids originate ▸ Microtriches microtrich behind scolex cytoplasm of tegument 101 circular muscle mitochondria longitudinal muscle CESTODES scolex thus the area for absorption of nutriments. The bases of The ultrastructure of microtriches can be used as a spine-like and blade-like microtriches have an electron- taxonomic character to be added to other characteristics dense ridge at their anterior edge. According to (Richmond and Caira 1991; Hoberg et al. 1995; Caira ▸ mature proglottids MacKinnon and Burt (1983) this ridge may function in and Tracy 2002; Ivanov and Brooks 2002; Ivanov 2004; preventing the microtriches from bending forward and Gil de Pertierra 2004, 2005). In our opinion more thus losing their grip against the mucosal epithelium of information of microtriches pattern could be useful for the host intestine. the determination of species in proteocephalideans. ▸ become egg sacs that are germinative zone passed in feces ▸ life cycle ▸ Eggs hatch into larvae --> eaten by an intermediate host and encyst in muscle ▸ Larvae called cysticercus stobila larvae ▸ Undercooked flesh eaten by the primary host ▸ Inverted scolex of larva then everts in definitive host’s gut CESTODES CESTODES ▸ mature proglottids ▸ many diverse live cycles ▸ become egg sacs that are passed in feces ▸ life cycle ▸ Eggs hatch into larvae --> eaten by an intermediate host and encyst in muscle ▸ Larvae called cysticercus larvae ▸ Undercooked flesh eaten by the primary host ▸ Inverted scolex of larva then everts in definitive host’s gut brain from a 9 year old infected with pork tapeworm CESTODES ▸ Tapeworm diet? ▸ metamerism? ▸ strobila ▸ germinative zone .